Optimization Method Of Fiber Trajectory Based On Gap Defect And Layup Pressure Analysis

Composite materials have become a kind of important aerospace structural materials.Because of the application of automatic fiber placement,composite materials are wildly used in aerospace and civil field.However,the domestic researches are still in its infancy.As the initial part of composite components manufacturing,trajectory planning has a significant impact on components quality and mechanical properties.In this paper,the multi-objective optimization method of pre-impregnated tow trajectory is studied for the layup of complex surfaces to meet the performance requirements.The factors such as layup error,layup quality and layup performance are synthetically considered in this method.The main contents of the paper are as follows:(1)The mathematical descriptions of curves on surfaces and complex surfaces are discussed.Especially,the mechanical analysis of the gap/overlap defect,the analysis of the turning radius of fiber trajectory and the mechanical analysis of the rolling contact of the flexible roller are carried out to lay a mathematics and mechanics foundation for the optimization of fiber trajectory.(2)The influences of offset direction deviation on layup pressure and contact pressure during layup process are studied respectively,and the corresponding calculation methods are given.The layup gap is calculated based on curve local approximation and the layup pressure is calculated based on laying pressure analysis.Then,in order to interpolate the trajectory of complex surfaces,a trajectory interpolation method which takes layup pressure,layup gap and layup efficiency as evaluation parameters is introduced.(3)The constant-step algorithm and multi-objective interpolation algorithm are used in a test,and the area of trajectory gap,the contact pressure fluctuation and kinematic performance of these two algorithms are compared and analyzed.The results of the test prove that multi-objective interpolation algorithm can reduce gap area,improve the stability of contact pressure and ensure the layup quality more efficiently compared with constant-step algorithm.(4)Take complex surfaces as the research object,based on the secondary development function of CATIA and VS2010 development platform,the functions of fiber trajectory planning,fiber trajectory interpolation and output,and dynamic simulation of automatic fiber placement system are realized,which provides software support for automatic fiber placement system.