Research On Defect Formationg Mechanism And Detection Technology Of Automated Fiber Placement Components

Automated fiber placement is an important automated manufacturing method for composite material which can achieve continuous variable angle and adapt to complex components with large curvature. But the molding process is affected by a variety of processing parameters, resulting in molding defects, which affect the molding quality. In this thesis, the intrinsic relationship of these two major defects of voids and delamination and the placement pressure and temperature were studied, which provides the theoretical basis for the engineering applications of automated placement.Firstly, the formation mechanism of the voids and delamination was studied. The relationship of the void’s growth and reduce and the placement pressure and temperature was built according to the change of the pressure in the voids. And the relationship of delamination and the placement pressure and temperature was built by the penetration of the resin to the fiber.Secondly, the further relationship of the voids and delamination and the placement pressure and temperature was studied through numerical modeling and finite element analysis. The void growth model was built and solved by MATLAB and the void diameter curves at different placement temperatures and pressures were draw. And the curing deformable model of prepreg fiber and resin flow model was established and analyzed by COMSOL Multiphysics, and then the relationships of delamination and placement temperature and pressure were obtained.Finally the voids detecting experiment was conducted. The active infrared detection technology was selected to detect the defects of the voids. And the optimal combination of solutions in the level within the range of processing parameters to obtain the minimum diameter of the voids was obtained, and the Finally, a bubble defect testing laboratory. By comparing selected active infrared detection technology bubble defects were detected by orthogonal experiment obtain the optimal combination of solutions to obtain the minimum diameter of the bubble in the level of processing parameters within the range of processing parameters, and the correctness of theoretical research before was verified.