Energy Absorption Characteristics And Optimization Design Analysis Of Multi-stable Structures

With the development of science and technology,the demand for new materials is increasing.In recent years,energy absorbing materials and structures have attracted continuous attention due to their characteristics of personnel and equipment protection,vibration isolation and impact resistance.Common working mechanisms of energy-absorbing materials and structures include:(1)energy absorption through plastic deformation;(2)energy absorption by viscoelasticity of materials.However,the energy absorbing structures based on plastic deformation cannot be reused,while the energy dissipation of viscoelastic materials and structures is related to the loading rate.In order to obtain a reusable energy absorbing structure independent of loading rate,a multi-stable material utilizing structural instability to realize the energy absorbing structure was proposed.Multi-stable mechanical metamaterials are composed of multiple flexible bistable structures which can be arranged periodically and have multiple stable positions in the deformation process.Due to the large nonlinear deformation of the whole structure and the elastic deformation in the structure,the multi-stable materials can realize the elastic reusable energy consumption.The main research contents of this paper are:1.The mathematical model and finite element model are established to analyze the bistable principle and energy dissipation principle of bistable curved beam structure.The appropriate finite element analysis method is selected to solve the nonlinear deformation problem of multi-stable structure.2.The finite element simulation of displacement loading/unloading of multi-stable structure considering geometric nonlinearity was carried out to analyze its load-displacement curve and energy absorption principle of multi-stable structure.The bistable single cell structure was assembled in array to study the influence of series and parallel periodic arrangement on the overall deformation and energy absorption of the structure.The dynamic response of the structure under transient impact load is analyzed to prove the impact protection effect of multi-stable structure.Several single cell models of curved beam structure with different configurations were established,and the finite element analysis of displacement loading was carried out to calculate the energy storage size of several single cell models,and then the energy absorption effect of several different linear types was compared.3.Study the structural shape characterization method of cosine beam with variable cross section based on multi-parameter regulation,establish the structural optimization model of multi-stable single cell structure with variable cross section according to the energy storage characteristics of multi-stable structure,and solve the optimization problem in Isight multi-island-GA to obtain the optimal structural shape of beam with variable cross section under the condition of constant total mass.The effectiveness of the optimization is verified by finite element analysis of the optimization results and dynamic response analysis of the structure under transient impact load.