Method and test device for determining mechanical properties of a workpiece by dynamic loading

Abstract

Method for determining mechanical properties of a workpiece (10) by dynamic loading of a test body (12) which comprises the workpiece (10), wherein the sample body (12) is fixed to a holding unit (20) of a test device (100) and is connected to a pulling unit (22) which is subjected to an impact load by a moving impact unit (32), wherein a force and / or acceleration exerted on the holding unit (20) when the impact unit (32) hits the pulling unit (22) is detected, wherein an acceleration exerted on the impact unit (32) is detected, characterized in that the workpiece (10) is mechanically connected to the sample body (12) via one or more joining connections (18) and / or is formed with joining connections (18), wherein, if possible, uniaxial stress states are dynamically introduced into a joining area of ​​the one or more joints (18) via the impact unit (32) into the test body (12), wherein the mechanical properties of the workpiece (10) are determined by adapting a simulation model to the detected values ​​of the force and / or acceleration on the holding unit (20) and / or the impact unit (32).

Description

State of the art

[0001] The invention relates to a method and a test device for determining mechanical properties of a workpiece by dynamic loading of a sample body as well as a computer program product and a device for data processing.

[0002] The development of material maps for crash simulations in the automotive sector is a highly challenging task due to the complexity of modeling the highly nonlinear material behavior. Extensive material tests are required to derive these characteristics. This requires various tests, some of which must be conducted quasi-statically and some dynamically. Each of these tests must be set up in a virtual environment to determine and validate the necessary input parameters through virtual testing. This is further complicated by the fact that some material values, such as damage parameters or crack energies, can only be adjusted via calibration. These must be increasingly approximated through a complex iterative process.In the automotive industry, this means that material cards for crash applications are an important part of a vehicle manufacturer's core know-how, because a detailed crash description can significantly reduce development times and thus costs.

[0003] DE 10 2005 048 251 B4 discloses a method for determining the mechanical properties of a material. A test specimen made of the material to be tested is dynamically loaded, and measured values ​​characterizing the load are recorded. These measured values ​​are then further processed in a computer. Based on computer-stored initial data on the test specimen and / or its material, a step-by-step approximation of the data determined by the simulation to the measured values ​​is carried out using an iterative calculation method that runs automatically during or immediately after the load and performs simulations. The test specimen is subjected to a mechanical shock load by a pendulum impact tester, and at least an acceleration and a force and / or strain of the test specimen are measured by means of a sensor.This measurement data is used to adapt the simulation to the measurement. The calculation method numerically simulates the behavior of the specimen under the applied load by dividing the specimen into sub-sections.

[0004] DE 10 2006 043 912 B4 further discloses a pendulum impact tester for material testing and determining the mechanical properties of a material that loads a test specimen by impact. Two pendulums are provided that can move toward each other. The test specimen can be attached to the end piece of one pendulum in such a way that, when the two pendulums collide, the test specimen is loaded with the relative speed of the pendulums. The pendulums are arranged to rotate around a common axis.

[0005] DD 2 39 040 A1 discloses a device with a pendulum for quality testing of welded or sealed seams. The device examines the peel forces transmitted through the weld immediately after the joining process. Disclosure of the invention

[0006] The object of the invention is to provide an improved method for determining mechanical properties of a workpiece by dynamic loading.

[0007] A further object is to provide a test device for determining mechanical properties of a workpiece by dynamic loading using such an improved method.

[0008] A further object is to provide a computer program product and a data processing device for such an improved method.

[0009] The objects are achieved by the features of the independent claims. Advantageous embodiments and advantages of the invention emerge from the further claims, the description, and the drawings.

[0010] According to one aspect of the invention, a method is proposed for determining the mechanical properties of a workpiece by dynamically loading a specimen comprising the workpiece. The specimen is fixed to a holding unit of a testing device and connected to a tensile unit, which is subjected to an impact load by a moving impact unit. A force and / or acceleration exerted on the holding unit upon impact of the impact unit on the tensile unit is recorded, and an acceleration exerted on the impact unit is recorded.

[0011] The workpiece is mechanically connected to the specimen via one or more joints and / or formed with joints.

[0012] Uniaxial stress states, if possible, are dynamically introduced into the joining area of ​​one or more joints via the impact unit into the specimen. The mechanical properties of the workpiece are determined by adapting a simulation model to the recorded force and / or acceleration values ​​at the holding unit and / or the impact unit.

[0013] By mechanically connecting the workpiece to the specimen via one or more joints, or alternatively or additionally forming one or more joints, it is possible to advantageously examine joints that exist between a workpiece and, for example, a sample element as part of the specimen, or with which the workpiece is secured in the specimen. However, it is also possible for the workpiece itself to have joints that are examined.

[0014] The proposed method advantageously enables an automated material card derivation process through a closed process flow between material characterization tests and an automated material card optimization process. Material characterization consists of clearly defined quasi-static and dynamic so-called coupon tests on a test device, in which the material behavior and failure are determined using material samples under clearly defined boundary conditions.

[0015] The method can be used to generate dynamic tests and thus velocity-dependent sample loads. The test device enables the mechanical characterization of dynamically loaded material samples or small components under defined uniaxial or biaxial stress conditions.

[0016] For this purpose, the test device can, for example, comprise at least one force measuring unit and / or at least one acceleration measuring unit, which are mechanically connected to the holding unit. Furthermore, the test device can comprise at least one further acceleration measuring unit, which is mechanically connected to the impact unit.

[0017] The test data can be advantageously processed in an optimization environment. For example, an interface between the test data, an explicit simulation environment, and a metamodel-based optimizer can be used. By combining predefined coupon tests and defined interfaces to an explicit solution algorithm, numerical material descriptions can be automatically generated and directly validated using this process.

[0018] Depending on the material, the structural application, and the dominant failure characteristic, different material loads are required to describe the material behavior. The test fixture provides different clamping systems, which can be selected to optimize the parameters. This allows for advantageous application of different loads, from compression and tension to bending. This is made possible by adapting the specimen clamping and impact unit.

[0019] The proposed method for deriving material maps can be advantageously used in the area of ​​joints. Adapted clamping concepts for the workpiece can be advantageously used. The aim here is to achieve as uniaxial stress states as possible in the joining area, with this load being dynamically introduced into the specimen via the impact unit. An adapted optimization model is advantageously used to determine the necessary characteristics. Compared to the state of the art, this involves at least two specimen elements with a joining area. The focus is on the joining element and not the material to be joined.

[0020] The impact unit, specimen definitions, and clamping of the test fixture can be adapted to joints. Joints are subject to various loading conditions, such as tension, peeling, shear, and torsion, which can lead to joint failure and must be determined separately. However, each of these values ​​already provides a partial range of a joint, which may result in only dominated failure values ​​being determined for the simulation, while others, such as torsion, are only considered elastically.

[0021] The focus here can be on surface joining connections such as adhesives, but also on point joining elements such as rivets and screws.

[0022] Advantageously, the proposed method can be used to determine dynamic bonding behavior or material behavior on and with a workpiece as input for numerical material card calibrations and for determining dynamic strengths.

[0023] The workpiece represents the material element or joining element to be determined. This can represent at least one of the following material elements or connecting elements: a large-volume material element, for example a foam core, a thick plastic, a filler, or the like; a point-like connecting element, for example a rivet, a weld spot, or the like; a linear connecting element, for example welds; a flat connecting element, for example adhesive joints; a cover layer connection. In this case, the workpiece represents both material, for example a foam core, and an adhesive joint, with the material-to-cover layer connection being analyzed. Joining connections to be examined can also be arranged at the connection of the workpiece to the two sample elements and / or to the holding unit and / or tensile unit.

[0024] According to a favorable embodiment of the method, the workpiece can be formed with at least two materials and / or structures, which are connected by point-like and / or linear and / or planar joints. Using the proposed method, very different types of joints can be examined and the corresponding material characteristics derived from them.

[0025] According to a favorable embodiment of the method, the workpiece can be connected to the specimen and / or the holding unit and / or the tensile unit by at least two point-like and / or linear and / or planar joining connections. Thus, joining connections can be used directly to secure the workpiece in the specimen or in the holding unit or in the tensile unit. In this way, different requirements for joining connections can be advantageously tested.

[0026] With a favorable design of the method, the workpiece and / or the joint can be subjected to shear or tensile loading. This allows different types of loading on joints, such as tension, peeling, shear, or torsion, which can lead to joint failure, to be determined separately.

[0027] In a favorable design of the method, the workpiece and / or the joint can be subjected to peeling or torsion loading. This allows different types of loading on joints, such as tension, peeling, shear, or torsion, which can lead to joint failure, to be determined separately.

[0028] According to a favorable design of the process, parameters of the simulation model can be adapted to the recorded values ​​of the force and / or acceleration on the holding unit and / or the impact unit using an optimization procedure. The test data can advantageously be processed in an optimization environment. For example, an interface between the test data, an explicit simulation environment, and a metamodel-based optimizer can be used. By combining predefined coupon tests and defined interfaces to an explicit solution algorithm, numerical material descriptions can be automatically created and directly validated using this process. The adjusted parameters can advantageously provide the desired material characteristics.

[0029] According to a favorable embodiment of the method, the mechanical properties of the workpiece can be determined using at least one material test from the group of shear calibration, double shear calibration, tensile calibration, detachment calibration, peel calibration, and torsion calibration. In this way, different types of loading on joints, such as tension, peel, shear, or torsion, which can lead to joint failure, can be determined separately.

[0030] According to a further aspect of the invention, a test device for determining the mechanical properties of a workpiece by dynamic loading is proposed, comprising a holding unit for positioning a sample body comprising the workpiece, a tensile unit for absorbing an impact load, wherein the sample body is fixed to the holding unit and connected to the tensile unit, a loading device for impact loading the tensile unit by means of a moving impact unit, and a data processing device for recording and / or simulating force and / or acceleration data. At least one force measuring unit and / or at least one first acceleration measuring unit are arranged on the holding unit, which determine a force and / or acceleration exerted on the holding unit upon impact of the impact unit.At least one second acceleration measuring unit is arranged on the impact unit, which determines the acceleration exerted on the impact unit. The data processing device has a program running therein that is designed to determine the mechanical properties of the workpiece.

[0031] The workpiece is mechanically connected to the specimen via one or more joints and / or formed with joints.

[0032] Uniaxial stress states, if possible, are dynamically introduced into the joining area of ​​one or more joints via the impact unit into the specimen. The mechanical properties of the workpiece are determined by adapting a simulation model to the recorded force and / or acceleration values ​​at the holding unit and / or the impact unit.

[0033] By mechanically connecting the workpiece to the specimen via one or more joints, or alternatively or additionally forming one or more joints, it is possible to advantageously examine joints that exist between a workpiece and, for example, a sample element as part of the specimen, or with which the workpiece is secured in the specimen. However, it is also possible for the workpiece itself to have joints that are examined.

[0034] The proposed test device advantageously enables an automated material card derivation process through a closed process flow between material characterization tests and an automated material card optimization procedure. Material characterization consists of clearly defined quasi-static and dynamic coupon tests on the test device, in which the material behavior and failure are determined using material samples under clearly defined boundary conditions.

[0035] Depending on the material, the structural application, and the dominant failure characteristic, different material loads are required to describe the material behavior. The test fixture provides different clamping systems, which can be selected to optimize the parameters. This allows for advantageous application of different loads, from compression and tension to bending. This is made possible by adapting the specimen clamping and impact unit.

[0036] The proposed test device can be advantageously used for material mapping in the area of ​​joints. Adapted clamping concepts for the workpiece can be advantageously used. The aim here is to achieve as uniaxial stress states as possible in the joining area, with this load being dynamically introduced into the specimen via the impact unit. An adapted optimization model is advantageously used to determine the necessary characteristics. Compared to the state of the art, this involves at least two specimen elements with a joining area. The focus is on the joining element and not the material to be joined.

[0037] The impact unit, specimen definitions, and clamping of the test fixture can be adapted to joints. Joints are subject to various loading conditions, such as tension, peeling, shear, and torsion, which can lead to joint failure and must be determined separately. However, each of these values ​​already provides a partial range of a joint, which may result in only dominated failure values ​​being determined for the simulation, while others, such as torsion, are only considered elastically.

[0038] The focus here can be on surface joining connections such as adhesives, but also on point joining elements such as rivets and screws.

[0039] Advantageously, the proposed test device can be used to determine dynamic bonding behavior or material behavior on and with a workpiece as input for numerical material card calibrations and for determining dynamic strengths.

[0040] The workpiece represents the material element or joining element to be determined. This can represent at least one of the following material elements or connecting elements: a large-volume material element, for example a foam core, a thick plastic, a filler, or the like; a point-like connecting element, for example a rivet, a weld spot, or the like; a linear connecting element, for example welds; a flat connecting element, for example adhesive joints; a cover layer connection. In this case, the workpiece represents both material, for example a foam core, and an adhesive joint, with the material-to-cover layer connection being analyzed. Joining connections to be examined can also be arranged at the connection of the workpiece to the two sample elements and / or to the holding unit and / or tensile unit.

[0041] The test device can be used to generate dynamic tests and thus speed-dependent sample loads. The test device enables the mechanical characterization of dynamically loaded material samples or small components under defined uniaxial or biaxial stress conditions.

[0042] For this purpose, the test device can, for example, comprise at least one force measuring unit and / or at least one acceleration measuring unit, which are mechanically connected to the holding unit. Furthermore, the test device can comprise at least one further acceleration measuring unit, which is mechanically connected to the impact unit.

[0043] According to a favorable design of the test device, the data processing device can be configured to adapt parameters of a simulation model to the recorded values ​​of the force and / or acceleration on the holding unit and / or the impact unit. The test data can advantageously be processed in an optimization environment. For example, an interface between the test data, an explicit simulation environment, and a metamodel-based optimizer can be used. By combining predefined coupon tests and defined interfaces to an explicit solution algorithm, numerical material descriptions can be automatically created and directly validated using this process. The adapted parameters can advantageously provide the desired material characteristics.

[0044] According to a favorable design of the test device, the workpiece can comprise at least two materials and / or structures connected by point-like and / or linear and / or planar joints. Thus, joints can be used directly to secure the workpiece in the specimen, the holding unit, or the tensile unit. In this way, different requirements for joints can be advantageously tested.

[0045] According to a favorable design of the test device, the workpiece can be connected to the specimen and / or the holding unit and / or the tensile unit by at least two point-like and / or linear and / or planar joints. Thus, joints can directly secure the workpiece in the specimen or in the holding unit or in the tensile unit. In this way, different requirements for joints can be advantageously tested.

[0046] According to a favorable design of the test device, the loading device can comprise a pendulum arm that can pivot about a rotational axis, with the impact unit located at one end of the pendulum arm. The pendulum arm can be used to conduct dynamic tests and thus generate velocity-dependent sample loads. The pendulum arm thus advantageously enables the mechanical characterization of dynamically loaded material samples or small components under defined uniaxial or biaxial stress conditions.

[0047] According to a favorable embodiment of the test device, the loading device can have an angle measuring unit. In particular, an angle measuring unit can be arranged on a rotational axis of the pendulum arm of the loading device. In this way, speed and acceleration values ​​of the loading device, and in particular of the impact unit, can advantageously be determined and used in the simulation to determine the material parameters.

[0048] According to a favorable design of the test device, the impact unit can have two impact elements that apply symmetrical loads to the tensile unit in the direction of movement of the impact unit. This allows a double, bilateral thrust to be applied to the workpiece with the joint.

[0049] According to a favorable embodiment of the test device, the sample body can comprise at least a first sample element and a second sample element, with the workpiece arranged between the first sample element and the second sample element. The first sample element can be connected to the holding unit, and the second sample element can be connected to the tensile unit. In this way, different types of loading on joints, such as tension, peeling, shear, or torsion, which can lead to joint failure, can be determined separately.

[0050] According to a favorable embodiment of the test device, the sample body can have at least a second sample element, wherein the workpiece is arranged between the second sample element and the holding unit.

[0051] The workpiece can be connected to the holding unit, and the second specimen element can be connected to the tensile unit. In this way, different types of loading, such as tension, peeling, shear, or torsion, which can lead to joint failure, can be determined separately.

[0052] According to a favorable design of the test device, the workpiece can be connected to the holding unit and the tensile unit. This advantageously allows for the formation of joints between the workpiece and the holding unit or between the workpiece and the tensile unit, which can be advantageously characterized in this way.

[0053] According to a further aspect of the invention, a computer program product is proposed which comprises commands or control instructions which, when executed by a computer, in particular a data processing device or the data processing unit mentioned in connection with the method according to the invention, cause this computer to execute at least one variant of the method according to the invention, in particular automatically or semi-automatically. The computer program product according to the invention can be a computer program. The method according to the invention can therefore therefore be wholly or partially computer-implemented or computer-implementable, i.e. can be encoded or represented by such a computer program or a corresponding program code. Likewise, the computer program product according to the invention can be a computer-readable data carrier on which a corresponding computer program is stored.

[0054] According to a further aspect of the invention, a data processing device is proposed. This device has means for executing, in particular in an automated or semi-automated manner, at least one variant of the method according to the invention. These means can in particular be the means described in connection with the aforementioned data processing device. The device according to the invention can therefore in particular have a corresponding processor, a data memory, and at least one input and / or output interface for executing the method or the corresponding computer program or program code. In particular, the device according to the invention can comprise the computer program product according to the invention.

[0055] Since the device according to the invention can therefore be set up in particular to carry out the method according to the invention and the method according to the invention can therefore be carried out by means of the device according to the invention, the device according to the invention can accordingly have some or all of the properties and / or features described in connection with the method according to the invention. drawing

[0056] Further advantages will become apparent from the following description of the drawings. The figures illustrate exemplary embodiments of the invention. The figures, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0057] Examples include: Fig. 1 Sample body and impact unit of a test device for determining mechanical properties of a workpiece by shear loading of a sample body according to an embodiment of the invention in a schematic plan view; Fig. 2 the test device according to Fig. 1 in a schematic side view; Fig. 3 the test device according to Fig. 2 with a data processing device in an isometric view; Fig. 4 Sample body and impact unit for a double shear load according to another embodiment of the invention in a plan view; Fig. 5 Sample body and impact unit for a tensile / separation load according to a further embodiment of the invention in a plan view; Fig. 6 Sample body and impact unit for a tensile / separation load according to a further embodiment of the invention in a plan view; Fig. 7 Sample body and impact unit for a tensile load and / or detachment load according to a further embodiment of the invention in a plan view; Fig. 8 Sample body and impact unit for a peeling load according to a further embodiment of the invention in a plan view; Fig. 9 Test specimen and impact unit for a peeling load according to Fig. 8 in a side view; Fig. 10 Test specimen and impact unit for a torsional load according to a further embodiment of the invention in a front view; Fig. 11 Test specimen and impact unit for a torsional load according to Fig. 10 in a plan view; Fig. 12 shows a process flow for automated material card generation according to an embodiment of the invention; and Fig. 13 a schematic representation of a data processing device for carrying out a method for determining mechanical properties of a workpiece by dynamic loading. Embodiments of the invention

[0058] In the figures, components of the same type or function similarly are designated by the same reference numerals. The figures are merely examples and are not to be construed as limiting.

[0059] The directional terminology used below, including terms such as "left," "right," "top," "bottom," "before," "behind," "after," and the like, is intended solely to enhance understanding of the figures and is in no way intended to limit the scope of the invention. The components and elements depicted, as well as their design and use, may vary according to the considerations of a person skilled in the art and may be adapted to specific applications.

[0060] Fig. 1 shows sample body 12 and impact unit 32 of a test device 100 for determining mechanical properties of a workpiece 10 by shear loading of a sample body 12 according to an embodiment of the invention in a schematic plan view, while in Fig. 2 the test device 100 is shown in a schematic side view. Fig. 3 shows the test device 100 with a data processing device 500 in an isometric view.

[0061] In Fig. Figure 3 defines the various views of the test device 100. A top view represents a view in the Z direction, a side view represents a view in the Y direction, and a front view represents a view in the X direction.

[0062] The test device 100 comprises a holding unit 20 for positioning the sample body 12, which comprises the workpiece 10, and a tensile unit 22 for absorbing an impact load. The sample body 12 is fixed to the holding unit 20 and connected to the tensile unit 22. The test device 100 further comprises a loading device 30 for applying an impact load to the tensile unit 22 by means of a moving impact unit 32, as well as a data processing device 500 for recording and / or simulating force and / or acceleration data.

[0063] At least one force measuring unit 50 and / or at least one first acceleration measuring unit 52 are arranged on the holding unit 20, which determine a force and / or acceleration exerted upon impact of the impact unit 32 on the holding unit 20. The force measuring unit 50 and the acceleration unit 52 are each shown schematically. At least one second acceleration measuring unit 54 is arranged on the impact unit 32, which determines an acceleration exerted on the impact unit 32.

[0064] The data processing device 500 has a program running therein which is designed to determine the mechanical properties of the workpiece 10.

[0065] The loading device 30 has a pendulum arm 38, which is pivotable about a rotation axis 40. The impact unit 32 is arranged at an end piece 42 of the pendulum arm 38.

[0066] The loading device 30 further comprises an angle measuring unit 56, which is arranged on a rotation axis 40 of the pendulum arm 38 of the loading device 30.

[0067] The data processing device 500 is designed to adapt parameters of a simulation model to the detected values ​​of the force and / or acceleration at the holding unit 20 and / or the impact unit 32.

[0068] The dynamic characterization of joints places special demands and derived characteristics on the impact unit 32 to be impacted, on the sample geometry and on the underlying clamping of the workpiece 10 or the sample body 12.

[0069] The mechanical properties of the workpiece 10 can be determined with the proposed test device 100 by means of at least one material test from the group of shear calibration, double shear calibration, tensile calibration, detachment calibration, peel calibration, torsion calibration.

[0070] The characteristics of the clamping system vary depending on the load cases or the joint being examined. The joint can be divided into point joints, such as rivets, screws, spot welding, and the like, and surface joints, such as adhesive bonds or welded joints, such as laser welding.

[0071] In the Fig. 1 and Fig. In the embodiment shown in Figure 2, the impact unit 32 has two impact elements 34, 36, which symmetrically load the traction unit 22 in the direction of movement 62 of the impact unit 32. Depending on the type of load test, the impact unit 32 can be designed differently.

[0072] The sample body 12 has a first sample element 14 and a second sample element 16. The workpiece 10 is arranged between the first sample element 14 and the second sample element 16. The first sample element 14 is connected to the holding unit 20, and the second sample element 16 is connected to the tensile unit 22.

[0073] The workpiece 10 is mechanically firmly connected to the test specimen 12 via joining connections 18.

[0074] The workpiece 10 represents the material element or joining element to be examined. This can represent at least one of the following material elements or connecting elements: a large-volume material element, for example a foam core, a thick plastic, a filler, or the like; a point-type connecting element, for example a rivet, a weld spot, or the like; a linear connecting element, for example welds; a planar connecting element, for example adhesive joints; a cover layer connection. In this case, the workpiece 10 represents both material, for example a foam core, and an adhesive joint, whereby the connection between the material and the cover layer can be analyzed. Joining connections to be examined can also be arranged at the connection of the workpiece to the two sample elements and / or to the holding unit and / or tensile unit.

[0075] Furthermore, the workpiece 10 itself can have joints 18, which can be subject to load tests. For example, the workpiece 10 can be designed as a connecting element or sandwich core element, or as an adhesive area.

[0076] Furthermore, the workpiece 10 can comprise at least two materials and / or structures which are connected by point-shaped and / or linear and / or planar joining connections 18.

[0077] The workpiece 10 can also be connected to the sample body 12 and / or the holding unit 20 and / or the pulling unit 22 by at least two point-shaped and / or linear and / or planar joining connections 18.

[0078] In the Fig. 1 and Fig. In the embodiment shown in Figure 2, the workpiece 10 is connected to the first sample element 14 via a joint 18. The first sample element 14 is attached to the holding unit 20. The holding unit 20 itself is firmly connected to a base plate 28.

[0079] Furthermore, the workpiece 10 is connected to the second sample element 16 via a joining connection 18. The second sample element 16 itself is connected to the pulling unit 22 via a connecting element 24. The second sample element 16 is supported on the base plate 28 via a support element 26, but can move freely in the direction of movement 60.

[0080] The pendulum arm 38 is connected to a fixed bearing 44 via a rotation axis 40. The angle measuring unit 56 is coupled to the pendulum arm 38 via the rotation axis 40.

[0081] The impact unit 32 has two impact elements 34, 36, which are connected via and to the second acceleration unit 54. As in Fig. As can be seen in Figure 2, the impact unit 32 is arranged at the end piece 42 of the pendulum arm 38. Depending on the type of load test, the impact unit 32 can be designed differently. Thus, the two impact elements 34, 36 can be arranged one above the other with respect to the pivoting plane of the pendulum arm 38, or even side by side.

[0082] According to the proposed method for determining mechanical properties of the workpiece 10 by dynamically loading the specimen 12 comprising the workpiece 10, the specimen 12 is fixed to the holding unit 20 of the test device 100 and connected to the tensile unit 22. The tensile unit 20 is subjected to an impact load by the moving impact unit 32. In this process, a force and / or acceleration exerted on the holding unit 20 when the impact unit 32 strikes the tensile unit 22 is recorded. Furthermore, an acceleration exerted on the impact unit 32 is recorded.

[0083] The mechanical properties of the workpiece 10 are then determined by adapting parameters of a simulation model to the recorded values ​​of the force and / or acceleration at the holding unit 20 and / or the impact unit 32.

[0084] The Fig. 1 and Fig. The embodiment shown in Figure 2 serves to investigate the effect of a shear load on the workpiece 10 or on joints in the workpiece 10 and / or with holding unit 20 and tensile unit 22. The workpiece 10 and / or the joint 18 can be subjected to shear or tensile loads.

[0085] During the measurement, the pendulum arm 38 is deflected from a vertical position and released. Due to gravity, the pendulum arm then performs a pendulum movement 64 back to the vertical and beyond. The impact elements 34, 36 of the impact unit 32 move in the direction of movement 62 past the holding unit 20, leaving the specimen 12 between them, and finally strike the tensile unit 22. The tensile unit 22 is thereby loaded in the direction of movement 60. This tensile load acts via the second specimen element 16, the workpiece 10, the first specimen element 14, the holding element 20, and the respective joints therebetween. These joints are subjected to shear stress.

[0086] The force values ​​determined with the force measuring unit 50 as well as the acceleration values ​​determined with the first acceleration measuring unit 52 and the second acceleration measuring unit 54 are registered with the data processing device 500.

[0087] The data processing device 500 can have a simulation model of the experimental setup, the parameters of which are adapted to the measured values ​​of force and acceleration. Parameters of the simulation model can be adapted, in particular by means of an optimization method, to the recorded values ​​of force and / or acceleration on the holding unit 20 and / or the impact unit 32. Depending on the level of detail of the simulation model, the joints can then be characterized using measurements with different force and acceleration values. In this way, mechanical properties of workpieces 10 with joints can advantageously be determined.

[0088] The Fig. 1 and Fig. The embodiment shown in Figure 2 serves as an experimental setup for an automated thrust calibration.

[0089] Fig. 4 shows test specimen 12 and impact unit 32 for a double shear load according to another embodiment of the invention in a plan view.

[0090] The Fig. The embodiment shown in Figure 4 serves as an experimental setup for an automated dynamic double thrust calibration, for example on an adhesive bond.

[0091] In this embodiment, the workpiece 10 is constructed in two parts. Both parts are arranged on either side of the first sample element 14, which is fixed to the holding unit 20. The outer sides of the two parts of the workpiece 10 are each connected to a second sample element 16, which in turn is fixed to the tensile unit 22 via connecting elements 24. In this way, the two impact elements 34, 36 of the impact unit 32 can impact the tensile unit 22 on either side of the sample body 12, thus symmetrically loading the two parts of the workpiece 10. In this way, the workpiece 10 can advantageously be subjected to double the shear force.

[0092] In the Fig. Figures 5 to 7 illustrate exemplary embodiments in which the workpieces 10 can be tested for tension and / or detachment. These exemplary embodiments serve as an experimental setup for automated tension / detachment calibration, for example, on a foam or a cover layer bond.

[0093] Fig. 5 shows test specimen 12 and impact unit 32 a tensile / separation load according to another embodiment in a side view.

[0094] The sample body 12 has only a second sample element 16. The workpiece 10 is arranged between the second sample element 16 and the holding unit 20 and is connected to the holding unit 20. The second sample element 16 is connected to the tensile unit 22. The workpiece 10 is connected to the second sample element 16 via a joining connection 18, and the second sample element 16 is connected to the tensile unit 22 via a joining connection 18. Both joining connections 18 can be advantageously characterized using the proposed method.

[0095] In Fig. 6, test specimen 12 and impact unit 32 for a tensile / separation load according to a further embodiment of the invention are shown in a plan view.

[0096] In this case, the second sample element 16 is omitted and the workpiece is connected to the holding unit 20 and to the tensile unit 22 via a joint 18 to be tested. The tensile unit 22 is, as in the embodiment in Fig. 5, symmetrically loaded by the impact elements 34, 36.

[0097] Fig. 7 shows test specimen 12 and impact unit 32 for a tensile load and / or detachment load according to a further embodiment of the invention in a plan view.

[0098] In this embodiment, the workpiece 10 is arranged between the two sample elements 14, 16, which in turn are connected to the holding unit 20 and the tensile unit 22 via joints 18. The tensile unit 22 is symmetrically loaded by the impact elements 34, 36. The workpiece 10 and / or the joints 18 can thus be advantageously characterized using the test device 100.

[0099] Fig. Figure 8 shows a top view of the specimen 12 and impact unit 32 for a peeling load according to another embodiment of the invention. Fig. 9, the specimen 12 and impact unit 32 are shown in a side view.

[0100] The embodiment serves as an experimental setup for an automated dynamic peel calibration, for example on a foam or an adhesive bond.

[0101] In this embodiment, the loading of the specimen 12 occurs unilaterally. The directions of movement 62, 60 of the impact unit 32 and the tensile unit 22 lie in the plane of the drawing, as in the embodiments of the previous figures.

[0102] The rod-shaped workpiece 10 is sandwiched between the two likewise rod-shaped sample elements 34, 36. The first sample element 14 is connected to the holding unit 20 via a joining connection 18. The second sample element 16 is also connected to the tensile unit 22 via a joining connection 18. To allow the two impact elements 34, 36 to impact the tensile unit 22, the tensile unit 22 has a tubular extension element 23. When the impact unit 32 impacts, the workpiece 10 and the joints 18 are subjected to a one-sided load perpendicular to the joints 18, so that the workpiece 10 and the joints 18 can be tested for peeling.

[0103] In Fig. 10, the test specimen 12 and impact unit 32 for a torsional load according to a further embodiment of the invention are shown in a front view, i.e. perpendicular to the direction of movement 62 of the impact unit, while the test device 100 in Fig. 11 can be seen in a top view.

[0104] The embodiment serves as an experimental setup for an automated dynamic torsion calibration, for example on a foam or an adhesive bond.

[0105] The directions of movement 60, 62 of the push unit 32 and the pull unit 22 are in Fig. 10 is directed out of the drawing plane, the impact unit 32 is therefore located behind the drawing plane, while the movement directions 60, 62 in Fig. 11 lie in the drawing plane.

[0106] When the impact unit 32 impacts, the workpiece 10 and the joints 18 are subjected to a one-sided load parallel to the joints 18, so that the workpiece 10 and the joints 18 can be tested for torsion.

[0107] Fig. 12 shows a process flow for automated material card generation according to an embodiment of the invention.

[0108] In process step S100, the automated material card generation process is controlled and the results are collected. The actual testing process begins in step S102 with conditioning of the specimen 12 with the workpiece 10. Quasi-static coupon tests are then performed in step S104, followed by dynamic coupon tests in step S106.

[0109] The measurement results are combined again in step S100 and transferred from there to the system S200 for automated material card generation. The measurement is recreated in a simulation S202, and the simulation model parameters are adjusted using an optimization environment S204. The parameters of the optimized simulation model are fed back to step S100 as material characteristics to output the specific material cards.

[0110] Fig. 13 shows a schematic representation of a data processing device 500, for example a computer 510, for executing a method for determining mechanical properties of a workpiece by dynamic loading. The data processing device 500 here has a data memory 514, a processor 512 connected thereto, and an interface 516 connected thereto for receiving and outputting data. Furthermore, the data processing device 500 has an interface to external devices 518, such as a network or an external storage system. A computer program 520 that implements the method is stored on the data memory 514. Corresponding program modules 522 here represent the method steps as described in Fig. 12 are shown. Reference symbol 10 Workpiece 12 specimens 14 first sample element 16 second sample element 18 Joint connection 20 holding unit 22 train unit 23 Extension element 24 connecting element 26 Support element 28 Base plate 30 loading device 32 shock unit 34 Impact element 36 impact element 38 pendulum arm 40 axis of rotation 42 end piece 44 fixed bearings 50 force measuring unit 52 first acceleration measuring unit 54 second acceleration measuring unit 56 angle measuring unit 60 Direction of movement of the traction unit 62 Direction of movement of the impact unit 64 Pendulum movement 70 Data processing system 100 test devices 500 data processing devices S100 Control Process Flow S102 Conditioning S104 quasi-static coupon tests S106 dynamic coupon tests S200 system for automated material card generation S202 Simulation S204 Optimization X Front view Y side view Z top view

Claims

[1] Method for determining mechanical properties of a workpiece (10) by dynamic loading of a test body (12) which comprises the workpiece (10), wherein the sample body (12) is fixed to a holding unit (20) of a test device (100) and is connected to a pulling unit (22) which is subjected to an impact load by a moving impact unit (32), wherein a force and / or acceleration exerted on the holding unit (20) when the impact unit (32) hits the pulling unit (22) is detected, wherein an acceleration exerted on the impact unit (32) is detected, characterized by , that the workpiece (10) is mechanically connected to the sample body (12) via one or more joining connections (18) and / or is formed with joining connections (18), wherein, if possible, uniaxial stress states are dynamically introduced into a joining area of ​​the one or more joints (18) via the impact unit (32) into the test body (12), wherein the mechanical properties of the workpiece (10) are determined by adapting a simulation model to the detected values ​​of the force and / or acceleration on the holding unit (20) and / or the impact unit (32). [2] Method according to claim 1, characterized by that the workpiece (10) is formed with at least two materials and / or structures which are connected by point-shaped and / or linear and / or planar joining connections (18). [3] Method according to claim 1 or 2, characterized by that the workpiece (10) is connected to the sample body (12) and / or the holding unit (20) and / or the pulling unit (22) by at least two point-shaped and / or linear and / or planar joining connections (18). [4] Method according to one of the preceding claims, characterized by that the workpiece (10) and / or the joint (18) is subjected to shear or tensile stress. [5] Method according to one of the preceding claims, characterized by that the workpiece (10) and / or the joint (18) is subjected to peeling or torsion loads. [6] Method according to one of the preceding claims, characterized by that parameters of the simulation model are adapted to the recorded values ​​of the force and / or acceleration on the holding unit (20) and / or the impact unit (32) by means of an optimization method. [7] Method according to one of the preceding claims, characterized by that the mechanical properties of the workpiece (10) are determined by means of at least one material test from the group of shear calibration, double shear calibration, tensile calibration, detachment calibration, peeling calibration, torsion calibration. [8] Test device (100) for determining mechanical properties of a workpiece (10) by dynamic loading, comprising - a holding unit (20) for positioning a sample body (12) which has the workpiece (10), - a tensile unit (22) for absorbing a shock load, wherein the test specimen (12) is fixed to the holding unit (20) and is connected to the tensile unit (22), - a loading device (30) for impact loading the traction unit (22) by means of a moving impact unit (32), - a data processing device (500) for recording and / or simulating force and / or acceleration data, wherein at least one force measuring unit (50) and / or at least one first acceleration measuring unit (52) are arranged on the holding unit (20), which determine a force and / or acceleration exerted on the holding unit (20) when the impact unit (32) strikes, wherein at least one second acceleration measuring unit (54) is arranged on the impact unit (32), which determines an acceleration exerted on the impact unit (32), characterized by , that the data processing device (500) has a program running therein which is designed to determine the mechanical properties of the workpiece (10), wherein the workpiece (10) is mechanically connected to the sample body (12) via one or more joining connections (18) and / or has one or more joining connections (18), wherein, if possible, uniaxial stress states are dynamically introduced into a joining area of ​​the one or more joining connections (18) in a targeted manner via the impact unit (32) into the test body (12). [9] Test device according to claim 8, characterized bythat the data processing device (500) is designed to adapt parameters of a simulation model to the detected values ​​of the force and / or acceleration on the holding unit (20) and / or the impact unit (32). [10] Test device according to claim 8 or 9, characterized by that the workpiece (10) comprises at least two materials and / or structures which are connected by point-shaped and / or linear and / or planar joining connections (18). [11] Test device according to one of claims 8 to 10, characterized by that the workpiece (10) is connected to the sample body (12) and / or the holding unit (20) and / or the pulling unit (22) by at least two point-shaped and / or linear and / or planar joining connections (18). [12] Test device according to one of claims 8 to 11, characterized bythat the loading device (30) has a pendulum arm (38) which is pivotable about a rotation axis (40), wherein the impact unit (32) is arranged on an end piece (42) of the pendulum arm (38). [13] Test device according to one of claims 8 to 12, characterized by that the loading device (30) has an angle measuring unit (56), in particular wherein an angle measuring unit (56) is arranged on a rotation axis (40) of the pendulum arm (38) of the loading device (30). [14] Test device according to one of claims 8 to 13, characterized by that the impact unit (32) has two impact elements (34, 36) which load the pulling unit (22) symmetrically in the direction of movement (62) of the impact unit (32). [15] Test device according to one of claims 8 to 14, characterized byin that the sample body (12) has at least a first sample element (14) and a second sample element (16), wherein the workpiece (10) is arranged between the first sample element (14) and the second sample element (16), wherein the first sample element (14) is connected to the holding unit (20) and the second sample element (16) is connected to the pulling unit (22). [16] Test device according to one of claims 8 to 15, characterized by in that the sample body (12) has at least a second sample element (16), wherein the workpiece (10) is arranged between the second sample element (16) and the holding unit (20), wherein the workpiece (10) is connected to the holding unit (20) and the second sample element (16) is connected to the pulling unit (22). [17] Test device according to one of claims 8 to 16, characterized by that the workpiece (10) is connected to the holding unit (20) and the pulling unit (22). [18] Computer program product comprising instructions which, when executed by a computer (510), cause the computer to carry out a method according to one of claims 1 to 7, in particular automatically. [19] Device (500) for data processing, comprising means (510, 512, 514, 516, 520, 522) for, in particular automated, execution of a method according to one of claims 1 to 7.

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