Studies in Fracture - and Materials-Mechanics

这项研究是资助研究的关系，微- 力学和陶瓷增韧机理的研究。 许多 已经尝试了一些技术来改善不同材料之间的结合 应用于层状复合材料的材料 电子器件和保护涂层。 研究将 研究了沿沿着界面断裂的多个方面 包括控制脆性粘合剂的韧性的参数 层、复合加载模式对脱粘的作用，以及粘结 通过在粘合剂层内偏转裂纹轨迹来增韧。 理论工作将进行微观裂纹和裂纹- 桥接，原则上可以操纵的两种基本机制 通过微结构处理来提高 多晶陶瓷 这项工作的目的是量化 从而可以进行可靠的韧性预测 基于微观结构特征。 的基础研究 三轴应力下塑性变形固体中的空穴 将进行。 “爆炸性”空洞增长的应力水平 将寻求发生。 这些应力状态代表了 似乎已经达到的材料稳定性限值， 最近的实验下高度约束流。

This research is funded to study the relationship of micro- mechanics and the toughening mechanism of ceramics. Many techniques have been tried to improve bonding between dissimilar materials with applications to composite materials, layered electronic devices, and protective coatings. Research will be conducted to study a number of aspects of fracture along interfaces including the parameters controlling toughness of a brittle adherent layer, the role of combined mode loading on debonding, and bond toughening by deflected crack trajectories within an adhesive layer. Theoretical work will be carried out on micro-cracking and crack- bridging, two basic mechanisms which can in principle be manipulated by micro-structural processing to improve the toughness of polycrystalline ceramics. The objective of this work is to quantify the mechanisms so that reliable toughness predictions can be made based on microstructural characterizations. A basic study of cavitation in plastically deforming solids under triaxial stressing will be conducted. Stress levels at which "explosive" void growth occurs will be sought. These stress states represent intrinsic material stability limits which appear to have been attained in recent experiments under highly constrained flow.