Analysis Of Rigidity For Frame-type Framework Of Aircraft Assembly Fixture

Assembly fixture is a tool for orientation and clamping in aircraft assembly, and the assembly fixtures'rigidity is one of the most important criterion to guarantee quality of the assembled aircraft. Computer aided engineering(CAE) has not been better applied to fixture design. Many fixtures have still been designed and verified according to accumulated know-how, which hardly ensures designed fixture adequate rigidity and better structural dimension. Combined with characteristics of assembly fixtures, it is researched as follows, by adopting CAE tool and optimization technology.Firstly, the theory of beam structure finite element is adopted in this thesis to analyze aircraft fixtures'structures. Discretization method for assembly fixtures is deep studied. A method of parametric finite element analysis is proposed, and is applied to analysis of fixtures series. The application shows the above method improves modeling speed and efficiency of analysis greatly.Secondly, a hybrid algorithm, which integrates structure optimization technology and general analysis software, is presented, and is used to optimize overall sizes and cross-section sizes of assembly fixtures. It ensures assembly fixtures ideal structural dimension.Finally, a software module for analysis of assembly fixtures is developed on MSC.Patran. The module includes geometric modeling, mesh generation, external loads and constraints on geometry, optimization analysis, and post-process. It has been used in actual design. The engineering case has proved the effectiveness of CAE and optimization function.