Analysis Of Mechanics Propeties Of Bolted High Temperature Resistant Polyimide Composite Laminates

Along with the development of the aviation industry,as aircraft cruising speed is higher and higher,there is a significantly increase in the aerodynamic heating.So work environment of the material is more bad and the use of materials selection is more severe.The high temperature resistant polyimide composites arises at the historic moment with wide use of space.However,the widely use of composite materials raises new questions.Main bearing parts usually use the bolt connection,and opening hole on the composite material will cause fiber breakage,geometrical discontinuities and entail local stress(or strain)concentration during loading.Therefore,study of the polyimide materials connection is of great significance for engineering applications.Related research content is as follows:Firstly,the paper introduced the concept of the composite connection failure and the status of research at home and abroad.Secondly,the paper introduced the basic knowledge of elastic mechanics of anisotropic materials,giving the calculation formula of stiffness matrix and flexibility matrix for orthogonal anisotropic materials.It described the current mainlly used criterion of material failure and stiffness degradation in detail.This paper briefly introduced the main module and the application field of the finite element software Ansys and Abaqus,and compare between them.Thirdly,Abaqus’ s Hashin criterion was used to predict the failure load of the single bolted composite joint.The developing processes of user subroutine USDFLD and VUMAT was introduced,and the corresponding three-dimensional progressive damage model was set up.It verified the effectiveness of the program respectively,with means of the criterion of 3D Hashin failure criteria and 3D Alvaro failure criterion and appropriate stiffness degradation rules from the paper.The law of how the geometric parameter W/D,E/D and fitting clearance between bolt and bolt hole affect bolted composite joint was studied.Finally,this paper chose VUMAT subroutine to simulate the comppsite joints under the condition of normal temperature and high temperature,getting the failure load and gradual damage figure of joints,and comparing them.Summaring the main contents of the paper,theconclusion was gived.The study of high temperature resistant polyimide composite joints was prospected according to the paper,hoping to provide some references for engineering application.