Fatigue Performance Analysis And Multi-objective Lightweight Optimization For Suspension Control Arm Base On ADAMS

Automotive lightweight design is the industry trend,is one of the three directions of automobile,It has become an essential part of the modern automobile design process to improve the auto parts by the FEM.The lightweight structure optimization of each component of the chassis accounted for the largest proportion of lightweight structure,control arm as the key component of Mcpherson suspension,The lightweight design has important effect to the stability of Mcpherson suspension.When a car is driving,The control arm is subject to random dynamic loads varying with time,subject to dynamic stress,easy to cause fatigue damage.Fatigue life failure is the main failure form for the control arm,so fatigue life is an important index for the development of control arm.This paper is based on a self-designed brand of car with the front Mcpherson rear torsion beam suspension,combined with finite element method(FEM)and multi-body dynamics method for lightweight design of Mcpherson suspension control arm,at the same time,research the fatigue life of the control arm,design a new aluminum alloy control arm structure to meet the basic performance indicators,provide reference for lightweight design of parts.First,used the six component acquisition system,obtained the six component of the wheel center on different road surface.Based on the theory of multi-body system dynamics,the rigid flexible coupling model of the front Mcpherson torsion beam suspension is established in ADAMS/Car,and verified the accuracy of the vehicle dynamic model.Tested the six component of the wheel core and loaded into the whole vehicle dynamic model,18 dynamic load spectra are extracted from the connection points of the steel structure control arm,and the static load of the control arm under four limiting conditions,such as acceleration,braking condition,steady state turn left and steady state turning.Secondly,Used Hypermesh software,Based on the theory of finite element analysis,Analysis the strength,rigidityand modal performance of welded steel structure control arm,Comparative analysis of the free modal test results of steel structure control arm,verified the accuracy of the finite element boundary constraint for the original structure,provided the constraint conditions for the optimization of aluminum alloy control arm structure.Then,based on the load spectrum of connecting points about control arm,combined the steel material's S-N curve,calculated the fatigue life of the control arm by using the inertia release method in FATIGUE software,check the result whether to meet the requirements of the existence of security risks,at the same time,provided the boundary conditions for the multi-objective optimization.Last,replacement control arm's material with the type 6061 aluminum alloy,topology optimization of aluminum alloy control arm by using Optistruct software,then,based on the result of topology optimization,reconfigurabled the model of control arm,parametriced the model of aluminum alloy control arm using Meshworks/Morpher software,with the Isight software interface,used Latin hypercube sampling method,built the multi objective optimization model.Carried out the multi-objective optimization of the aluminum alloy control arm,analysis the modal,stiffness and strength with the multi objective optimization of aluminum alloy control arm and compared with the welded steel structure,the results showed that the performance of the optimized aluminum alloy control arm is improved,the mass of control arm reduced by 52% compared with the steel structure control arm,meet the expected lightweight targets.