Assembly Deviation Analysis Considering Composite Flexible Part’s Fiber-layup-angle Error

The errors of fiber layup angles in laminated composite structure,which occur during manufacturing process are inevitable.And these errors decide the performance of mechanical behavior in flexible assembly,which is composed of composite flexible panels.Based on the foundation of previous theory of flexible assembling deviation analysis,this thesis studies the effect of composite layup angle errors on flexible assembling deviation.Then,this thesis establishes a composite flexible parts assembling deviation analysis model that takes composite layup angles errors into consideration.And it applies an optimization method of flexible assembling deviation to realize deviation compensation.The main research contents and results are as follows:This thesis will introduce the study of influence,which is caused by composite layup angles errors,in flexible assembling deviation.It will state the structural features of laminated composite and the definition of layup briefly.The stiffness analysis of laminated composite will be elucidated as well.This thesis established the finite element model of composite flexible parts assembling according to the practical process of assembly.It stimulates the practical distribution of fiber layup in manufacturing by experiment design that is based on uniform design method.And,it focuses on the effects of different fiber layup conditions on composite flexible parts assembling.This thesis will establish a model of composite flexible parts assembling deviation analysis with fiber layup angle errors consideration.In the small angle error case,this thesis establishes an approximate mathematical expression of super stiffness matrix by the first order Taylor series expansion..It detaches the layup angle factor from the flexible assembly deviation analysis model.When it comes to large angle error,this thesis applies the second order Taylor series expansion as analysis method.At last,the validity of the model proposed in this thesis will be checked by analyzing an instance’s deviation of vertical stabilizer composite front edge assembly.Research in compensation of composite flexible parts assembling deviation.In this part,normal fixture adjustment of over-deterministic points will be leaded in the model that proposed in this thesis.The paper deduces the linear constraint equation based on the fixture adjustment to transform this issue into a classical quadratic programming problem.Then,the thesis solves this optimization problem by Lagrange multiplier methods.A flexible fixture will be designed to realize the adjustment of over-deterministic points.Through a fiberglass panel assembly experiment,the thesis compares the deviations before and after compensation.And the results show that the compensation can improve the performance of flexible assembling deviations.