A device and method for detecting the composite strength of a skin material of an automobile crash dummy

Abstract

The application discloses a kind of composite strength detection device and method of car crash dummy skin material, it is related to material mechanics analysis technical field, including main support, impact, tension, alignment and control unit.Main support contains crossbeam, impact unit is equipped with impact force regulating component with punch, the clamping structure on the tension unit is installed in crossbeam, two-dimensional translation slide platform is supported with turntable under crossbeam, alignment system contains cross laser projector and machine vision unit on crossbeam.Impact and tension unit height is regulated by adjusting crossbeam height, impact unit accurately adjusts impact force, dynamic force sensor real-time collection mechanics data;Tension unit is adapted to adjust clamping force by multiple force sensor feedback, to avoid affecting result.Alignment system realizes sample translation and rotation by two-dimensional translation slide platform and turntable, combined with laser positioning and machine vision accurate control position, and dispersion decreases.The device can accurately detect the impact and tensile composite strength of polyurethane material, reduce manual intervention and shorten test time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material mechanics analysis, in particular to a device and method for detecting the composite strength of a skin material of an automobile crash dummy. BACKGROUND

[0002] The core equipment of automobile crash test is a crash dummy, and the bionics degree determines the scientificity and reliability of the test. The skin of the dummy needs to match the mechanical properties of real skin. Polyurethane (TPU) has become the mainstream material for the skin of the dummy due to its excellent performance. However, the shortcomings of the existing polyurethane strength detection method restrict the optimization of the material and the improvement of the overall bionics degree of the dummy.

[0003] Polyurethane is used in many fields such as automobile safety components and medical protection. However, the precise detection of its tensile and impact composite strength is a difficult problem in the industry. Currently, the industry mainly conducts uniaxial tensile, compression and other static tests according to standards such as ISO 37 and ASTM D412. Although the static mechanical parameters such as elastic modulus can be obtained, there are still many significant defects.

[0004] When polyurethane material is used for the development of high-simulation dummy skin, there are many key defects in performance testing: first, in terms of load simulation, the material bears multiple-step and multi-directional composite loads in actual crashes, but uniaxial testing cannot reproduce this scenario, resulting in a deviation between the test results and the actual failure mode; second, the loading rate adaptability is insufficient, the viscoelasticity of polyurethane makes its mechanical properties highly sensitive to loading rate, and traditional static testing cannot reflect the dynamic response in high-speed crashes, and existing high-strain-rate testing equipment is costly and cannot integrate impact and tensile loading; third, the testing specifications and equipment capabilities are lacking, and existing equipment is mostly single-function, and polyurethane as a soft material is prone to test fixture stress concentration and sample slippage, and dynamic impact and static tensile time sequence coupling simulation technology is not mature, and the improvement scheme also has problems such as complex structure, high cost, poor adaptability, etc. The above defects make it difficult to accurately characterize the failure mechanism of polyurethane under complex conditions, hindering the development and performance verification of high-simulation dummy skin materials.

[0005] Therefore, there is an urgent need for a composite strength detection device and method that can accurately detect the composite strength of polyurethane materials and provide key technical support for the development and optimization of dummy skin materials. SUMMARY

[0006] To solve the above technical problems, the present application provides a device and method for detecting the composite strength of a skin material of an automobile crash dummy, which conducts impact and tensile tests on polyurethane materials.

[0007] To achieve the above purpose, the present application provides the following solutions:

[0008] The present application provides a device for detecting the composite strength of a skin material of an automobile crash dummy, which comprises:

[0009] a main support structure comprising a gantry frame, a crossbeam of the gantry frame being capable of lifting;

[0010] a percussion unit comprising a percussion force regulating assembly and a punch; the percussion force regulating assembly is arranged on the crossbeam, and a free end of the percussion force regulating assembly is provided with the punch;

[0011] a stretching unit comprising an upper clamping structure, the upper clamping structure being arranged on the crossbeam;

[0012] an alignment system comprising a two-dimensional translation stage, a turntable, a cross laser projector and a machine vision unit; the two-dimensional translation stage is located below the crossbeam, and the turntable is arranged on the two-dimensional translation stage and used for carrying a material to be detected; the cross laser projector and the machine vision unit are arranged on the crossbeam;

[0013] a control unit, the control unit being electrically connected with the crossbeam, the percussion force regulating assembly, the upper clamping structure, the two-dimensional translation stage, the turntable, the cross laser projector and the machine vision unit respectively.

[0014] Optionally, the percussion unit further comprises a dynamic force sensor; the percussion force regulating assembly is electrically connected with the dynamic force sensor.

[0015] Optionally, the percussion force regulating assembly comprises a pressure regulating valve, an electromagnetic valve and a pneumatic cylinder arranged in sequence; the punch is arranged at an end of a piston rod of the pneumatic cylinder; the dynamic force sensor is electrically connected with the pressure regulating valve.

[0016] Optionally, a plurality of force sensors are arranged on the upper clamping structure; the plurality of force sensors are electrically connected with driving members of the upper clamping structure.

[0017] Optionally, the main support structure comprises a temperature and humidity controllable test cabin, and the gantry frame, the stretching unit, the percussion unit and the alignment system are arranged in the temperature and humidity controllable test cabin.

[0018] The temperature and humidity controllable test cabin comprises a cabin room surrounded by heat insulation glass, and a refrigerating fin and a double-channel dehumidifying / humidifying system are arranged in the cabin room; a plurality of temperature sensors are arranged in the heat insulation glass, and the refrigerating fin, the double-channel dehumidifying / humidifying system and the plurality of temperature sensors are electrically connected with the control unit respectively.

[0019] Optionally, the upper clamping structure comprises a linear slide rail, a sliding clamping block and a fixed clamping block, and the driving member of the upper clamping structure comprises a clamping cylinder; the linear slide rail is parallel to the piston rod of the clamping cylinder, the sliding clamping block is slidingly arranged on the linear slide rail, and the fixed clamping block is fixedly arranged at one end of the linear slide rail away from the clamping cylinder.

[0020] Optionally, the upper clamping structure comprises a clamping surface, and the clamping surface comprises a hard base plate, an elastic buffer layer and a polyurethane surface layer with micro-texture in sequence; and the plurality of force sensors are arranged at the four corner positions of the clamping surface.

[0021] The application further discloses a method for detecting the composite strength of a skin material of an automobile crash dummy.

[0022] Punch test, install the sample, position the sample, align the sample edge with the cross laser projection, then the machine vision unit takes a top view of the sample, the algorithm identifies the position deviation (Delta X, Delta Y, theta) of the sample contour and the preset reference frame, translates and / or rotates the sample according to (Delta X, Delta Y, theta) until the position error is less than ±0.05mm and the angle error is less than 0.1°; control the impact speed to impact the sample, and record the impact force peak value, energy absorption rate and crack propagation morphology;

[0023] Tensile test, clamp both ends of the sample, during the closing process of the clamp, monitor the pressure value in real time through a plurality of piezoelectric sensors, if |max(P)-min(P)|>15%*average, trigger the slide micro-motion compensation to eliminate the eccentric load; perform the tensile test at a preset speed, record the load-displacement curve, and keep the load for a first set time after the tensile test is completed to eliminate the viscoelastic rebound effect of the sample.

[0024] Optionally, the first set time is not less than 20 seconds.

[0025] The application has the following technical effects compared with the prior art:

[0026] When the automobile crash dummy skin material composite strength detection device provided by the application is used, the height of the gantry frame beam can be adjusted to control the height of the impact unit and the tensile unit, and the impact force control assembly and the upper clamping structure are combined to respectively realize accurate adjustment of the impact force and the tensile length; the mechanical data in the impact test process is collected in real time by the dynamic force sensor. After the tensile unit is fixed to the sample through the upper clamping structure, the clamping force can be adjusted according to the pressure values fed back by the multiple force sensors, so as to avoid the influence of improper clamping force on the test results. The two-dimensional translation slide table carried by the alignment system can realize the translation of the sample in the plane, the turntable can complete the rotation of the sample in the plane, and the positioning guidance of the cross laser projector and the accurate identification of the machine vision unit can realize high-precision control of the sample position, guarantee the accuracy and reliability of the test data, reduce the problem of asymmetric load caused by sample inclination, and reduce the dispersion of the composite strength test data to below 7%; relying on the above operation, the impact and tensile composite strength of the polyurethane material can be accurately detected, the manual intervention in the test process is reduced, and the test time is shortened. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Fig. 1 It is a structural schematic diagram of the automobile crash dummy skin material composite strength detection device of the present application.

[0029] Fig. 2 It is a structural schematic diagram of the tensile unit in the automobile crash dummy skin material composite strength detection device of the present application.

[0030] Fig. 3 It is a structural schematic diagram of the impact unit in the automobile crash dummy skin material composite strength detection device of the present application.

[0031] Explanation of reference numerals: 1, beam; 2, tensile unit; 3, impact unit; 4, protractor disc; 5, two-dimensional translation slide table; 6, clamping air cylinder; 7, sliding clamping block; 8, linear slide rail; 9, fixed clamping block; 10, clamping surface; 11, pressure regulating valve; 12, electromagnetic valve; 13, pneumatic cylinder; 14, piston rod. DETAILED DESCRIPTION

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1:

[0034] like Figs. 1 to 3 As shown, this embodiment provides a composite strength testing device for the skin material of a car crash dummy, comprising:

[0035] The main support structure includes a gantry frame, and the crossbeam 1 of the gantry frame can be raised and lowered;

[0036] Impact unit 3 includes an impact force control component and a punch; the impact force control component is mounted on the crossbeam 1, and the free end of the impact force control component is provided with a punch;

[0037] The tensioning unit 2 includes an upper clamping structure, which is disposed on the crossbeam 1;

[0038] The alignment system includes a two-dimensional translation slide 5, a turntable, a cross laser projector, and a machine vision unit; the two-dimensional translation slide 5 is located below the crossbeam 1, and a turntable is set on the two-dimensional translation slide 5 to support the material to be inspected; the cross laser projector and the machine vision unit are set on the crossbeam 1.

[0039] The control unit is electrically connected to the crossbeam 1, the impact force adjustment component, the upper clamping structure, the two-dimensional translation slide 5, the turntable, the cross laser projector, and the machine vision unit.

[0040] When the composite strength detection device for the skin material of the automobile crash dummy provided by the application is used, the height of the gantry frame beam 1 can be adjusted to control the height of the impact unit 3 and the tensile unit 2, and the impact force control assembly and the upper clamping structure are combined to realize accurate adjustment of the impact force and the tensile length respectively. The mechanical data during the impact test is collected in real time by the dynamic force sensor. After the tensile unit 2 fixes the sample through the upper clamping structure, the clamping force can be adjusted according to the pressure values fed back by the multiple force sensors to avoid the improper clamping force affecting the test results. The two-dimensional translation slide 5 carried by the alignment system can realize the translation of the sample in the plane, the turntable can complete the rotation of the sample in the plane, and the positioning guidance of the cross laser projector and the accurate identification of the machine vision unit can realize high-precision control of the sample position, guarantee the accuracy and reliability of the test data, reduce the problem of asymmetric load caused by the sample inclination, and reduce the dispersion of the composite strength test data to below 7%. Relying on the above operation, the impact and tensile composite strength of the polyurethane material can be accurately detected, the manual intervention in the test process is reduced, and the test time is shortened.

[0041] The turntable can adopt a protractor 4, and the surface of the protractor 4 is provided with scales in the circumferential direction to facilitate observation of the rotation angle of the protractor 4.

[0042] The impact unit 3 further comprises a dynamic force sensor; the impact force control assembly is electrically connected with the dynamic force sensor, and the dynamic force sensor is electrically connected with the control unit. The control unit receives the signal of the dynamic force sensor and controls the impact force of the impact force control assembly according to the signal.

[0043] The impact force control assembly can output impact force through air pressure, hydraulic pressure or electric thrust, and the corresponding impact force control assembly adopts an air pressure control system, a hydraulic control system or an electric push rod device. As long as the impact force control assembly type can meet the impact force requirement, it belongs to the protection scope of the application.

[0044] Optionally, in an embodiment of the application, the impact force control assembly comprises a pressure regulating valve 11, an electromagnetic valve 12 and a pneumatic cylinder 13 arranged in sequence; the punch is arranged at the end of the piston rod 14 of the pneumatic cylinder 13; and the dynamic force sensor is electrically connected with the pressure regulating valve 11. Changing the output pressure of the pressure regulating valve 11 can realize the adjustment of the air pressure and airflow entering the pneumatic cylinder 13, and finally realize the adjustment of the impact force of the punch, and the control unit records the impact force. The built-in three-axis accelerometer and piezoelectric force sensor in the punch monitor in real time to form a closed-loop feedback. If the measured impact force deviates from the target, the control system will dynamically adjust the opening degree of the electromagnetic valve 12 to correct the air pressure, so as to ensure the accuracy and repeatability of the impact force output.

[0045] The upper clamping structure is provided with four force sensors; the four force sensors are electrically connected to the driving part of the upper clamping structure.

[0046] The upper clamping structure comprises a linear slide rail 8, a sliding clamp block 7 and a fixed clamp block 9, and the driving part of the upper clamping structure comprises a clamping cylinder 6; the linear slide rail 8 is parallel to the piston rod 14 of the clamping cylinder 6, the sliding clamp block 7 is slidingly arranged on the linear slide rail 8, and the fixed clamp block 9 is fixedly arranged at one end of the linear slide rail 8 away from the clamping cylinder 6.

[0047] The upper clamping structure comprises a clamping surface 10, which comprises a hard base plate, an elastic buffer layer and a high-friction polyurethane surface layer with micro textures arranged in sequence, which can effectively disperse stress and prevent the sample from slipping or being damaged.

[0048] The four force sensors are arranged at the four corner positions of the clamping surface 10, which can monitor the clamping force distribution in real time, and the air pressure of the clamping cylinder 6 is fine-tuned through the linkage of the electric proportional valve, so as to actively maintain the uniformity and stability of the clamping force in the whole process, solving the problem of premature failure or data deviation of soft materials caused by improper clamping during testing.

[0049] The rotating disc of the index plate 4 adopts a 180° rotating servo index plate 4 rotating disc, which is controlled by a control unit to complete the rotation of the sample in the plane, and the double stations thereof respectively bear a tensile lower clamp and an impact anvil, and realize rigid support and rapid switching through a pneumatic locking mechanism.

[0050] The main support structure comprises a temperature and humidity controllable test cabin, and the gantry frame, the tensile unit 2, the impact unit 3 and the alignment system are all arranged in the temperature and humidity controllable test cabin.

[0051] The temperature and humidity controllable test cabin comprises a cabin surrounded by heat-insulating glass, and a refrigerating fin and a double-channel dehumidifying / humidifying system are arranged in the cabin; a plurality of temperature sensors are arranged in the heat-insulating glass, and the refrigerating fin, the double-channel dehumidifying / humidifying system and the plurality of temperature sensors are electrically connected to the control unit.

[0052] The refrigerating fin adopts a semiconductor refrigerating fin, the temperature control range is -40℃~+80℃, the double-channel dehumidifying / humidifying system has a humidity range of 20%~90%RH, the heat-insulating glass adopts double-layer heat-insulating glass, the inner wall of which is embedded with an array of Pt100 platinum resistance temperature sensors, which can feed back the regional temperature difference in real time (the accuracy is ±0.5℃). The performance attenuation of the polyurethane material caused by temperature influence can be avoided, and the influence of the material in different environments can be simulated.

[0053] Embodiment two

[0054] The embodiment provides a method based on the automobile crash dummy skin material composite strength detection device in embodiment one, which comprises the following steps:

[0055] Punch test, install the sample, position the sample, align the sample edge with the cross laser projection, then the machine vision unit takes a top view of the sample, the algorithm identifies the sample contour and the preset reference frame position deviation (ΔX, ΔY, θ), according to (ΔX, ΔY, θ) translation and / or rotation of the sample, until the position error <±0.05mm, angle error <0.1°; control the impact speed to impact the sample, record the impact force peak, energy absorption rate and crack propagation morphology;

[0056] Tensile test, clamp both ends of the sample, during the closing process of the clamp, monitor the pressure value in real time through multiple piezoelectric sensors, if |max(P)-min(P)| > 15%×average, trigger the slide micro-motion compensation to eliminate the eccentric load; perform tensile test at the preset speed, record the load-displacement curve, and keep the load for 30s after tensile completion to eliminate the viscoelastic rebound effect of the sample.

[0057] The control system dynamically adjusts the punching energy based on the residual thickness and damage degree in the tensile stage through the PID algorithm to avoid test failure caused by overload or insufficient energy. Immediately after impact, trigger the tensile test, the tensile actuator on the gantry beam 1 descends, and the upper clamp clamps the upper end of the sample. Start the servo motor to move upward at the preset speed for tensile test, record the load-displacement curve. Keep the load for 30 seconds after tensile completion to eliminate the viscoelastic rebound effect of the polyurethane. The final data is processed by special software to output tensile strength, elongation at break, impact toughness and damage evolution curve, etc. Multi-dimensional parameters.

[0058] The specific design theory and formula are as follows:

[0059] 1. Tensile stage mechanical model

[0060] (1) Tensile stage mechanical model

[0061] The tensile pre-strain of polyurethane material ( ) is realized by servo motor driven clamp displacement, which is defined as:

[0062]

[0063] In the formula:

[0064] : Change in sample tensile length (mm), measured directly by the displacement of the ball screw driven by the servo motor, with an accuracy of ±0.01 mm.

[0065] : Initial gauge length of the sample (mm), usually set to 50 mm or 100 mm according to international standards (such as ISO 37), and the clamping position must be symmetrical through the laser centering system with a deviation of <0.05 mm.

[0066] This formula is used to quantify the deformation of the material during the tensile preloading stage. By controlling ΔL, the tensile strain of the dummy skin due to the pre-tightening of the seat belt or the deformation of the vehicle body during a collision can be simulated (e.g., 0%~300%). The percentage form in the formula facilitates intuitive evaluation of the ductility of the material and provides a pre-damage benchmark for subsequent impact tests.

[0067] During the tensile process, the true stress (σ) of the material is measured in real time by a multi-axis force sensor:

[0068]

[0069] In the formula:

[0070] : Tensile force (N), measured in real time by a multi-axis force sensor.

[0071] : Initial cross-sectional area of the specimen (mm 2 ), calculated based on the specimen thickness (1~50 mm) and width (standard 25 mm), and the initial dimensions need to be calibrated by a micrometer.

[0072] : Poisson's ratio of the material (typical value for polyurethane 0.3~0.4).

[0073] Since the cross-sectional area of the material will shrink due to the Poisson effect during tensile, the traditional engineering stress (σ ) will underestimate the actual stress. This formula introduces a correction term to more accurately reflect the stress state of the material. This formula is based on the isotropic assumption, and the cross-sectional area shrinkage is two-dimensional, so a square correction term is used. If the geometry of the specimen in the actual test is not isotropic (e.g., only the thickness direction of the sheet material shrinks), the formula needs to be adjusted based on the explicit assumption. However, standard tensile specimens are generally considered isotropic.

[0074] (2) Strain rate control equation

[0075] The tensile speed (v) of the servo motor satisfies:

[0076]

[0077]

[0078] In the formula:

[0079] : Tensile speed of the servo motor (unit: mm / s), closed-loop control is achieved through encoder feedback, and the speed error is <±0.5%.

[0080] ​​​​In high-speed stretching ( When using a high-response servo motor (e.g., rated power 3 kW) and a low-inertia ball screw (lead 10 mm), it is necessary to use a high-response servo motor to avoid strain rate fluctuations caused by mechanical delay.

[0081] 2. Dynamic model of the impact phase

[0082] (1) Calculation of impact velocity and energy

[0083] Impact head speed of pneumatic impact module ( Controlled by a pneumatic valve, satisfying:

[0084]

[0085] In the formula:

[0086] The kinetic energy of the punch (J) is set by adjusting the air pressure (0.1~1.0 MPa);

[0087] Punch weight (g), supports modular replacement (50~200g).

[0088] Dynamic impact force during the impact process ( The data is collected by a piezoelectric sensor and compared with the displacement of the impact head. Related:

[0089]

[0090] In the formula:

[0091] Impact head acceleration (m / s²) 2 The acceleration is measured in real time by an accelerometer.

[0092] The dynamic stiffness (N / mm) of polyurethane material is obtained by fitting a real-time force-displacement curve, reflecting the nonlinear response of the material under high strain rate.

[0093] This formula decomposes the impact force into inertial force and material resistance, and can distinguish between the kinetic energy consumption of the impact head and the plastic deformation energy of the material, providing data support for optimizing polyurethane formulations.

[0094] (2) Criteria for crack propagation

[0095] The critical condition for surface crack initiation during impact is based on the Griffith energy criterion:

[0096]

[0097] In the formula:

[0098] Critical energy release rate (J / m 2 ) of the material, which characterizes the material's ability to resist crack propagation, is a key indicator for evaluating the anti-tearing performance of the dummy skin.

[0099] Crack tip stress (MPa);

[0100] Pre-crack length (mm);

[0101] Polyurethane elastic modulus (MPa), determined by the initial slope of the stress-strain curve in the stretching phase.

[0102] 3. Coupled model of composite load

[0103] (1) Timing control equation for impact-tension

[0104] Tensile pre-strain (ε ) and impact trigger time (t ) are controlled through closed-loop feedback to ensure timing error :

[0105]

[0106] Where:

[0107] Tensile start time (s);

[0108] Target pre-strain (e.g. 150%), adjusted in real time through the stretching phase.

[0109] Actual strain rate (s -1 ).

[0110] This equation ensures seamless connection between impact and tension actions, avoiding pre-strain relaxation due to delay.

[0111] (2) Composite stress intensity factor

[0112] Equivalent stress intensity factor (K ) under impact and tensile composite load uses the superposition principle:

[0113]

[0114] Where:

[0115] : (tension contribution);

[0116] : impact contribution, geometric correction factor).

[0117] : geometric correction factor, determined by table lookup according to the ratio of specimen width (W) to crack length (a), typical value 1.0~1.2. W a : specimen thickness (unit: mm), measured by micrometer.

[0118] This formula is based on linear elastic fracture mechanics, superimposes tensile and impact stress fields, quantitatively evaluates the failure risk of materials under complex load, and provides a theoretical basis for setting safety thresholds (such as ).

[0119] 4. Standardization of the formula

[0120] (1) Parameter calibration method

[0121] Elastic modulus : obtained by fitting the initial linear segment (strain <5%) of the tensile test, and the average value of 3 repeated tests is taken.

[0122] Dynamic stiffness : 5 impact tests are performed on the same specimen, and the median value is taken after removing outliers.

[0123] (2) Error control

[0124] Tensile strain error: calibrated by laser displacement sensor, ensuring that the ΔL measurement error is <±0.1 mm.

[0125] Impact energy error: calibrate the kinetic energy of the impact head under no load, compensate for friction loss, and the total error is <±2%.

[0126] It should be noted that for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, any reference signs in the claims should not be considered as limiting the claims involved.

[0127] It should be noted that for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, any reference signs in the claims should not be considered as limiting the claims involved.

[0128] ​The principles and implementation manners of the present application are described in the specification by using specific examples, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A device for testing the composite strength of skin materials used in automobile collision dummy experiments, characterized in that, include: The main support structure includes a gantry frame, wherein the crossbeam (1) of the gantry frame is capable of being raised and lowered; The impact unit (3) includes an impact force control component and a punch; the impact force control component is disposed on the crossbeam (1), and the punch is disposed at the free end of the impact force control component; The stretching unit (2) includes an upper clamping structure, which is disposed on the crossbeam (1); The alignment system includes a two-dimensional translation slide (5), a turntable, a cross laser projector, and a machine vision unit; the two-dimensional translation slide (5) is located below the crossbeam (1), and a turntable is provided on the two-dimensional translation slide (5) for carrying the material to be inspected; the cross laser projector and the machine vision unit are provided on the crossbeam (1); The control unit is electrically connected to the crossbeam (1), the impact force control component, the upper clamping structure, the two-dimensional translation slide (5), the turntable, the cross laser projector and the machine vision unit respectively.

2. The composite strength testing device for automobile collision dummy skin materials according to claim 1, characterized in that, The impact unit (3) also includes a dynamic force sensor; the impact force control component is electrically connected to the dynamic force sensor.

3. The composite strength testing device for automobile collision dummy skin materials according to claim 2, characterized in that, The impact force control assembly includes a pressure regulating valve (11), a solenoid valve (12), and a pneumatic cylinder (13) arranged in sequence; the punch is located at the end of the piston rod (14) of the pneumatic cylinder (13); the dynamic force sensor is electrically connected to the pressure regulating valve (11).

4. The composite strength testing device for automobile collision dummy skin material according to claim 1, characterized in that, The upper clamping structure is equipped with multiple force sensors; the multiple force sensors are electrically connected to the drive component of the upper clamping structure.

5. The composite strength testing device for automobile collision dummy skin materials according to claim 4, characterized in that, The upper clamping structure includes a linear slide rail (8), a sliding clamping block (7), and a fixed clamping block (9). The driving component of the upper clamping structure includes a clamping cylinder (6). The linear slide rail (8) is parallel to the piston rod (14) of the clamping cylinder (6). The sliding clamping block (7) is slidably disposed on the linear slide rail (8). The fixed clamping block (9) is fixedly disposed at one end of the linear slide rail (8) away from the clamping cylinder (6).

6. The composite strength testing device for automobile collision dummy skin material according to claim 4, characterized in that, The upper clamping structure includes a clamping surface (10), which includes a rigid substrate, an elastic buffer layer and a high friction coefficient polyurethane surface layer with fine texture arranged in sequence. The plurality of force sensors are disposed at the four corners of the clamping surface (10).

7. The composite strength testing device for automobile collision dummy skin materials according to claim 1, characterized in that, The main support structure includes a temperature and humidity controllable test chamber, and the gantry frame, the tensile unit (2), the impact unit (3) and the alignment system are all installed inside the temperature and humidity controllable test chamber; The temperature and humidity controllable test chamber includes a compartment enclosed by heat-insulating glass. The compartment is equipped with a cooling chip and a dual-channel dehumidification / humidification system. Multiple temperature sensors are installed inside the heat-insulating glass. The cooling chip, the dual-channel dehumidification / humidification system, and the multiple temperature sensors are electrically connected to the control unit.

8. A method for testing the composite strength of skin materials used in automobile collision dummy tests based on any one of claims 1 to 7, characterized in that, include: The stamping test involves installing the specimen and positioning it so that its edge is aligned with the crosshair laser projection. Then, a machine vision unit captures a top-view image of the specimen. An algorithm identifies the positional deviation (ΔX, ΔY, θ) between the specimen outline and a preset reference frame. Based on (ΔX, ΔY, θ), the specimen is translated and / or rotated until the positional error is < ±0.05 mm and the angular error is < 0.1°. The specimen is then impacted at a controlled impact speed, and the peak impact force, energy absorption rate, and crack propagation morphology are recorded. For the tensile test, clamp both ends of the specimen. During the clamping process, multiple piezoelectric sensors monitor the pressure value in real time. If |max(P)-min(P)| > 15%×average, the slide table micro-motion compensation is triggered to eliminate the off-center load. The tensile test is performed at a preset speed, and the load-displacement curve is recorded. After the tensile test is completed, the load is maintained for the first set time to eliminate the viscoelastic rebound effect of the specimen.

9. The method for testing the composite strength of automotive collision dummy skin materials according to claim 8, characterized in that, The first set time is not less than 20 seconds.

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