胶结界面失稳破坏及应力动态传递的实验和理论研究

Due to simple operation of the tensile test method of joint plates and wide application of joint system in aerospace, machinery, electronics and other fields, the researches on the tensile test method of joint plates have been undergoing the extensive attention. At the same time, joint system is an optional element of the structure design of advanced materials, and its strength and failure behavior are closely dependent of the physical and geometrical characteristics, bonding properties and service environment etc., and contains the frontier scientific problems in solid mechanics and cross areas, so a lot of researches on the strength and failure problems for the joint system have been carrying out. Pre-experimental study of the applicant shows that the instability failure of bonding interface layer is a main feature of the joint system destruction. In the project, for the strength and failure problems of the metal plate/polymer glue system, we plan to study the dependence of joint system strength on the joint layer thickness systematically, from the experiment, modeling and computation, and study the dependence of instability characteristics of bonding layer on the layer thickness, as well as study the stress dynamic redistribution characteristics within the connected plate. Through this project research, the physical mechanism of the interface layer instability and failure will be clarified, and the strength size effect of the ultrathin interfacial bonding layer of the joint system will be characterized, and the physical mechanism of the structure catastrophe led to by dynamic redistribution of transient stresses at instantaneous interfacial failure etc. will be revealed.

由于胶结板拉伸试验方法操作简便以及胶结体系在航空航天、机械、电子等领域的广泛应用，因此对该试验方法的研究受到广泛重视。同时，胶结体系是先进材料结构设计的备选要件，其强度和破坏行为又密切地依赖胶层的物理与几何特性、界面结合特性以及服役环境等，蕴含着固体力学及交叉领域的前沿科学问题，因此人们开展了对胶接体系强度和失效问题的大量的研究。通过申请者的前期初步实验研究发现，胶结界面层的失稳破坏是胶结体系破坏的主要特征。本项目针对金属板块/聚合物胶层体系的强度和破坏问题，从实验、建模和计算三方面系统地研究胶结体系的强度对胶层厚度的依赖关系；研究胶层的失稳特征对胶层厚度的依赖关系；研究胶层失稳破坏过程中，胶结件内应力的动态传递特征。试图通过本项目的研究，阐明界面层失稳破坏的物理机制、刻划超薄胶结界面层情况下胶结体系强度的尺度效应、揭示界面破坏瞬间应力的动态再分配诱导结构灾变的物理机制等。

通过对项目四年的研究，实现了下列核心目标：提出了一种能够合理地表征胶接性能的圆柱形斜截面胶结的实验试样，可充分体现胶结界面由胶接性能主导破坏的力学行为，克服了以往搭接板式的胶结试样由应力奇异性主导失效的缺点；通过系统地实验研究，揭示出了胶结体系胶结强度的跨尺度力学行为和灾变失效特征及其非平衡、非稳定和能量耗散等力学机制；提出了一种应变梯度粘弹性跨尺度力学理论并成功地用以刻画胶结体系的动态强化-软化力学行为；把对胶结体系胶结界面的跨尺度力学理论和方法成功地应用于对发动机叶片先进热障涂层和生物多级材料的强化-软化表征；为了进一步揭示出胶结体系胶结界面的强化-软化机理，还从分子动力学模拟和内聚力模型等效出发系统地研究了金属/陶瓷界面的破坏机制。在项目执行过程中共发表学术论文32篇，其中SCI收录论文30篇。