碳纤维增强复合材料多向层板I/II混合型断裂准则研究

CFRP laminates have been widely used in aerospace and other engineering fields. Delamination is a main damage pattern of composite laminates and delamination under complex loadings is one of the focus problems in the composite mechanics. Most of the existing experimental studies are carried out for unidirectional laminates. However, the failure mechanism of multidirectional laminates, which are widely used in engineering, is complex and influenced by many factors. Up to now, fracture toughness model and fracture criterion for mixed mode I/II delamination, which can effectively characterize the delamination behavior of multidirectional laminates, have not yet been established. This project intends to study the quasi-static delamination mechanism of CFRP multidirectional laminates from the macroscopic and microscopic aspects, and to reveal the mechanism of influencing factors on fracture toughness. Then, a universally applicable fracture toughness model with concise form and clear physical meaning will be established. Combing with the in-depth understanding on the failure mechanism, a mixed mode I/II fracture criterion with clear physical meaning will be established. By using the virtual crack closure technique, cohesive zone model, extended finite element and other advanced numerical methods, simulation on the quasi-static delamination behavior of multidirectional laminates under complex loadings will be achieved from the macro and micro scales, which can provide support for the prediction on the failure process and static strength of composite laminated structures with initial delamination damage.

碳纤维增强复合材料层板在航空航天等工程领域被广泛应用。分层损伤是复合材料层板的主要损伤形式。复杂载荷下复合材料层板的分层开裂是复合材料力学研究的焦点问题之一。现有实验研究大多针对单向层板开展，获得的成果也主要适用于单向层板；而工程中普遍应用的复合材料多向层板失效机理复杂，影响因素众多，迄今尚未建立可有效表征复合材料多向层板分层开裂的混合型分层断裂韧度模型和混合型断裂准则。本项目拟从宏观和微观两方面研究碳纤维增强复合材料多向层板分层准静态扩展机理，揭示断裂韧度影响因素的作用机制，进而建立形式简洁、物理意义明确而又普遍适用的分层断裂韧度模型；结合对分层失效机理的深入认识，建立物理意义明确的I/II混合型断裂准则。采用VCCT、内聚力模型、扩展有限元等先进数值方法，实现宏、细观尺度复杂加载状态下的复合材料多向层板准静态分层扩展行为模拟，支持含分层损伤复合材料层合结构的失效过程分析和静强度预测。

碳纤维增强复合材料层板在航空航天等工程领域被广泛应用。分层损伤是复合材料层板的主要损伤形式。复杂载荷下复合材料层板的分层开裂是复合材料力学研究的焦点问题之一。工程中普遍应用的复合材料多向层板失效机理复杂，影响因素众多，迄今尚未建立可有效表征复合材料多向层板分层开裂的混合型分层断裂韧性模型和混合型断裂准则。本项目从宏观和微观两方面研究碳纤维增强复合材料多向层板分层准静态扩展机理，揭示了断裂韧性影响因素的作用机制，进而建立形式简洁、物理意义明确而又普遍适用的分层断裂韧性模型；结合对分层失效机理的深入认识，建立了物理意义明确的I/II混合型断裂准则。采用虚拟裂纹闭合技术、内聚力模型、扩展有限元等先进数值方法，实现了复杂加载状态下的复合材料多向层板准静态分层扩展行为模拟，支持含分层损伤复合材料层合结构的失效过程分析和静强度预测。相关研究成果在国际复合材料和力学领域高水平期刊上发表SCI论文24篇，授权国家发明专利2项；指导毕业博士2名、硕士7名，在读博士生4名、硕士生6名。国内外学术会议做邀请报告3人次、口头报告6人次。