细观尺度下考虑界面特性的异质金属层状复合板冷塑性变形损伤行为-机理相关性

Damage is one of the unavoidable defects in the cold-forming process of laminated composite. It will seriously affect the work safety of the artifact, which has become a technical bottleneck restricting its wide application. The interface features of the laminated composite of sheets make the damage process extremely complex. The correlation between damage behavior and mechanism of cold-forming based on interface features has become a key scientific problem to be solved urgently in the research, development and application of forming technology of laminated composite. The project takes the Ti-Al composite laminates that is urgently needed in the high-tech fields such as aerospace and rail transit as the research object. Based on the damage of Ti-Al composite laminates at the meso-scale, this project focuses on four aspects: (1) Research of damage model based on cohesive-GTN at the meso-scale. (2) Research of cold-forming damage behavior based on interface features. (3) Research of cold-forming damage mechanism based on interface features. (4) Research of active control of damage. The conclusion has great scientific significance in development of cold plastic forming theory and technology about laminated composite.

损伤是异质金属层状复合板冷塑性变形过程中易产生的缺陷之一，一旦产生将严重影响构件安全服役效能，已成为制约异质金属层状复合板广泛应用的技术瓶颈。异质金属层状复合板特有的界面特性使其损伤行为异常复杂。考虑界面特性的冷塑性变形损伤行为-机理相关性，已成为层状复合板成形技术研究、发展及应用亟需解决的关键科学问题。本项目以航空航天、轨道交通等高技术领域迫切需要的Ti-Al层状复合板为研究对象，紧扣细观尺度下Ti-Al层状复合板损伤这一主线，重点开展四个方面研究：（1）细观尺度下基于内聚力-GTN混合模型的损伤建模；（2）基于界面特性的Ti-Al层状复合板冷塑性变形损伤行为；（3）基于界面特性的Ti-Al层状复合板冷塑性变形损伤机理；（4）Ti-Al层状复合板冷塑性变形损伤缺陷主动防控策略。研究结果对发展异质金属层状复合板冷塑性变形先进理论与技术具有重要科学意义。

异质金属层状复合板兼备各异质金属良好的综合性能，广泛用于航空航天、轨道交通等高技术领域。损伤是异质金属层状复合板冷塑性变形过程中易产生的缺陷之一，一旦产生将严重影响构件安全服役效能，已成为制约异质金属层状复合板广泛应用的技术瓶颈。异质金属层状复合板特有的界面特性使其损伤行为异常复杂。考虑界面特性的冷塑性变形损伤行为-机理相关性，已成为层状复合板成形技术研究、发展及应用亟需解决的关键科学问题。本项目以航空航天、轨道交通等高技术领域迫切需要的异质金属层状复合板为研究对象，基于层状复合板界面特性对损伤行为和损伤机理的敏感性，研究了异质金属层状复合板的几何特征、材料特性和冷塑性变形损伤行为；探明了复合板界面区微观结构、成分分布规律、硬度分布规律。基于剥离试验和剪切试验获得了法向应力、切向应力、法向界面开裂特征位移、切向界面开裂特征位移等内聚力模型关键参数，基于实验并结合有限元逆向标定法获得了初始孔洞体积分数、失效时孔洞体积分数、临界孔洞体积分数、形核时第二相粒子的体积百分比等GTN模型关键参数；基于界面特征考虑内聚力-GTN混合模型建立了异质金属层状复合板冷塑性变形有限元损伤模型，并通过物理实验验证了模型的可靠性。研究了不同关键界面参数、不同关键层内参数、不同界面特征等条件对层状复合板冷塑性变形过程中微裂纹萌生、扩展演化、分布等影响行为；揭示了上述条件下异质金属层状复合板冷塑性变形损伤行为与损伤机理相关性，提出了异质金属层状复合板冷塑性成形缺陷主动防控策略。本项目以应用基础研究为主，成果不但可以丰富异质金属层状复合板成形理论和技术，而且可为提高构件成形质量、挖掘成形潜力提供实用的理论依据，对发展异质金属层状复合板冷塑性变形先进理论与技术具有重要科学意义。