Holistic structural integrity process (HOLSIP) research for hybrid structure applications

该提案概述了调查和建模物理裂纹扩展过程的研究，这些过程导致“混合”结构在疲劳载荷下失效。混合结构在这里被定义为已经使用粘合的复合材料进行了加固或修复的金属结构。 这种复合“增强件”（对于未破裂的金属结构）或“补片”（在破裂的金属结构的情况下）通常是多层硼/环氧树脂或其他高刚度纤维增强材料。混合结构在各种应用中（例如飞机、船舶、压力容器、生物医学植入物、车辆结构、航天器等）具有巨大的潜力，然而，由于目前还不存在用于可靠地预测故障的精确分析工具，因此它们在可靠性关键部件中的应用极其有限。 这是由于缺乏基本知识的混合结构内的多个和相互作用的故障过程机制（需要创建一个准确的故障/寿命预测模型的结构完整性评估），限制了它们的广泛使用。 这项研究将利用UBC先前开发的知识，设施和专业知识来构建和测试小规模样本，以研究混合结构几何形状，疲劳裂纹扩展和剥离率之间的机制和相互作用，以便正确识别和建模失效机制。所获得的信息将被用来创建一个裂纹扩展模型的混合结构，需要为这些复杂的结构开发一个新的风险/可靠性分析策略。这一新的战略-整体结构完整性过程（HOLSIP）-将开发一个具体的重点是应用粘接复合材料修复金属飞机结构。其目标是开发必要的知识和预测模型，以克服现有的障碍，以证明这项技术用于修复民用飞机结构。这项研究对于从目前存在的大量老化民用飞机的延寿计划中获得经济效益至关重要，并且由于9/11事件后飞机购买的减少，未来将增加。

This proposal outlines research to investigate and model the physical crack growth processes that lead to failure in a "hybrid" structure under fatigue loading. A hybrid structure is defined here as a metal structure that has been reinforced or repaired using a bonded composite material. This composite "reinforcement" (for an uncracked metal structure) or "patch" (in the case of a cracked metal structure) is typically a multi-layer boron/epoxy or other high stiffness fiber-reinforced material. Significant potential exists for the use of hybrid structures for a variety of applications (e.g. aircraft, ships, pressure vessels, biomedical implants, vehicle structures, spacecraft, etc.), however their use for reliability-critical components is extremely limited as accurate analytical tools for reliably predicting failure do not currently exist. It is due to a lack of basic knowledge of the multiple and interacting failure process mechanisms within the hybrid structure (required for the creation of an accurate failure/life prediction model for structural integrity assessment) that limits their widespread use. This research will utilize knowledge, facilities and expertise previously developed at UBC to construct and test small-scale specimens to investigate the mechanisms and interaction between hybrid structure geometry, fatigue crack growth and disbonding rate in order to properly identify and model the failure mechanisms. The information obtained will be used to create a crack growth model for hybrid structures, required for development of a new risk/reliability analysis strategy for these complex structures. This new strategy - the HOLolistic Structural Integrity Process (HOLSIP) - will be developed with a specific focus on the application of bonded composite repairs for metal aircraft structures. The goal is to develop the necessary knowledge and prediction models to overcome existing barriers to the certification of this technology for repairing civilian aircraft structures. This research is crucial to obtaining economic benefit from the life-extension programs for the vast fleets of ageing civilian aircraft that currently exist, and will be increasing in the future due to reductions in aircraft purchases after the events of 9/11.