Research On Method And Application Of BESO Based On Element Stress

A requisite part of engineering design is structural optimization,topology optimization can change the structure of the original topology scheme according to the constraint,load and optimization target,and obtain the best layout of the material.It has become one of the hot spots of structural optimization.The evolutionary structure optimization algorithm(ESO)does not produce the intermediate density of the variable density method by gradually removing the elements to obtain the optimal topology structure and easy to fulfill that ESO integrates with the ANSYS software,therefore it has been a boom since it born,but the existence of the question that unit once deleted,and afterward not restored,the subsequent development of BESO has solved the issue.At present,the research of BESO method is still more than the theoretical aspect.The BESO theory and methods are still in the continuous development,but the engineering application of BESO is several.Therefore,based on the traditional BESO algorithm,this paper proposes a bidirectional evolutionary structural optimization method based on the element stress.The TBT-ML500 deep-hole drilling Arbor bar is used as the research object,and its topology optimization and reconstruction design are carried out.The study content can be summarized as the following:(1)The basic concepts and principles of ESO algorithm are analyzed,an evaluation index based on stress and volume is given to evaluate the optimization quality and efficiency of the algorithm.According to the different optimization goals of ESO algorithm,the pros and cons of stress criterion,stiffness criterion and frequency criterion are studied respectively,the general process of ESO algorithm based on stress criterion is given.Based on the numerical instability problem in ESO method,the causes and solutions are analyzed,and an example is given to analyze the issue of checkerboard lattice the validity of the ESO algorithm and the feasibility of the ESO algorithm(2)On the basis of ESO algorithm,I study the different principle of traditional BESO algorithm,and the general flow of BESO algorithm is given.Then,in accordance with the shortcomings of BESO algorithm,the BESO algorithm based on element stress is proposed,by removing and adding unit,to get the topology structural of the target volume,and on this basis,in accordance with the level of strain energy,to ensure the volume of the same premise,deletion and recovery unit further,to obtain the optimal topology institutions.This method takes into account the stress level of the structure and volume changes in cells,avoiding the oscillation,improve quality and optimize efficiency,effectively avoid the traditional BESO algorithm in the calculation method and "shock phenomenon".Finally,the optimization of the beam structure is carried out to verify the superiority of the improved BESO algorithm.(3)Aiming at the improved BESO algorithm proposed in this paper,two kinds of topology optimization algorithm programs are developed by using the APDL language in ANSYS to delete and add the functions of the unit,including the stiffness maximization design under the mass constraint and the light-weighting design under the static and dynamic performance;based on UIDL language development BESO algorithm is different Optimization of the graphical interface and parameterized block diagram,the original interface to ANSYS implements the menu addition and extends the topological optimization of ANSYS.(4)The BESO algorithm based on element stress is applied to the arbor structure of TBT-ML500 deep-hole drilling machine,and the optimal configuration is obtained,the rigidity maximization design of the arbor is based on the quality constraint.Based on the reconstructed design of the optimized configuration of the arbor,and the static performance analysis of the reconstructed model shows that the quality,stress and deformation of the optimized boom are reduced,and the overall quality from 741 kg to 672.4kg,decreased by 9.26%;the maximum deformation from 9.3?m to 8.4?m;decreased by 9.68%;the maximum stress from 4.237 MPa to 3.618 MPa,reduced by 14.61%,achieve the maximum rigidity of the arbor The correctness of the reconstructed model is verified by the comparison of the frequency and the vibration pattern before and after the optimization,and the validity of the algorithm is also verified.