含离散源损伤复合材料加筋板剩余强度及其修理技术研究

Study on Residual Strength of Composite Stiffened Panel with Discrete Source Damage and Repair Technique

飞机复合材料结构在使用过程中难免遭受离散源损伤,这种损伤会严重降低结构的承载能力。针对含穿透性切口的复合材料加筋板,采用试验和数值分析方法研究其拉伸载荷作用下的剩余强度,并根据设计应变设计了金属补片机械连接修理方案,提出了一种评估复合材料机械连接修理结构剩余强度的数值分析方法。分析方法以有限元模拟为主,用壳元模拟层压板,用梁元模拟紧固件,用多点约束模拟紧固件与孔的接触,用0°层点应力准则预估复合材料破坏载荷。通过试验验证了评估方法,得到了修理结构强度恢复率。本文的研究对于飞机复合材料结构修理技术研究有一定的借鉴意义。

Aircraft composite structure will inevitably suffer discrete source damage in its service life. This kind of damage will decrease load bearing capacity of structure severely. In this paper,tensile residual strength of composite stiffened panel with penetrated cut-out is studied by numerical simulation and experimental investigation. Based on finite element analysis and ultimate strain limits,a metal patch bolted repair pattern is designed. An evaluating method is proposed for metal bolted repair composite panel in which skin and stiffener are modeled by using shell element whereas the fasteners are modeled by beam elements. MPC technique is adopted to simulate the constraint between fastener and hole. The point criterion is incorporated to obtain the failure load. The analysis method is validated by test results. The strength recovery ratio of damaged panel and repaired panel are gotten. The research of this paper will provide support information for composite structure repair technique.