Energy Absorption Characteristics And Optimization Design Of Composite Semi-circular Corrugated Beam

Fiber reinforced composites have good energy absorption characteristics,which can be used to manufacture energy absorbing structures and to improve the crashworthiness of aircrafts.Due to the complexity of composite material's energy absorption mechanism,the mechanical behavior and failure mode after impact are significantly different from metal material.Therefore,it is really need to deeply understand the energy dissipation mechanism of the composite materials and rationally apply its characteristics.The main research content of this paper is as follows:Three kinds of composite corrugated beams with different fiber layup angles are designed and manufactured.The fiber layups of the test pieces are[0/90]_4s,[0/45/-45/0]_2s and[45/-45]_4s.Quasi-static axial compression tests are carried out for these composite corrugated beams.After the test,the energy absorption characteristics,energy absorption mechanism and failure morphology of composite corrugated beams are investigated in detail.The material constitutive model of the MAT54 material model and the Chang-Chang failure criterion are elaborated and their applicability is analyzed in detail.Simple parametric models are established to output the stress-strain curve of the material model.Next,the detailed parametric analysis of the material model is performed to identify parameters which affect shell element failure and element deletion.Based on the parametric study of MAT54material model,the axial compression model of composite corrugated beam single-shell model is established through variable parameter analysis.Since the single-shell model can not simulate the failure morphology of composite structures,expecially the delamination damage.The multi-shell model method of composite corrugated beams is studied.The multi-shell model of composite corrugated beam uses beam element as the cohesive element between layers,and the weak link is composed of shell elements with decreasing height.Finally,based on the axial compression test results of composite corrugated beams,the composite corrugated beam multi-layer shell model is proved to be effective.Based on the multi-shell finite element model of the composite corrugated beam,this chapter mainly optimizes the structure of the trigger and the layup angle.Firstly,corrugated beam muti-shell models with different forms of triggers are established to research the influence on the energy absorption characteristics of the structure.Secondly,this chapter introduces the optimization model and the theory of optimization in detail.The response surface model and the quadratic sequence optimization algorithm are used to optimize the fiber layup angle of the composite corrugated beam structure.Finally,the effectiveness of the optimization results is verified.This paper combines the composite corrugated beam static axial compression test with the finite element model to deeply investigate the energy absorption mechanism and energy absorption characteristics.Based on the Chang-Chang failure criterion,the axial compression multi-shell model of composite corrugated beam is established.This research can provide reference for crashworthiness analysis of the composite material fuselage structure,which has practical engineering significance.