不同预加载对聚酰胺66后继屈服强度影响的研究  

Research on the influence of different preloads on the subsequent yield strength of PA66

作　　者：詹鑫鑫 罗雅云 王鹤峰 金涛 树学峰 ZHAN Xinxin;LUO Yayun;WANG Hefeng;JIN Tao;SHU Xuefeng(College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]太原理工大学机械与运载工程学院,山西太原030024

出　　处：《实验力学》2022年第4期475-487,共13页Journal of Experimental Mechanics

基　　金：国家自然科学青年基金(11802199);西安交通大学机械结构强度与振动国家重点实验室开放基金(SV2019-KF-15);国家自然科学基金(11772217);2020年度山西省高等学校科技创新项目(2020L0063)资助。

摘　　要：利用万能试验机对施加了不同预加载位移的聚酰胺66(PA66)试样在3种不同应变率条件下进行单轴压缩、剪切和复合压剪测试,研究预加载和应变速率对材料力学性能的影响。结果表明,不同预加载位移下PA66的后继屈服行为和硬化行为都表现出显著的应变率敏感性,且预加载位移的大小对PA66后继屈服强度有明显的影响。在压缩和剪切复合加载实验中,利用压剪杆试样(SCBS)的测试方法引入了4种不同的加载角度(15°、30°、45°、50°);对不同预加载位移的PA66后继屈服正、剪应力进行分析可知,4个角度的正、剪应力均随着预加载位移的增加而增大,基于此引入改进的von-Mises(MMC)屈服准则,对测试得到的不同应变率下PA66的实验屈服轨迹进行理论描述。进一步结合von-Mises等效塑性应变标定了预加载后PA66后继屈服面的演化参数,结果表明,在一定的塑性应变范围内PA66的后继屈服行为表现出等向强化的加工硬化规律。In order to understand the effect of preloading on the mechanical properties of materials,a universal material testing machine was used to perform quasi-static tests of uniaxial compression,shear and combined compression-shear loaded with three strain rates on PA66 with different preload positions in this work.The research results show that the subsequent yield behavior and hardening behavior of PA66 under different preloading displacements perform significant strain rate sensitivity,and the magnitude of the preloading displacement has a significant effect on the subsequent yield strength of PA66.For the combined Shear-Compression test,the SCBS(Shear-Compression Bar Specimen)test method is used to introduce four different angles of the chute(15°,30°,45°and 50°),and the subsequent yielding of PA66 with different preload displacements is positive.Shear stress analysis shows that the positive and shear stresses of the four angles all increase with the increase of the preload displacement.The MMC yield criterion is introduced to verify the experimental yield loci and theoretical yield surface of the corresponding strain rate of different preloads.Finally,Mises equivalent plastic strain is used to calibrate the evolution of the subsequent yield surface of PA66 after preloading.The results show that within a certain range of plastic strain,the subsequent yield behavior of PA66 material exhibits an isotropically strengthened work hardening law.

关 键 词：PA66 预加载位移 后继屈服行为 应变率效应 准静态 

分 类 号：O334.3[理学—一般力学与力学基础]