韧性点接触结构屈服失效机理及非线性力学行为实验研究

韧性材料点接触结构广泛存在于各类工程结构中，然而点接触结构内部变形的复杂性和变形测量手段的局限性制约了对其屈服与失效机理的清晰认识，严重影响了相关工程结构强度估计、力学行为描述等问题的有效解决。项目采用衍射重叠相位恢复等先进光学测量方法，研制针对点接触结构内部变形场与接触面积的同步测量系统，测量分析结构承载过程中接触体内部变形场及接触面积的演化规律；利用强度分析方法确立接触体局部屈服与结构宏观力学行为的对应关系，建立结构屈服的有效判据，确立结构屈服强度的关键影响参量；利用数值计算和理论推导确立结构屈服过程中接触面上的应力分布形式，分别建立点接触强度表达式和描述其屈服失效行为的非线性力学模型。本项目研究成果将为韧性材料点接触结构的强度设计和力学行为预测提供理论指导。

Point-contact structures of ductile materials are widely used in various engineering structures, however, the complexity of internal deformation of point-contact structures and the limitation of deformation measurement methods restrict the clear understanding of its yield and failure mechanism, which seriously affects the effective solution of the problems such as strength estimation and mechanical behavior description of relevant engineering structures. The study adopts advanced optical measurement methods such as ptychographical iterative engine to develop a synchronous measurement system for the deformation field inside the point-contact structure and contact area, and measures and analyzes the evolution law of the deformation field and contact area inside the contact body during the bearing process of the structure; The relationship between the local yield of contact body and the macroscopic mechanical behavior of structure was established by means of strength analysis; By means of numerical calculation and theoretical derivation, the stress distribution on the contact surface during the yield process of the structure is established. The research results of this study will provide theoretical guidance for strength design and mechanical behavior prediction of ductile point-contact structures.