A high-speed collision material card for automobile steel and its application method

Abstract

The invention discloses a high-speed collision material card for automobile steel and an application method thereof, comprising the following steps: step one, classification of automobile steel, wherein a technician classifies automobile steel materials; step two, testing different types of steel, wherein the technician performs a high-speed tensile test on mild steel, and the technician performs a failure damage test on high-strength steel; and step three, high-speed tensile data processing: the technician processes the data of high-speed tensile of mild steel at different rates, and uses a Swift‑Hockett‑Sherby constitutive model to fit and extrapolate the data. The invention studies dynamic mechanical properties and fracture failure properties through experiments, develops a dynamic mechanical material card for mild steel and a GISSMO fracture failure card for high-strength steel, and simultaneously applies the two material cards to CAE collision analysis, thereby being able to accurately predict the dynamic mechanical deformation of metal materials and the fracture failure characteristics of metal materials, and solving the problem of inaccurate precision of material cards in automobile factories.

Description

Technical Field

[0001] The invention relates to the technical field of metal material detection and CAE automobile collision safety simulation analysis, and in particular to a high-speed collision material card for automobile steel and an application method thereof. Background Art

[0002] At present, the number of traffic accidents in the world remains high, and automobile collision safety has received more and more attention from people. The relevant collision regulations have also put forward specific requirements for the crash resistance of automobiles. However, due to the huge cost of actual vehicle collision tests, it is not suitable for periodic inspection and improvement of designed vehicles. Given that CAE collision analysis is currently the main method for automobile factories to analyze the collision performance of vehicle models, however, traditional static mechanical performance material cards cannot meet the high-precision collision simulation performance evaluation, and the material cards for collision simulation analysis in automobile factories are prone to inaccurate accuracy.

[0003] The present invention studies dynamic mechanical properties and fracture failure properties through experiments, develops dynamic mechanical material cards for mild steel and GISSMO fracture failure cards for high-strength steel, and simultaneously applies the two material cards to CAE collision analysis, which can accurately predict the dynamic mechanical deformation of metal materials and the fracture failure characteristics of metal materials, solves the problem of inaccurate precision of material cards in automobile factories, provides accurate data card support for collision analysis and structural optimization of new models in automobile factories, shortens the development cycle, reduces the experimental workload, and reduces the research and development cost. Summary of the invention

[0004] The purpose of the present invention is to provide a high-speed collision material card for automobile steel and an application method thereof, so as to solve the problem that the traditional static mechanical property material card proposed in the above background technology cannot meet the high-precision collision simulation performance evaluation, and the material card accuracy of the collision simulation analysis of the automobile factory is prone to inaccurate.

[0005] To achieve the above object, the present invention provides the following technical solution: a high-speed collision material card for automobile steel and an application method thereof, comprising the following steps:

[0006] Step 1: Classification of steel for automobiles: technicians classify steel materials for automobiles;

[0007] Step 2: Test different types of steel: technicians conduct high-speed tensile tests on mild steel, and technicians conduct failure damage tests on high-strength steel;

[0008] Step 3: High-speed tensile data processing: The technicians process the data of high-speed tensile of mild steel at different rates and use the Swift-Hockett-Sherby constitutive model to fit and extrapolate the data;

[0009] Step 4: Create the original dynamic mechanics material card: The technicians create the original dynamic mechanics material card in the LS-dyna software based on the curve obtained after processing the high-speed tensile data of mild steel;

[0010] Step 5: Verify the validity of the test: verify the validity of the test data of mild steel and the fitting to obtain the true stress-plastic strain curve of mild steel;

[0011] Step 6. Output accurate material card: Output the dynamic mechanical material card of the calibrated soft steel;

[0012] Step 7: Obtain material fracture curves under different stress triaxiality conditions: technicians conduct failure tests on high-strength steel to obtain force-displacement curves during the failure test process;

[0013] Step 8: Make the GISSMO original fracture failure material card: The technicians use LS-Dyna to calculate the stress triaxiality of the failure part of the high-strength steel and the equivalent strain at the time of failure, and combine the static and high-speed tensile curves to make the GISSMO original fracture failure material card;

[0014] Step 9: Benchmarking of finite element simulation model: Technical personnel establish a finite element simulation model of the corresponding failure test of high-strength steel, and use finite element simulation to perform benchmarking and optimization curves;

[0015] Step 10: Output fracture failure card: Output GISSMO fracture failure card of high-strength steel after benchmarking;

[0016] Step 11, CAE collision analysis: Based on the classification of automobile steel grades, the dynamic mechanical material card of soft steel and the fracture failure material card of high-strength steel are simultaneously brought into the CAE collision analysis.

[0017] As a preferred technical solution of the present invention, in the step 1, the steel materials for automobiles are classified into two types: soft steel and high-strength steel.

[0018] As a preferred technical solution of the present invention, in the step 2, the soft steel is subjected to a high-speed tensile test. On a high-speed tensile testing machine, the engineering stress-strain curves of each material at quasi-static and dynamic strain rates of 8 strain rates are tested. Each test is repeated at least 3 times. The 8 strain rates are 0.001 / s, 0.01 / s, 0.1 / s, 1 / s, 10 / s, 100 / s, 500 / s and 1000 / s, respectively. The technicians make strain curves for the soft steel under the engineering stresses of the 8 strain rates.

[0019] As a preferred technical solution of the present invention, the Swift-Hockett-Sherby constitutive model in step three fits and extrapolates the data to obtain an extension to 1 curve that is convenient for engineering application, ensuring that no intersection occurs between the strain rate curves.

[0020] As a preferred technical solution of the present invention, the validity of the test is verified in step five, a finite element model of the sample stretching is established, and the test data curves at different strain rates are benchmarked until the benchmark data deviation is less than 5%. When the data deviation is greater than 5%, the data of high-speed stretching at different rates are reprocessed, and the Swift-Hockett-Sherby constitutive model is used to fit and extrapolate the data to obtain an extension to 1 curve that is convenient for engineering application.

[0021] As a preferred technical solution of the present invention, in step seven, the technicians conduct failure tests on high-strength steel. There are six types of failure tests, namely, shear test, static tensile shear test, R5 notch tensile test, R20 notch tensile test, center hole tensile test and perforation test. Each test is repeated at least 3 times. The high-strength steel is subjected to shear test, static tensile shear test, R5 notch tensile test, R20 notch tensile test, center hole tensile test and perforation test for more than three times.

[0022] As a preferred technical solution of the present invention, in step nine, finite element simulation is used to perform benchmarking and optimization curves, which are respectively loading failure material card fracture test simulation benchmarking, grid size coefficient test simulation benchmarking and strain rate coefficient test simulation benchmarking, and the benchmarking data deviation is less than 5%. When the data deviation is greater than 5%, the stress triaxiality of the failure site and the equivalent strain at the time of failure are recalculated by LS-Dyna, and the static and high-speed tensile curves are combined to make the GISSMO original fracture failure material card.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: through experimental research on dynamic mechanical properties and fracture failure properties, a dynamic mechanical material card for mild steel and a GISSMO fracture failure card for high-strength steel are developed, and the two material cards are simultaneously applied to CAE collision analysis, which can accurately predict the dynamic mechanical deformation of metal materials and the fracture failure characteristics of metal materials, solve the problem of inaccurate precision of material cards in automobile factories, provide accurate data card support for collision analysis and structural optimization of new models of automobile factories, shorten the development cycle, reduce the experimental workload, and reduce R&D costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of the present invention;

[0025] Figure 2 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] See also Figure 1-2 The present invention provides a high-speed collision material card for automobile steel and an application method thereof, comprising the following steps:

[0028] Step 1: Classification of steel for automobiles: technicians classify steel materials for automobiles;

[0029] Step 2: Test different types of steel: technicians conduct high-speed tensile tests on mild steel, and technicians conduct failure damage tests on high-strength steel;

[0030] Step 3: High-speed tensile data processing: The technicians process the data of high-speed tensile of mild steel at different rates and use the Swift-Hockett-Sherby constitutive model to fit and extrapolate the data;

[0031] Step 4: Create the original dynamic mechanics material card: The technicians create the original dynamic mechanics material card in the LS-dyna software based on the curve obtained after processing the high-speed tensile data of mild steel;

[0032] Step 5: Verify the validity of the test: verify the validity of the test data of mild steel and the fitting to obtain the true stress-plastic strain curve of mild steel;

[0033] Step 6. Output accurate material card: Output the dynamic mechanical material card of the calibrated soft steel;

[0034] Step 7: Obtain material fracture curves under different stress triaxiality conditions: technicians conduct failure tests on high-strength steel to obtain force-displacement curves during the failure test process;

[0035] Step 8: Make the GISSMO original fracture failure material card: The technicians use LS-Dyna to calculate the stress triaxiality of the failure part of the high-strength steel and the equivalent strain at the time of failure, and combine the static and high-speed tensile curves to make the GISSMO original fracture failure material card;

[0036] Step 9: Benchmarking of finite element simulation model: Technical personnel establish a finite element simulation model of the corresponding failure test of high-strength steel, and use finite element simulation to perform benchmarking and optimization curves;

[0037] Step 10: Output fracture failure card: Output GISSMO fracture failure card of high-strength steel after benchmarking;

[0038] Step 11, CAE collision analysis: Based on the classification of automobile steel grades, the dynamic mechanical material card of soft steel and the fracture failure material card of high-strength steel are simultaneously brought into the CAE collision analysis.

[0039] In step one, the steel materials used in automobiles are classified into two types: soft steel and high-strength steel.

[0040] In step 2, the soft steel is subjected to a high-speed tensile test. On a high-speed tensile testing machine, the engineering stress-strain curves of each material at a total of 8 strain rates in quasi-static and dynamic conditions are tested. Each test is repeated at least 3 times. The 8 strain rates are 0.001 / s, 0.01 / s, 0.1 / s, 1 / s, 10 / s, 100 / s, 500 / s and 1000 / s, respectively. The technicians make strain curves for the soft steel under engineering stresses at 8 strain rates.

[0041] In step 3, the Swift-Hockett-Sherby constitutive model fits and extrapolates the data to obtain an extension-to-1 curve that is convenient for engineering applications, ensuring that no intersection occurs between the strain rate curves.

[0042] In step five, the validity of the test is verified, a finite element model of the specimen stretching is established, and the model is compared with the test data curves at different strain rates until the deviation of the benchmark data is less than 5%. When the data deviation is greater than 5%, the data of high-speed stretching at different rates are reprocessed, and the Swift-Hockett-Sherby constitutive model is used to fit and extrapolate the data to obtain an extension to 1 curve that is convenient for engineering application.

[0043] In step seven, the technicians conduct failure tests on the high-strength steel. There are six types of failure tests, namely shear test, static tensile shear test, R5 notch tensile test, R20 notch tensile test, center hole tensile test and perforation test. Each test is repeated at least 3 times. The high-strength steel is subjected to shear test, static tensile shear test, R5 notch tensile test, R20 notch tensile test, center hole tensile test and perforation test for more than three times.

[0044] In step nine, finite element simulation is used to perform benchmarking and optimization curves, including loading failure material card fracture test simulation benchmarking, mesh size coefficient test simulation benchmarking and strain rate coefficient test simulation benchmarking, and the benchmarking data deviation is less than 5%. When the data deviation is greater than 5%, the stress triaxiality of the failure site and the equivalent strain at the time of failure are recalculated by LS-Dyna, and the static and high-speed tensile curves are combined to make the GISSMO original fracture failure material card.

[0045] According to the above records, the present invention, the technicians divide the automobile steel into two types: soft steel and high-strength steel. The technicians place the soft steel on a high-speed tensile testing machine, and test the engineering stress-strain curves of each material at quasi-static and dynamic strain rates of 8, and each test is repeated at least 3 times. The 8 strain rates are 0.001 / s, 0.01 / s, 0.1 / s, 1 / s, 10 / s, 100 / s, 500 / s and 1000 / s, respectively. The technicians process the data of high-speed tensile testing of soft steel at different rates, and use the Swift-Hockett-Sherby constitutive model to fit and extrapolate the data to ensure that no intersection occurs between the strain rate curves. The technicians establish the original dynamic mechanical material card of the soft steel material in the LS-dyna software according to each strain rate curve. The technicians establish a finite element model of the specimen stretching. The specimen size and loading method are the same as those in the test, and the test data curves at different strain rates are benchmarked. If the data deviation is greater than 5%, the soft steel data is processed again until the benchmark data deviation is less than 5%. The technicians output the calibrated soft Steel dynamic mechanical material card, high-strength steel is subjected to shear test, static tensile shear test, R5 notch tensile test, R20 notch tensile test, center hole tensile test and perforation test for more than three times. The technicians obtain the force-displacement curve of the high-strength steel corresponding to the failure test process. The technicians use LS-Dyna to calculate the stress triaxiality of the failure site and the equivalent strain at the time of failure. Combined with the static and high-speed tensile curves, the GISSMO original fracture failure material card is made. The technicians load the failure material card fracture test simulation benchmarking, grid size coefficient test simulation benchmarking, strain rate coefficient test simulation benchmarking, and use finite element simulation to benchmark and optimize the curve. If the data deviation is large, the force-displacement curve of the high-strength steel corresponding to the failure test process is obtained again until the benchmarking data deviation is less than 5%. The high-strength steel GISSMO fracture failure card after benchmarking is output. According to the classification of automobile steel grades, the soft steel dynamic mechanical material card and the high-strength steel fracture failure material card are simultaneously brought into the CAE collision analysis in the CAE collision analysis, which can accurately predict the deformation and failure characteristics of metal materials.

[0046] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-speed collision material card for automobile steel and its application method, characterized in that: The following steps are involved: Step 1: Classification of steel for automobiles: technicians classify steel materials for automobiles; Step 2: Test different types of steel: technicians conduct high-speed tensile tests on mild steel, and technicians conduct failure damage tests on high-strength steel; Step 3: High-speed tensile data processing: The technicians process the data of high-speed tensile of mild steel at different rates and use the Swift-Hockett-Sherby constitutive model to fit and extrapolate the data; Step 4: Create the original dynamic mechanics material card: The technicians create the original dynamic mechanics material card in the LS-dyna software based on the curve obtained after processing the high-speed tensile data of mild steel; Step 5: Verify the validity of the test: verify the validity of the test data of mild steel and the fitting to obtain the true stress-plastic strain curve of mild steel; Step 6. Output accurate material card: Output the dynamic mechanical material card of the calibrated soft steel; Step 7: Obtain material fracture curves under different stress triaxiality conditions: technicians conduct failure tests on high-strength steel to obtain force-displacement curves during the failure test process; Step 8: Make the GISSMO original fracture failure material card: The technicians use LS-Dyna to calculate the stress triaxiality of the failure part of the high-strength steel and the equivalent strain at the time of failure, and combine the static and high-speed tensile curves to make the GISSMO original fracture failure material card; Step 9: Benchmarking of finite element simulation model: Technical personnel establish a finite element simulation model of the corresponding failure test of high-strength steel, and use finite element simulation to perform benchmarking and optimization curves; Step 10: Output fracture failure card: Output GISSMO fracture failure card of high-strength steel after benchmarking; Step 11, CAE collision analysis: Based on the classification of automobile steel grades, the dynamic mechanical material card of soft steel and the fracture failure material card of high-strength steel are simultaneously brought into the CAE collision analysis.

2. The high-speed collision material card for automobile steel and its application method according to claim 1, characterized in that: In the step 1, the steel materials used in automobiles are classified into two types: soft steel and high-strength steel.

3. The high-speed collision material card for automobile steel and its application method according to claim 1, characterized in that: In the step 2, the soft steel is subjected to a high-speed tensile test. On a high-speed tensile testing machine, the engineering stress-strain curve of each material at a total of 8 strain rates in quasi-static and dynamic conditions is tested. Each test is repeated at least 3 times, and the 8 strain rates are 0.001 / s, 0.01 / s, 0.1 / s, 1 / s, 10 / s, 100 / s, 500 / s and 1000 / s, respectively.

4. The high-speed collision material card for automobile steel and its application method according to claim 1, characterized in that: In the step 3, the Swift-Hockett-Sherby constitutive model is used to fit and extrapolate the data to obtain an extension-to-1 curve that is convenient for engineering applications.

5. The high-speed collision material card for automobile steel and its application method according to claim 1, characterized in that: In step 5, the validity of the test is verified by establishing a finite element model of the sample stretching and comparing it with the test data curves at different strain rates until the deviation of the benchmarking data is less than 5%.

6. The high-speed collision material card for automobile steel and its application method according to claim 1, characterized in that: In step seven, the technicians conduct failure tests on high-strength steel. There are six types of failure tests, namely, shear test, static tensile shear test, R5 notch tensile test, R20 notch tensile test, center hole tensile test and perforation test. Each test is repeated at least 3 times.

7. The high-speed collision material card for automobile steel and its application method according to claim 1, characterized in that: In the step nine, finite element simulation is used to perform benchmarking and optimization curves, including loading failure material card fracture test simulation benchmarking, grid size coefficient test simulation benchmarking and strain rate coefficient test simulation benchmarking, and the benchmarking data deviation is less than 5%.

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