力学学报 ›› 2018, Vol. 50 ›› Issue (5): 1063-1080.doi: 10.6052/0459-1879-18-172

• 固体力学 • 上一篇    下一篇

准静态条件下金属材料的临界断裂准则研究1)

于思淼, 蔡力勋2), 姚迪, 包陈, 陈辉, 彭云强, 韩光照   

  1. 西南交通大学力学与工程学院应用力学与结构安全四川省重点实验室, 成都 610031
  • 收稿日期:2018-05-30 出版日期:2018-09-18 发布日期:2018-10-18
  • 通讯作者: 2)蔡力勋, 教授, 主要研究方向:断裂与疲劳、强度理论、材料测试理论与技术. E-mail: lix_cai@263.net
  • 基金资助:
    1)国家自然科学基金资助项目(11472228).

THE CRITICAL STRENGTH CRITERION OF METAL MATERIALS UNDER QUASI-STATIC LOADING1)

Yu Simiao, Cai Lixun2), Yao Di, Bao Chen, Chen Hui, Peng Yunqiang, Han Guangzhao   

  1. Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China
  • Received:2018-05-30 Online:2018-09-18 Published:2018-10-18

摘要: 本文针对9种金属材料完成了具有不同约束程度的10类试样的延性断裂试验, 获得了发生拉、压、扭和裂尖断裂等破坏形式构型试样的载荷-位移试验关系; 基于圆棒漏斗试样拉伸试验所得直至破坏的载荷-位移曲线, 采用有限元辅助试验(finite-element-analysis aided testing, FAT)方法得到了9种材料直至破坏的全程等效应力-应变曲线, 以此作为材料本构关系通过有限元分析获得了各类试样直至临界破坏的载荷-位移关系模拟. 载荷-位移关系模拟结果与试验结果有较好的一致性, 表明用于解决试样颈缩问题的FAT方法所获得的全程材料本构关系针对各向同性材料具有真实性和普适性. 对应9种材料、10类试样的36 个载荷-位移临界断裂点, 通过有限元分析获得了对应的材料临界断裂应力、应变与临界应力三轴度, 研究表明, 第一主应力在延性变形过程中为主控断裂的主导参量; 通过研究光滑、缺口、裂纹等构型试样的断裂状态, 提出了$-1$至3范围的应力三轴度下由第一主应力主控的统一塑性临界断裂准则.

关键词: 延性材料|有限元辅助测试|塑性变形|临界断裂准则

Abstract: For 10 types of specimens with different constraints, ductile fracture tests of 9 metal materials under unidirection loading were performed, and their load-displacement relations were measured. Based on the load-displacement curves of notched round bar, the full-range equivalent constitutive relationships of materials up to failure were obtained by FAT (finite-element-analysis aided testing) method. Further, the simulated force-displacement curves for different specimens were obtained based on the full-range constitutive relations, which agree well with the experimental force-displacement curves. The results demonstrate that the full-range constitutive relations up to failure obtained by FAT method have uniqueness for the materials. The critical fracture parameters such as critical stress, critical strain and critical stress triaxiality are investigated by failure simulations for the 36 specimens with different constraints. The first principal stress is suggested to be the master parameter to control ductile fracture. By analyzing the critical behaviors of the specimens which are smooth, notched and cracked, respectively, a unified strength criterion for ductile materials with stress triaxiality varying from $-1$ to 3 is proposed.

Key words: ductile materials|finite element aided testing method|plastic deformation|critical fracture criterion

中图分类号: 

  • O346