Materials failure under some sort of loading is a well-known natural phenomenon, and the reliable prediction of materials failure is the most important key issue for many different kinds of engineering structures based on their safety considerations. In this research, instead of establishing empirical models, the material failure process was modeled as a nonequilibrium process based on the microstructural mechanism. Then, the evolution equations were established and the stability analysis was carried out to obtain the critical conditions for the materials failure. It was found that the material strength was a global property in nature, and the commonly used local criteria based on the most dangerous point failure were not the rational assumption. Based on the idea, some examples were considered, such as the size effect of the material strength, the strength of the polycrystalline metals, the stress-strain relationship of the ultrafine crystalline metal with nanoscale growth twins, the strength of lithium niobite crystal specimens with notches. All of the theoretical predictions gave reasonable results compared with the experimental data.

某种载荷下的材料破坏是众所周知的自然现象，基于各种安全性考虑，可靠地预测材料破坏是许多不同类型工程结构的最重要的关键问题。在这项研究中，不是建立经验模型，而是基于微观结构机理将材料破坏过程建模为非平衡过程。然后，建立了演化方程，并进行了稳定性分析以获得材料破坏的关键条件。发现材料强度本质上是全球属性，基于最危险点破坏的常用局部标准不是合理的假设。基于此想法，我们考虑了一些示例，例如材料强度的尺寸效应，多晶金属的强度，具有纳米级孪晶的超细晶体金属的应力-应变关系，带缺口的铌铌酸锂晶体试样的强度。与实验数据相比，所有理论预测都给出了合理的结果。