KR20220142122A - Method for analyzing stiffness change of trunk exchange vehicle after collision and method for evaluating safety of repaired vehicle using therof - Google Patents

Abstract

The present invention relates to a method for evaluating safety about a repaired vehicle by analyzing a stiffness change of a vehicle body due to an accident repair of the vehicle and, more specifically, to a method for analyzing stiffness changes of a vehicle trunk before and after an accident repair, and a repaired vehicle safety evaluation method using the same. In accordance with the present invention, in order to solve limitations of existing technology which is unable to solve vague distrust and anxiety about a repaired vehicle due to inability to provide accurate information about the safety of the repaired vehicle, the method comprises the following steps of: conducting a crash test through the same method as that of an actual vehicle; checking a damaged part and the condition thereof in case of a crash which is the same as an actual vehicle crash through simulation; interpreting and analyzing a state change of the vehicle after repair through a commercial program; and based on the analysis result, comparing stiffness changes of the vehicle body before and after the accident to check and evaluate the safety of the corresponding vehicle, thereby solving vague distrust and anxiety about the repaired vehicle and securing safety and reliability.

Description

Method for analyzing stiffness change of trunk exchange vehicle after collision and method for evaluating safety of repaired vehicle using therof}

The present invention relates to a method of analyzing a change in the stiffness of a vehicle body according to an accident repair of a vehicle and evaluating the safety of a repaired vehicle based on the analysis result, and more particularly, generally, the skeleton of the vehicle body during a vehicle crash accident If damage or deformation occurs in major parts such as the frame or the frame, even if the damaged part is repaired, the strength of the car body will be lower than that at the time of initial shipment, which raises concerns about the performance and safety of the vehicle. In order to solve the problems of the prior art, in which a method for providing accurate information on the safety of a repaired vehicle was not provided in order to resolve such distrust or anxiety, although the value of the vehicle is greatly reduced due to the increase in distrust and anxiety. , A method of analyzing the stiffness change before and after accident repair of a vehicle trunk, and analyzing the change in stiffness before and after accident repair of a vehicle trunk, which is configured to evaluate the safety of a repaired vehicle through the results, and a method for evaluating the safety of a repaired vehicle using the same will be.

In addition, the present invention, as described above, in order to solve the limitations of the prior art that could not solve the vague distrust and anxiety about the repaired vehicle because accurate information on the safety of the repaired vehicle was not provided, the current sales frequency in the domestic market Select one passenger car with a high level and conduct a rear impact test in the same way as the actual vehicle using the vehicle’s drawings, materials and related data, and check the damaged area and condition in the same collision as in the case of a real vehicle collision through simulation Thus, for example, F-D curve, effective plastic strain, and force by speed, such as the change in the stiffness of the car body after the crash repair, can be analyzed using commercial software. It is analyzed through finite element analysis (FEA) using , it relates to a method of analyzing the stiffness change before and after accident repair of a vehicle trunk, which is configured to resolve vague anxiety and distrust about the repaired vehicle, and to secure safety and reliability, and a method for evaluating the safety of the repaired vehicle using the same.

Recently, as a passenger car has become a major means of transportation, most households purchase a car and operate it for the purpose of business, commuting, and leisure activities.

In general, vehicle-to-vehicle accidents are caused by front collision, rear collision, and side collision. Rigidity can protect occupants, but in the case of a rear-end collision, the trunk and back panel absorb shock to protect passengers. can

In addition, if a collision or contact accident occurs while driving the vehicle, repairs are made at the repair shop. On the other hand, if the trunk is deformed, repairs are made by removing the welded part with a drill and re-welding by exchanging the trunk. Distrust and anxiety about the vehicle increase, and furthermore, the value of the vehicle decreases after repair, or there are many cases in which lawsuits are filed for collapse damage.

That is, in general, if the body frame, which is the main skeletal part, is deformed during a collision or contact accident of a vehicle, characteristics such as rigidity of the body frame are deteriorated compared to the time of initial shipment through the repair process. If the safety of the driver or passengers is not guaranteed due to the change in the rigidity of the vehicle body in the event of a re-accident while driving, a small accident can lead to serious personal injury.

Therefore, since the change in the rigidity of the vehicle body frame before and after the accident repair is a part directly related to the safety of the vehicle and the safety of the driver, it is desirable to accurately grasp the degree of the changed rigidity after the repair and to operate the vehicle after confirming the safety of the vehicle.

Here, as an example of the prior art related to the apparatus and method for analyzing the stiffness of a vehicle body as described above, first, for example, "a method of analyzing the stiffness of a vehicle body" as presented in Korean Patent Publication No. 10-1974892 There is this.

More specifically, in the above-mentioned Registered Patent Publication No. 10-1974892, a mass corresponding to the mass of the equipment or cover is set at a predetermined position within an area where the equipment or cover is fixed or connected to the fixed connection part of the vehicle body skeleton model. and a stiffness analysis step of performing a stiffness analysis in consideration of the inertial force acting on the mass-setting vehicle body skeleton model when the vehicle is running with respect to the mass-setting vehicle body skeleton model, comprising: Even before the equipment or cover is determined in the model, by setting the mass equivalent to these in place of the equipment or cover, the rigidity of the vehicle body is constructed so that accurate stiffness analysis can be performed in consideration of the inertial force acting when the vehicle is running. how to interpret it.

In addition, as another example of the prior art related to the apparatus and method for analyzing the rigidity of a vehicle body as described above, for example, "a method of analyzing the rigidity of a vehicle body" as presented in Korean Patent Publication No. 10-0288236 have.

More specifically, the above-mentioned Korean Patent Publication No. 10-0288236 provides a method comprising: performing a low-frequency idle vibration analysis through a vehicle body finite element model; Detailed modeling of the sensitive panel sensitive to high-frequency vibration from low-frequency idle vibration analysis and analysis data of previous vehicle models; setting a target stiffness for the panel sensitive part, and setting an excitation node, an excitation direction, and an excitation frequency region for high-frequency vibration analysis from analysis data of the previous vehicle model; Calculating the frequency response characteristics through random response analysis by point mobility of the panel sensitive unit with the excitation direction and the excitation node set in the set excitation frequency region; According to the frequency response characteristics, the rigidity level of the panel sensitive part is identified, and if the determined rigidity level is greater than the set rigidity target value, including the step of manufacturing a prototype car and performing a test evaluation, the booming area ( 200Hz to 400Hz), reduce the number of test cars produced and develop by reflecting the improvement plan in the prior development stage by performing stiffness analysis on the stiffness level and sensitive parts for cowl, dash, follower, roof, package tray, spare tire room, etc. It relates to an automobile panel stiffness analysis method using point mobility, which is configured to reduce the production cost of automobiles by shortening the period.

As described above, in the prior art, various technical contents for analyzing the rigidity of a vehicle body have been presented. However, since most of the contents of the prior art as described above are applied in the design or production stage of a vehicle, the limitations were clear.

That is, as described above, it is not known how much the stiffness reduction occurs after the accident repair of the vehicle, and thus the safety of the repaired vehicle is not guaranteed. In order to solve the problem of the vehicle body, the analysis method of stiffness change before and after vehicle accident repair of a new configuration, which is configured to confirm the safety of the repaired vehicle, through analysis of the change in stiffness before and after the repair of the vehicle body, and the vehicle safety evaluation method using the same Although it is desirable to present it, there is still no device or method that satisfies all such requirements.

Korean Patent Publication No. 10-1974892 (2019.04.26.) Korean Patent Publication No. 10-0288236 (2001.02.05.)

The present invention is to solve the problems of the prior art as described above, and therefore, an object of the present invention is to repair the damaged part when damage or deformation occurs in major parts such as the skeleton or frame of the vehicle body during a vehicle crash accident. Since the strength of the vehicle body is lowered compared to when it was initially shipped, concerns about the performance and safety of the vehicle arise. In order to solve the problem of the prior art in which a method that can provide accurate information on the safety of the repaired vehicle was not presented in order to resolve the anxiety, the stiffness change before and after the accident repair was analyzed for the vehicle trunk, and through the results The purpose of this study is to provide a method for analyzing the stiffness change before and after accident repair of a vehicle trunk, which is configured to evaluate the safety of a repaired vehicle, and a method for evaluating the safety of a repaired vehicle using the same.

In addition, another object of the present invention is to solve the limitations of the prior art that could not solve the vague distrust and anxiety about the repaired vehicle because accurate information on the safety of the repaired vehicle was not provided as described above. Select one passenger car with high sales frequency in Check the condition, for example, F-D curve (F-D curve), effective plastic strain (Effective plastic strain), force by speed, etc. Changes in condition before and after accident repair, such as the change in stiffness of the car body after crash repair can be analyzed through finite element analysis (FEA) using commercial software, and the safety of the vehicle can be confirmed and evaluated by comparing the change in stiffness before and after a crash for a trunk exchange vehicle based on the analysis result. It is intended to provide a method for analyzing the stiffness change before and after accident repair of a vehicle trunk, which is configured to resolve vague anxiety and distrust about the repaired vehicle, and to secure safety and reliability, and a method for evaluating the safety of the repaired vehicle using the same.

In order to achieve the above object, according to the present invention, in the method for analyzing the stiffness change before and after accident repair of a vehicle trunk, data on specifications and rear collision tests for various actual vehicles are collected, respectively, and accidents on the vehicle trunk A database building step in which a process of constructing a database for analyzing stiffness change before and after repair is performed; a modeling step in which a process of establishing an analysis model for a finite element analysis (FEA) for an analysis target vehicle to be analyzed is performed based on the contents of the database constructed in the database building step; a test step in which a process of measuring a state change before and after accident repair for the trunk of the vehicle to be analyzed is performed through a rear impact test using a finite element analysis (FEA) using the analysis model modeled in the modeling step; and an analysis step in which, based on the test result of the test step, an analysis step of performing an analysis on a state change before and after accident repair for the trunk of the analysis target vehicle is performed is performed by a computer or dedicated hardware. There is provided a stiffness change analysis method before and after accident repair of a vehicle trunk, characterized in that it is configured.

Here, in the database building step, data on the specifications of various actual vehicles, data on the results of rear impact tests for each vehicle, and data on tensile test results before and after trunk repair are collected, respectively, in a database format It is characterized in that the processing of building a database for analyzing the stiffness change before and after accident repair for the vehicle trunk is configured to be performed by storing it as a .

In this case, the database construction step includes crash test data according to a crash test method and a repair method based on the Research Council for Automobile Repairs (RCAR) or New Car Assessment Program (NCAP) standards for each vehicle and data on the state after repair It is characterized in that it is configured such that the process of collecting and building the database is performed.

In addition, in the test step, by using the analysis model modeled in the modeling step, accident repair for each speed with respect to the trunk of the vehicle to be analyzed for each speed through a rear impact test using finite element analysis (FEA) It is characterized in that it is configured to perform a process of measuring the front and rear impact stiffness, stress, strain rate, energy absorption force, displacement, and effective plastic strain, respectively.

In addition, the analysis step, based on the test result of the test step, calculates an F-D curve for the energy absorption force (Force) and the displacement amount (Displacement) for the trunk of the analysis target vehicle before and after accident repair The process of performing an analysis on the change in energy absorption according to the speed; a process of calculating the change in effective plastic strain for each speed and performing an analysis on the amount of deformation before and after accident repair for the trunk of the vehicle to be analyzed; And it is characterized in that the processing including the process of calculating the change in the energy absorption force (Force) for each speed and analyzing the energy absorption force before and after the accident repair for the trunk of the analysis target vehicle is configured to be performed, respectively.

Furthermore, according to the present invention, there is provided a computer-readable recording medium in which a program configured to cause the computer to execute the method for analyzing the stiffness change before and after accident repair of a vehicle trunk described above is recorded.

Further, according to the present invention, in the safety evaluation method of a repaired vehicle, an inspection step in which a process of inspecting the state of the repaired vehicle after repair is performed using the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk described above; and an evaluation step in which processing for evaluating the safety of the repaired vehicle is performed based on the inspection result of the inspection step, wherein the processing is configured to be performed by a computer or dedicated hardware. this is provided

Here, in the evaluation step, based on the inspection result of the inspection step, when a specific inspection result value does not satisfy a predetermined reference value or a predetermined reference range, it is determined that the safety of the repaired vehicle is insufficient and operation is unsuitable It is characterized in that the processing is configured to be performed.

Alternatively, in the evaluation step, based on the inspection result of the inspection step, each inspection result value is compared with the value at the time of initial shipment of the repaired vehicle, and the difference between the specific inspection result value and the value at the time of initial shipment is a predetermined reference value However, when it does not satisfy the predetermined reference range, it is determined that the safety of the repaired vehicle is insufficient, and a process for determining that the operation is unsuitable is performed.

Alternatively, the evaluation step is configured to classify the safety of the repaired vehicle according to a predetermined criterion, and a process for determining the safety of the repaired vehicle by grade based on the inspection result of the inspection step is performed. do it with

As described above, according to the present invention, according to the present invention, one passenger car with high sales frequency in the domestic market is selected, and a crash test is performed in the same way as a real vehicle by using the drawings, materials, and related data of the vehicle, and simulation is performed. Through this, the damaged parts and conditions are checked during the same collision as in the case of a real vehicle collision. is analyzed through finite element analysis (FEA) using commercial software, and based on the analysis results, a vehicle configured to confirm and evaluate the safety of the vehicle by comparing the change in stiffness before and after a crash accident for a trunk exchange vehicle By providing a method for analyzing the stiffness change before and after accident repair of a trunk and a method for evaluating the safety of a repaired vehicle using the same, the safety and reliability of the repaired vehicle can be secured, thereby eliminating vague anxiety and distrust of the repaired vehicle.

In addition, according to the present invention, as described above, the stiffness change analysis method before and after accident repair of the trunk of a vehicle configured to analyze the change in stiffness before and after accident repair for the trunk exchange vehicle and evaluate the safety of the repaired vehicle through the result, and By providing a method for evaluating the safety of a repair vehicle using this method, when damage or deformation occurs in major parts such as the skeleton or frame of the vehicle body in a crash accident, the strength of the vehicle body is lower than that at the time of initial shipment, even if the damaged part is repaired. Concerns about the performance and safety of the vehicle arise, and as a result, vague distrust and anxiety about the vehicle being repaired increases, and the value of the vehicle is greatly reduced. It is possible to solve the problems of the prior art in which a method for providing information is not provided.

1 is a view showing the specifications of a test vehicle used in a crash test applied to an embodiment of the present invention in a table.
2 is a diagram schematically showing the contents of a finite element analysis modeling work applied to an embodiment of the present invention.
3 is a view showing a state of performing a tensile strength test according to an embodiment of the present invention.
Figure 4 is a view showing the results of comparing the tensile strength of the normal parts and the parts after welding is summarized in a table.
5 is a view showing the results of comparing the errors for each part between the test results of the test vehicle and the test results of the analysis vehicle, arranged in a table.
6 is a graph showing internal energy according to the speed of a normal vehicle and a trunk exchange vehicle.
7 is a view showing the result of comparing the force and displacement for each speed on the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a diagram showing an FD diagram at 15 km.
8 is a view showing the results of comparing the force and displacement for each speed on the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a diagram showing an FD diagram at 30 km.
9 is a view showing the results of comparing the force and displacement for each speed on the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a diagram showing an FD diagram at 40 km.
10 is a view showing the results of comparing the force and displacement for each speed on the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a diagram showing an FD diagram at 50 km.
11 is a view showing a result of comparing effective plastic deformation for each speed of a trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a view showing the amount of deformation at 15 km.
12 is a view showing a result of comparing effective plastic deformation for each speed of a trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a view showing the amount of deformation at 30 km.
13 is a view showing the results of comparing the effective plastic deformation for each speed of the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and shows the amount of deformation at 40 km.
14 is a view showing the results of comparing the effective plastic deformation for each speed of the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention, and is a view showing the amount of deformation at 50 km.
15 is a view showing the results of analyzing the state change of force for each speed after a crash test of a normal vehicle and a repair vehicle in which CO ₂ welding is performed on the trunk after an accident, showing the force at 15 km.
16 is a view showing the results of analyzing the state change of force for each speed after a crash test of a normal vehicle and a repair vehicle in which CO ₂ welding is performed on the trunk after an accident, showing the force at 30 km.
17 is a view showing the results of analyzing the state change of force for each speed after a crash test of a normal vehicle and a repair vehicle in which CO ₂ welding is performed on the trunk after an accident, showing the force at 40 km.
18 is a view showing the results of analyzing the state change of force for each speed after a crash test of a normal vehicle and a repair vehicle in which CO ₂ welding is performed on the trunk after an accident, showing the force at 50 km.
19 is a flowchart schematically showing the overall configuration of a method for analyzing stiffness change before and after accident repair of a vehicle trunk according to an embodiment of the present invention.
20 is a flowchart schematically showing the overall configuration of a method for evaluating the safety of a repaired vehicle using a method for analyzing stiffness change before and after accident repair of a vehicle trunk according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a specific embodiment of the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to the present invention and the safety evaluation method of the repaired vehicle using the same will be described.

Here, it should be noted that the content described below is only one embodiment for carrying out the present invention, and the present invention is not limited to the content of the embodiment described below.

In addition, in the following description of the embodiments of the present invention, for parts that are the same as or similar to those of the prior art, or that can be easily understood and implemented at the level of those skilled in the art, the detailed description is provided for the sake of brevity. It should be noted that o was omitted.

That is, in the present invention, as will be described later, when damage or deformation occurs in major parts such as the skeleton or frame of the vehicle body during a vehicle collision accident, even if the damaged portion is repaired, the strength of the vehicle body is lower than that at the time of initial shipment. Concerns about the performance and safety of the vehicle are raised, and as a result, vague distrust and anxiety about the vehicle being repaired increases, and the value of the vehicle is greatly reduced. In order to solve the problems of the prior art in which a method that can provide It relates to a method for analyzing stiffness change before and after accident repair and a method for evaluating the safety of a repaired vehicle using the same.

In addition, the present invention is currently sold in the domestic market in order to solve the limitations of the prior art that could not solve the vague distrust and anxiety about the repaired vehicle because accurate information on the safety of the repaired vehicle was not provided, as will be described later. A passenger vehicle with high frequency is selected and the rear impact test is conducted in the same way as the actual vehicle by using the vehicle's drawings, materials and related data, and the damaged parts and conditions in the same collision as in the actual vehicle collision are analyzed through simulation. After confirming, for example, F-D diagram, effective plastic deformation, and force by speed, such as the change in the stiffness of the car body after the crash repair, are analyzed through finite element analysis (FEA) using commercial software. And, based on the analysis result, it is configured to confirm and evaluate the safety of the vehicle by comparing the stiffness change before and after the collision accident with respect to the trunk exchange vehicle, thereby resolving vague anxiety and distrust about the repaired vehicle and improving safety and reliability. It relates to a method for analyzing the stiffness change before and after accident repair of a vehicle trunk configured to secure

Subsequently, with reference to the drawings, the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to the present invention and the specific content of the method for evaluating the safety of the repaired vehicle using the same will be described.

In general, the trunk part of a passenger car is formed as a monocoque type integral body configured to maintain the rigidity of the body by bending or overlapping several sheets of steel plate to reinforce it, connecting it to the side panel and the rear panel, and welding it. It is used to mass-produce vehicles while performing assembly and welding work step by step.

Here, the car body absorbs the load and vibration of the vehicle, and reinforcement is added to the parts necessary to maintain rigidity during manufacture. together the transformation occurs.

In other words, when repairing after a car accident, the deformed car body is pulled or stretched using a jig to maintain the basic frame, then the damaged part is straightened and the deformed car body is cut using a saw, cutter, or welding machine. Welding work is done.

At this time, replacement parts are installed in the original place of the parts removed by working with CO ₂ welding or spot welding. This is the process of repairing damage.

In addition, if a re-accident occurs while the vehicle is running after the rear accident repair is completed, the difference in stiffness and safety between the vehicle at the time of shipment and the vehicle after repair due to the change in the stiffness of the vehicle body increases the damage. Therefore, in the present invention, as will be described later, a method for judging the safety of a repaired vehicle by comparing the change in stiffness before and after repairing a vehicle accident was proposed.

To this end, in the embodiment of the present invention to be described below, one vehicle is selected from among the currently operated semi-medium passenger vehicles, and the rear collision test is performed in the same manner as the actual vehicle using the material, drawings, and data of the entire vehicle. , and through simulations, the damaged parts and conditions were confirmed in the same collision as in the case of a real vehicle collision. Through finite element analysis (FEA), for example, F-D curve, effective plastic strain, and force by speed, such as the stiffness change of the vehicle body before and after accident repair The state changes were compared and analyzed, and the safety of the repaired vehicle could be evaluated through the analysis results.

More specifically, first, a car crash test is described. In order to check the stability of the vehicle, the crash test is performed by moving the vehicle against a fixed wall or column shape, or by moving and hitting an obstacle to determine damage or deformation of the vehicle, or It is a test that judges the force applied to the vehicle by evaluating the damage to the human body and the vehicle. The standard is not the car itself, but the passengers or pedestrians in the car when the vehicle collides. It is to check and judge how much impact there is by calculating the impact.

That is, for example, in a frontal collision, the vehicle collides and the occupant jumps forward. At this time, the area covered by the seat belt is pressed, so in the frontal collision test situation, the amount of chest displacement is measured as a dummy or the degree of head injury is determined. measure

In addition, in the embodiment of the present invention, the test method of the World Research Council for Automobile Repairs (RCAR) is applied, which is an accident that mainly occurs in the middle and low speed section, such as a driving pattern on a city road. As a test method that can represent the type, it is a method to evaluate the damage and repairability of a new car.

In other words, even in a crash accident under the same conditions, depending on the vehicle model, there are a car model with a lot of damage and parts with a lot of damage and a car model with a lot of damage is judged to have bad damage, and if there is little damage, it is judged to have good damage. do.

Also, in Korea, there is an RCAR test conducted by the Automobile Technology Research Institute under the Insurance Development Institute to calculate car insurance premiums before and after the launch of a new car for domestic sale. This is done in such a way that damage and repairability are assessed and graded.

In more detail, the repair cost is calculated by reflecting vehicle damage and repairability in a complex manner, and it is classified from the lowest grade to the highest grade of 26, and the damage and repairability evaluation grade is divided into grades 1 to 26 (26 steps). The higher the grade (closer to the 26th grade), the better the damage and repairability during a low-speed collision of the vehicle. , reflecting the paint evaluation) and the frequency index reflecting the damage rate of the vehicle.

Here, the vehicle's depth index (reflecting damage and repairability) is calculated by evaluating the impact characteristics, parts price, working hours, labor and painting labor for each model. The characteristics of damage and repairability due to the collision test on the rear side are indexed.

Next, if the trunk repair method is described, the repair method when the trunk is damaged is, first, with sheet metal correction work, after removing the damaged parts of the rear bumper and rear panel, check the damaged trunk condition, and the part that can be worked with sheet metal In the case of , modify it by applying heat using an oxygen welding machine, or restore it to tension by correcting the deformed part using a straightening sheet metal equipment. and sealing operation.

Here, when restoration is impossible due to damage to the trunk, an exchange operation is performed. After making and processing a hole with a drill in the same place, it is joined by CO ₂ welding or spot welding, and the welding part is grinded and sealed and then painted.

Therefore, through the repair process as described above, the characteristics of the body frame or trunk parts change, and among them, the change in rigidity is directly related to the safety of the vehicle and the safety of the driver. It is desirable to evaluate the safety of the vehicle by determining the degree of rigidity and determine whether to drive or not.

Accordingly, in the present invention, by applying the test method and repair method as described above, a crash test using an actual vehicle is performed, and the result of measuring the change in stiffness after repair and analysis using finite element analysis (FEA) Through this, the stiffness change analysis and safety evaluation were performed on the repaired vehicle.

More specifically, first, referring to FIG. 1 , FIG. 1 is a view showing the specifications of a test vehicle used in a crash test applied to an embodiment of the present invention in a table.

As shown in Figure 1, in the embodiment of the present invention, the test vehicle is a vehicle that is actually running in Korea, and the drawings and specifications were obtained after requesting the manufacturer's research institute, and the parts applied to the test are currently repair parts in the aftermarket. We purchased the parts to be sold, and selected an experienced mechanic who has been working for more than 20 years at the vehicle service center to perform welding work and make samples.

In addition, referring to FIG. 2, FIG. 2 is a view schematically showing the contents of a finite element analysis modeling work applied to an embodiment of the present invention.

As shown in Figure 2, in the embodiment of the present invention, CAD data for finite element analysis (FEA) and modeling for analysis were applied, and then the test method and physical properties of parts applied to the vehicle, tensile test, and variables were applied, Through the process of comparing and verifying the data from the crash image and the actual vehicle, analysis and evaluation were performed according to the previously recognized test method.

Here, the speed, thickness, mass, gross weight, etc. of the initial modeling values were made like a new car and the values were applied, and the analysis of the finite element model was carried out as shown in the table shown in FIG. 2 , that is, first using CAD data. Clean-up and mid-space were extracted by applying to the entire body of the vehicle, and after modeling the rear trunk and delineating the front and rear fixed walls and barriers, the shell and solid elements and elements were checked, and the material and property boundary point modeling was checked and assumed After setting the boundary conditions, the rear impact test was conducted, and the welding properties were applied to meet the crash test standards. For modeling, a weight of 1232 kg was applied in the finite element analysis, the number of parts was 779, and the number of nodes was 943,770 1,108,874 for dog and element, 901,062 for cell, 67,469 for solid, and 139443 for 1D.

In addition, the vehicle was determined to be in a normal state, and thermal deformation occurs in the actual vehicle when welding is performed in the actual accident repair vehicle, but the residual stress is ignored because it is too many factors in the CAE configuration, so the residual stress is ignored, and the same as the material of the vehicle. The analysis was conducted by applying it, and the effect on safety and passengers was determined by checking and comparing the energy absorption rate, stiffness, and F-D diagram of the normal vehicle and the vehicle after repair.

Next, referring to FIG. 3, FIG. 3 is a view showing a state in which a test for tensile strength is performed in an embodiment of the present invention.

3, in the embodiment of the present invention, in order to determine how much strength can be secured in the event of a collision by determining the physical properties of the material, the same parts as the trunk of the actual vehicle are purchased and the tensile strength after welding operation. was tested, and for this purpose, the tensile strength test was conducted by requesting a tensile test from the Korea Institute of Machinery and Electronics.

In more detail, samples were made and tested by cutting the trunk and spot welding parts of the normal vehicle and the parts welded with CO ₂ after the repair of the accident vehicle. As a result, the stiffness of the trunk after welding compared to the normal trunk It was confirmed that this was weakened by about 14%.

That is, referring to FIG. 4 , FIG. 4 is a view showing the results of comparing the tensile strength of the normal parts and the parts after welding in a table.

As shown in FIG. 4 , the tensile test result can be used as indirect data to prove that the rigidity is weaker than that of the initial state during welding repair after replacement of the trunk, which is the main part of the vehicle body due to a vehicle accident. However, it can be confirmed that the mechanical rigidity after repair is much weaker than when it was initially shipped.

Next, the verification of test results by finite element analysis (FEA) will be described. Carrying out a crash test by causing a re-accident in a vehicle that has been repaired in an accident is a very difficult situation to use in an actual vehicle due to the nature of the crash test of the vehicle. Testing is necessary by selecting many objects and vehicles, such as the selection of a work area of In this embodiment, in order to ensure reliability in the finite element analysis (FEA), the NCAP (New Car Assessment Program) test data of the actual vehicle and the finite element analysis data were respectively compared to check whether they are the same as in an actual collision.

That is, referring to FIG. 5 , FIG. 5 is a view showing the results of comparing errors for each part between the test results of the test vehicle and the test results of the analysis vehicle in a table.

In the results shown in FIG. 5, modeling and verification were performed using the Korean New Car Assessment Program (KNCAP) test method for the actual vehicle, and the error range was checked after performing the analysis using the same test method. It was confirmed that most of the results occurred in a similar form, and as a result of checking the deformation of the steering column and A-pillar of the vehicle in order to secure reliability after modeling, there was little deviation in the crash test data and analysis, and good results were obtained. indicated.

Here, the cause of the error in the analysis of the deformation part of the steering column is somewhat different, but it seems to have little effect because the interior material of a normal vehicle is partially omitted in the CAE analysis. In the test, there is some foam on the fixed wall and it has a structure to absorb shock, so a slight difference occurs, but this is negligible.

In addition, in the result shown in FIG. 5, the result of the actual vehicle for the amount of deformation after the collision and the result obtained by performing the test after modeling the analysis vehicle have an error of 6.1% compared to the actual vehicle, but this is the material characteristic of the barrier in the analysis vehicle. It is judged that this occurs because it is difficult to apply the same in the analysis of the collision part.

Furthermore, in the results shown in FIG. 5, the difference between the steering column part and the A-pillar is that the steering part is made of only iron plates by analysis with the interior material, plastic parts, or rubber parts removed in the case of the steering part. It has been confirmed that there is a slight difference from the A-pillar part, and the possibility of an error is judged to be very low because the 3D distance measurement data is used for the amount of deformation in the actual vehicle.

Continuingly, referring to FIG. 6 , FIG. 6 is a graph showing internal energy according to the speed of a normal vehicle and a trunk exchange vehicle.

As shown in FIG. 6 , in this embodiment, after removing the spot welding part of the rear trunk for restoration after an accident, the internal energy of the vehicle working with CO ₂ welding is compared with that of the normal vehicle and repaired with the normal vehicle. Afterwards, an analysis was performed on the amount of deformation and force for each speed of the vehicle, where the internal energy means energy consumed by the deformation of the vehicle during a collision, and as a result of the analysis, it was confirmed that there was no significant difference in the rear trunk.

In addition, referring to FIGS. 7 to 10 , FIGS. 7 to 10 show the results of comparing the force and displacement for each speed to the vehicle trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention. As the diagrams respectively, FIG. 7 shows an F-D curve at 15 km, FIG. 8 shows an F-D curve at 30 km, FIG. 9 shows an F-D curve at 40 km, and FIG. 10 is an F-D curve at 50 km. are respectively shown.

7 to 10, in the result of comparing the force and vehicle displacement during the collision test by speed (Force vs. Displacement), the state in which a constant shock absorption occurs is the most stable, and the curve is the shock absorption It means that is not made uniformly, which means that the deviation of the absorption capacity is severe, and in the results shown in Figs.

That is, in a vehicle that has been welded after replacing the trunk, unlike at low speed, at high speed of 40 to 50 km/h, the body deformation is very severe and the welded part is in a state where no force can be received. The state characteristics that are very unfavorable to shock absorption appear in all areas, and the deformation is greatly increased during a high-speed collision, and in fact, the steel plates overlap and deform.

This means that the energy absorption rate of a vehicle welded with CO ₂ after replacing a trunk is smaller than that of a conventional vehicle. Therefore, if an accident occurs at a high vehicle speed, it is judged to have a large impact on the safety of passengers.

Next, the collision analysis results for each speed will be described with reference to FIGS. 11 to 14. FIGS. 11 to 14 show the speed of the trunk through a crash test for a normal vehicle and an accident repair vehicle according to an embodiment of the present invention. It is a view showing the results of comparing the effective plastic strain by star, respectively, in which FIG. 11 shows the amount of strain at 15 km, FIG. 12 shows the amount of strain at 30 km, and FIG. 13 shows the amount of strain at 40 km, FIG. 14 shows the amount of deformation at 50 km, respectively.

11 to 14, FIGS. 11 to 14 are images of effective plastic strain diagrams showing the amount of deformation in which the magnitude of the plastic strain in a multiaxial stress state is expressed as an equivalent uniaxial plastic tensile strain, and the amount of deformation is the property of material properties It is proportional to the elongation value, and in the interpretation of this example, a value of 1 means 100%.

11 to 14, as a result of analyzing the state change after a crash test of a normal vehicle and a repair vehicle in which CO ₂ welding was performed on the trunk after an accident, the greater the vehicle's collision speed, the greater the amount of deformation, and the deformation portion is not uniform. In particular, at a speed of 40 to 50 km/h, the trunk welding part falls and dries, and it can be confirmed that the part that distributes the impact also occurs locally.

In addition, referring to FIGS. 15 to 18 , FIGS. 15 to 18 show the results of analyzing the state change of force for each speed after a crash test of a normal vehicle and a repair vehicle in which CO ₂ welding is performed on the trunk after an accident In the drawings, Fig. 15 shows the force at 15 km, Fig. 16 shows the force at 30 km, Fig. 17 shows the force at 40 km, and Fig. 18 shows the force at 50 km, respectively.

As shown in FIGS. 15 to 18 , as a result of analyzing the state change of force after a crash test between a normal vehicle and a repair vehicle in which CO ₂ welding was performed on the trunk after an accident, the resistance of the vehicle occurring at the beginning of the vehicle collision In, it can be seen that the power of the repair vehicle, which has been subjected to CO ₂ welding on the trunk after the accident, is significantly lower than that of the normal vehicle except for the 40 km section.

That is, in general, a normal vehicle is welded by spot welding at the time of shipment, whereas, when repairing a rear collision accident of a vehicle, a certain portion of the deformed trunk is corrected and the welded part is machined with a drill to make a hole. After forming, the trunk is removed and the new trunk parts are CO ₂ welded, and then painting and finishing work are performed _. In order to more accurately understand the change in characteristics such as the decrease in stiffness and to check the effect on the vehicle after repair, as in the case of the actual vehicle, as described above, after replacing the trunk, welding is performed and tensile test and finite element analysis (FEA) are performed. Through this, the impact stiffness in the steady state and after accident repair was compared through the FD diagram for each speed and the effective plastic strain and force analysis, respectively.

As a result, as described above, first, in the tensile strength test for the welded part, it was confirmed that the strength of the material after welding was reduced by about 20% compared to the material of the normal vehicle, and the analysis of the change in the FD curve of the accident vehicle in which the trunk was welded In, the repair vehicle has severe body deformation at a speed of 40 to 50 km/h and the welding part is in a state where it cannot receive force, and it is confirmed that the strength of the spot welded normal vehicle is CO ₂ welded repair vehicle. It was confirmed that it remained strong compared to .

In addition, in the effective plastic strain diagram, which shows the amount of deformation expressed by the equivalent uniaxial plastic tensile strain, the size of the plastic deformation degree in a multiaxial stress state increases as the vehicle collision speed increases, and the deformation portion tends to occur non-uniformly. In particular, it was confirmed that at a speed of 40 to 50 km/h, the trunk welding part fell and dried, and the part that disperses the impact occurred only locally.

In addition, from the result of analyzing the change in force, which means the vehicle's resistance, which occurs at the beginning of the vehicle's collision after the crash test of a normal vehicle and an accident repair vehicle in which CO ₂ is welded to the trunk, except for the 40km section, the trunk It was confirmed that the power of the repair vehicle welded to CO2 was lower than that of the normal vehicle welded with spot (SPOT) welding.

Therefore, it is possible to easily implement the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to the embodiment of the present invention from the above contents and the method for evaluating the safety of the repaired vehicle using the same. That is, referring to FIG. 19, FIG. 19 is a flowchart schematically showing the overall configuration of a method for analyzing stiffness change before and after accident repair of a vehicle trunk according to an embodiment of the present invention.

As shown in FIG. 19, the method for analyzing the stiffness change before and after accident repair of the vehicle trunk according to the embodiment of the present invention is largely divided into data on the specifications of various actual vehicles and the results of performing a front crash test on the vehicle. A database construction step (S10) in which the processing of constructing a database for analysis of stiffness changes before and after vehicle trunk accident repair is performed by collecting data on the data and data on the tensile test results before and after trunk repair, respectively, and storing them in a database format (S10); , a modeling step in which a process of performing modeling for finite element analysis of an analysis target vehicle to be analyzed is performed based on the contents of the data about the actual vehicle stored in the database built in the database building step (S10) ( Using the vehicle model modeled in S20) and modeling step (S20), the energy absorption force (Force), displacement (Displacement) and effective plastic deformation ( Effective plastic strain) is measured in the test step (S30), and the F-D curve for the energy absorption force and displacement measured in the test step (S30) is calculated and stored in the trunk. Analyze the change in energy absorption capacity according to the speed before and after the accident repair for Korea, and calculate the change in effective plastic strain for each speed to compare and analyze the amount of strain before and after the accident repair for the trunk. Including the analysis step (S40) in which the process of comparing and analyzing the resistance force before and after accident repair for the trunk is performed by calculating the state change of force, which means the resistance of the vehicle that occurs at the initial stage of the collision of the vehicle by speed (S40) can be configured.

Here, in the database building step (S10) and modeling step (S20), as described above with reference to FIGS. 1 to 5, data is collected through a crash test and repair method according to the RCAR and KNCAP standards, and these Modeling for finite element analysis can be constructed using data.

In addition, the test step (S30) and the analysis step (S40) are, as described above with reference to FIGS. 6 to 18, collision stiffness, stress ( Stress), strain rate, and energy absorption rate are measured respectively, and the current state of the repaired vehicle is identified by comparing and analyzing the F-D diagram, effective plastic deformation and force for each speed with the state at the time of initial shipment. The processing may be configured to be performed.

In addition, referring to FIG. 20, FIG. 20 is a flowchart schematically showing the overall configuration of a method for evaluating the safety of a repaired vehicle using the method for analyzing stiffness change before and after accident repair of a vehicle trunk according to an embodiment of the present invention.

As shown in Fig. 20, the safety evaluation method of the repaired vehicle using the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to the embodiment of the present invention is performed as shown in the above steps (S10 to S40). Based on the inspection step (S50) and the inspection result, in which the process of verifying the state after the repair of Alternatively, by comparing each inspection result value with the value at the time of initial shipment, if the difference between the specific inspection result value and the value at the time of initial shipment does not satisfy the predetermined reference value or range, the repair vehicle is judged to be insufficient and operated It may be configured to include an evaluation step (S60) in which a process of determining the safety of the repaired vehicle by grade is performed by determining that this is inappropriate, or by dividing the safety grade according to a predetermined standard.

Here, in the above-described embodiment of the present invention, the present invention has been described with respect to the case of analyzing the change in stiffness before and after accident repair for the trunk of the vehicle and evaluating the safety of the repaired vehicle based on the analysis result as an example. It is not necessarily limited to the case of the above-described embodiment, that is, the present invention is, in addition to the trunk, other main parts of the vehicle, such as, for example, the front or side frames or panels, characteristics before and after repair, and It is possible to apply various changes and modifications as needed by those skilled in the art within the scope without departing from the spirit and essence of the present invention, such as analyzing performance changes and comprehensively reflecting the results in safety evaluation. It should be borne in mind

Therefore, as described above, the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to the embodiment of the present invention and the method for evaluating the safety of the repaired vehicle using the same can be implemented, thereby, according to the present invention, sold in the domestic market One high-frequency passenger vehicle is selected and the vehicle's drawings, materials, and related data are used to conduct a crash test in the same way as the actual vehicle, and through simulation, the damaged area and condition are confirmed in the same collision as the actual vehicle. Thus, for example, F-D diagram, effective plastic deformation, and force by speed, such as the change in the stiffness of the car body after the crash repair, are analyzed through finite element analysis (FEA) using commercial software. , a method of analyzing the stiffness change before and after accident repair of a vehicle trunk configured to confirm and evaluate the safety of the vehicle by comparing the stiffness change before and after a crash accident for a trunk exchange vehicle based on the analysis result and the repair vehicle using the same By providing the safety evaluation method, it is possible to secure the safety and reliability of the repaired vehicle, thereby eliminating vague anxiety and distrust of the repaired vehicle.

In addition, according to the present invention, as described above, the stiffness change analysis method before and after accident repair of the trunk of a vehicle configured to analyze the change in stiffness before and after accident repair for the trunk exchange vehicle and evaluate the safety of the repaired vehicle through the result, and By providing a method for evaluating the safety of a repair vehicle using this method, when damage or deformation occurs in major parts such as the skeleton or frame of the vehicle body in a crash accident, the strength of the vehicle body is lower than that at the time of initial shipment, even if the damaged part is repaired. Concerns about the performance and safety of the vehicle arise, and as a result, vague distrust and anxiety about the vehicle being repaired increases, and the value of the vehicle is greatly reduced. It is possible to solve the problems of the prior art in which a method for providing information is not provided.

As described above, the detailed contents of the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to the present invention and the safety evaluation method of the repaired vehicle using the same have been described through the embodiments of the present invention as described above. It is not limited to the contents described in the example, and therefore, the present invention may be modified, changed, combined, replaced, etc. in various ways according to design needs and other various factors by those of ordinary skill in the art to which the present invention belongs. It goes without saying that this is possible.

Claims (10)

In the method of analyzing the stiffness change before and after accident repair of a vehicle trunk,
A database construction step in which a database construction step is performed to collect data on specifications and rear crash tests for various real vehicles, respectively, and build a database for analysis of stiffness changes before and after accident repair for vehicle trunks;
a modeling step in which a process of establishing an analysis model for a finite element analysis (FEA) for an analysis target vehicle to be analyzed is performed based on the contents of the database constructed in the database building step;
a test step in which a process of measuring a state change before and after accident repair for the trunk of the vehicle to be analyzed is performed through a rear impact test using a finite element analysis (FEA) using the analysis model modeled in the modeling step; and
Based on the test result of the test step, a process including an analysis step in which a process of analyzing a state change before and after accident repair on the trunk of the analysis target vehicle is performed is performed by a computer or dedicated hardware A method for analyzing stiffness change before and after accident repair of a vehicle trunk, characterized in that it becomes.
The method of claim 1,
The database building step is
Data on the specifications of various real vehicles, data on the results of rear impact tests for each vehicle, and data on tensile test results before and after trunk repair are collected and stored in the vehicle trunk in the form of a database. A method of analyzing stiffness change before and after accident repair of a vehicle trunk, characterized in that the processing of building a database for analysis of stiffness change before and after accident repair is performed.
3. The method of claim 2,
The database building step is
For each vehicle, the database is built by collecting crash test data according to the crash test method and repair method based on RCAR (Research Council for Automobile Repairs) or NCAP (New Car Assessment Program) standards and data on the state after repair. A stiffness change analysis method before and after accident repair of a vehicle trunk, characterized in that the processing is performed.
The method of claim 1,
The test step is
Using the analysis model modeled in the modeling step, collision stiffness before and after accident repair, stress ( Stress), strain rate, energy absorption force (Force), displacement and effective plastic strain (Effective plastic strain), each of which is configured to be processed so as to change stiffness before and after accident repair analysis method.
The method of claim 1,
The analysis step is
Based on the test result of the test step, by calculating the FD curve for the energy absorption force and displacement, the energy absorption power change according to the speed before and after the accident repair for the trunk of the vehicle to be analyzed. the process of performing the analysis for;
a process of calculating the change in effective plastic strain for each speed and performing an analysis on the amount of deformation before and after accident repair for the trunk of the vehicle to be analyzed; and
Accident of a vehicle trunk, characterized in that the processing including the process of calculating the change in energy absorption force (Force) for each speed and analyzing the energy absorption force before and after accident repair for the trunk of the analysis target vehicle is performed, respectively Analysis method of stiffness change before and after repair.
A computer-readable recording medium having recorded thereon a program configured to cause the computer to execute the method for analyzing the stiffness change before and after the accident repair of a vehicle trunk according to any one of claims 1 to 5.
In the safety evaluation method of a repair vehicle,
An inspection step in which a process of inspecting the state of the repaired vehicle after repair is performed using the method for analyzing the stiffness change before and after the accident repair of the vehicle trunk according to any one of claims 1 to 5; and
and a process including an evaluation step in which a process for evaluating the safety of the repaired vehicle is performed based on an inspection result of the inspection step is configured to be performed by a computer or dedicated hardware.
8. The method of claim 7,
The evaluation step is
Based on the inspection result of the inspection step, when a specific inspection result value does not satisfy a predetermined reference value or a predetermined reference range, it is determined that the safety of the repaired vehicle is insufficient and a process for determining that operation is unsuitable is performed. A method for evaluating the safety of a repair vehicle, characterized in that.
8. The method of claim 7,
The evaluation step is
Based on the inspection result of the inspection step, each inspection result value is compared with the value at the time of initial shipment of the repaired vehicle, and the difference between the specific inspection result value and the value at the time of initial shipment satisfies a predetermined reference value or a predetermined reference range If not, it is determined that the safety of the repaired vehicle is insufficient, and a process for determining that the operation is unsuitable is performed.
8. The method of claim 7,
The evaluation step is
Safety evaluation of a repaired vehicle, characterized in that it is configured to classify the safety of the repaired vehicle according to a predetermined standard, and to perform a process of judging the safety of the repaired vehicle by grade based on the inspection result of the inspection step Way.

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