Integrated Design Of Structure And Material Of Carbon Fiber Reinforced Plastics (CFRP)

Composite materials play an important role in vehicle lightweight by their excellent mechanical and physical properties.The traditional forward design of composite is usually concerned with the macro structure optimization of the component,neglecting the properties of the material of the composite material itself,and unable to give full play to the maximum material potential of the composite material.So the integrated design of carbon fiber composite structure and materials is studied.The research on the integrated design of carbon fiber composite structure and material is to consider the interaction and coupling between the macro structure and the micro material,and the concurrent design structure and material.Based on multiple scales(microscopic,mesoscopic and macro),the influence relationship of integrated design is established.In this paper,we use the homogenization method of two scale asymptotic expansion to solve the equivalent elastic parameters of all scales,and relate them to different scales.The structure of each scale is analyzed,and the finite element model is modeled by software ABAQUS.Then,the non-dominated sorting genetic algorithm(NSGA-?)is applied to optimize the material parameters and structural parameters in order to optimize the macro mechanical properties in the elastic stage.The front fender of automobile is selected for the integrated design of macro components,then the mechanical condition is analyzed,and the mechanical performance requirements are specified.After analysis,we choose light weight and large stiffness of outer panel as targets,and other stiffness and first-order modal requirements are constrained.Two kinds of common automotive carbon fiber composites: unidirectional fiber reinforced composites and plain woven composites are selected.Unidirectional composites involve two dimensions: micro and macro.The microscopic cell element and macro structure are analyzed,and the design variables are selected by the micro volume fraction and the macro layer angle.The optimization results show that under the requirements of mechanical properti es,the quality is reduced by 61% compared with the metal material and the stiffness of t he outer plate is improved to achieve the purpose of light weight.Woven composites consist of three dimensions: micro,mesoscopic and macro.The structure of each scale is analyzed,and the micro volume fraction,mesoscopic fiber bundle width and thickness,and macro ply angle are selected as design variables.The optimiz ation results were reduced by 58% compared with the metal material.Comparing the two kinds of composite materials,both of them can achieve lightweight purposes.The specific choice needs to be considered in combination with actual working conditions and requirements.