A new mechanism for the formation of ply wrinkles due to shear between plies
A new mechanism for the formation of ply wrinkles due to shear between plies
复制标题
DOI：
10.1016/j.compositesa.2013.03.002
复制
发表时间：
2013-06-01
影响因子：
8.7
通讯作者：
Potter, Kevin
中科院分区：
文献类型：
--
作者：
Lightfoot, James S.;Wisnom, Michael R.;Potter, Kevin
面外铺层变形的形成使复合材料的力学性能显著降低。面内纤维错位也会导致抗压强度降低，然而这些缺陷的来源被误解了。本文提出了一种新的皱纹形成机理，它是基于复合材料与刀具热膨胀系数不匹配而产生的剪切力，以及在固结过程中向半径方向发生的铺层滑移过程。使用U形工具，使用光学显微镜对复合材料梁中的缺陷进行了表征，结果表明，工具的几何形状和预浸料桥接会导致“不稳定位置”，这会导致高达750个卡纸的褶皱，以及00层高达50层的面内错位。通过省略释放膜来增加摩擦剪应力，防止了皱纹的形成，支持了本文提出的机理。(C)2013爱思唯尔有限公司。保留所有权利。
The formation of out-of-plane ply deformation causes significant reductions in the mechanical properties of composites. In-plane fibre misalignments also cause reductions in the compressive strength, yet the origins of these defects are misunderstood. This paper presents a new mechanism for the formation of wrinkles, which is based upon the shear forces generated as a result of mismatches in the coefficient of thermal expansion of composite and tool, as well as the process of ply slippage that occurs during consolidation into radii. Using a U-shaped tool, defects in composite spars have been characterised using light microscopy, showing that the tool geometry and prepreg bridging leads to "instability sites," which lead to wrinkles up to 750 jam in height as well as in-plane misalignment of 00 plies of up to 50. Increasing the frictional shear stress through omission of release film prevents the formation of wrinkles, supporting the mechanism presented in this paper. (C) 2013 Elsevier Ltd. All rights reserved.