结构完整性分析中的多尺度力学方法

Application of Multiscale Mechanics Methods in Structural Integrity Analysis

结构完整性分析一直是机械工程和力学等领域专家学者研究的重要课题。目前在工程装备的设计和评估中应用的安全规范大都是经验性的,亟需开发一种严谨且准确的力学分析方法,不仅可以提高结构完整性评估的精度,还可以安全地提高装备的运行效率。多尺度力学方法可以从材料在不同空间尺度上的微观结构出发,对材料的力学行为进行研究,是能从基础底层推动结构完整性分析的关键。着重回顾近年来关于金属结构材料方面多尺度力学方法的相关研究成果。首先,以分子动力学方法作为微尺度研究方法的代表,介绍金属结构材料的微观变形和断裂机制研究进展。然后,以晶体塑性的连续介质理论为代表,介绍以塑性变形的物理机制和晶体学特征为基础的多尺度力学方法,这种方法考虑晶体弹塑性变形行为的各向异性,具有坚实的物理基础,是一种具有高度可靠性的结构完整性分析方法。最后,笔者就多尺度力学方法目前面临的研究难点和未来发展方向进行了简要讨论。

Structural integrity analysis has always been an important subject studied by scientists in the fields of mechanical engineering and mechanics. Because most of the safety regulations applied in the design and evaluation of engineering equipment are empirical, it is urgent to develop a rigorous and accurate mechanical analysis method, which can not only improve the accuracy of structural integrity assessment, but also safely improve the operating efficiency of equipment. Multiscale mechanics methods can study the mechanical behavior of materials from the microstructure of materials in different spatial scales, which is the key to fundamentally promote the structural integrity analysis from the bottom of the foundation. This article focuses on reviewing recent research achievements on multiscale mechanics for the analysis of metallic structural materials. First, molecular dynamics method is selected as a representative of microscopic research methods to introduce the research progress of deformation and fracture mechanisms of metallic structural materials at microscale. Then, based on continuum theory of crystal plasticity, a kind of multiscale mechanics with the consideration the physical mechanism and crystallographic characteristics of plastic deformation is introduced. This method takes into account the anisotropy of crystal elastic-plastic deformation behavior and has a solid physical foundation. Hence, it is a highly reliable structural integrity analysis method. Finally, the authors briefly discuss the current research difficulties and future development directions of multiscale mechanics.