Strength Analysis And Multi-objective Optimization Of A Diesel Engine Turbocharger Support

The turbocharger bracket is a structure to stabilize the turbocharger and connect it with the engine block.In the process of working,it is affected by the weight of the supercharger and the vibration of the whole structure,resulting in a harsh working condition.As the engine design tends to be miniaturized and compact,the design space of supercharger bracket becomes smaller and smaller,which puts forward higher requirements for the design and performance of supercharger bracket.Therefore,the stiffness and strength analysis of supercharger bracket becomes the key of structural design.The strength check and modal analysis of the bracket structure in the engine product design stage is of great significance to improve the safety and reliability of the structure.Taking the bracket structure of a diesel engine supercharger as the research object,this paper analyzes the strength of four groups and eight brackets by using the finite element method,and carries out the multi-objective optimization design for the bracket with large deformation and stress.Firstly,the detailed three-dimensional solid model of supercharger bracket is constructed,and the finite element model is established on the basis of determining the material properties and boundary conditions according to the engineering practice and design requirements.In order to solve the contradiction between the calculation accuracy and the calculation scale,the mesh independence analysis is carried out.The results show that 2mm is more suitable for this strength simulation mesh discretization;Secondly,based on the maximum shear stress intensity theory,the strength of all the support structures was checked,and it was found that the stress and deformation of the left low pressure stage large support were too large,which did not meet the actual needs and needed to be optimized;In order to further investigate the vibration problem,the constrained modal analysis of the target bracket is carried out,and the phenomenon of lower natural frequency is found;Finally,a parametric model is designed for the left low-pressure stage large support,with the maximum low-order natural frequency and minimum mass as the optimization objectives,the stress and deformation as the constraints,and the multi-objective optimization design of response surface method is carried out based on NSGA-Ⅱ algorithm.The results show that the first-order natural frequency of the target bracket is increased by 69.90% compared with that before optimization,and the key target is achieved.The research results of this paper can provide useful reference for the structural design and optimization of construction machinery.