Study On Compressive Mechanical Properties And Optimal Design Of BCB Lattice Structure

As a kind of multi-functional lightweight structure with low density,high specific stiffness and high specific strength,lattice structure has a stable energy absorption rate in the compression process and a strong ability to resist buckling and impact.Lattice structure has great application potential in aerospace,biomedical,new heat exchanger and other fields.With the rapid development of additive manufacturing technology,a reliable method for the preparation of lattice structures is provided,which makes the large-scale application of lattice structures possible.Lattice structure is composed of cell structure arranged periodically in space and the corresponding relationship between structure and performance can be designed and predicted.Therefore,in order to obtain a lattice structure with better efficiency,it is necessary to accurately grasp the influence of structural design parameters on its performance,so as to optimize the structural parameters and obtain the desired optimal performance.In this paper,the compression mechanical properties of BCB lattice structure as the research object,using mechanical experiments,theoretical analysis,finite element simul ation,neural network,genetic algorithm and other methods to optimize and analyze the BCB lattice structure,under the premise that the lattice structure has enough bearing capacity to achieve lightweight structure and optimal compression performance.Firstly,considering the technical requirements of SLM technology,BCB lattice structures with different parameters are prepared for compression experiments.The collected stress-strain curves are compared with the mechanical properties derived from Timoshenk o beam theory,and the deformation mechanism and energy absorption of lattice structures are analyzed.Secondly,the quasi-static compression process of lattice structure is simulated by two finite element analysis methods,solid element and beam element,and the stress distribution and mechanical response in the compression process of lattice structure are analyzed,and the influence of different design parameters on the structure performance is analyzed by orthogonal experiment.It is found that the two methods achieve good results in the calculation of the equivalent yield stress of the structure,but the solid element is better than the beam element in the energy absorption value of the structure,and the beam element is far less than the solid element in the requirement of computing resources.The influences on the load performance of BCB lattice structure Z bearings are in descending order: rod radius,rod length,spatial Angle and horizontal Angle.The influences on the energy absorption performance of the structure are in descending order: radius,spatial Angle,rod length and horizontal Angle.Thirdly,a large number of quasi-static compression data of lattice structure are collected by means of parametric modeling,and the relationship model of latti ce structure parameters with its bearing capacity and energy absorption performance is established by using BP neural network.The results show that the prediction error rate of 90.36% model performance is less than 9%,and the accuracy is high.Finally,the lattice structure was designed and optimized by genetic algorithm to achieve the optimization of the lattice structure quality and energy absorption performance.Based on the optimization results,the finite element simulation analysis was carried out t o prove the effectiveness of the optimization results.