Material testing apparatus for testing the material of a test piece

Abstract

The present invention relates to a test piece (102), in particular to an apparatus (100) for material testing of a battery device. The apparatus (100) includes a test piece holder device having a test piece holder (101) for holding the test piece (102) to be tested, a rod device (110) that moves in a direction toward the test piece holder (101) to transmit a mechanical load to the test piece (102), and an electromechanical actuator (120) that moves at least one of the rod device (110) and the test piece holder device relative to each other along the longitudinal impact direction (103). The electromechanical actuator device is configured to adjust the speed between 0 m / s and 12 m / s arbitrarily between the rod device (110) and the test piece holder device in order to transmit a mechanical load to the test piece (102).

Description

Technical Field

[0001] The present invention relates to a test piece, particularly an apparatus for material testing of a battery, and a method for material testing of a test piece.

Background Art

[0002] In material testing, it is necessary to expose a material sample to various different types of stresses. For example, a material sample is subjected to tensile stress or compressive stress for a certain period of time. For example, a testing machine may be designed to provide a tensile test, where the material sample is stretched with a specific tensile force. Further, impact tests and bending tests may be performed on other testing machines, where an impact element is pressed against the material sample for the purpose of the test. Further, testing machines are usually designed for different types of loading speeds. For example, a general-purpose testing machine can be used for quasi-static tests (low speed) only, usually a servo-hydraulic machine is used for repeated fatigue tests, and a dedicated machine (special servo-hydraulic machine or split Hopkinson bar) is used for high-speed loading conditions.

[0003] The force can be applied statically or dynamically. Since particularly high forces act during the test, the requirements for the testing machine are very high, especially with regard to durability and vibration safety. For this reason, testing machines are usually designed for one specific loading condition only, the purpose being to provide sufficient test performance for this one loading condition.

Summary of the Invention

[0004] Therefore, there may be a need to provide an apparatus for testing a material under a plurality of different loading conditions.

[0005] This need can be met by an apparatus and a method for material testing of a test piece as described in the subject matter of the independent claims.

[0006] According to a first aspect, an apparatus for material testing of a test piece is described. The apparatus includes a test piece holder device having a test piece holder for holding the test piece to be tested, a rod device that moves in a direction toward the test piece holder to transmit a mechanical load to the test piece (whereby the rod device transmits a mechanical load to the test piece), and an electromechanical actuator device for moving the rod device. The electromechanical actuator device is configured to relatively move the rod device along the longitudinal impact direction toward the test piece holder, and the electromechanical actuator device is configured to adjust the speed between the rod device and the test piece holder device to any speed from 0 m / s to 12 m / s (e.g., constant, variable (i.e., accelerating or decelerating)) in order to transmit a mechanical load to the test piece.

[0007] According to a further aspect, a method for material testing of a test piece by the above-described apparatus is provided. According to this method, the test piece to be tested is attached to the test piece holder. At least one of the rod device and the test piece holder moves relative to each other so that the rod device transmits a mechanical load to the test piece for material testing of the test piece, and the speed is adjusted to any speed from 0 m / s to 12 m / s.

[0008] The test piece tested using the above-described apparatus may be part of a material such as a metal element or a plastic element, may be in a sheet-like shape, or may be in a solid shape. Further, the test piece to be tested may be part of a product such as a semi-finished or finished device. For example, the test piece to be tested may be a battery cell, a multi-cell device, a battery module, or a battery pack. This device may be used for tensile tests and impact tests for testing the mechanical properties of materials, and is also capable of a withstand voltage test of the battery. Therefore, the test piece holder can hold the device in a form suitable for, for example, the rod device to transmit a mechanical load (tensile force, traction force, or pressing force) to the housing of the device, for example. The purpose is to provide material testing for each housing.

[0009] The test piece holder device has, for example, a test piece holder designed to hold the test piece in a particularly removable manner. For example, the test piece holder can include a clamping element for clamping the test piece to be tested. Further, the test piece holder may include a magnet, particularly a permanent magnet or an electromagnet. The purpose is to fix the test piece, particularly a metal test piece, to the holding device.

[0010] The test piece holder device itself may be removably fixed to a receiving part of the device, particularly in the exemplary embodiments described below. Further, the test piece holder may include a chamber in which the test piece is disposed and into which a rod device can move movably. Through the opening of this chamber, the impact element of the rod device reaches the sample attached to the sample holder.

[0011] The rod device has an impact element with an impact part designed to be pressed against the test piece. In a further exemplary embodiment, the rod device has a tension element for transmitting a pulling force to the test piece. Thereby, the rod device is configured to move in a direction towards and away from the test piece holder. The rod device is driven by an electromechanical actuator device and can move at an adjustable speed and with an adjustable impact force against the test piece.

[0012] The electromechanical actuator assembly has at least one electromechanical actuator. The electromechanical actuator can be coupled to a rod device (i.e., a force transmission rod) to move the rod device relative to the specimen holder. As will be described later, additionally or alternatively, further electromechanical actuators may be coupled to the specimen holder, whereby the specimen holder can be moved relative to the rod device. Thus, the expression "adjust the speed between 0 m / s and any speed up to 12 m / s relative to each other between the rod device and the specimen holder device" is defined such that the rod device can be driven towards the specimen holder device, the specimen holder device can be driven towards the rod device, or both, and thus the rod device and the specimen holder device can move relative to each other. Specifically, a constant speed or a variable speed (i.e., acceleration or deceleration) may be adjusted within the range of 0 m / s to 12 m / s. That is, during the test time interval, the speed may vary over time.

[0013] The electromechanical actuator may be, for example, an electric motor or a servo motor that drives the rod device with a desired impact force at a desired speed along the impact direction. In an exemplary embodiment described later, the electromechanical actuator can be a linear motor. The electromechanical actuator is specifically configured to apply an impact energy of more than 100 J (joules), particularly more than 200 J, and even more particularly more than 500 J to the specimen.

[0014] According to the approach of the present invention, the electromechanical actuator assembly is configured to move the rod device at a speed of at least 4 m / s, particularly 10 m / s, and more particularly 12 m / s. The speed of 4 m / s means that the speed can be adjusted to any speed between 0 m / s and 6 m / s for transmitting a mechanical load to the test piece between the rod device and the test piece holder device. In an exemplary embodiment, a constant speed or a variable speed (i.e., acceleration or deceleration) may be adjusted within the range of 0 m / s to 6 m / s or within the range of 0 m / s to 4 m / s. For example, when driving the rod device against the test piece at 3.6 m / s, a force of 25 kN can be applied.

[0015] Therefore, for example, the rod device can be driven, for example, between 0 m / s and 12 m / s. Therefore, a plurality of load conditions can be applied. For example, the rod device can, for example, impact the test piece at a high frequency, or the rod device can be statically pressed or pulled against the test piece, whereby the pressing / rod device transmits a mechanical load to the test piece. Depending on the actual test piece holder, various mechanical loads such as, for example, a compressive load, a tensile load, a shear load, and / or a bending load can be transmitted. For example, the rod device can, for example, apply a load to the test piece at a high frequency for performing a repeated test or a fatigue test, or (using the same device) the rod device can also apply a static load to the test piece. Also, the rod device may apply a load to the test piece at a high speed for performing a high strain rate test. Therefore, with the mentioned device, it is possible to apply a plurality of different load conditions for material testing within one and the same device. Therefore, a material test including both a destructive test and a non-destructive test of the test piece to be tested can be provided. In contrast to the conventional approach, the present invention combines a general-purpose testing machine used exclusively for quasi-static tests (low speed), a servo-hydraulic machine used for repeated fatigue tests, and a dedicated machine for high-speed load conditions (e.g., a special servo-hydraulic machine or a split Hopkinson bar) in one device.

[0016] According to a further exemplary embodiment, when the device is placed on the ground, the impact direction is parallel to the horizontal direction. That is, the impact direction, and thus the movement direction of the rod device, is orthogonal to the direction of gravity. By applying such a horizontal alignment of the rod device, the influence or disturbance caused by gravity along the impact direction is minimal, allowing the same movement or acceleration without being affected to be possible in both directions. This approach is contrary to many conventional approaches where the impact direction is vertical in order to generate a higher impact force using the weight of the impact tool.

[0017] According to a further exemplary embodiment, the specimen holder, the electromechanical actuator assembly, and the rod device are configured to press the rod device against the specimen with a pressing force exceeding 5 kN, particularly exceeding 15 kN, and more particularly exceeding 20 kN or 25 kN.

[0018] According to a further exemplary embodiment, the electromechanical actuator assembly and the rod device are configured to perform a static test that applies a constant pressing force to the specimen being tested and / or a dynamic test that varies the impact force within a predetermined time range. Thus, it is also possible to provide with this rod device a test that alternately repeats static and dynamic loads on the specimen. The force during the static test may not be generated constantly by the rod device controlled by the electromechanical actuator assembly. For example, in a static test, the force is continuously increased to a specific level or until the specimen breaks, while providing a very slow movement of the rod device. However, so-called creep tests are also possible, where the force is kept constant over a long period of time. In a dynamic test, for example, using a pre-acceleration phase, it is possible to provide a faster movement of the rod device, whereby the load introduction device of the specimen or the specimen holder is impacted at a specific speed and / or impact energy. All of these test cases can be performed with the described material testing device.

[0019] For example, in the static creep test described above, a constant force is provided over a long period of time. However, this force does not necessarily have to be constant. In a static test, it is possible to continuously increase the force up to a certain level or until the test piece breaks, while providing a very slow movement of the rod device. In a dynamic test, a pre-acceleration phase can be used to provide a faster movement of the rod device, such that the test piece, or the load introduction device of the test piece holder, is impacted with a specific speed and / or impact energy.

[0020] According to a further exemplary embodiment, the electromechanical actuator device has an electromechanical actuator assembly configured to move a rod device along an impact direction towards and away from a test piece holder, for example, to perform static and / or repetitive tests applying various loads to the test piece. Thus, it is possible not only to apply a pressing force to the test piece in a direction towards the test piece, but also to apply a tensile force in a direction away from the test piece. Therefore, the device of the present invention can also provide tensile tests, as well as various load conditions between further compression / bending tests and tensile tests. Repetitive tests (e.g., continuously applying tensile and compressive loads to the test piece at high frequencies) are also provided. To provide a tensile test, the rod device can be firmly fixed to the test piece, for example, by a clamp connection, a screw connection, or a welded joint.

[0021] According to a further exemplary embodiment, the electromechanical actuator device further has an electromechanical actuator configured to move a specimen holder device along an impact direction toward and away from a rod device, particularly for performing static tests, dynamic tests, or repetitive tests that apply various loads to a specimen. For example, the rod device may be fixedly attached to a support base so as not to be movable, and the specimen holder device may be movably attached to the support base along the impact direction. For example, the specimen holder device may be attached to the support base via a guide rail extending along the impact direction. Further, both the rod device driven by an electromechanical actuator and the specimen holder driven by a further electromechanical actuator can be movable relative to each other. Accordingly, a plurality of different load conditions can be applied. In a static test, a higher pressing force can be generated by at least two electromechanical actuators. Further, in a dynamic test, a faster reaction time and an appropriate acceleration profile can be provided by two electromechanical actuators.

[0022] Thus, in a one-stage electromechanical actuator device having one electromechanical actuator, using the one electromechanical actuator, the speed and the speed interval can each be a continuous interval of 0 to 6 m / s. The one-stage device includes one motor that moves in the direction of the specimen. Further, when using a two-stage electromechanical actuator device having the above-described electromechanical actuator and a further electromechanical actuator, the speed value can be doubled, i.e., 0 to 12 m / s. The two-stage device provides two reciprocating electromechanical actuators, one having a specimen holder and the other having a rod device.

[0023] According to a further exemplary embodiment, the rod device has a stiffness exceeding 400 kN / mm. Thus, the rod device can be designed to have a stiffness exceeding 400 kN / mm so that a high pressing force can be applied to the test piece. Specifically, when the impact direction is parallel to the horizontal direction and thus orthogonal to the direction of gravity, the weight for providing each highly rigid rod device can be negligible.

[0024] According to a further exemplary embodiment, the rod device has an impact element and a force transmission element, in particular a force transmission rod, coupled to the electromechanical actuator. The impact element is, in particular, harder than the test piece to be tested. Further, the impact element may include a conical or pyramidal shape having an impact tip. The impact element may also include a hemispherical shape having a round ball-shaped impact portion. The impact element may also include an impact edge extending in the longitudinal direction or an impact / pin spike applying force at a point.

[0025] A force transmission element such as a force transmission rod provides a coupling between the impact element and the electromechanical actuator. The force transmission element may be coupled to the movable part of the electromechanical actuator, for example directly or via respective gears. The force transmission element may be coupled to the sliding part of the linear motor as will be described later in the exemplary embodiments.

[0026] According to a further exemplary embodiment, the impact element is removably coupled to the force transmission element. Thus, for example, it is possible to exchange impact elements of different designs and shapes in order to test the test piece using different load conditions. Further, when the impact element is damaged, each replacement of the impact element is possible. The impact element can be coupled to the force transmission element by a screw connection or a clamp connection. In an alternative embodiment, the force transmission element and the impact element may each be integrally formed as one part.

[0027] According to a further exemplary embodiment, the rod device further has a force sensor for measuring the impact force between the impact element and the test piece to be tested.

[0028] According to a further exemplary embodiment, the force sensor is arranged between the impact element and the force transmission element. Thus, when the force sensor is arranged close to the impact element, direct measurement of the force sensor and also appropriate accessibility are possible. Specifically, when the force sensor is attached near the impact element at the front, no time delay of the force signal occurs during dynamic measurement, so a very accurate force measurement is provided. Thus, for example, instead of a delay signal from the engine controller of the actuator unit, a direct signal is used.

[0029] According to a further exemplary embodiment, the force sensor is removably attached to at least one of the impact element and the force transmission element. Thus, different types of force sensors can be applied to different load conditions, or a defective sensor can be replaced.

[0030] According to a further exemplary embodiment, the force sensor is a piezoelectric sensor. A piezoelectric sensor is a sensor that measures a change by converting a change in pressure, acceleration, temperature, strain, or force into an electric charge using the piezoelectric effect. In force measurement, the piezoelectric sensor may have a thin film and a large base, and the applied pressure ensures the formation of each electrical signal indicating the applied force, especially when loading each element in one direction. Additionally or alternatively, a strain gauge sensor, i.e., a DMS sensor, can also be used as a force sensor for measuring the strain of the rod device.

[0031] According to a further exemplary embodiment, the electromechanical actuator is a linear motor having a movable sliding part to which a rod device is coupled and a stator that extends along the impact direction. The sliding part can be driven relative to the stator along the impact direction by an electromechanical driving force that can be generated between the stator and the sliding part. The linear motor generates a linear driving force along its length and thus along the impact direction. A typical operating mode is a Lorentz type actuator, in which the applied force is linearly proportional to the current and the magnetic field. By means of the linear motor, the impact force and speed of the rod device can be accurately adjusted. Also, the acceleration can be accurately adjusted for a desired load condition.

[0032] According to a further exemplary embodiment, the force transmission element is coupled to the movable sliding part. The force transmission element has a length, particularly along the impact direction, which is longer than the moving distance of the sliding part along the impact direction. Thus, the maximum moving distance of the sliding part can be used to move the rod device. This is because, due to the sufficient length of the force transmission element, the impact element arranged on the force transmission element does not collide with the structural elements of the linear motor.

[0033] According to a further exemplary embodiment, the stator has a rectangular stator table in particular. In each exemplary embodiment, the stator table has a length along the impact direction and a width orthogonal to the impact direction, and the length is longer than the width of the stator table. Thus, when the stator is formed as the stator table, a large support area is provided for the stator and the sliding part that functions as the movable part of the electromagnetic motor. The stator table is adapted to also transmit a high load to the sliding part in order to further transmit the high load to the test piece and / or to accelerate the sliding part at high speed. Further, the stator table forms a robust stator that transmits the weight or vibration of the high load to the ground via the support base.

[0034] According to a further exemplary embodiment, the stator table has at least one conductive coil. Each coil can be wound around the table and thus can form each magnetic field necessary to interact with the slider to generate a driving force. Specifically, three coil groups can be provided on the stator table, thereby providing a three-phase linear induction motor. Depending on the direction of the current flowing through the wire of the coil, each magnetic field is formed, which impedes the magnetic field of the permanent magnet in the movable part (i.e., the slider) of the linear electric motor. The arrangement of the permanent magnets of the slider is mounted between two coil arrays (one is mounted on the upper stator table and the other is mounted on the lower stator table), and both are arranged so as to be orthogonal to the direction of the slider in which the magnetic poles move. The conversion of the movable part, i.e., the slider, is achieved by changing the direction of the current in the coil over time. The coil is powered from an external power source via a cable. The dimensions of the permanent magnet and the coil are such as to enable a linear test motor with dynamic characteristics from a low speed of 0 m / s to exceeding 3 m / s.

[0035] In a further exemplary embodiment, at least one conductive coil is liquid-cooled, particularly water-cooled. In particular, when providing a static load condition where the impact element is pressed against the test piece without moving at all, high temperatures can occur in each coil that interacts with the slider. Therefore, by cooling each conductive coil, the test period can be extended by cooling the coil. For example, the stator, particularly the stator table, has cooling water channels formed near the arrangement of the coils to provide liquid cooling.

[0036] According to a further exemplary embodiment, the linear motor has a temperature sensor that measures the temperature of at least one coil. As described above, when providing a static load condition in which the impact element is pressed against the test piece without moving at all, high temperatures can occur in each coil that interacts with the sliding part. Therefore, one or more temperature sensors are arranged near the coils, whereby an over-temperature rise of any coil can be detected.

[0037] According to a further exemplary embodiment, the stator has a further stator table, in particular rectangular, which contains in particular at least one further conductive coil, and the sliding part is slidably arranged between the stator table and the further stator table. Therefore, by providing two stator tables sandwiching the sliding part, a stronger magnetic field can be provided for driving the sliding part.

[0038] The linear motor can have a support structure that holds the stator table and the further stator table. Furthermore, the support structure may be part of the support base, as will be described later. Each induction rail may be fixed to the support structure to provide a slidable connection with the sliding part. The induction rail can have a dovetail shape, and the sliding part can have dovetail grooves formed therein respectively, and vice versa.

[0039] According to a further exemplary embodiment, the sliding part has a magnet element, in particular a permanent magnet element. In an exemplary embodiment, the magnet elements are arranged in sequence along the impact direction. The magnet elements can form, for example, neodymium magnets.

[0040] In an exemplary embodiment, particularly when a sliding part is arranged between two stator tables, one row of magnets can be arranged above the sliding part, and the other row of magnets can be arranged below the sliding part. The sliding part can have a robust sliding plate between the two rows of magnets, particularly a metal plate made of, for example, aluminum, and the rows of magnets are arranged on opposite surfaces of the sliding plate respectively.

[0041] In an alternative embodiment of the linear motor, each conductive coil may be arranged in the sliding part, and correspondingly, each permanent magnet is arranged in the stator element, particularly in the stator table.

[0042] According to a further exemplary embodiment, the weight of the sliding part exceeds, for example, 60 kg, 80 kg, or 100 kg. Thus, a high impact energy is provided by a high mass, for example, exceeding 60 kg. The weight of the sliding part can be particularly high because the impact direction is oriented horizontally, and thus is significantly higher than any other electrodynamic testing machine having a vertical impact direction. In particular, in the conventional approach, the goal is to provide a low mass for high-frequency tests. However, in the device according to the present invention, particularly when the sliding part is arranged between two stator tables, a high-frequency sliding movement can be achieved even by the high speed of the sliding part and the impact device.

[0043] According to a further exemplary embodiment, the device further comprises at least one stopper element configured to stop the movement of the sliding part along the impact direction, and the stopper element is made of an elastomeric material in particular. The stopper element is designed to limit the movement of the sliding part along the impact direction. The stopper element may be fixed to the housing of the device and / or may be directly or indirectly fixed to the support base described below. Since the stopper element is made of an elastomeric material, it is possible to smoothly attenuate the impact force of the sliding part on the stopper element, and furthermore, it is possible to provide a spring force that accelerates the sliding part in the opposite direction due to the elastomeric properties. In particular, in high-frequency tests, each spring force may be desirable.

[0044] According to a further exemplary embodiment, the device further comprises a support base on which a test piece holder, a rod device, and an electromechanical actuator device are (directly or indirectly via a coupling support element) attached. The support base is robustly formed, for example, by a framework of steel rods that can be placed on the ground. The support base transmits the force of weight and dynamic forces to the ground respectively.

[0045] According to a further exemplary embodiment, the device further comprises at least one guide rail extending along the impact direction, and the guide rail is coupled to the support base. The movable part (such as a sliding part) of the rod device and / or the electromechanical actuator is slidably coupled to the guide rail. The guide rail may be directly coupled to the support base via a support structure, for example. Furthermore, the sliding part can also be fixed to the stator element (such as a stator table and / or a further stator table) of the linear motor in order to support the sliding part and the rod device. The stator table is coupled to the support base via a support structure, for example.

[0046] According to a further exemplary embodiment, the support base is configured to provide a stiffness exceeding 600 kN / mm. Thus, high-weight forces, and even dynamic forces, can be transmitted to the ground without generating vibrations that could adversely affect the test procedure. This stiffness can be provided by the robust framework of the steel beams described above and further by the shear plates described below.

[0047] According to a further exemplary embodiment, the support base has a support plate, in particular an aluminum plate, to which at least the test specimen holder and the electromechanical actuator device are attached. The support plate forms a robust and rigid receiving surface and can be arranged on top of the strong framework of the steel beams of the support base. By arranging the support plate in the horizontal plane, forces directed along the horizontal direction are effectively damped and absorbed.

[0048] According to a further exemplary embodiment, the support base comprises at least one vertically oriented shear panel extending between the ground on one side and the test specimen holder, the rod device, and the electromechanical actuator device on the other side (and, for example, between the support plate and the ground). The shear panel is in particular a vertically oriented sheet, in particular a metal sheet. By providing the vertically oriented shear panel, forces spreading along the vertical direction and further along the impact direction (in particular shear forces) are absorbed and damped by the vertically oriented shear panel. Specifically, each sheet-like panel is sufficient to damp each force, thereby also providing a lightweight solution for damping vertical forces.

[0049] According to a further exemplary embodiment, the shear panel is configured to have a natural frequency exceeding 300 Hz along the impact direction. The natural frequency (i.e., the characteristic vibration frequency) can be adjusted by providing the respective thickness of the shear panel and by using a suitable material such as metal.

[0050] According to a further exemplary embodiment, the specimen holder is removably coupled to the holder receiving portion of the support base. Thus, by providing a removable specimen holder, each specimen holder can be pre-assembled with the specimen to be tested before fixing the holder to the holder receiving portion. For example, a plurality of specimen holders can be pre-assembled with each specimen to be tested. This improves the test procedure and makes the test procedure more efficient. The specimen holder can be fixed to the holder receiving portion, for example, by a screw connection or a clamp connection.

[0051] According to a further exemplary embodiment, the holder receiving portion has at least one receiving groove, and the specimen holder has at least one receiving pin. The receiving pin is slidable within the receiving groove for removably coupling the specimen holder to the holder receiving portion, and the receiving groove is formed particularly orthogonally to the impact direction. The holder receiving portion can have, for example, a plurality of receiving grooves extending in a horizontal plane orthogonally to the impact direction. The specimen holder may have respective receiving pins slidable within the grooves along a direction orthogonal to the impact direction. Thus, in the specimen to be tested, the force induced by the impact of the rod device is directed orthogonally to the sliding direction of the receiving pins within the grooves so that the force can be directly transmitted from the specimen holder over the entire recommended area. Thus, a robust, simple and removable fixation of the specimen holder to the entire recommended area of the support base is provided.

[0052] In an alternative embodiment, the holder receiving portion may have receiving pins extending in the vertical direction, and the specimen holders may each have receiving grooves. Thus, the specimen holder and its respective receiving grooves can be fixed by receiving the receiving pins of the holder receiving portion.

[0053] It should be noted that the embodiments of the present invention are described with reference to different subjects. In particular, some embodiments are described with reference to claims related to apparatuses, while on the other hand, other embodiments are described with reference to claims related to methods. However, those skilled in the art will assume from the above and the following descriptions that, unless otherwise noted, in addition to any combination of features belonging to a certain type of subject, any combination between features related to different subjects, particularly any combination between the features of claims related to apparatuses and the features of claims related to methods, is also considered to be disclosed in the present application.

Brief Description of the Drawings

[0054] The aspects defined above and further aspects of the present invention will be apparent from the examples of the embodiments described hereinafter and will be described with reference to the examples of the embodiments. The present invention will be described in more detail hereinafter with reference to examples of embodiments, but the present invention is not limited thereto.

[0055]

Figure 1

Figure 2

Figure 3

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Modes for Carrying Out the Invention

[0056] The illustrations in the drawings are schematic. It should be noted that the same reference numerals are provided for similar or identical elements in different drawings.

[0057] Figures 1 and 2 show perspective views of an apparatus 100 for material testing of a test piece 102 according to an exemplary embodiment of the present invention. FIG. 2 shows a more detailed view of the front portion including in particular a test piece holder 101 and a rod device 110.

[0058] The apparatus 100 includes a test piece holder 101 that holds a test piece 102 to be tested, a rod device 110 that moves in a direction toward the test piece holder 101 to transmit a mechanical load to the test piece 102, and an electromechanical actuator device having an electromechanical actuator device that moves at least one of the rod device 110 and the test piece holder device relative to each other. The electromechanical actuator 120 is configured to adjust the speed along the longitudinal impact direction 103 between 0 m / s and any speed up to 12 m / s between the rod device 110 and the test piece holder 101, and the electromechanical actuator device is configured to move the rod device 110 at a speed exceeding at least 12 m / s. For example, the electromechanical actuator device has an electromechanical actuator 120 that moves the rod device 110 at a speed of, for example, 6 m / s. Further, the electromechanical actuator device has a further electromechanical actuator that moves the test piece holder device at a speed of, for example, 6 m / s. Accordingly, both the test piece holder device and the rod device 110 can move relative to each other within the range of 0 m / s to 12 m / s.

[0059] The test piece holder 101 is designed to hold the test piece 102 in a removable manner with respect to the holder receiving portion 132 of the support base 130. For example, the test piece holder 101 can have a clamping element that clamps the test piece 102 to be tested. By providing a removable test piece holder 101, each test piece holder 101 can be pre-assembled with the test piece 102 to be tested before fixing the holder 101 to the holder receiving portion 132.

[0060] The holder housing part 132 has at least one housing groove 133, and the test piece holder 101 has at least one housing pin. The housing pin is slidable within the housing groove 133 in order to removably couple the test piece holder 101 to the holder housing part 132. The housing groove 133 is formed especially orthogonally to the impact direction 103. The holder housing part 132 can have, for example, in a horizontal plane, a plurality of housing grooves 133 extending orthogonally to the impact direction 103. Each housing pin of the test piece holder 101 slides through the groove along a direction orthogonal to the impact direction 103. Thus, in the test piece 102 being tested, the force induced by the impact of the rod device 110 is directed orthogonally to the sliding direction of the housing pin within the groove 132 so that the force can be directly transmitted from the test piece holder 101 to the entire recommended area 132.

[0061] The rod device 110 includes an impact element 111 having an impact part designed to be pressed against the test piece 102 being tested. Thereby, the rod device 110 is configured to move in a direction toward the test piece holder 101. The rod device 110 is driven by an electromechanical actuator 120 and can move relative to the test piece 102 at an adjustable speed and with an adjustable impact force.

[0062] The electromechanical actuator 120 can be, for example, an electric motor or a servo motor that drives the rod device 110 at a desired speed along the impact direction 103 using a desired impact force. In an exemplary embodiment, the electromechanical actuator 120 is a linear motor. The electromechanical actuator 120 is specifically configured to impart an impact energy of more than 100 J to the test piece 102.

[0063] The electromechanical actuator 120 is configured to move the rod device 110 at a speed exceeding at least 3 m / s. Therefore, a plurality of load conditions can be applied. For example, the rod device 110 can impart an impact to the test piece 102 at a high frequency, or the rod device 110 may be statically pressed against the test piece 102, or a static tensile / traction force may be applied to the test piece 102. Therefore, with the device 100 mentioned, it is possible to apply a plurality of different load conditions for material testing within one and the same device.

[0064] The device 100 is configured such that when the device 100 is placed on the ground, the impact direction 103 is parallel to the horizontal direction h. That is, the impact direction 103, and thus the moving direction of the rod device 110, is orthogonal to the direction of gravity (along the vertical direction v). By applying such a horizontal alignment of the rod device 110, the influence or disturbance caused by gravity along the impact direction 103 is minimal, so that the same movement or acceleration without being affected is possible in both directions. Therefore, a static test that applies a constant pressing force to the test piece 102 to be tested, and / or a dynamic test that changes the impact force within a predetermined time range can be provided. The electromechanical actuator 120 and the rod device 110 are configured to press the rod device 110 against the test piece 103 using a pressing force exceeding 5 kN.

[0065] Furthermore, the electromechanical actuator 120 is configured to move the rod device 110 along the impact direction 103 towards and away from the test piece holder 101. Therefore, it is possible not only to apply a pressing force to the test piece 102 in the direction towards the test piece 102, but also to apply a tensile force in the direction away from the test piece 102. Therefore, the device of the present invention can also provide a tensile test, as well as various load conditions between the pressing / bending test and the tensile test. To provide a tensile test, the rod device 110 can be firmly fixed to the test piece.

[0066] The rod device 110 has an impact element 111 and a force transmission rod 112 coupled to an electromechanical actuator 120. The impact element 111 is, in particular, harder than the test piece 102 to be tested. Further, the impact element 111 can include a longitudinally extending impact edge in the illustrated exemplary embodiment.

[0067] The force transmission rod 112 provides a connection between the impact element 111 and the electromechanical actuator 120. The force transmission rod 112 can be coupled to a movable part, for example, a sliding part 121 of the electromechanical actuator 120. The weight of the sliding part 121 exceeds 100 kg. Thus, a high impact energy is provided by a high mass, for example, exceeding 60 kg.

[0068] The impact element 111 is removably coupled to the force transmission rod 112. Thus, for example, in order to test the test piece 102 under different load conditions, it is possible to exchange the impact element 111 with different designs and shapes. Further, when the impact element 111 is damaged, each replacement of the impact element 111 is possible.

[0069] The rod device 110 further has a force sensor 113 for measuring the impact force between the impact element 111 and the test piece 102 to be tested. The force sensor 113 is disposed between the impact element 111 and the force transmission rod 112. Thus, when the force sensor 113 is disposed near the impact element 111, direct measurement of the force sensor 113 and further appropriate accessibility are also possible. Specifically, when the force sensor 113 is attached near the impact element 111 at the front, since no time delay of the force signal occurs during dynamic measurement, very accurate force measurement is provided.

[0070] The force sensor 113 is removably attached to at least one of the impact element 111 and the force transmission rod 112. The force sensor 113 can be a piezoelectric sensor or a DMS sensor.

[0071] In an exemplary embodiment, the electromechanical actuator 120 is a linear motor having a movable sliding part 121 to which the rod device 110 is coupled, and a stator 122 that extends along the impact direction 103. The sliding part 121 can be driven relative to the stator 122 along the impact direction 103 by an electromechanical driving force that can be generated between the stator 122 and the sliding part 121. The linear motor generates a linear driving force along its length and thus along the impact direction 103. A typical operating mode is a Lorentz type actuator, in which the applied force is linearly proportional to the current and the magnetic field. By means of the linear motor, the impact force and speed of the rod device 110 can be accurately adjusted.

[0072] The force transmission rod 112 is coupled to the movable sliding part 121. The force transmission rod 112 has a length particularly along the impact direction 103, and this length is longer than the moving distance of the sliding part 121 along the impact direction 103. Therefore, the maximum moving distance of the sliding part 121 can be used to move the rod device 110. This is because, due to the length of the force transmission rod 112, the impact element 111 arranged on the force transmission rod 112 does not collide with the structural elements of the linear motor.

[0073] In this embodiment, the stator 122 is made up of a rectangular stator table 123 and a further stator table 124. The stator tables 123, 124 have a length along the impact direction 103 and a width orthogonal to the impact direction 103, and the length is longer than the width of the stator tables 123, 124.

[0074] The sliding part 121 is slidably arranged between the stator table 123 and the further stator table 124. Therefore, by providing two stator tables 123, 124 that sandwich the sliding part 121, a stronger magnetic field for driving the sliding part 121 can be provided.

[0075] The sliding part 121 has magnet elements 127, in particular permanent magnet elements. The magnet elements 127 are arranged in sequence along the impact direction 103. The magnet elements 127 can form, for example, neodymium magnets. One row of magnets 127 can be arranged above the sliding part 121, and the other row of magnets 127 can be arranged below the sliding part 121. The sliding part 121 has a robust sliding plate between the two rows of magnets, in particular a metal plate made of, for example, aluminum, and the rows of magnets are arranged on opposite surfaces of the sliding plate.

[0076] The stator tables 123, 124 have conductive coils 125. Each coil 125 is around its respective stator table 123, 124 and generates the respective magnetic field necessary to interact with the magnets 127 of the sliding part 121 to generate a driving force. Specifically, three coil groups 125 can be provided on one of the stator tables 123, 124, whereby a three-phase linear induction motor can be provided. The conductive coils 125 are liquid-cooled, in particular water-cooled. In particular, when providing a static load condition in which the impact element 111 is pressed against the test piece 102 without moving at all, high temperatures may occur in each coil 125 that interacts with the sliding part 121.

[0077] Furthermore, the linear motor has a temperature sensor 126 for measuring the temperature of the coils 125. As described above, when providing a static load condition in which the impact element is pressed against the test piece without moving at all, high temperatures may occur in each coil 125 that interacts with the sliding part 121.

[0078] The device 100 further comprises a support base 130 on which the test piece holder 101, the rod device 110, and the electromechanical actuator 120 are (directly or indirectly via coupling support elements) attached. The support base 130 transmits the force of weight and dynamic forces to the ground respectively.

[0079] Furthermore, the support base 130 has at least one guiding rail 131 extending along the impact direction 103. The sliding part 121 of the electromechanical actuator 120 is slidably coupled to the guiding rail 131. The guiding rail 131 can have a dovetail shape, and the sliding part 121 can have dovetail grooves shaped respectively to provide a slidable coupling, and vice versa. The guiding rail 131 is directly coupled to the support base 130 via a support structure and may also be fixed to the stator tables 123, 124 to support the sliding part 121 and the rod device 110. The stator tables 123, 124 are coupled to the support base 131 via a support structure, for example. The support structure may be part of the support base 130.

[0080] The apparatus 100 can further include a housing 201 that houses the electromagnetic actuator 120.

[0081] FIG. 3 shows an apparatus 100 according to an exemplary embodiment of the present invention, particularly provided with a support base 130. The support base 130 is configured to provide a rigidity exceeding 600 kN / mm. Thus, high-weight forces, and further dynamic forces, can be transmitted to the ground without generating vibrations that could adversely affect the test procedure. The support base 130 is robustly formed, for example, by a framework 303 of steel rods that can be placed on the ground. This rigidity can be further provided by the robust framework 303 of the steel beams described above and by the vertical shear panels 302.

[0082] The vertical shear panel 302 extends between the ground on one side and the specimen holder 101, the rod device 110, and the electromechanical actuator 130 on the other side (and, for example, between the support plate 134 and the ground). The shear panel 302 is, in particular, a vertically oriented sheet, in particular a metal sheet. By providing the vertical shear panel 302, forces (in particular shear forces) that spread along the vertical direction v and further along the impact direction 103 are absorbed and attenuated by the vertical shear panel 302. According to a further exemplary embodiment, the shear panel 302 is configured to have a natural frequency exceeding 300 Hz along the impact direction 103.

[0083] The support base 130 has, in particular, a support plate 134, in particular an aluminum plate, to which at least the specimen holder 101 and the electromechanical actuator 120 are attached. The support plate 134 forms a robust and rigid receiving surface and can be arranged on the strong framework 303 of the steel beam of the support base 130. By arranging the support plate 134 in the horizontal plane, forces directed along the horizontal direction h are effectively attenuated and absorbed.

[0084] The device 100 further comprises at least one stopper element 301 configured to stop the movement of the sliding part 121 along the impact direction 103, and the stopper element 301 is made, in particular, of an elastomeric material. The stopper element may be fixed to the housing 201 of the device 100 and / or directly or indirectly fixed to the support base 130. The housing 201 may further have a robust rear plate 304 and a robust front plate 305, to which the stopper element 301 is attached to limit the movement of the sliding part 121.

[0085] Figures 4 and 5 show an exemplary embodiment of an apparatus 100 that provides a rod apparatus 110 for applying a traction force FT to a test piece 102. The test piece holder 101 is fixed to the receiving part / plate 132. Further, the test piece holder 101 has a clamping element 402, for example a clamping jaw, which clamps the test piece 102 so as not to be movable with respect to the support base 130. A gripping element 401 is arranged away from the clamping element 402 and is provided on the movable force transmission rod 112. For example, the gripping element 401 is attached to the free end of the force transmission rod 112. Specifically, the force transmission rod 112 has a split part and forms a fork-shaped end. The fork-shaped end 403 passes through the test piece 102. A gripping element 401 is arranged at the end of the fork-shaped end 403. The gripping element 401 grips the test piece 102 that is arranged away from the clamping part of the clamping element 402. The gripping element 401 can fix the test piece 102, for example, by clamping or by form-fit fixing. Therefore, when the force transmission rod 112 moves out from the housing 201 and thus along the respective horizontal movement directions, the gripping element 401 moves away from the clamping element 402, whereby the traction force FT is transmitted to the test piece 102 to be tested.

[0086] Note that the term "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. Also, elements described in connection with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the claims.

Description of Reference Signs

[0087] 100 Apparatus 101 Test piece holder 102 Test piece 103 Impact direction 110 Rod apparatus 111 Impact element 112 Force transmission rod 113 Force sensor 120 Electromechanical actuator 121 Sliding part 122 Stator 123 Stator table 124 Further stator table 125 Coil 126 Temperature sensor 127 Magnet element 130 Support base 131 Inductive rail 132 Accommodating part 133 Accommodating groove 134 Support plate 201 Housing 301 Stopper element 302 Shear panel 303 Framework 304 Rear plate 305 Front plate 401 Gripping element 402 Clamping element 403 End part v Vertical direction h Horizontal direction FT Traction force

Claims

1. An apparatus for material testing of test specimens, comprising: a test specimen holder device having a test specimen holder for holding a test specimen to be tested; a rod device that moves relative to the test specimen holder to transmit a mechanical load to the test specimen; and an electromechanical actuator device that moves at least one of the rod device and the test specimen holder device relative to each other along a longitudinal impact direction. The electromechanical actuator device is configured to adjust the speed between 0 m / s and 12 m / s between the rod device and the test specimen holder device in order to transmit a mechanical load to the test specimen. Device.

2. The apparatus according to claim 1, wherein when the apparatus is disposed on the ground, the longitudinal impact direction is parallel to the horizontal direction.

3. The apparatus according to claim 1 or 2, wherein the test specimen holder device, the electromechanical actuator device, and the rod device are configured to press the rod device against the test specimen with a pressing force exceeding 5 kN, particularly exceeding 15 kN, and more particularly exceeding 25 kN.

4. The apparatus according to claim 1 or 2, wherein the electromechanical actuator device and the rod device are configured to perform a static test of applying a pressing force to the test specimen to be tested and / or a dynamic test of changing the impact force within a predetermined time range.

5. The apparatus according to claim 1 or 2, wherein the electromechanical actuator device has an electromechanical actuator configured to move the rod device along the longitudinal impact direction toward and away from the test specimen holder, particularly for performing a static test or a repeated test of applying various loads to the test specimen.

6. The apparatus according to claim 1 or 2, further comprising an electromechanical actuator configured to move the test specimen holder device along the longitudinal impact direction toward and away from the rod device, particularly for performing a static test, a dynamic test, or a repeated test of applying various loads to the test specimen.

7. The apparatus according to claim 1 or 2, wherein the rod device has a rigidity exceeding 400 kN / mm.

8. The apparatus according to claim 5, wherein the rod device has an impact element and a force transmission element coupled to the electromechanical actuator, particularly a force transmission rod.

9. ​ The device according to claim 8, wherein the impact element is removably coupled to the force transmission element.

10. The device according to claim 8, wherein the rod device further comprises a force sensor for measuring an impact force between the impact element and the test piece to be tested.

11. The device according to claim 10, wherein the force sensor is disposed between the impact element and the force transmission element.

12. The device according to claim 10, wherein the force sensor is removably attached to at least one of the impact element and the force transmission element.

13. The device according to claim 10, wherein the force sensor is a piezoelectric sensor.

14. The electromechanical actuator is a linear motor having a movable sliding part to which the rod device is coupled and a stator extending along the longitudinal impact direction, The device according to claim 5, wherein the movable sliding part is drivable relative to the stator along the longitudinal impact direction by an electromechanical driving force that can be generated between the stator and the movable sliding part.

15. The rod device has an impact element and a force transmission element, in particular a force transmission rod, coupled to the electromechanical actuator, The force transmission element is coupled to the movable sliding part, The device according to claim 14, wherein the force transmission element has a length along the longitudinal impact direction, and the length is longer than a moving distance of the movable sliding part along the longitudinal impact direction.

16. The device according to claim 14, wherein the stator has a rectangular stator table in particular.

17. The stator table has a length along the longitudinal impact direction and a width orthogonal to the longitudinal impact direction, The device according to claim 16, wherein the length is longer than the width of the stator table.

18. The device according to claim 16, wherein the stator table has at least one conductive coil.

19. The device according to claim 18, wherein the at least one conductive coil is liquid-cooled, in particular water-cooled.

20. The device according to claim 18, wherein the linear motor has a temperature sensor for measuring the temperature of the at least one coil.

21. The stator has a further rectangular stator table in particular, which particularly includes at least one further conductive coil. The device according to claim 18, wherein the movable sliding part is slidably arranged between the stator table and the further stator table.

22. The device according to claim 14, wherein the movable sliding part has a magnet element, in particular a permanent magnet element.

23. The device according to claim 22, wherein the magnet elements are arranged in sequence along the longitudinal impact direction.

24. The device according to claim 14, wherein the weight of the movable sliding part exceeds 60 kg, 80 kg, or 100 kg.

25. Further comprising at least one stopper element configured to stop the movement of the movable sliding part along the longitudinal impact direction, The device according to claim 15, wherein the stopper element is made of an elastomer material in particular.

26. The device according to claim 1 or 2, further comprising a support base to which the test piece holder, the rod device, and the electromechanical actuator device are attached.

27. Further comprising at least one guide rail extending along the longitudinal impact direction, The guide rail is coupled to the support base, The device according to claim 26, wherein the movable part of the rod device and / or the electromechanical actuator is slidably coupled to the guide rail.

28. The device according to claim 26, wherein the support base is configured to provide a rigidity exceeding 600 kN / mm along the longitudinal impact direction.

29. The device according to claim 26, wherein the support base has a support plate, in particular an aluminum plate, to which at least the test piece holder device and the electromechanical actuator device are attached.

30. The support base has at least one vertical shear panel extending between the ground on one side and the test piece holder device, the rod device, and the electromechanical actuator device on the other side, The device according to claim 26, wherein the shear panel is a vertical sheet, in particular a metal sheet.

31. The device according to claim 30, wherein the shear panel is configured to have a natural frequency exceeding 300 Hz along the longitudinal impact direction.

32. The device according to claim 26, wherein the test piece holder device is removably coupled to a holder receiving portion of the support base.

33. The holder receiving portion has at least one receiving groove, The test piece holder device has at least one receiving pin, the receiving pin being slidable within the receiving groove for removably coupling the test piece holder device to the holder receiving portion, the device according to claim 32, wherein the receiving groove is formed particularly orthogonally to the longitudinal impact direction. **Claim 34** The device according to claim 1 or 2, wherein the test piece to be tested is a battery device. **Claim 35** A method for material testing of a test piece by means of the device according to claim 1 or 2, comprising: attaching a test piece to be tested to the test piece holder, and moving at least one of the rod device and the test piece holder relative to each other so that the rod device transmits a mechanical load to the test piece for material testing of the test piece, and adjusting the speed to an arbitrary speed between 0 m / s and 12 m / s. A method comprising the steps.

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