The experimental study presented herein, investigated the residual strength of bolted joints on Carbon Fiber Reinforced Polymer (CFRP) airframe structures within the context of structural damage tolerance and airworthiness regulations. The damage scenario assumed, subjected a series of bolted joint CFRP laminate specimens to quasi-static bearing loading following bolt pull-through failure events of different magnitude. Representative CFRP laminate specimens manufactured from AS7/8552 carbon fiber/epoxy matrix system were artificially damaged under bolt pull-through loading, following the herein proposed modifications to the current pull-through ASTM testing procedure. The specimens were subsequently tested in static bearing loading for examining the specimen residual bearing strength. The residual joint bearing strength was related to the displacement travelled passed the initial failure stage in pull-through mode and was measured up to a maximum of a 13% decrease for the tested samples and the maximum damage imposed. The study explored of safe utilization of bolted joints at higher operating loading levels within the context of the current airworthiness regulations. The inherent damage arrest features of the joints were highlighted. The study concluded with comments and suggestions on the expansion of the current utilization spectrum of damaged bolted joints from pull-through loading in airframe design, bound by the current airworthiness certification requirements.

本文介绍的实验研究在结构损伤容限和适航性规定的背景下，研究了碳纤维增强聚合物（CFRP）机身结构上螺栓连接的残余强度。假设发生了损坏情况，在一系列不同程度的螺栓穿通破坏事件之后，一系列螺栓连接CFRP层压板样本承受了准静态轴承载荷。按照本文提出的对当前穿通ASTM测试程序的修改，由AS7 / 8552碳纤维/环氧树脂基体系统制造的代表性CFRP层压板样品在螺栓穿通载荷下被人为损坏。随后，在静态轴承载荷下对样本进行测试，以检查样本的残余轴承强度。残余的关节轴承强度与在拉拔模式下经过初始失效阶段时经过的位移有关，并且对于测试样品和施加的最大破坏，最大测量值降低了13％。该研究探索了在当前适航性规定的背景下，在较高的工作负荷水平下安全利用螺栓连接的方法。突出了关节固有的止损功能。该研究的结论和建议是，根据当前的适航审定要求，扩大机身设计中的拉拔载荷损坏的螺栓连接的当前利用范围。