| At present,Carbon Fiber Reinforced Polymer(CFRP),as an important potential solution for realizing vehicle weight reduction,has received widespread attention and recognition from the automotive industry.In 2016,China’s “Energy-saving and New Energy Vehicle Technology Roadmap” clearly stated that by 2030,the use of carbon fiber in automobiles should reach 5% of the vehicle’s weight.Under this background,it is of great significance to carry out in-depth application of CFRP materials in automobiles.The joints of car body,as an important load-bearing structure,usually have complex force conditions and are directly related to the performance of the vehicle.This article selects a CFRP T-joint of car body as the research object,and conducts the following research:Firstly,this paper takes the traditional metal T-joint at the bottom of the B-pillar of automobile as the reference object for design,and the characteristics and feasibility of CFRP T-joint forming process are taken into account,and then the design of CFRP T-joint structure is carried out.After comprehensive consideration of conditions and influencing factors,the appropriate raw materials and process forms were selected for the preparation of CFRP T-joints.And the test of mechanical properties of CFRP material was performed according to ASTM(American Society for Testing and Materials)standards.Then,the transverse bending loading test of CFRP T-joint was carried out.The load-displacement curve of the loading point was output and recorded.The key mechanical properties such as the transverse bending stiffness K and the peak load capacity F were obtained.Observed and analyzed the influence of the failure type of the T-joint on its mechanical properties.The finite element model was established using Abaqus software to simulate the transverse bending test of the CFRP T-joint,and the simulation results showed good agreement with the test results.Finally,a DOE of the transverse bending test of the T-joint was performed using the Optimal Latin hypercube.According to the selected test sample point and its corresponding finite element analysis results,an RBF agent model is established for the transverse bending stiffness K and mass M of the T-joint.Based on the established RBF agent model,the NSGA-II genetic algorithm was used to optimize the structure of the T-joint in Isight,and the effectiveness of the optimization results was verified.The paper show that: the designed CFRP T-joint can be successfully prepared by selecting suitable raw materials and molding process.The progressive damage at the upper side of the T-joint results in a reduction in its transverse bending stiffness,and the large area of failure on the underside of the structure can make it almost completely lose its transverse bending capacity.A finite element model that accurately restores test conditions can accurately simulate and predict test results.Through the structural optimization process,the weight of the CFRP T-joint is reduced while the transverse bending mechanical properties are significantly improved. |
