| With the increasing number of cars,how to further improve the safety of the car has become a very important thing,and the anti-collision beam is the first car part that comes into contact with the hit object when the entire vehicle is in a frontal collision.Effectively designing the front crash beam so that it can maximize the design performance has become a top priority.At the same time,with the continuous improvement of the collision safety regulations,the attention to the safety of the car and the protection requirements after the collision has also been continuously improved,and the standards of car safety have become more and more strict.The design and manufacturing standards are still in a state of test-taking standards.There are different optimized designs for different collision detection,resulting in various styles and materials of automobile front crash beams,and there is no unity and planning within the industry..Therefore,starting from the geometric structure of the anti-collision beam,this paper conducts finite element simulation detection and corresponding experimental analysis for the front anti-collision beam of the same material with different sizes and different geometric structures,and finds out the advantages and disadvantages of various structural designs.Based on the structure,the lightweight design of the front anti-collision beam of a certain model is carried out.The main contents are:(1)Taking five front anti-collision beams with the same material and different structures as the research objects,construct their three-dimensional models,and mark their size parameters,so as to lay a solid foundation for the subsequent comparative analysis.The modal analysis experiment is carried out on the front anti-collision beams,and the finite element modal experimental simulation is carried out on the models established for the five front anti-collision beams at the same time.Comparing the results of the two methods to verify the accuracy of the anti-collision beam model,it is verified that the errors of the two results are not more than 30%,and most of the results are within the range of 20%,which verifies the accuracy of the model.And the error situation is analyzed.Verify the natural frequency of the anti-collision beam.After testing,the first-order frequency of each beam body exceeds 100 Hz,far exceeding the range of20-80 Hz of the shock frequency of the whole vehicle.Frequency coupling affects its performance.Lay a good foundation for the subsequent lightweight design.(2)Carry out the finite element static simulation analysis of the established vehicle front anti-collision beam model,constrain the bottom surfaces of the energy-absorbing boxes on both sides of the anti-collision beam,and apply four forces with different action points on the front of the beam body to analyze Its deformation status and the difference between each beam body,find the relationship between the result and its structure,and optimize the structure that causes the corresponding result,and then carry out a comparative simulation experiment according to the above loading method.The corresponding conjectures are verified,so as to establish the direction and theoretical support for the subsequent optimization.According to the first point load case,the stiffness of the beam is determined as No.5 beam > No.2 beam > No.3 beam >No.1 beam > No.4 beam,but in the remaining three cases,the No.2 beam is 0.92449mm0.34025 mm,0.90015 mm deformation exceeds all beam deformations and is the best anticollision beam with bending resistance.For the problems of other beams exposed under various working conditions,three sets of comparative simulation analyses were set up to determine the influence of various structures of the beam body on the bending resistance of the beam body.The results obtained: the front design of the beam body should avoid stress concentration,and it is better to keep the front part on a plane;the design of the front part of the beam body should have a certain radian,which is beneficial to improve its bending resistance;the beam body is designed to have A certain radian is appropriate.Within the design index,the larger the radian,the greater the bending resistance;the position of the energy-absorbing box of the anti-collision beam has an impact on the bending resistance of the beam body.The closer the distance between the two energy-absorbing boxes,the greater the bending resistance On the premise that the position of the energy-absorbing box is determined and meets the design standards,reducing the length of the beam body is conducive to improving its bending resistance performance and enhancing its low-speed collision performance;the beam body should be designed to maintain a certain rigidity and bending resistance Otherwise,the energy-absorbing box will lose its working conditions,and the stress on the beam body cannot be well transferred to the energyabsorbing box,which makes the beam body more easily deformed and has potential safety hazards;increasing the thickness of the beam body can increase the stiffness and strength of the beam body.Bending resistance,but will also greatly increase the weight of the beam body,and the improvement in bending resistance is not large.Therefore,when designing the beam body,the thickness is not the preferred optimization condition.(3)Carry out collision simulation on the established anti-collision beam model,set the collision simulation for each type of anti-collision beam model according to the speed of lowspeed collision(4km/h)and high-speed collision(50km/h),and the rigid barrier for collision is It is suitable for 1300 kg of a certain model.At the same time,a collision test of 9m/s and an impact mass of 200 kg were for the energy-absorbing box to verify the impact performance of each energy-absorbing box.The results show that under low-speed collision conditions,all beam designs are qualified,and the No.2 beam is ahead of other anti-collision beams with minimum deformation of 7.046 mm,while under high-speed collision,the No.4 beam has a maximum kinetic energy of 106.8KJ The absorption amount ranks first among all beams.After analysis,it is concluded that its energy-absorbing box,that is,the c-type energy-absorbing box,has the best energy-absorbing effect.The collision simulation of the energy-absorbing box shows that the ctype energy-absorbing box leads other energy-absorbing boxes with a maximum kinetic energy absorption of 8099.9627 J.So the beam body of the No.2 beam and the c-type energy-absorbing box is selected as the optimization objects.To pave the way for the subsequent lightweight design.(4)Design optimization scheme for collision results and performance of anti-collision beams.The beam body and energy-absorbing box performed well before being selected as the basis for optimization.Low-speed crash and high-speed crash verification tests with the same settings as before were performed on the optimized beam.It has been verified that the final ctype optimization scheme can optimize the low-speed collision deformation of the original car anti-collision beam by 54.1%.And the optimization of its low-speed collision energy absorption performance also has an optimization effect of 1.51%,and basically absorbs the kinetic energy of low-speed collisions,and minimizes the damage to important parts of the rear car from lowspeed collisions as much as possible.At the same time,for the energy absorption effect of highspeed collision,the energy absorption is increased by 9.1KJ,and the optimization rate reaches9.76%.Therefore,it is determined that the modified c beam is used as the optimization scheme and lightweight optimization is carried out.The optimization method is topology optimization,and the model is modified according to the final scheme of topology optimization,and the final lightweight optimization scheme d beam is obtained.After the finite element low-speed collision and finite element high-speed collision analysis,its collision performance has been preserved.Compared with the original car beam No.1 beam,the weight is reduced by 0.49 kg,and the weight reduction rate reaches 9.63%.The lightweight effect is obvious,and the weight is optimized.The program was successful. |
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