Metal-composite airframes will suffer various defects during their lifetime. One category of defects is composite laminate delamination. This study evaluates the criticality of delaminations existing around adjacent fastener holes in the carbon-fibre-reinforced plastic spar web of the F/A-18 aircraft’s trailing-edge flap. The evaluation is based on experiments and analyses. First, an intensive experimental program for determining necessary material values of F/A-18 is described. Multiple delaminations of the flap spar web are then modelled by varying the set of delaminated hole edges and the interface of delamination. The interaction of defects at the start of delamination propagation is studied via the developed interaction parameter. The results suggest that the interaction parameter can show significant differences in the interaction per delamination case and that the interface of delamination is an important variable. Finally, operator-dependent control parameters are studied, and it is found that the criticality of a delamination case is merely dependent on true material parameters.

中文翻译：

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芬兰 F/A-18 飞机襟翼梁多部位分层临界分析

金属复合材料机身在其使用寿命期间会遭受各种缺陷。一类缺陷是复合层压板分层。这项研究评估了 F/A-18 飞机后缘襟翼的碳纤维增强塑料翼梁腹板中相邻紧固件孔周围存在分层的严重性。评估基于实验和分析。首先，描述了确定 F/A-18 必要材料值的强化实验程序。然后通过改变分层孔边缘的集合和分层界面来模拟翼梁腹板的多个分层。通过开发的相互作用参数研究了分层传播开始时缺陷的相互作用。结果表明，相互作用参数可以显示每个分层情况下相互作用的显着差异，并且分层界面是一个重要变量。最后，研究了与操作员相关的控制参数，发现分层情况的临界性仅取决于真实的材料参数。