Characteristic Parameters Identification And Structural Lamination Optimization About The Carbon Fiber Reinforced Composites

In the context of the "Made in China 2025" national strategy,automobiles are classified as one of the ten "breakthroughs to be vigorously promoted in key areas",and automobile lightweight has become an important trend of global automobile development.Material replacement is one of the important ways to reduce the weight of automobiles,and carbon fiber composite materials are widely used in automobile bodies and various parts due to its excellent material properties.However,carbon fiber composites have relatively complex spatial structure and the properties of their components vary greatly,so their mechanical behavior is complex and their properties are difficult to predict.Therefore,the acquisition of the characteristic parameters of carbon fiber composite material has important theoretical significance and practical value for the theoretical and numerical study of the material and its application.In addition,structural design is the key to the design of carbon fiber materials,especially the layering sequence of carbon fiber composite materials has a greater impact on the material properties,so it has important engineering practical significance to carry out optimization design research on its layering sequence.Therefore,the main work carried out and completed in this paper based on the above issues is as follows:1.For carbon fiber composite material T700/E44,a quasi-static mechanical performance test was carried out.Uniaxial tensile and uniaxial compression tests were carried out on unidirectional plates and composite plates of 0°,90°and [0°/90°/45°/45°/90°/0°]s,and the materials' tensile strength,elastic modulus,Poisson's ratio and compressive strength were effectively obtained.The damage morphology of the sample was analyzed.2.Based on the T700/E44 multi-condition test,a phased and rapid identification of the carbon fiber composite material characteristic parameters was developed.First,based on various tests,the corresponding positive problem model is established,and the unsolved parameters of each stage are determined by sensitivity analysis.Secondly,in order to improve the calculation efficiency,the radial basis approximate model is used to replace the real numerical calculation to establish the inverse problem model of parameter identification,and the intergenerational genetic algorithm is used to solve and obtain the characteristic parameters of carbon fiber composite materials.Finally,the inverse parameters are applied to the numerical calculation of unidirectional plate materials and compared with the test results.The results show that the material parameter inverse method can effectively and quickly obtain the characteristic parameters of composite materials.3.The genetic algorithm is used to optimize the ply angle sequence of the laminated board structure.Firstly,the tensile test model of the laminated plates is established by reverse parameters.Secondly,a mathematical model for the optimization of lay-up Angle sequence is established,constraints are determined,and appropriate genetic algorithm control parameters are selected to obtain two optimal lay-up sequences.Finally,a comparative analysis is made between the preferred layer and the conventional layer,the results show that the mechanical properties of the preferred layer are obviously better than the conventional layer,and an optimal layup was determined.4.Numerical models of carbon fiber thin-walled round tube specimens with conventional layup and two preferred layups under transverse compression impact were established,and the load time history,stress,energy absorption and failure morphology of the layup under dynamic loads were obtained.The results show that the overall performance of [0°/90°/0°/0°/±45°/±45°]s is the best.Carried out the Hopkinson test of the best layer,and compared with the simulation,the test results are in good agreement with the simulation results.