Recent engineering design practice for materials and structures relies more and more on damage-tolerant criteria. Such a design approach is attained mainly by employing materials showing a certain level of fracture toughness.

This work aims to explore a way to generate fracture toughness in materials that intrinsically shows no toughness at all, i.e. brittle materials. The key idea lies in the introduction of inelastically deformed sub-regions (e.g. circular inclusions) in the base material, which inevitably generate a residual stress field.

To accomplish this purpose, the advanced Phase-Field method coupled with the eigenstrain theory is employed, respectively to simulate the crack propagation behavior and to introduce a residual stress field in a pre-notched sample. Information about crack propagation and displacement externally imposed is used to obtain the resistance curve (R-curve) for several configurations.

One of the main findings of this research regards the possibility of originating fracture toughness in intrinsically brittle materials upon appropriate positioning of one inclusion - containing a certain amount of inelastic deformation – with respect to a notch tip. This result demonstrates that accurate design of residual stress is crucial to attaining unprecedented material or structure performance, and the method shown here represents a valid tool to exploit this advanced design capability.

最近的材料和结构工程设计实践越来越依赖于损伤容忍标准。这种设计方法主要是通过使用具有一定断裂韧性水平的材料来实现的。

这项工作旨在探索一种在本质上完全没有韧性的材料（即脆性材料）中产生断裂韧性的方法。关键思想在于在基材中引入非弹性变形的子区域（例如圆形夹杂物），这不可避免地会产生残余应力场。

为实现这一目的，结合本征应变理论的先进相场方法分别被用来模拟裂纹扩展行为并在预开槽的样品中引入残余应力场。有关外部施加的裂纹扩展和位移的信息用于获得几种配置的电阻曲线（R曲线）。

这项研究的主要发现之一是关于在一个夹杂物（包含一定量的非弹性变形）相对于缺口尖端的适当定位后，在固有脆性材料中产生断裂韧性的可能性。这一结果表明，残余应力的精确设计对于获得前所未有的材料或结构性能至关重要，此处显示的方法是利用这种先进设计能力的有效工具。