Method for thermo-mechanical testing of test specimens and testing device therefor

Abstract

The present invention relates to a method for thermomechanical testing of test specimens, characterized in that the test specimens are subjected to a high velocity thermal mass flow.The present invention also relates to a test device for thermomechanical testing of test specimens.

Description

[Technical field]

[0001] An object of the invention is a method for thermomechanical testing of test specimens. Another object of the invention is a test device for thermomechanical testing of test specimens. [Background technology]

[0002] A fire shield must not only provide a shield against the heat of a fire, but also have a sufficiently high resistance to seizure, especially over time. An example is the shielding of an accumulator in an electric motor-driven vehicle from the passenger compartment of this vehicle. This must be designed so that a battery fire does not directly penetrate the passenger compartment and that passengers can safely stop the vehicle and leave it or be rescued within the time specified in the test regulations. Other applications of this type of shielding are fire shielding systems for buildings, ships and aircraft. It is therefore necessary to select or develop materials that have suitable properties for such shielding and have a sufficiently high resistance to fire over time. For this purpose, it is necessary to test the material of interest as a function of the acting energy and the material flow ("acting properties"). In the context of the present invention, this is called "thermo-mechanical testing".

[0003] It is known from the state of the art to test the intended materials in a realistic arrangement using practical means. The extent to which the fire shield is damaged is determined by human observation of the test specimen. The disadvantage of this previously known solution is that the fire resistance and its dependence on the exposure characteristics can only be determined very imprecisely. This is due to variability in the energy and material flows. Furthermore, an objective test procedure for testing specimens in such an arrangement is not possible, since the reproducibility is very poor.

[0004] It is therefore an object of the present invention to provide a method for thermomechanical testing of test specimens which ensures increased reproducibility.Furthermore, it is an object of the present invention to provide a test device for thermomechanical testing of test specimens which is reproducible and has a compact design. Summary of the Invention

[0005] This problem is solved by a method having the features of patent claim 1 and by a test device having the features of patent claim 22.

[0006] Each of the subclaims relates to preferred or further embodiments of the invention, the respective features of which can be freely combined with one another, within the scope of technical expedience, if necessary, even beyond the scope of the various claims.

[0007] The method according to the present invention is a method for thermo-mechanical testing of a test specimen by subjecting the specimen to a high velocity thermal mass flow.

[0008] Thanks to the method according to the invention, accurate fire testing of test specimens can be realized without the expense of a real arrangement. This means that test specimens can be tested more quickly and cost-effectively before the material is used for fire shielding, or a corresponding pre-selection can be made from a large number of materials before further tests are carried out. The damage pattern of the test specimens, in particular the damage pattern on the side facing the mass flow, can be evaluated in terms of relative damage intensity, and different test specimens can be compared with each other objectively. A further advantage of the method according to the invention is the increased reproducibility compared to the prior art, since technically identical results are obtained when the method is carried out again with similar test specimens, creating an objective test method that offers the possibility of comparing different test specimens in an objective and standardized way.

[0009] After carrying out the method according to the invention, the test piece is damaged but not necessarily burned off, i.e. it is intact. However, it is also possible for the test piece to be burned off. As an advantageous further development of the method, it may be provided that at least one measured value is determined by a determination device. The measured value is not limited to the determination of a physical variable (e.g. force or temperature, acoustic measurement variable), but may also mean, for example, the determination of an image. The term "measured value" should therefore be interpreted broadly. Preferably, the measured value is determined before and / or during and / or after exposure to the high-velocity thermal mass flow. Thanks to the determination device, the information value of the method according to the invention can be further improved.

[0010] As an advantageous further development of the method, it can be provided that the period from the start of the exposure to the occurrence of burn-through of the test specimen is determined by a determination device.

[0011] Thanks to this further development, it is now possible to precisely measure the time it takes for a test specimen to burn out, which can be taken as a measure of the fire-shielding properties.

[0012] As an advantageous further development, the force acting on the test specimen as a result of the load is continuously determined by a determination device. The determined force or force curve can provide information on the acting mass flow, which can be used for standardization between two or more runs of the method according to the invention, thus improving reproducibility. In other words, the fluctuation of the acting characteristic can be determined and taken into account accordingly during the evaluation.

[0013] Preferably, it may be provided that the time span from the start of the impact to the occurrence of a force drop due to burn-through of the test specimen is determined.

[0014] A particularly preferred method is one for determining the burn-through resistance of a test specimen over time by subjecting the test specimen to a thermal rapid mass flow, continuously determining the force acting on the test specimen as a result of the application, and determining the time interval from the start of the application to the occurrence of a force drop due to burn-through of the test specimen.

[0015] The force is determined by a determination device. For this purpose, the force introduced by the thermal fast mass flow into the test piece is determined continuously over the entire time of application so that the time span from the start of application to the occurrence of a force drop due to or resulting from burn-through of the test piece can be determined. The time is determined using a time measuring device, which allows the time span, i.e. the time difference, between the start of application and the occurrence of a force drop due to burn-through of the test piece to be determined. The determination device can include a time measuring device.

[0016] In other words, the force introduced by the mass flow to the test specimen during the entire time that the test specimen is exposed to the thermal fast mass flow (hereinafter also referred to as mass flow for short) is determined by a determination device designed as a force measuring device and can preferably be plotted on a force-time curve (also referred to as force-time curve). As soon as the test specimen burns out, there is a drop in the force. That is, the force introduced by the mass flow to the test specimen suddenly decreases. This is because the mass flow, which flows through or passes through the test specimen due to the burnout of the test specimen, no longer introduces a force to the test specimen, or at least introduces only a small force. The time at which the force drops corresponds to the time at which the test specimen burns out, so that the time span from the start of the load to the occurrence of the burnout of the test specimen can be determined very accurately. Preferably, the time at which the force drops corresponds to the time at which the burnout of the test specimen begins. Thanks to the method according to the invention, the time span can be determined with an accuracy of 1 / 10 (0.1) seconds.

[0017] The burn-through resistance of a test specimen corresponds to the time from the start of exposure to the occurrence of burn-through of the test specimen, i.e. the breakthrough of the heat-fast mass flow through or through the test specimen. The burn-through resistance over time can therefore be considered as a property of a part or material that can indicate the fire protection properties and resistance to thermal effects of this part or material. Preferably, the method according to the invention is suitable for determining the pulse curve, in particular by determining the force continuously.

[0018] A high velocity thermal mass flow (mass flow for short) is provided by the impacting medium and applies heat and force to the test piece. The high velocity thermal mass flow can be in the form of a beam directed towards the test piece. The force introduced by the mass flow to the test piece, i.e. the force acting on the test piece, is given by the impact of the mass flow with a flow velocity. The mass flow may be added with particles, the mass flow being particularly preferably a gas flow. The mass flow preferably has a flow velocity of at most more than 50 m / s, particularly preferably more than 100 m / s and most preferably more than 200 m / s. Preferably, the flow velocity is supersonic and is higher than 300 m / s. This is closest to the thermal runaway condition of the accumulator. Since the mass flow has a temperature significantly higher than the ambient temperature, heat is at least locally transferred to the test piece and its temperature increases. Preferably, the maximum temperature of the mass flow is higher than the melting temperature of the test piece. Preferably, the maximum temperature of the mass flow is higher than 500 ° C, particularly preferably higher than 600 ° C and very particularly preferably higher than 800 ° C. This means that the burn-through resistance over time can also be measured for test specimens made of materials with a relatively high melting point. Preferably, the maximum temperature that can be generated in the test specimen is higher than the melting point of the test specimen, in particular the maximum temperature that can be generated is higher than the temperature of the mass flow. The mass flow has a temperature higher than the ambient temperature, and when it impinges on the test specimen, the kinetic energy of the mass flow is converted into thermal energy, i.e. a temperature increase in the test specimen. This means that the test specimen can be heated to a temperature higher than the temperature of the mass flow itself. This saves energy and costs.

[0019] Burning through a specimen, also called specimen breakthrough, means that the specimen breaks through an obstacle in the mass flow. Breaking through a specimen means that the mass flow at least locally melts and / or burns the material of the specimen, resulting in a change in the geometry of the specimen. In other words, the material at least locally melts, flows out of the area of ​​influence of the mass flow and / or at least partially burns.

[0020] In a preferred further development, the applied force is determined continuously with a time resolution of at least 1 / 25 s. This means that 25 force measurements are recorded per second. In a particularly advantageous development, the time resolution is at least 1 / 50 s. Thanks to such a time resolution, the accuracy of the method according to the invention can be further improved.

[0021] The test specimens can preferably be designed, for example, as plate-shaped test specimens or as parts with a different geometric shape than the plate-shaped. The method according to the invention therefore offers the possibility to test both plate-shaped test specimens and real parts such as housings or lids for burn-through resistance over time.

[0022] Preferably, the force drop caused by the burning of the test piece can be 50% or more, particularly preferably 80% or more, of the force applied before the force drop. Particularly preferably, the force drop can be 50% or more, particularly preferably 80% or more, of the force applied just before the force drop. This means that the force drops sharply during burn-through compared to the previously almost constant force, which allows the time and thus the duration of the burn-through of the test piece to be accurately determined. Preferably, the force drop occurs within a time of less than 2 seconds, particularly preferably less than 1.5 seconds, most preferably less than 1 second. In this way, the force drop represents a kind of jump in the force-time diagram, so that the start time of the force drop and thus the start time of the burn-through can be accurately determined.

[0023] In an advantageous further development of the method, the mass flow passes through an opening in the test piece formed by the burn-through. Since the mass flow is thus not directed towards the end of the test piece but preferably towards the centre of the test piece, an opening is formed in the test piece by the burn-through, which opening preferably has a substantially circular shape, in particular a substantially circular shape, through which the mass flow flows after the burn-through. Since the mass flow flows through the opening and therefore at least does not impinge on the test piece at all, no or only very small forces are applied to the test piece after the burn-through, in contrast to the time before the burn-through. In other words, since the mass flow passes through the burn-through and the resulting opening in the test piece, it can flow through the test piece unhindered, i.e. without exerting significant forces on the test piece. This means that the force drop due to the burn-through is more rapid, which further improves the measurement accuracy.

[0024] In another advantageous development of the method, the start time of the load is determined by the force increase. At the moment when the mass flow is applied to the test specimen, a force is also applied, and the previously unloaded test specimen is loaded by the mass flow, i.e., a force is applied. This makes it possible to determine the time when the force increase starts. It is also conceivable and possible that the application start time is not the same as the force increase start time, but a later time, for example a time having a certain time interval relative to the force increase start time, or that the application start time is the time at which the force reaches a first maximum value (first inflection point of the force-time curve), which is caused, for example, by the start pulse of the mass flow. In this way, for example, a pre-heating phase of the test specimen can be taken into account, which further improves the determination of the burn-through resistance over time.

[0025] However, in another version of the method, it is also conceivable and possible to determine the exposure start time by the start time of the fast heat mass flow, for example the ignition time. In such an embodiment of the method, it is possible to simulate, for example, the ignition of a fire occurring in the field, since the start time of the mass flow can be considered as the ignition start time of the fire. In this way, the method according to the invention does not only provide a single way to determine the burn-through resistance over time. Rather, the method according to the invention also provides the possibility to determine in one run the time of ignition, the time of the start of the force increase, and the time of the first maximum value, and the resulting time period, thus providing an overall result on the burn resistance of the test specimen over time. In this way, the method according to the invention can not only provide very accurate measurement results, but also save costs and resources.

[0026] In another advantageous development of the method, the temperature of the test piece is determined. The temperature is determined by a temperature measuring device while the test piece is exposed to the mass flow. The determining device preferably consists of a temperature measuring device. The temperature measuring device can be designed, for example, as a thermocouple, a thermometer, an infrared thermometer, etc. The temperature measuring device can preferably be designed as an analog or digital measuring device. Preferably, the temperature is determined continuously over time and a temperature-time curve is recorded which can be used to determine the burn-through resistance over time. It is also possible for the force-time curve to be recorded redundantly simultaneously. Preferably, the temperature is measured in the part of the test piece towards which the mass flow is directed. In particular, it is preferred to measure the temperature on the side of the test piece facing away from the mass flow. This allows the temperature to be measured in the part of the test piece exposed to the mass flow without being directly hit by the mass flow. In other words, the test piece shields the temperature measuring device. The side of the test piece facing away from the mass flow is the side of the test piece facing away from the side on which the mass flow hits before burning. In other words, the side facing away is the reverse side of the side that is hit by the ground current before burn-through. In practical applications, the side of the specimen facing away from the ground current is the side of the specimen that should be shielded from the fire. Furthermore, this allows us to draw conclusions about the thermal conductivity of the specimen.

[0027] This method can be further developed to measure the temperature at multiple points on the test piece, allowing the temperature distribution and spread, i.e., temperature change over time, to be determined.

[0028] In a further advantageous further development of the method, the start of exposure can be determined by exceeding a certain temperature of the test specimen, i.e. the time of the start of exposure corresponds to the time when the certain temperature of the test specimen, i.e. the previously defined temperature, is exceeded, which makes it possible to disregard the pre-heating phase of the test specimen when determining the burn-through resistance over time, i.e. to exclude the pre-heating phase from the period used as a measure of the burn-through resistance over time.

[0029] As a further advantageous further development of the method, it can be provided that the force and temperature are determined in a joint data acquisition device. This can be done, for example, by a measurement computer in the form of a computer. This provides the possibility of automatically analyzing the measurement results, for example by determining different ways of determining the duration as a measure of the burn-through resistance over time, as described above. Preferably, the common data acquisition device can consist of a multimeter. Preferably, the determination device consists of a data acquisition device.

[0030] Furthermore, as an advantageous further development of the method, it can be provided that the pulse acting on the test specimen is determined by the force acting over time. In this way, the impulse or impulse curve introduced into the test specimen by the mass flow can be determined from the force determined continuously over the application time. The impulse essentially corresponds to the so-called thrust integral of the mass flow. The shear integral serves as a measure of damage. The impulse is preferably between 1 Newton second (Ns) and 250 Ns. Mass flows that introduce impulses of up to 100 Ns into the test specimen have proven to be particularly advantageous. This results in cost and resource savings.

[0031] As an advantageous further development, it may be provided that thermal photographs and / or thermographs of the test specimen are recorded. This can be done, for example, using an infrared camera, whereby the determination device can include an infrared camera. This allows the temperature spread in the test specimen to be determined over the exposure time, and also makes it possible to determine so-called hot spots in the test specimen. The thermal photographs and / or thermography are preferably carried out on the side of the test specimen facing away from the mass flow. This has the advantage that interference caused by ground currents is reduced and the shielded side of the test specimen is observed. As a further advantageous development, the thermography can be carried out as differential thermography, thereby reducing the albedo. In this way, the burn-through resistance over time can be measured using a determination device consisting of an infrared camera.

[0032] In a further advantageous further development, it can be provided that the film recording of the impact is preferably recorded at a frame rate of 30 frames per second (abbreviated fps) or more, particularly preferably 100 frames per second or more, very particularly preferably 200 frames per second or more. The film can be recorded, for example, by a high-speed camera, whereby the determination device can constitute a high-speed camera. Preferably, the film recording is made of the impact of the mass flow on the test piece and / or the side of the test piece facing away from the mass flow. In this way, the determination device consisting of a high-speed camera can be used to determine the burn-through resistance over time.

[0033] As an advantageous further development, it can be provided that the data acquisition device, designed for example as a computer, also records thermal photography and / or thermography and / or camera film recordings in addition to the forces and temperatures.

[0034] Preferably, the data acquisition device is designed to automatically synchronize the curves of the measured values ​​(e.g., force or temperature) of the respective measuring device with the film recording and / or thermal photography and / or thermography using markers. The obtained data is preferably stored in a common file by the data acquisition device. For example, an ignition pulse, a light or acoustic ignition signal, etc., serves as a marker for synchronization.

[0035] As an advantageous further development, it can be provided that the data acquisition device is designed to analyze the film for sparks on the side of the specimen facing away from the ground current by automatic image evaluation and thus determine the time when the sparks start to fly. The onset of the sparks on the side of the specimen facing away from the ground current corresponds to the burn-through of the specimen. This can be done in addition to the force or temperature measurement, but the force or temperature measurement can also be omitted.

[0036] In a further advantageous further development, it can be provided that the data acquisition device is designed to analyze the film by automatic image evaluation and determine the time when the mass flow starts to act on the test specimen. In other words, the relevant times for determining the time period, i.e. the start time of the impact and the time of burn-through, can be determined, so that the burn-through resistance can be determined by automatic image evaluation of the film recording. In this way, redundancy with respect to other measuring devices can be realized and the accuracy can be further increased. Alternatively, the automatic image analysis can be performed without the use of additional measuring devices.

[0037] As an advantageous further development of the method, it can be provided that an acoustic signal is determined during the impact, which can be determined by an acoustic measuring device, for example consisting of a microphone.Preferably, the determining device consists of an acoustic measuring device.

[0038] The acoustic measuring device is preferably connected to a data acquisition device, which means that all acquired measurement data can be processed and synchronized in a common data acquisition device.

[0039] A further advantage is that the acoustic signal can also be started before the load is applied, which allows the time when the mass flow starts to act on the test specimen to be determined acoustically, providing redundancy here and serving as a marker for the synchronization of the individual measurement sequences. It also allows the acoustic evaluation to be carried out without the use of additional measuring devices.

[0040] Additionally, the acoustic signal can be used to determine the time for a test specimen to burn through, i.e., the acoustic measurement device can be used to determine a time span as a measure of burn-through resistance over time.

[0041] Furthermore, acoustic measuring devices can also provide redundancy for other measuring devices, which are also based on different measurement principles. Furthermore, determining the acoustic signal has the advantage that the measurement properties are not impaired by smoke generation during exposure, as is possible with optical measuring devices, for example cameras. This allows the flame resistance to be reliably measured even if other measuring devices fail, and the measurement of the acoustic signal makes costly test repetitions unnecessary.

[0042] In a further advantageous embodiment of the method, it may be provided that the jet velocity of the mass flow is determined. The jet velocity can be determined by a jet velocity measuring device, for example by Doppler spectroscopy. Preferably, the beam velocity can be determined spatially before the mass flow impinges on the test piece. In other words, a jet velocity measuring device is arranged spatially between the impingement means and the test piece. This has the advantage that, for example, in addition to the force or temperature applied to the test piece, the jet velocity is also determined continuously and can be plotted over time, so that the changes in the force / temperature curve can be compared with the changes in the jet velocity curve, thereby further increasing the measurement accuracy of the method according to the invention. The mass flow rate can be calculated from the force and velocity measurements. Alternatively or additionally, it is also possible to determine the jet velocity on the side of the test piece facing away from the mass flow, i.e. the jet velocity of the mass flow is determined here after burn-through. The jet velocity of the mass flow can also be called the flow rate of the mass flow.

[0043] In an advantageous further development, the test piece consists of a material for a battery housing or is a battery housing or a part of a battery housing. The method according to the invention is particularly suitable for determining the material, i.e. the material of the battery housing, a part of the battery housing or the battery housing itself. The battery housing is used to hold and shield the battery. The battery is also understood to be an accumulator, in particular a lithium-ion accumulator for automobiles. In case of a fire in such an accumulator, it is necessary to protect the occupants of the automobile from the fire so that they can leave the vehicle without injury before the fire penetrates into the passenger compartment.

[0044] In a further advantageous development, the mass flow is directed orthogonally or obliquely at the specimen, which allows the specimen to be exposed to the mass flow at an angle corresponding to the practical conditions of subsequent use, thus increasing the variability of the method. Alternatively or additionally, it is also conceivable to adjust the distance between the means for supplying the mass flow and the specimen in order to customize the temperature profile and the beam characteristics.

[0045] In a preferred embodiment of the process, the mass flow is delivered by rocket propellant charges, mass-fed acetylene burners, flame spray, galvanic elements or plasma spray, also known as impaction means. Rocket propellant charges designed as solid composite propellant charges have proven to be particularly advantageous as they provide a reproducible and partially constant (more uniform) mass flow over the impact time, improving reproducibility, due to the very small tolerances between the individual propellant charges.

[0046] In an advantageous further development, the galvanic element is designed as a secondary element, also known as an accumulator. The galvanic element is composed of at least one cell. The galvanic element is particularly preferably designed as a lithium-ion accumulator. Such a design of the charging means allows the test strip to be tested under simulated conditions.

[0047] As an advantageous further development, the galvanic element is preferably arranged so that the earth current leaves the galvanic element against the force of gravity, which, in contrast to a suspended arrangement, offers the advantage that no or only small amounts of flammable liquid electrolyte leave the galvanic element before the earth current appears, thus countering uncontrolled combustion and even deflagration.

[0048] As a further advantageous further development, it can be provided that the fuel for the pressurizing means for supplying the mass flow is metered at least before the start of pressurization and after pressurization, preferably the metering takes place continuously during pressurization. In this way, the mass of the fuel is determined before, during or after pressurization, so that it can be compared with the fuel consumption of other tests and thus any defects in the pressurizing means can be determined. The metering can be carried out, for example, by means of a mass measuring device such as a balance.

[0049] As an advantageous further development, it can be provided that the mass flow flows through a nozzle, the discharge characteristics of which are thereby adjusted. In this case, the mass flow flows from the pressurizing means through a nozzle and impinges on the test piece after passing through the nozzle, the nozzle being preferably located at a distance from the test piece. The nozzle has a predefined nozzle shape, which is designed in such a way that the discharge characteristics of the mass flow delivered by the impact means can be appropriately modified and adapted, and thus adapted to the real conditions of thermal runaway, in particular with regard to temperature, ejection angle and momentum. By using the nozzle, the mass flow can be modified in its discharge characteristics to correspond more closely to real conditions, for example failure of a lithium-ion battery. In particular, the following geometrical characteristics of the nozzle can be varied: the central nozzle aperture, the opening angle of the cone, the length of the central nozzle aperture, the length of the cone.

[0050] The nozzle is preferably used in combination with a rocket propellant charge.

[0051] Further, a test device for thermomechanical testing of a test specimen is proposed, which comprises a holder having a receiving portion capable of receiving the test specimen directly or indirectly, and an application means for supplying a high-velocity thermal mass flow that can be directed towards the test specimen.

[0052] Thanks to the test device according to the invention, materials can be tested or preselected with respect to their fire protection properties without great effort and expense.

[0053] The inspection apparatus is preferably suitable for carrying out the aforementioned method together with all the aforementioned further developments. All the aforementioned features of the method and their advantageous further developments can therefore be transferred accordingly to the inspection apparatus. Similarly, all the features of the inspection apparatus and its subsequently implemented further developments can also be transferred to the method and its advantageous further developments.

[0054] The test device preferably comprises a determination device, thanks to which the measured values ​​can be determined before and / or during and / or after loading. Preferably, the determination device comprises at least one of the following means: a force measuring device, a time measuring device, a temperature measuring device, an acoustic measuring device, an infrared camera, a high-speed measuring device, a data acquisition device. The determination device can comprise these individually or in combination.

[0055] Furthermore, the reproducible conditions (and their measurement) allow the relative resistance of specimens to be compared based on surface damage and / or backside temperature, so that an efficient pre-screening (pre-selection) of specimen variants can be performed in order to subject the "best" specimens to further, much more complex fire tests.

[0056] The determination device is preferably designed to determine the burn-through resistance of a test strip, in particular to determine the burn-through resistance of a test strip over time.

[0057] This allows accurate measurement of the time it takes for the test piece to burn out.

[0058] As an advantageous further development, it can be provided that the determination device comprises a force measuring device operatively coupled to the holder and configured to determine the force introduced on the test specimen by the mass flow.

[0059] This test device can therefore be used to continuously measure the force introduced into the test specimen by the thermal fast mass flow over the entire application time, allowing the fluctuations in mass flow to be easily measured and taken into account when analysing the test, further increasing the accuracy of the test.

[0060] Furthermore, the time span from the start of application to the occurrence of a drop in force due to or resulting from burn-through of the test specimen can be determined. For this purpose, the force measuring device is preferably designed to record the force continuously over the application time.

[0061] The holder of the test device has a receiving part which can receive the test strip directly or indirectly, i.e. by means of an intermediate element, and which is preferably designed as a recess or opening which can receive the test strip or the intermediate element, so that the test strip is preferably immovably and precisely positioned relative to the receiving part, at least in the direction of action of the mass flow.

[0062] The holder can be operatively connected to a force measuring device, whereby the force measuring device is configured to determine the force introduced to the test specimen by the mass flow. In other words, the holder and its receiving part are operatively connected to the force measuring device in such a way that at least a flow of force is ensured between the test specimen that can be received in the receiving part and the force measuring device. This means that the force applied to the test specimen by the mass flow can be determined by the force measuring device.

[0063] The application means is designed to provide a high velocity thermal mass flow, and the application means is directed such that the mass flow impinges on a specimen receivable by the receiving portion, i.e., the application means is directed at a predetermined location on the test specimen as determined by the receiving portion.

[0064] As an advantageous further development, the holder consists of a heat-resistant and fire-resistant material, for example made of steel and / or ceramic, which ensures that the holder is not damaged by the mass flow when the test specimen is exposed to the mass flow and increases the service life of the test device.

[0065] As an advantageous further development, the force measuring device can include a force transducer. The force transducer is also known as a force sensor or load cell. In particular, the force transducer can be designed as a piezoelectric force transducer. The force measuring device is preferably arranged between the platform and a rigid support structure, such as a machine bed, a foundation or a bracket. As a preferred further development, the force measuring device has a nominal force of 250N to 750N, particularly preferably 500N.

[0066] The mass flow introduces a force in a known direction into the specimen, so that it acts either in compression or tension. This improves accuracy and simplifies the calibration process. Standard weights of 1 kg or 5 kg are particularly suitable for calibration.

[0067] In an alternative embodiment, the force measuring device can be used to measure the displacement (movement) of the mount relative to a rigid bracket, with an elastic element arranged between the mount and the bracket. The elastic element can consist of at least one spring element, for example in the form of a spiral spring or a Belleville spring. Since the stiffness of the elastic element is known, the force acting on the bracket can be calculated based on the displacement of the bracket relative to the rigid bracket. As an advantageous further development, it is conceivable to translate the displacement of the bracket by means of a lever mechanism, which allows the measurement accuracy to be further improved. Furthermore, a damping element can be provided between the mount and the rigid bracket. This allows vibrations of the system to be damped, which allows the force measurement accuracy to be further improved.

[0068] In an advantageous further development, the determination device can have a temperature measuring device for determining the temperature of the test piece. The temperature measuring device preferably consists of a thermocouple and / or a thermometer and / or an infrared thermometer. The temperature measuring device preferably consists of a plurality of thermocouples and / or a plurality of thermometers and / or a plurality of infrared thermometers. The temperature measuring device can preferably be designed as an analog or digital measuring device. Preferably, it is arranged on or towards the side of the receiving part or of the test piece facing away from the application means, i.e. it determines the temperature at the back of the test piece or, if a plurality of thermocouples and / or a plurality of thermometers and / or a plurality of infrared thermometers are used, determines the temperature at the back of the test piece and its distribution. The side facing away from the exposure means corresponds to the side of the test piece facing away from the mass flow.

[0069] In a further advantageous further development, the impact means is accommodated in a blind hole opening of the carrier element. The carrier element can be designed as a tube closed on one side, with a cup-shaped recess in which the loading means is accommodated and advantageously held in a precise position. Preferably, the carrier element has a locking device, which fixes the carrying means relative to the carrier element so that the carrying means does not fall off the carrier element. The locking device can be designed as a force-locking locking device, e.g. a clamping device, and / or as a positive-locking locking device, e.g. a locking or latching element. The support element can be detachably or non-detachably connected to the bracket. In the case of a detachable design, the carrier element is exchangeable so that it can be changed to suit the application means. This means that the inspection device can be used universally and is not limited to a specific application means.

[0070] In an advantageous embodiment, the application means can be adjusted relative to the holder, so that it can be positioned in a desired position relative to the bracket and its mounting and thus relative to the test piece, and the mass flow can be applied to the test piece in a desired manner. The carrier element is preferably adjustably held on the bracket.

[0071] It may preferably be provided that the angle and / or the distance between the impact means and the holder is adjustable. In this way, the impact means can be adjusted so that the mass flow impacts the test piece orthogonally or obliquely. Furthermore, the distance between the impact means and the holder and its receptacle, and thus to the test piece that can be accommodated in the receptacle, can also be adjusted. Preferably, the carrier element is held pivotally on the bracket. Alternatively or additionally, the carrier element can be held on the bracket so that it can be translated and displaced, whereby the distance between the carrier element and the holder can be adjusted and / or the carrier element can be adjusted parallel to the receptacle or the test piece, whereby when the angle of the application means is set, it is directed towards the receptacle or the test piece, i.e. the mass flow preferably hits the center of the test piece. The adjustable angle is preferably between 0° and 60°, particularly preferably between 0° and 45°. An angle of 0° corresponds to the mass flow being directed perpendicularly to the receptacle or the test piece.

[0072] The test device preferably has a baffle plate, which is arranged on the side of the receiver facing away from the impact means. The baffle plate is preferably made of or consists of a heat- and fire-resistant material, for example steel or ceramic material. It should not be understood in the sense that the baffle plate must necessarily be made of sheet metal. The baffle plate is also called a baffle element. The baffle plate is arranged in the mass flow arrangement such that after the test piece has burned, the mass flow is directed in a predetermined direction by the baffle plate. This allows the mass flow to be directed towards the extraction device. The baffle plate is preferably rotatably and / or translationally adjustable relative to the holder. This allows the baffle plate to be adjusted to a set position of the impact means so that the mass flow can be directed in a desired direction, preferably towards the trigger device. The baffle plate is preferably arranged in a force-separated manner from the force measuring device. This ensures that the force measuring device determines only the force applied to the test piece and that the measurement is not falsified by the mass flow hitting the impact plate after burn-through.

[0073] As an advantageous further development, a test specimen holder is provided which can accommodate the test specimen, whereby the test specimen holder is accommodated in the receptacle. Thanks to the test specimen holder, the test specimen can be accommodated on the testing device easily, conveniently and time-savingly. The test specimen holder preferably has a mesh grid which can cover the test specimen. This ensures that the test specimen is positioned on the test specimen holder. The test specimen holder is preferably made of steel or aluminum or consists of such materials.

[0074] The mesh grid is preferably made of a material resistant to high temperatures and thermal shocks, preferably a fiber-reinforced ceramic. Preferably, the fiber composite ceramic is a ceramic fiber-reinforced ceramic. Advantageously, the fibers are oriented long fibers. Preferably, the grid is a woven fabric of ceramic long fibers embedded in a ceramic matrix. The ceramic long fibers and / or the matrix are particularly preferably made of a metal oxide ceramic material, such as aluminum oxide or mullite. However, other ceramic materials for the fibers and / or the matrix are also possible. A large number of materials are known from the prior art that are basically suitable for both the matrix and the fibers.

[0075] It has been shown that such mesh grids are particularly suitable for test specimens containing organic insulation, as they are able to withstand high thermal loads.

[0076] The mesh grid is preferably 3 cm wide to allow mass flow to act unimpeded on the test specimen. 2 More than 25cm 2 The central aperture has an area of ​​3 cm for low scattering mass flow (mass flow aperture solid angle less than 10°). 2 From 7cm 2 , especially 5cm 2 It is particularly preferred that the central opening has an area of ​​10 cm for a scattered mass flow (mass flow opening solid angle is greater than 10°). 2 More than 20cm 2 It has the following surface area:

[0077] Tests have shown that the scattering mass currents correspond approximately to the currents of damaged battery cells. In particular, a distance between the charging means and the test specimen of 40 mm to 60 mm has proven to be advantageous. A particularly advantageous arrangement is a mass flow with an opening angle of 40°, the loading means being at a distance of 50 mm from the test specimen and an area of ​​the central opening of the mesh grid of 16 cm 2 It is.

[0078] The opening angle is the opening angle of the mass flow cone, which is twice the angle between the generatrix and the axis of the cone.

[0079] Preferably, the opening clearance angle has a value between 3° and 10°. Preferably, the mesh is fixed at a distance from the surface of the specimen. This can be done, for example, by fixing the mesh to a specimen holder or by fixing it floating on the specimen. By "floating mount" it is meant that the mesh grid is stationary on the specimen or held at a defined distance from it. The mesh is subjected to a force in the vertical downward direction, for example due to the weight of the mesh or of the parts connected to it. The floating mesh grid can also be provided with vertical guides that allow the mesh grid to move vertically but fix it in the XY plane. Preferably, the distance between the mesh grid and the specimen surface is 1-5 mm.

[0080] In an advantageous embodiment, the specimen holder is designed like a frame so that the specimen can be inserted therein, and thanks to such a design it can be ensured that the specimen holder is not damaged when the specimen is exposed to the mass flow and / or that this does not or only slightly influences the measurement result.

[0081] In an advantageous version of the test device, a fixing device can be provided for fixing the test piece or the test piece holder in the receiving part. This fixing device can be switched between a fixing position and a release position, in which the test piece or the test piece holder is fixed relative to the receiving part and in which the test piece or the test piece holder can be picked up or removed from the receiving part in the release position. The fixing device can be designed as a clamping device, for example a clamping lever or a tension lever. Alternatively or additionally, the fixing device can also be designed as a positive locking device. Furthermore, the fixing device can also be formed by threaded elements such as screws, nuts or stud bolts. The fixing device ensures that the test piece or the test piece holder does not move during the application of the mass flow. As an advantageous further development, such a fixing device can also be additionally provided on the test piece holder in order to fix the test piece relative to the test piece holder.

[0082] As an advantageous further development, the determination device can consist of a high-speed camera and / or an infrared camera and / or an acoustic measuring device. The infrared camera can be used to record thermal photographs and / or thermographs of the test specimen. This infrared camera is directed towards the recording part or towards the test specimen insertable therein. It is preferably directed towards the side of the receiving part facing the exposure means or towards the test specimen insertable therein. This allows thermal photographs or thermographs of the rear side of the test specimen to be recorded. The high-speed camera (also called high-speed camera) can be used to record on film the application of the mass flow to the test specimen. For this purpose, the high-speed camera is preferably directed towards the test specimen which can be recorded in the recording part so that a film recording of the impact of the mass flow on the test specimen and / or a film recording of the side of the test specimen facing away from the mass flow can be made. Preferably, the high-speed camera is installed so that an image frequency of 30 frames per second or more, particularly preferably 100 frames per second or more, can be recorded. Preferably, the high-speed camera can constitute an optical filter device which acts, for example, like a kind of welding goggles. This improves the film recording of the impact. Two high-speed cameras can also be provided, one of which consists of an optical filter device, which is preferably directed towards the impact part of the mass flow on the test specimen. The acoustic measuring device is preferably designed as a microphone. Particularly preferably, this microphone is designed as a directional microphone and is directed towards the impact means or towards the test specimen. It is also possible for the test device to have two microphones, one of which is directed towards the impact means and the other towards the test specimen. This acoustic measuring device has the advantage that its measuring properties are not impaired by smoke generation during the impact.

[0083] As an advantageous further development, it can be provided that the infrared camera and / or the high-speed camera and / or the acoustic measuring device are adjustably mounted on the console, whereby the infrared camera and / or the high-speed camera can be optimally focused on the impact part of the mass flow.

[0084] As a further advantageous further development, the testing device can comprise an extraction device and / or a blowing device or can be connected to such devices.

[0085] The extractor can be used to extract gases and fumes generated by the mass flow. It can, for example, be arranged on the side of the receiver or the test specimen facing away from the mass flow so that the mass flow is at least partially extracted after burning. Alternatively or additionally, the extractor can be arranged on the side of the receiver facing the mass flow so that the fumes generated during exposure can be extracted by this device. This has the advantage that when using a high-speed camera, the view of the test specimen is maintained during exposure and is not impaired by the fumes. The use of a high-speed camera can thus further improve the accuracy of the test, for example when determining the burn-through resistance over time.

[0086] The extraction device can be part of the inspection device or can be connected, for example, by a hose. The extraction device preferably consists of a wet scrubber and / or a HEPA filter (High-Efficiency Particulate Air / Arrestance Filter). The wet scrubber is used to wash away components harmful to health and the environment, such as acids and exhaust gases. The HEPA filter cleans soot, fine particles and dust.

[0087] A blower can be provided as an alternative or in addition to the extractor, whereby it is preferably arranged on the side of the receiver facing the mass flow. The blower is installed and arranged to move the smoke generated during impact by a fluid flow, in particular an air flow. This has the advantage that, when a high-speed camera is used, the view of the test specimen remains clear during the exposure and is not impaired by smoke. The use of a high-speed camera thus allows an even greater accuracy in the measurement of the burn-through resistance over time. The fluid flow must be dimensioned such that it has a technically negligible effect on the mass flow rate during the exposure.

[0088] Preferably, the blower device may comprise a compressed air lance for directing the flow of fluid, which may be connected to a compressed air hose for connection to a pneumatic system. Alternatively or additionally, the blower device may comprise a fan and / or a compressor.

[0089] In a further advantageous further development of the test device according to the invention, the force measuring device is at least partially surrounded by a shield or seal. Particularly preferably, the force measuring device is completely sealed by a seal, whereby the electric lines are hermetically routed through the seal. The shield or seal is preferably a hermetically sealed heat seal. In this way, the negative interference effects of gases and particles released by the mass flow on the force measuring device are at least significantly reduced, so that falsification of the force measurement is counteracted, as a result of which the measurement accuracy of the test device is further improved.

[0090] As an advantageous further development, a jet velocity measuring device can be provided to determine the jet velocity of the mass flow. The jet velocity measuring device can also be called a flow velocity measuring device. Preferably, the jet velocity measuring device is a Doppler spectrometer. Preferably, the jet velocity measuring device can be arranged between the pick-up part and the application means so that the jet velocity can be determined spatially before the mass flow impacts the test piece. Alternatively or additionally, the jet velocity measuring device or a further jet velocity measuring device can be arranged on the side of the receiving part or the test piece facing away from the impact means. This allows the jet velocity to be determined after the test piece has burned out.

[0091] As an advantageous further development, the pressure means is designed to provide an impulse of between 1 Newton second (Ns) and 250 Ns, particularly preferably between 1 Ns and 100 Ns.

[0092] In a further advantageous further development, the application means is designed to provide a mass flow for between 2 and 30 seconds, particularly preferably between 5 and 25 seconds. This ensures that the mass flow acts on the test specimen for a sufficient time to be able to determine the burn-through resistance and that the mass flow does not continue to flow for an unnecessary period after burn-through. In other words, the flow time can be adapted to the properties of the test specimen and to the flow time of the fire to be simulated, for example the thermal runaway of a lithium-ion battery.

[0093] Preferably, the fuel for the pressurizing means is selected such that the mass flow has a predetermined flow rate, momentum, temperature, opening angle and chemical composition. A fuel supply device may adapt and supply the fuel to the pressurizing means according to a demand profile. It is thus possible to adjust the fuel and its amount before or during pressurization. The mass flow can thus be adjusted according to the intended test parameters.

[0094] In a preferred embodiment, the pressure applying means comprises a device designed to apply the particles to a mass flow, preferably a gas flow, which makes it possible, for example, to adjust the force introduced by the mass flow on the test specimen.

[0095] Preferably, the test apparatus comprises a mass measuring device for determining the mass of the fuel intended for the pressurizing means, which may for example be in the form of a balance, or the volume of the fuel may be measured and the mass determined therefrom.

[0096] As an advantageous further development, the pressurizing means can have a nozzle or be coupled to such a nozzle. Preferably, the nozzle has a nozzle outlet channel with a predefined length and a predefined opening cross section and a predefined opening angle. The nozzle therefore has a predefined nozzle shape at the outlet end. The nozzle shape can be selected in such a way that different discharge characteristics can be set with the same type of impingement means, for example so that the impact area of ​​the mass flow and / or the impact speed and momentum of the mass flow can be set. The nozzle shape is determined, for example, by the length of the nozzle outlet channel (corresponding to the length of the outlet cone, also called the outlet cone), the opening cross section (diameter of the outlet opening) and the opening angle (cone opening angle of the outlet opening). This allows the impulse and the impact area to be specifically adjusted.

[0097] The opening angle of the nozzle outlet can be selected depending on the desired emission characteristics. For example, it can be zero, so that the nozzle outlet is formed by a circular cylindrical channel. Preferably, the opening angle has a value between 45 ° and 135 °. The opening angle corresponds to twice the angle between the generatrix and the axis of the cone.

[0098] Thanks to the adaptability of this nozzle geometry, it is possible to simulate the emission characteristics of different lithium-ion batteries during failure (also called thermal runaway), especially with regard to the opening angle of the hot gas and particle emission cone (exit cone, nozzle exit channel), the temperature at the impact point, the integrated mass momentum at the impact surface, the mass momentum per surface and the injection velocity.

[0099] Alternatively, the nozzles can be arranged on a carrier element that holds the pressurizing agent. This means that nozzles of different shapes can be easily attached to the carrier element and the mass flow of the pressurizing agent can be directed through them. It can be provided that the nozzles have an adjustable nozzle shape, preferably also adjustable during pressurization. In this way, the mass flow can be further equalized in terms of its flow characteristics over the duration of the impingement.

[0100] In an advantageous embodiment of the test device according to the invention, the pressurizing means is designed as a rocket propellant charge, an acetylene burner with mass feed, a flame atomization device, a galvanic element or a plasma atomization device. The rocket propellant charge can also be called a rocket or rocket motor.

[0101] Preferably, the rocket propellant charge is a solid composite propellant charge. Such solid composite propellants have proven particularly advantageous because they provide a more uniform mass flow over the impact time and improved repeatability due to very close tolerances between the individual propellants.

[0102] Preferably, the rocket propellant charge can be actuated by electrical ignition, which is simple, practical and can be achieved without significant effort.

[0103] In an advantageous further development, the galvanic element is designed as a secondary element, also known as an accumulator. The galvanic element is composed of at least one cell. The galvanic element is particularly preferably designed as a lithium-ion accumulator. Such a design of the charging means allows the test strip to be tested under simulated conditions.

[0104] As an advantageous further development, the galvanic element is preferably arranged so that the earth current leaves the galvanic element against the force of gravity, which has the advantage that in such an upright arrangement, as opposed to a suspended arrangement, no or very little flammable liquid electrolyte escapes from the galvanic element, thereby preventing uncontrolled combustion and even fire.

[0105] As an advantageous further development, the testing device and / or the determination device comprises a data acquisition device, which can be designed, for example, as a computer. The data acquisition device is preferably electrically connected to at least one of the aforementioned measuring devices or to all of the aforementioned measuring devices and is configured to record the measurement signals of the measuring devices.

[0106] As an advantageous further development, shielding means and / or steering devices are arranged between the pressure means and the receiving part.

[0107] Thanks to the shielding means arranged in this way it is ensured that the impact means is not damaged or destroyed by reflection of ground currents, especially when the distance between the impact means and the test specimen is small. The shielding means is preferably made of a material that is resistant to high temperatures and thermal shocks, preferably a fiber-reinforced ceramic.

[0108] The shielding means can preferably be designed as a perforated screen with holes through which the mass flow can pass. The orifice plate is preferably attached directly to the pressure means so that the holes correspond to the nozzles of the pressure means. Alternatively, the shielding means can be arranged remotely from the pressure means. In this case, the holes are dimensioned such that the mass flow can pass unhindered. As a particularly advantageous further development, the mass flow strikes the test piece obliquely, i.e. at a slight incline, so that most of the reflection of the mass flow strikes the shielding means and the impact means is even better protected.

[0109] Thanks to such a steering device, the mass flow can be appropriately steered in its propagation. The steering device is preferably arranged between the impact means and the test piece, in particular the steering device is arranged at the impact section on the side of the test piece facing the impact means. The steering device is fixed to the test piece by means of fixing means, for example screws. It has been shown to be particularly advantageous to design the steering device in a pyramidal or wedge-shaped manner. Thanks to such a design of the steering device, the so-called thermal runaway of lithium-ion batteries can be simulated more realistically than in the prior art. In such a thermal runaway, metal battery components are rapidly and massively ejected, pyramidal deposits are formed and the high-velocity hot gases are deflected accordingly. This is an ejection characteristic that is completely different from a perpendicularly impinging jet. This means that with the test device according to the invention, very realistic conditions can be simulated with the described steering device.

[0110] The damage intensity can be adjusted and set by changing the angle of the steering device; at an angle of 45° the main intensity of the mass flow is directed parallel to the specimen surface. An angle between the beam direction and the surface normal of the steering device of 30° to 45° is advantageous.

[0111] In an advantageous further development, the steering device is made of or consists of a ceramic or metallic material, in particular steel.

[0112] Preferably, the steering device is designed as a wedge, with two surfaces that conduct the mass flow, the angle of one surface relative to the specimen surface being equal or unequal to the angle of the second surface relative to the specimen surface, so that real conditions can be more accurately simulated on the test device.

[0113] The test device is preferably suitable for carrying out the method according to the invention for testing test strips as described above and its further embodiments, whereby the test device can preferably also have the further embodiments as described above.

[0114] It should be noted that the specified further developments and features of the advantageous embodiments can be freely combined with one another to the extent that is technically possible, even if not explicitly stated in the text, this also applies beyond the scope of the device and method claims. [Brief description of the drawings]

[0115] Further advantages and features of the method according to the invention and of the test device according to the invention are shown in the following embodiments which are explained in more detail with reference to the figures.

[0116] Show these:

[0117] [Figure 1]FIG. 1 is a schematic diagram of a first embodiment of a testing apparatus according to the present invention prior to application of a high velocity thermal mass flow to a test specimen. [Diagram 2] FIG. 2 is a schematic diagram of a first embodiment of a testing apparatus according to the present invention during application of a high velocity thermal mass flow to a test specimen. [Diagram 3] FIG. 3 is a schematic view of a first embodiment of a testing device according to the invention after burn-off of the test specimen. [Figure 4A] FIG. 4A is a schematic representation of a force-time diagram according to a force-time curve obtained by carrying out the method according to the invention. [Figure 4B] FIG. 4B is a schematic diagram of a force-time diagram in which the test specimen withstood the load without burning. [Diagram 5] FIG. 5 is a schematic diagram of a second embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen. [Figure 6] FIG. 6 is a schematic diagram of a second embodiment of a testing device according to the invention after the test specimen has been burned off. [Figure 7] FIG. 7 is a schematic diagram of a third embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen. [Figure 8] FIG. 8 is a schematic diagram of a fourth embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen. [Figure 9] FIG. 9 is a schematic diagram of a fifth embodiment of a testing apparatus according to the present invention, showing the application of thermal rapid mass flow to a test specimen. [Figure 10] FIG. 10 is a schematic diagram of a sixth embodiment of a testing apparatus according to the present invention during application of a high velocity thermal mass flow to a test specimen. [Figure 11] FIG. 11 is a schematic diagram of a seventh embodiment of a testing apparatus according to the present invention, showing a state in which a thermal rapid mass flow is being applied to a test piece. [Figure 12] FIG. 12 is a schematic diagram of an eighth embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen. [Figure 13]FIG. 13 is a schematic diagram illustrating a ninth embodiment of a testing apparatus according to the present invention during application of a high velocity thermal mass flow to a test specimen. [Figure 14] FIG. 14 is a schematic cross-sectional view of a nozzle for adjusting the emission characteristics of a mass flow. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0118] In the various figures, identical parts are always given the same reference numbers and therefore are generally named or mentioned only once.

[0119] 1 to 3 show a first embodiment of a test device 10 according to the invention. The test device 10 is used to test a test specimen 50 according to the method according to the invention. The test device 10 comprises a holder 30 with a receiving part 32 for directly receiving the test specimen 50. A load means 20 designed as a rocket motor is held in a fixed, non-displaceable first bearing 98, which is shown here diagrammatically as a clamp. In FIG. 1, the load means 20 has not yet been ignited and therefore the test device is shown in a state before the test specimen 50 is pressurized by a high-velocity thermal mass flow 22, which in the following will be called mass flow for short. The load means 20 is directed towards the test specimen 50 in such a way that the mass flow 22 strikes the test specimen 50, as can be seen in FIG. 2.

[0120] Furthermore, the testing device 10 comprises a force measuring device 40 operatively connected to the holder 30. This force measuring device 40 is designed as a load cell and is accommodated in a sealed housing 42. The force measuring device 40 is held in a non-displaceable second bearing 99 so that the force F introduced by the mass flow on the test specimen 50 can be measured. In a first embodiment example of the testing device 10 shown in Figs. 1 to 3, the plate-shaped test specimen 50 is held directly in the receiving part 32. For this purpose, the receiving part 32 is designed as an edge of the holder 30 which defines a recess 33, the edge being stepped so that the test specimen 50 can be inserted therewith reliably and at the same time the support of the test specimen 50 is ensured when the test specimen 50 is acted upon by the mass flow 22, as shown in Fig. 2, such that the force flow from the test specimen 50 is introduced via the receiving part 32 into the holder 30, which in turn transmits the force flow to the force measuring device 40. The test piece 50 has a front surface 51 and a back surface 52, the front surface 51 facing the loading means 20, and the back surface 52 facing in a direction away from the loading means 52. The test piece 50 rests with an end of the back surface 52 placed on the receiving portion 32, so that the maximum area of ​​the back surface 52 does not contact the receiving portion 32, i.e., it is non-contact.

[0121] The holder 30 is diagrammed as a pot-shaped part, preferably made of steel, having a base 34 operatively coupled to the force measuring device 40 such that the holder 30 stands on the force measuring device 40 and thus ensures a flow of force from the holder 30 to the force measuring device 40.

[0122] FIG. 2 shows the test device of FIG. 1 during the application of the mass flow 22 to the test specimen 50. The mass flow 22 is provided by a load means 20, which is here designed as a rocket motor filled with a solid composite propellant and is also called a pressurizing means. The load means 20 is directed towards the test specimen 50 in such a way that the mass flow 22 strikes the test specimen 50 at an impact point 55 on the front side 51 and introduces heat and a force F into the test specimen 50. The impact point 55 can also be called the impact point. The load means 20 ejects the mass flow 22 and presses it against the test specimen 50, whereby a force F is introduced into the holder 30 via the receiving part 32, which is coupled to the force measuring device 40 via the base part 34, and the force F introduced into the test specimen 50 by the mass flow 22 is determined by the force measuring device.

[0123] The method according to the invention can be used to determine the burn resistance of a test specimen 50 over time, in this case by means of a determination device consisting of a force measuring device. As can be seen in Fig. 2, by applying a high velocity thermal mass flow 22 to the test specimen 50 and continuously determining the force F acting on the test specimen 50 as a result of the application by means of the force measuring device 40, the time span ts from the start of the application to the occurrence of a drop in force due to burn-through of the test specimen 50 is determined.

[0124] FIG. 3 shows the test device 10 according to the invention shown in FIGS. 1 and 2 after the test specimen 50 has been burned. The result of burning the test specimen 50 can be seen in FIG. 3. Due to the input heat, the mass flow 22 is burned or burned through the opening 58 of the test specimen 50. Since the mass flow 22 can now flow through the burnt opening 58 of the test specimen 50, no or only a very small force is applied to the test specimen 50, so that a drop in force occurs, which is determined by the force measuring device 40. The described method according to the invention thus makes it possible to determine the time span ts from the start of the application of force to the occurrence of the force drop due to the burn-through of the test specimen 50. This can be best seen in the force-time diagram of FIG. 4a.

[0125] Figure 4a is a force-time diagram which illustrates a force-time curve determined by the method according to the invention, for example by one of the test devices according to the invention shown in Figures 1 to 3 and 5 to 8. The force F exerted by the mass flow 22 on the test specimen 50 was determined over time t. Such a force-time curve can be determined by the force measuring device 40.

[0126] At a start time t0, which indicates the start of the application of the mass flow 22 to the test specimen 50, the force increases sharply to a maximum force F2. Thereafter, the force decreases to a force F1, and the force applied by the mass flow 22 remains relatively constant from time t1 to time t2. The period between time t0 and time t1 indicates the starting impulse of the load means 20 designed as a rocket motor. After the starting impulse occurs, the load means designed as a rocket motor provides a constant mass flow 22, which introduces heat and force evenly and continuously to the test specimen 50, so that from time t1 to time t2, a substantially constant force acts on the test specimen 50. At time t2, the test specimen 50 reaches a seizure resistance over time, so that seizure begins at time t2. For example, as shown in FIG. 3, since the opening 58 is burned into the test specimen 50 by the mass flow 22, which can then flow through the opening 58 of the test specimen 50, and thus no or only very small forces are introduced into the test specimen 50, there is therefore a quasi-steep drop in force from force F1 to force F3 from the start of burn-through, which corresponds to time t2. The drop in force to the level of force F3 ends at time t3, when the burn-through of the test specimen ends. In other words, the time t2 of the burn-through is determined by the jump in force between the force level due to force F1 (force plateau) and the force level due to force F3 (force plateau). Thus, the time span ts can be determined as a measure of the burn-through resistance over time, between the start of loading t0 and the occurrence of the force drop due to the burn-through of the test specimen 50 at time t2. Thus, the method according to the invention allows the burn-through resistance over time, i.e. the time span ts, to be determined. Since the mass flow 22 continues to flow for a certain time after burn-through and flows over the edge of the opening 58, a small force F3 is also introduced into the specimen 50 after burn-through. The following relationship applies: F2>F1>F3>0. From the moment t4 onwards, the force F3 drops to a value of 0 at time t5, as the decreasing propellant (fuel) causes a so-called burn-out of the load means 20, which is designed as a rocket motor.

[0127] Figure 4b is a force-time diagram which illustrates a force-time curve determined by one of the test devices according to the invention shown in Figures 1 to 3 and 5 to 8. The force F exerted by the mass flow 22 on the test specimen 50 is determined over time t, so that in this case the test specimen 50 resisted the impact of the mass flow 20 without being burned out. Such a force-time curve can be determined by the force measuring device 40.

[0128] At the start time t0, which indicates the start of the application of the mass flow 22 to the test specimen 50, the force increases sharply to a maximum force F2. After that, the force decreases to a force F1, and the force applied by the mass flow 22 remains relatively constant from time t1 to time t4. The period between time t0 and time t1 indicates the starting impulse of the load means 20 designed as a rocket motor. After the starting impulse occurs, the load means designed as a rocket motor provides a constant mass flow 22, which introduces heat and force evenly and continuously to the test specimen 50, so that from time t1 to time t4, a substantially constant force acts on the test specimen 50. From time t4, the force decreases from force F1 to 0 at time t5, as the propellant designed as a rocket motor burns due to fuel exhaustion. In contrast to the force curve of FIG. 4a, the test specimen 50 did not burn, so there is no decrease from force F1 to force F3>0 due to burning. The test specimen 50 survived the entire time of loading (t0 to t5) without burning, which means that the time span ts > t5 - t0.

[0129] 5 and 6 are schematic diagrams of a second embodiment of a testing apparatus 10 according to the present invention, with FIG. 5 showing the test specimen 50 during application of a high velocity thermal mass flow 22 and FIG. 6 showing the test specimen after it has been burned off.

[0130] The structure of the second example embodiment is based on the testing device 10 of the first example embodiment, whereby the illustrated loading means 20, the force measuring device 40 and the receiving part 32 of the holder 30 as well as the test specimen 50 correspond to those of the first testing device 10 of the first example embodiment and are therefore not repeated to avoid redundancy. All the features described above with respect to the similar components are transferable.

[0131] In this embodiment, the load means 20 is not supported by a clamping device, but by a support beam 73 of a bracket 70. The bracket 70 may also be referred to as a frame or support unit. The force measuring device 40 is also attached to the bracket 70 and is supported thereon, specifically by a support leg 71 of the bracket 70.

[0132] The holder 30 is shown diagrammatically as a pot-shaped part, with a base 34 by which it stands on the force measuring device 40 of the determination device and is thus operatively connected thereto in such a way that a flow of forces is ensured from the holder 30 to the force measuring device 40. The holder 30 can move at least to a small extent relative to the bracket 70 so that the force F introduced by the mass flow 22 on the test specimen 50 can be determined. In an embodiment not shown, a guide device can be provided between the bracket and the holder to guide the holder so that it can move in one direction.

[0133] The baffle plate 60 is arranged in the holder 30 and is arranged at one end of a support arm 72 of a bracket 70. The support arm 72 extends through a hole-like recess 35 in the side wall of the holder 30, which protrudes through the hole-like recess 35 with play, so that a force-related decoupling of the baffle plate 60 to the holder 30 and thus to the force measuring device 40 is guaranteed. The baffle plate 60 is inclined, i.e. arranged obliquely, to the front surface 51 of the test specimen 50, so that the mass flow 22 flowing through the opening 58 of the test specimen 50 during burn-through is directed towards the extraction system, as can be clearly seen in FIG. 6. The baffle plate is preferably inclined between 30° and 60° to the front surface 51 of the test specimen 50. A suction nozzle 65 of the extraction system is shown here diagrammatically. This suction nozzle 65 is guided through a further recess in the other side wall of the holder 30.

[0134] An infrared camera 84 is disposed on the support arm 72 and is aimed at the back surface 52 of the test specimen 50 to record thermographic images of the back surface 52 while the test specimen 50 is exposed to the mass flow 22. The infrared camera 84 is mounted on the support arm 72 so that its orientation can be adjusted. The infrared camera 84 forms part of the determination apparatus.

[0135] Furthermore, a temperature measuring unit 81 is arranged on the back surface 52 of the test piece 50 near the impact part 55. The temperature measuring unit 81 is designed as a thermocouple and is glued to the back surface 52 of the test piece.

[0136] Mounted on the bracket 70 are a first high-speed camera 82 with an optical filter 821 and a second high-speed camera 83, each of which can be adjusted in orientation. The high-speed cameras 82, 83 form part of a determination device. The first high-speed camera 82 is directed towards the impact part 55 of the mass flow 22. The second high-speed camera 83 is directed towards the mass flow 22 and its impact part 55 and the test specimen 50. However, it can also be aligned so that the loading means 20 is also recorded. The two high-speed cameras record a film of the impact.

[0137] FIG. 7 is a schematic diagram of a third embodiment of a testing apparatus 10 in accordance with the present invention shown during application of a high velocity thermal mass flow 22 to a test specimen 50.

[0138] The structure of the third example embodiment is based on the testing device 10 of the second example embodiment, whereby the loading means 20, the force measuring device 40 and the receiving part 32 of the holder 30 correspond to those of the second example embodiment and are therefore not repeated to avoid redundancy. All the features described with respect to the similar components previously described are transferable.

[0139] The structure of the bracket 70 and its function are similar to those of the bracket 70 of the second embodiment of Figures 5 and 6, the support beam 73 carrying the load means 20 being adjustable in the height direction H by means of a first adjustment device 77. Thus, the distance of the load means 20 relative to the receiving part 32 and therefore to the test specimen 50 can be adjusted.

[0140] The loading means 20 is received in a blind hole opening of the carrier element 90. The carrier element 90 is designed as a tube closed on one side. The carrier element 90 is provided with a locking device (not shown), which fixes the loading means 20 relative to the carrier element 90 so that the loading means 20 cannot fall off the carrier element 90.

[0141] The carrier element 90 is pivotally held in a pivot direction W by a lockable joint 92 on the bearing beam 73 of the bracket 70, so that the angle of the loading means 20 relative to the receiver 32 and thus to the test specimen 50 is adjustable, and it is also possible for the mass flow 22 to impinge obliquely on the front surface 51 of the test specimen 50. The adjustable angle is preferably between 0° and 60°, particularly preferably between 0° and 45°. An angle of 0° corresponds to the mass flow 22 being directed perpendicular to the receiver 32 or test specimen 50, as shown in FIG. 7.

[0142] The carrier element 90 is held by the second adjustment device 78 on the support beam 73 of the bracket 70 so as to be translatably displaceable in the vertical direction V, and the carrier element 90 can be adjusted parallel to the receiving part 32 or the test piece 50, so that the mass flow 22 can be set toward the receiving part 32 or the test piece 50 depending on the set angle of the carrier element 90 and the loading means 20 accommodated therein. The mass flow 22 is set toward the receiving part 32 or the test piece 50, preferably so that the mass flow 22 impinges on the center of the test piece 50.

[0143] The first adjusting device 77 can be designed as a manual, electromotive, pneumatic or hydraulic adjusting device. The second adjusting device 78 can also be designed as a manual, electromagnetic, pneumatic or hydraulic adjusting device.

[0144] Mounted on the bracket 70 are a first high speed camera 82 with an optical filter 821 and a second high speed camera 83, each of which can be adjusted in orientation. The first high speed camera 82 is directed towards the impact part 55 of the mass flow 22. The second high speed camera 83 is directed towards the mass flow 22 and its impact part 55 and the test specimen. However, it can also be aligned so that the loading means 20 is also recorded. The two high speed cameras record a film of the impacts and form part of the determination device for testing the test specimen.

[0145] An infrared camera 84 is disposed on the support arm 72 of the bracket 70 and is constructed and positioned similarly to the second example embodiment.

[0146] The baffle plate 60 is arranged in the holder 30 with an adjustable position and angular orientation at one end of the support arm 72 of the bracket 70. The support arm 72 extends through a hole-like recess in the side wall of the holder 30, which decouples the holder 30 from the holder 30 in terms of force. The baffle plate 60 is inclined with respect to the front face 51 of the test specimen 50, so that in the event of burn-through, the mass flow 22 flowing through the opening of the test specimen 50 is directed towards the extraction system. The inclination angle of the baffle plate can preferably be adjusted between 30° and 60° with respect to the front face 51 of the test specimen 50. The suction nozzle 65 of the extraction system is shown diagrammatically. This suction nozzle 65 is guided through a further recess in the other side wall of the holder 30.

[0147] Furthermore, a temperature measuring unit 81 is arranged on the back surface 52 of the test piece 50 near the impact part 55. The temperature measuring unit 81 is designed as a thermocouple and is glued to the back surface 52 of the test piece.

[0148] In contrast to the first two embodiments, the test strip 50 is not received directly in the receiving part 32 of the holder 30, but indirectly. For this purpose, a test strip holder 38 is provided in which the test strip 50 is received, which is received in the receiving part 32. The test strip holder 38 preferably has a mesh grid 59 which is laid flat on the test strip 50. In this way, the test strip 50 is securely held on the test strip holder 38. The test strip holder 38 has a frame-like design so that the test strip 50 can be inserted therein.

[0149] A first clamping device 37 is provided for fixing the test specimen holder 38 in the receiving part 32 and is designed here as a clamping lever. This clamping device 37 is switchable between a clamping position and a release position, in which the test specimen holder 38 is fixed relative to the receiving part 32 and in which the test specimen holder 38 can be received in or removed from the receiving part 32.

[0150] Furthermore, second fastening devices 39 for fastening the test specimens 50 in the test specimen holder 38 are provided, which are designed as screw elements and are shown diagrammatically.

[0151] Furthermore, the test device 10 comprises a data acquisition device 100, which is designed as a computer and can also be called a measurement computer. The data acquisition device 100 is electrically connected to all the aforementioned measuring devices and is set up to record the measurement signals of the measuring devices. That is to say, the data acquisition device 100 is connected via a data line 101 to the force measuring device 40, the temperature measuring unit 81, the first high-speed camera 82, the second high-speed camera 83 and the infrared camera 84. This can be designed as a data bus.

[0152] In embodiments not shown, it is also conceivable and possible that the first and second adjustment devices 77, 78 each have a position sensor and / or are controlled by a data collection device in the case of a non-manual design.

[0153] Additionally, the data acquisition device 100 may be used to electrically ignite the load means 20 to initiate recording of the measurements.

[0154] FIG. 8 illustrates a fourth embodiment of a testing apparatus 10 according to the present invention during application of a high velocity thermal mass flow 22 to a test specimen 50 .

[0155] This fourth embodiment corresponds substantially to the first embodiment shown in Figs. 1-3, but with the addition of a perforated diaphragm-like shielding means 24 arranged between the load means 20 and the receiver 32. Moreover, in contrast to the first embodiment, the holder 30 is slightly inclined, so that the mass flow 22 does not strike the test piece 50 exactly perpendicularly. As a result, most of the reflection of the mass flow 22 strikes the shielding means 24, which is well protected from damage. The shielding means 24, designed as a perforated opening 24, is made of a material that is resistant to high temperatures and thermal shocks. The shielding means 24 has holes 26 through which the mass flow 22 can flow. The shielding means 24, designed as a perforated orifice, is attached directly to the load means 20, in such a way that the holes 26 correspond to the nozzles of the load means 20. In another embodiment, not shown, the shielding means can be arranged at a distance from the pressure means. The holes are dimensioned such that the mass flow can flow unhindered. All other aspects of the test apparatus 10 of the fourth example embodiment correspond to those of the first example embodiment and will not be repeated here to avoid redundancy.

[0156] FIG. 9 is a schematic diagram of a fifth embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen.

[0157] The construction of the fifth embodiment is based on the test device 10 of the second embodiment, the only difference being that the fifth embodiment of FIG. 9 is made up of an acoustic measuring device 85 designed as a microphone. By means of the acoustic measuring device 85 it is possible to record during the application of the mass flow 22 to the test specimen 50, which allows additional information on the course of the application to be determined. For example, the acoustic measuring device 85 can be used to accurately determine the ignition time t0 of the load means 20. Furthermore, the time at which the test specimen 50 burns can also be determined by the acoustic measuring device. The acoustic measuring device is therefore part of the determination device. This allows for redundancy of other measuring devices, such as force measuring devices or cameras. Furthermore, the acoustic measuring device has the advantage that, unlike a camera, its measuring properties are not impaired by the generation of smoke during exposure. The acoustic measuring device can also constitute the determination device without other measuring devices. In other words, the burn-through resistance of the test specimen over time can be measured by the acoustic measuring device alone.

[0158] All other described features of the second example embodiment of FIG. 5 can be transferred to the fifth example embodiment of FIG. 9 without limitation.

[0159] FIG. 10 is a schematic diagram of a sixth embodiment of a testing apparatus 10 according to the present invention during application of a high velocity thermal mass flow 22 to a test specimen 50.

[0160] The test device 10 comprises a holder 30 with a receiving part 32 in which the test specimen 50 is directly held. The receiving part 32 is designed as an edge of the holder 30 which defines a recess 33, whereby the edge is stepped so that the test specimen 50 can be securely inserted therein. The load means 20 is designed here as a galvanic element, i.e. a lithium-ion accumulator, and is held on a fixed, non-displaceable first bearing 98, which is shown here diagrammatically as a holder 79 fixed to a clamping device. The holder 79 extends through a hole-like recess 35 in the side wall of the holder 30, the holder 79 protruding through the hole-like recess 35 with play, so that a decoupling of the forces of the load means 20 from the holder 30 and thus from the force measuring device 40 is ensured.

[0161] The mass flow 22 is provided by the load means 20. The load means 20 is directed towards the test specimen 50 in such a way that the mass flow 22 impinges on the test specimen 50 at an impact point 55 on the front side 51 and introduces heat and a force F into the test specimen 50. The impact point 55 can also be called the impact point. The load means 20 ejects the mass flow 22 and presses it against the test specimen 50, thereby introducing a force F through the receiving part 32 into the fixing device 37 designed as a screw and into the holder 30 which is connected to the force measuring device 40 via the base part 34, so that the force F introduced into the test specimen 50 by the mass flow 22 is determined by the force measuring device.

[0162] Using the method according to the invention, the burn-through resistance of the test specimen 50 can be measured over time. As can be seen in Fig. 10, the test specimen 50 is subjected to a high-velocity thermal mass flow 22 from the galvanic element 20, and the force F acting on the test specimen 50 as a result of the application is continuously determined by the force measuring device 40, so that the time span ts from the start of the application to the occurrence of a drop in force due to burn-through of the test specimen 50 is determined. Additionally or alternatively, the determining device can also consist of other or further measuring devices.

[0163] The load means 20 is arranged in the holder 30 such that the mass flow 22 flows out of the galvanic element against the force of gravity, i.e. upwards. This has the advantage that in contrast to a suspended arrangement, in such an upright arrangement, there is little or no leakage (escaping) of flammable liquid electrolyte from the galvanic element 20, thereby preventing uncontrolled combustion or even ignition.

[0164] The test apparatus 10 comprises a force measuring device 40 operably connected to the holder 30. The force measuring device 40 is contained in a sealed housing 42. The force measuring device 40 is held in a non-displaceable second bearing 99 so as to be able to measure the force F introduced by the mass flow on the test specimen 50.

[0165] Furthermore, a temperature measuring unit 81 is arranged on the back surface 52 of the test piece 50 near the impact portion 55 so as to measure the temperature of the test piece 50 during the impact. The temperature measuring unit 81 is designed as a thermocouple.

[0166] FIG. 11 is a schematic diagram of a seventh embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen.

[0167] The configuration of the seventh embodiment is based on the test device 10 of the second embodiment, and the seventh embodiment of FIG. 11 differs only in that it is equipped with a blower device 67. This blower device has a compressed air lance 69 connected to a compressed air hose 68 fixed to a bracket 70 and connected to a compressor (not shown). The blower device 67 is installed and arranged so that the smoke generated during pressurization is kept away by the air flow. This has the advantage that when a high-speed camera is used, the view of the specimen is kept clear during exposure and is not impaired by smoke. In other words, the use of a high-speed camera can further improve the accuracy of the test specimen test, especially the measurement accuracy of the burn-through resistance over time. The fluid flow must be dimensioned so that it has only a technically negligible and insignificant effect on the mass flow rate during exposure.

[0168] All other described features of the second embodiment of FIG. 5 can be transferred to the seventh embodiment of FIG. 11 without limitation.

[0169] FIG. 12 is a schematic diagram of an eighth embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen.

[0170] The structure of the eighth example embodiment is based on the test device 10 of the seventh example embodiment, the only difference being that the eighth example embodiment of Fig. 12 does not include a force measuring device. The determination device for determining the burn-through resistance over time consists here of high-speed cameras 82 and 83, by means of which the time span ts is determined by the method according to the invention.

[0171] All other described features of the seventh example embodiment of FIG. 11 in combination with aspects of the second example embodiment of FIG. 5 may be transferred without limitation to the eighth example embodiment of FIG.

[0172] FIG. 13 is a schematic diagram of a ninth embodiment of a testing apparatus according to the present invention during application of a thermal rapid mass flow to a test specimen.

[0173] The configuration of the ninth embodiment is based on the testing device 10 of the first embodiment, and differs only in that the ninth embodiment of FIG.

[0174] The wedge-shaped steering device 25 can be used to appropriately steer the propagation of the mass flow 22, as is clearly shown in FIG. 13. The wedge-shaped steering device 25 is placed between the load means 20 and the test specimen 50, in particular on the front surface 51 of the test specimen 50 facing the load means 20. The steering device 25 is fixed to the test specimen by means of screws, not shown. The steering device 25 is made of steel. The steering device 25, designed as a wedge, has two surfaces that direct the mass flow, so that the angle of one surface to the test specimen surface is the same as the angle of the second surface to the test specimen surface. This allows real situations to be simulated more accurately on the test device. When the mass flow 22 hits the steering device 25, this mass flow is practically halved and accordingly diverted to the side. The steering device acts more or less like a spade. The steering device 25 can be easily integrated into other embodiments.

[0175] FIG. 14 shows a schematic longitudinal section of a nozzle 21. This nozzle 21 can be incorporated into all previously illustrated embodiments in order to suitably adjust the emission characteristics of the mass flow. The nozzle 21 has a conical or cone-shaped nozzle outlet passage 211 with a given length 212, a given opening cross section 213 and a given opening angle α. The opening cross section 213 here represents the inlet cross section from the supply line to the nozzle outlet passage. Due to the cone angle, the final exit cross section can be easily determined by calculation. The walls of the outlet passage may be curved, for example convexly or concavely.

[0176] In principle, all advantageous further developments of the measuring devices, cameras and the like shown in the other exemplary embodiments can also be transferred to the inspection device shown in FIG. [Explanation of symbols]

[0177] 10. Test equipment 20...Loading means 21 Nozzle 22...mass flow 24...Shielding means 25. Steering device 26...hole 30. Holder 32 Receiving part 33 Recess 34 Base section 35 Recess 37...1st fixing device 38... Test specimen holder 39...Second fixing device 40...force measuring device 42....Sealed housing 50 Test piece 51...Front 52...Back side 55 Impact part 58...Opening 59 Mesh grid 60···Baffle plate 65... Extraction system suction nozzle 67... Blower 68···Compressed air hose 69...Compressed Air Lance 70 Bracket 71...Support leg 72 Support arm 73 Support beam 77...1st adjustment device 78...Second adjustment device 79... Support 81 Temperature measuring unit 82 High-speed camera 821 Optical Filter 83 High-speed camera 84 Infrared camera 85 Acoustic measuring device 90···Carrier element 92...Joint 98···No. 1 bearing 99... No. 2 bearing 100 Data collection device 101... Data line 211 Nozzle outlet passage 212...Length 213...Aperture cross section α...Aperture angle t0...Start time ts: Time span as an indicator of burn-through resistance over time

Claims

1. A method for thermo-mechanical testing of a test specimen (50), comprising exposing the test specimen (50) to a high velocity thermal mass flow (22).

2. 2. The method of claim 1, wherein the measurement is determined by a determination device.

3. 3. The method according to claim 1 or 2, characterized in that the time span (ts) from the start of exposure to the occurrence of burn-through of the test specimen (50) is determined by a determination device.

4. 10. A method according to any one of the preceding claims, characterized in that the force (F) acting on the test specimen (50) as a result of the load is determined continuously by a determination device.

5. The method of claim 4, further comprising determining a time span (ts) from the initiation of the load to the occurrence of a force drop due to burn-through of the test specimen (50).

6. 10. The method according to any one of the preceding claims, characterized in that the mass flow (22) flows through an opening (58) in the test specimen (50) created by burn-through.

7. 10. A method according to any one of the preceding claims, characterized in that the start time (t0) of the loading is determined by an increase in force.

8. 10. A method according to any one of the preceding claims, characterized in that the temperature of the test specimen (50) is measured.

9. 9. The method of claim 8, characterized in that the temperature is measured on a side (52) of the test piece (50) facing away from the mass flow (22).

10. 10. The method of claim 8 or 9, characterized in that the onset of exposure is determined by exceeding a predetermined temperature of the test specimen.

11. Method according to any one of claims 8 to 10, characterized in that the determination of the forces and / or the temperature is performed in a common data acquisition device (100).

12. 12. The method of claim 11, wherein the common data collection device (100) comprises a multimeter.

13. 10. The method according to any one of the preceding claims, characterized in that the impulse acting on the test specimen (50) is determined by the force (F) acting over the time span (ts).

14. 10. A method according to any one of the preceding claims, characterized in that a thermal photograph and / or a thermograph of the test specimen (50) is recorded.

15. 10. The method according to any one of the preceding claims, characterized in that an acoustic signal is detected during loading.

16. 10. The method according to any one of the preceding claims, characterized in that an injection velocity of the mass flow (22) is determined.

17. 10. The method according to any one of the preceding claims, characterized in that the test strip (50) consists of a battery housing material or is a battery housing or part of a battery housing.

18. 10. The method according to any one of the preceding claims, characterized in that the mass flow (22) is directed perpendicular or obliquely to the test piece (50).

19. 10. The method according to any one of the preceding claims, characterized in that the mass flow (22) is supplied by a rocket propellant charge, an acetylene burner with mass feeding, flame spray or plasma spray.

20. 10. The method according to any one of the preceding claims, characterized in that the mass flow (22) flows through a nozzle (21), whereby the emission characteristics of the mass flow (22) are adjusted.

21. A test device (10) for thermomechanical testing of a test specimen (50), comprising a holder (30) having a receiving portion (32) capable of receiving said test specimen (50) directly or indirectly; and a loading means (20) for providing a high velocity thermal mass flow (22) that can be directed toward the test specimen (50).

22. 22. The test device (10) of claim 21, characterized in that the test device (10) comprises a decision device.

23. 23. Test device (10) according to claim 22, characterized in that the determination device is designed to determine the burn-through resistance of the test strip (50), in particular the burn-through resistance of the test strip (50) over time.

24. 24. The testing device (10) of claim 22 or 23, characterized in that the determination device comprises a force measuring device (40) operatively coupled to a holder (30) and configured to determine a force (F) introduced on the test specimen (50) by the mass flow (22).

25. 25. Testing device (10) according to any one of claims 21 to 24, characterized in that the determining device comprises a temperature measuring unit (81) for determining the temperature of the test specimen (50).

26. 26. Test device (10) according to any one of claims 21 to 25, characterised in that the loading means (20) is accommodated in a blind hole opening of a carrier element (90).

27. 27. Testing device (10) according to any one of claims 21 to 26, characterized in that the loading means (20) is adjustable relative to the holder (30).

28. 28. Testing device (10) according to any one of claims 21 to 27, characterized in that the angle and / or distance of the loading means (20) relative to the holder (30) is adjustable.

29. 29. A testing device (10) according to any one of claims 21 to 28, characterized in that a baffle plate (60) is arranged on the side of the receiving portion (32) facing away from the loading means (20).

30. A test device (10) as described in any one of claims 21 to 29, characterized in that a test strip holder (38) capable of accommodating the test strip (50) is provided, and the test strip holder (38) is accommodated in the receiving portion (32).

31. 31. Test device (10) according to claim 30, characterized in that the test strip holder (38) is designed in the form of a frame so that the test strip (50) can be inserted therein.

32. 32. A test device (10) according to any one of claims 21 to 31, characterized in that a fixing device (37, 39) is provided for fixing the test strip (50) or the test strip holder (38) to the receiving part (32).

33. Test device (10) according to any one of claims 21 to 32, characterized in that the determination device comprises a high-speed camera (82, 83) and / or an infrared camera (84) and / or an acoustic measurement device (85).

34. 34. A testing device (10) according to any one of claims 21 to 33, characterized in that it comprises or can be connected to a stripping device and / or a blowing device (67).

35. 35. A testing device (10) according to any one of claims 21 to 34, characterized in that the force measuring device (40) is at least partially surrounded by a shield or enclosure (42).

36. 36. A test device (10) according to any one of claims 21 to 35, characterized in that a jet velocity measuring device is provided for determining the jet velocity of the mass flow (22).

37. 37. A test device (10) according to any one of claims 21 to 36, characterized in that the load means (20) is designed as a rocket propellant charge, an acetylene burner with a bulk supply, a flame spray device, a galvanic element or a plasma spray device.

38. The test apparatus (10) of claim 37, wherein the rocket propellant charge is a solid composite propellant charge.

39. 40. The test apparatus (10) of claim 37 or 38, wherein the rocket propellant charge is operable by electrical ignition.

40. 40. A testing device (10) according to any one of claims 21 to 39, characterized in that a shielding means (24) and / or a steering device (25) are arranged between the load means (20) and the receiving part (32).

41. 41. Test device (10) according to any one of claims 21 to 40, characterized in that the loading means consist of a nozzle (21) or can be coupled to such a nozzle.

42. 42. A test device according to claim 41, characterized in that the nozzle (21) has a nozzle outlet channel (211) with a predetermined length (212), a predetermined opening cross section (213) and a predetermined opening angle (α).

43. A test device (10) for carrying out a method for testing a test strip (50) according to any one of claims 1 to 20 using a test device (10) according to any one of claims 21 to 42, characterized in that the test device (10) has a design according to any one of claims 21 to 42.

Images