Fiber misalignment in composites in the form of in-plane waviness and out of-plane wrinkling, is a major defect arising from processes such as hot drape forming. This work studies the micro-level mechanisms of forming in-plane fiber waviness and out-of-plane wrinkling. An out-of-autoclave unidirectional prepreg system by SOLVAY (CYTEC), CYCOM 5320/T650-35 was used to conduct multiple forming experiments and study the effects of various parameters including forming temperate and lay-up sequence. The effect of partial impregnation, or ‘Engineered Vacuum Channels’, in out-of-autoclave prepreg systems on the intra-ply separation/slippage and consequently fiber misalignment was studied and found to be a significant contributor to micro-level mechanisms. Cross sectioning and microscopy of the parts and examination of the end termination profiles were used to analyze the effect of forming parameters on ply end-shortening and consequently fiber misalignment.

复合材料中的纤维不齐度以面内起伏和面外起皱的形式出现，是由诸如热悬垂成型等工艺引起的主要缺陷。这项工作研究了形成平面内纤维波纹和平面外起皱的微观机制。CYCOM 5320 / T650-35采用SOLVAY（CYTEC）的高压灭菌单向预浸料系统进行多次成型实验，并研究了包括成型温度和铺层顺序在内的各种参数的影响。研究了高压釜外预浸料系统中部分浸渍或“工程真空通道”对层内分离/打滑的影响，以及因此对纤维错位的影响，发现其对微观机理起了重要作用。