Contact Force Model And Variation Analysis In The Variation Analysis Of Flexible Sheet Metal Assembly

A large number of flexible sheet metal parts and nonmetal thin-walled parts are used in theAirplane structure. These parts are prone to distort during assembly; therefore, the assemble accuracyof flexible parts will directly influence the whole performance of airplane. From the perspective of theassembly process, riveting is the main technology used in airplane sheet metal assembly. Due to smallcraft stiffness, massive assembly connecting surface and complex assembly force, the rivetingdeformation is large and the riveting deviation is difficult to be predicted. As a consequence, theassemble deformation of flexible parts becomes the main reason of the manufacturing deviation ofairplane. The existing assembly simulation methods of flexible parts mainly focus on the automotiveassembly process, which generally neglects the phenomenon of sheet contact. This paper aims at thecontact problem in flexible sheet metal parts assembly simulation. The main contributions are asfollows:Finite element analysis of the flexible sheet metal parts assembly deviation model based on thelinear elastic hypothetic is introduced. This paper has summarized the finite element analysis method,including the establishment of the mesh model of flexible parts, and the application of boundaryconditions to finite element analysis model. Monte Carlo simulation method, Method of InfluenceCoefficient(MIC) and the linear elastic hypothetic method are compared. The basic approach ofextraction of stiffness matrix of super elements for the linear elastic hypothetic method is introduced.The contact force model in the variation analysis of flexible sheet metal assembly is analyzed.The contact force model includes the interference analysis based on geometric detect, the contactforce and contact balancing algorithm and assembly force correction due to the change of contactstate.The analysis case of assembly with contact model is given. The assembly processes with andwithout contact model in the visual C++environment are analyzed respectively and verified viacomparison with experimental results.