Resin treatment of free edges to aid certification of through thickness laminate strength
Resin treatment of free edges to aid certification of through thickness laminate strength
复制标题
DOI：
10.1016/j.compstruct.2016.02.074
复制
发表时间：
2016-06-20
影响因子：
6.3
通讯作者：
Newley, Richard
中科院分区：
文献类型：
--
作者：
Fletcher, Timothy A.;Kim, Tatiana;Newley, Richard
大型航空航天部件通常通过测试狭窄的试样进行认证，例如弯曲层压板，其具有暴露的自由边缘。已发现这些边缘（不存在于生产部件中）会使弯曲层压板的3D强度降低20%以上，表明这种认证方法过于保守。自由边缘还产生奇点，使得有限元（FE）建模是具有挑战性的，这通常使用粘性层间区域的非线性分析来近似。提出了一种新的处理工艺，即在弯曲层合板的自由边涂上一层树脂。这显著降低了边缘效应并延迟了故障。树脂边缘处理使弯曲层合板试样的强度提高了16%。该处理还简化了有限元建模，允许非零应力垂直于层压板边缘，消除奇异性。这使得使用线性有限元模型，收敛于层压板边缘。本文提出的线性有限元方法是保守的，它预测处理后的弯曲层合板的强度在平均试验值的5%以内。因此，它表明，树脂边缘处理可以用来提高认证测试和有限元模型的可靠性。(C)2016爱思唯尔有限公司版权所有。
Large aerospace parts are typically certified by testing narrow specimens, such as curved laminates, which have exposed free edges. These edges (not present in the production part) have been found to reduce the 3D strength of curved laminates by over 20%, showing this certification method is unreasonably conservative. The free edges also create a singularity, such that finite element (FE) modelling is challenging, which is typically approximated using non-linear analysis of cohesive interlaminar zones. A new treatment process is developed whereby a layer of resin is applied to the free edges of curved laminates. This significantly reduces the edge effect and delays failure. The resin edge treatment increases the strength of the curved laminate test specimens by 16%. The treatment also simplifies FE modelling by allowing for non-zero stresses normal to the laminate edge, removing the singularity. This enables use of linear FE models, which converge at the laminate edge. A linear FE method developed in this paper is conservative and predicts the strength of treated curved laminates to within 5% of the average test value. Hence it is shown that the resin edge treatment can be used to improve reliability of both certification tests and FE models. (C) 2016 Elsevier Ltd. All rights reserved.