| The aircraft structure contains a large number of weakly rigid sheet metal parts, as well asflexible composite components and the assembly of aircraft flexible parts need the help of assemblyfixture. Due to the shape error, positioning error of the compliant parts and the positioning error of theassembly fixture, compliant parts tend to deform during the assembly process, and this will seriouslyaffect the manufacturing quality of the aircraft. Currently, the research of deviation analysis ofcompliant assembly is mainly focused on automotive sheet metal wedding process, and thespecialized research for aircraft assembly is fewer. In the support of National Natural ScienceFoundation of China (50905084,51275236) and Aeronautical Science Foundation of China(2010ZE52054), the thesis studies the geometric continuity analysis model of surface error; researchesthe statistical analysis model of assembly fixture boards’ positioning deviation; creates the Piecewise-Linear elastic force model of assembly force and assembly deformation under the small deformation,linear elastic assumption; establishes the statistical deviation analysis model of compliant assembly.The main contents and achievements are as follows:The geometric continuity analysis model of compliant parts surface error is studied. Due togeometric continuity, the key measurement points on the surface of compliant parts are notindependent but related. Legendre polynomials and Sine polynomials are introduced to portray thewarping and waviness deviation curves. Combining with the variance of the measurement points’deviation, a geometric covariance model is established. Finally, a case study on sheet metals wasdiscussed. The geometric covariance by the proposed approach was compared with the onestatistically calculated from the error data. The results show the geometric covariance model couldcharacterize the real surface variation effectively.The statistical analysis model of assembly fixture boards’ positioning deviation is researched.The fit error of hole-pin-hole (slot) as well as its relationship with the deviation of key points on thefixture boards is researched based on linear algorithm of deterministic location. At last, this statisticalanalysis model is tested by Monte Carlo simulation with the help of Vis/VSA.The Piecewise-Linear elastic analysis model for compliant assembly is studied. A linear elasticmodel reflects the relationship of assembly force and assembly deformation is established based onthe assumption of small and linear elastic deformation. Finally, the effectiveness of the model isverified though assemblies test. The statistical deviation analysis model of compliant assembly is established. Combined with thePiecewise-Linear elastic model and statistical theory, the statistical deviation analysis model ofcompliant assembly is created. Statistical analysis model is applied to certain type of aircrafthorizontal tail fixed leading edge skin and rib plate assembly instance. The validity and applicabilityof the statistical model is verified by Monte Carlo simulation with the help of Vis/VSA. |
