Complex Joints Mechanical Connection Load Distribution Engineering Algorithm Research

Along with the composite material is gradually extensive in the application of the aviation realm, a lot of inevitable joint problems appear。 Because of anisotropy of the composite material, the stress distribution in joint becomes extraordinary complex; And then because of the brittleness characteristic of the composite material , the load distribution of multi-fastener mechanical joints becomes seriously uneven; But the complicated bearing-load joints of airplane are mostly made by metal。 Owing to above three reasons, in this thesis, the model of the single fastener in composite mechanical joints is built up, and the distribution of the stress and force around the hole is analyzed for different laminates to study further the invalidation theory of fasteners ; Aiming at multi-fastener joint , mainly study the load distribution after considering the factors , such as the laminate parameter, alignment pattern and the form of joint, and the conclusion has higher practical value for the design of composite fasteners in aircraft design; Aiming at bearing-load joints, this thesis build up three-dimensional of the familiar metal fasteners and analyze the stress distribution and the load distribution in complicated joint, and it is intended to the design of complicated metal fastener,. The main work of thesis contains following several aspects:Firstly, introduce the main work on composite mechanical joints that has been did in domestic and foreign, including the related theories, applying the condition and designing on trial method etc。 The main joint forms are carried on the research currently in composite mechanical joints, and the merit and shortcoming of various joint forms are analyzed。Secondly, compared a few existing methods of building up the finiteelement model, then study practically the different characteristics of simplification model and their applied scopes and calculate and analyze the data by example, finally found the textual research method and the model to computer。In text introduces the interrelated finite element theory in chief, mainly describes the analysis software MSC/NASTRAN adopted and the modeling technique in joints。Thirdly, the load distribution of joints with three fasteners in line is calculated and compared with experimental data, which proves that the present method is effective and conveniens And considered the influence of different layer parameter, study the stress analysis, the distribution of the force around the hole and the load distribution。 At the same time, study the load distribution of composite fastener mechanical joints, considered the joint forms and the space between fasteners。 The result indicates that the finite element model and the calculation method adopted have the higher accuracy and can be used for the engineering calculation。Fourthly, aiming at the metal bearing-load joints in the aircraft structure currently, build up three-dimensional model and analyze the stress distribution and the load distribution of complicated metal fasteners 。The work done has the leading meaning to the design of complicated metal fastenerso...