Effect of triaxial stress distribution upon roughness of brittle fracture surface
Effect of triaxial stress distribution upon roughness of brittle fracture surface
复制标题
三轴应力分布对脆性断裂表面粗糙度的影响
DOI：
10.1051/matecconf/201930011007
复制
发表时间：
2019
影响因子：
--
通讯作者：
Yuki Nishizono and Fuminori Yanagimoto
中科院分区：
文献类型：
--
作者：
Noritaka Nakamura;Tomoya Kawabata;Yasuhito Takashima;Yuki Nishizono and Fuminori Yanagimoto
为了观察应力三轴性对脆性断口的影响，我们进行了两种不同应力三轴性的实验。结果表明，两试样裂纹分支启动速度均发生变化，且速度受应力三轴性的影响。弯曲工况下分支启动速度约为0.86cr（cr：瑞利波速度），高于拉伸工况下的0.59cr。认识到在高应力三轴性条件下，分支容易发生，因为在弯曲条件下应力三轴性较低。另一方面，镜雾过渡速度不受应力三轴性的影响。通过对断口表面的观察，提出了微分支生长时发生分支的理论。用微支模型进行有限元计算，证明在弯曲条件下微支难以生长。此外，我们提出了一个定性的解释，当应力三轴性较高时，微分支容易生长，因为微分支的生长受到t应力的影响。这是因为该现象不在主裂纹扩展平面上。
To observe the effect of stress triaxiality upon brittle fracture surface, we performed two types of experiments which differ in stress triaxiality. As a result, crack branch starting speed changes in two specimens and the speed was affected by stress triaxiality. In bending condition, branch starting speed is around 0.86cr(cr: Rayleigh wave speed), which is higher than that in tensile condition, 0.59cr. It was realized that in higher stress triaxiality, branching is easy to occur because in bending condition stress triaxiality is said to be lower. On the other hand, mirror-mist transition speed is not affected by stress triaxiality. By fracture surface observation, we proposed that branch occurs when microbranch grew. This proposition was supported by FEM calculation with microbranch model, it was proved that in bending condition microbranch is difficult to grow. Additionally, we proposed a qualitative explanation that microbranch is easy to grow when stress triaxiality is higher because growth of microbranch is affected by T-stress. It is since the phenomena is not on the main crack propagating plane.