复合材料加筋板长桁终止端失效机制

Failure mechanism at stiffener runout in stiffened composite panels

由于设计要求或设计限制条件,壁板的长桁常常在翼肋或机身框附近、机翼的前后梁附近、机翼与机身的开口附近、机翼的油箱附近等部位终止。在面内载荷作用下,截面形状突变和传载路径偏移在端头处会产生应力集中,极易引起缘条/蒙皮界面脱胶分层。对三种构型的长桁终止端典型件在单向拉、压载荷下的破坏机制进行了试验研究与数值模拟,结果表明,拉伸时的失效是由面外剥离应力与层间剪应力的共同作用所致,而压缩时的失效主要是由层间剪应力所致。

In an aircraft structure, it is often necessary to runout some of the stiffeners to satisfy detailed design requirements. Depending on the structural design, stiffeners for a wing structure may terminate at a chord- wise splice, at the forward or rear spar, at a rib, or at a structural discontinuity, such as an access hole. But an abrupt stiffener termination can cause highly localized bending gradients due to stiffness discontinuities and load-path centricities. In this paper, both experiment tests and FEM models relating to three different stiffener runout specimens were presented and the failure modes of these specimens were discussed in detail. In tension, the failure is deduced by peel stress and interlaminar shear stress. In compression, the failure is deduced by interlaminar shear stress only.