Research On Hot Stamping Of Invar Based On Flexible Mould

Composite materials have been widely used in aircraft parts, in order to solvethe problem of its forming temperature heat matching, the molding material need tohave a approximate constant expansion coefficient at about150oC. Because ofInvar’s almost constant expansion coefficient in room temperature, it has beenwidely used in all kinds of occasions that require constant temperature. So Invar issuitable as the material of composite materials forming mould. Invar’s machiningperformance is very bad, so it not only has a long processing cycle but also wastesmore materials and costs more. So this paper is going to from the perspective ofmulti-point flexible mould processing do some related designs of flexible mouldand analyze the forming performance of Invar based on flexible mould.This paper first focuses on the related designs of multi-point flexible mould,and compile the software interface with the algorithm that can calculate the heightof flexible pole. With flexible pole utilization as the research point, the paperdiscusses the arrangement of flexible pole scheme. At last part，the structure offlexible pole is designed, then we verify the feasibility of the design throughstrength check.The second part of paper is by means of finite element simulation analyzingInvar’s hot stamping formability based on multi-point flexible mould. First of all,we do the hot compression experiment to get the constitutive model of Invar. Andwe establish the finite element model based on multi-point flexible mould, set up thesimulation boundary conditions and set the related parameters.Through the finite element simulation, the paper studies the dimpling andspringback during the stamping process. We explore the influence of the differentthickness and curvature radius of sheet to the dimpling and study the differentcurvature radius of the ball of flexible pole and the spacing between flexible polesfor the influence of the dimpling. Also, the paper studies the springback of differentforming curvature radius, sheet thickness, stamping velocity and holding time.Finally this paper proposes a method to control the springback.