Effect of Stress Triaxiality and Strain Rate on Ductile Fracture Initiation in Steel
Effect of Stress Triaxiality and Strain Rate on Ductile Fracture Initiation in Steel
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应力三轴度和应变率对钢延性断裂萌生的影响
DOI：
10.2534/jjasnaoe1968.1999.186_475
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
M. Toyoda
中科院分区：
文献类型：
--
作者：
H. Shimanuki;H. Furuya;Takehiro Inoue;Y. Hagiwara;M. Toyoda
众所周知，延性裂纹萌生的临界应变取决于应力三轴性。除非大变形产生初始裂纹，否则延性裂纹可能发生在结构件的应变集中区域。如此大的变形发生在船舶碰撞、地震等情况下，并且应变率通常很高。但是，应变速率对延性裂纹萌生的影响尚不清楚。为了研究对延性裂纹萌生条件的影响，对SM400B、SM490A、SM490B和SN490B钢进行了不同拉伸速度下的轴对称缺口钢筋拉伸试验。并评估引发延性裂纹的临界应变。为了估计动态拉伸试验期间的应力-应变状态，使用了热机械耦合有限元分析（MARC K7.2）。结果表明，应变速率对引发延性裂纹的临界应变的影响很小。结果还表明，如果载荷通过位移控制，较高屈强比的钢材有利于延性裂纹的萌生。
It is widely known that the critical strain to ductile crack initiation depends on the stress triaxiality. And the ductile crack may occur at the strain concentration region in the structural member unless initial crack by large deformation. Such large deformations occurs during ship crash, seismic condition, etc. And then, strain rates are usually high. But, the strain rate effect to the ductile crack initiation is not known.To study the effect on ductile crack initiation condition, the axisymmetrically notched bar tensile tests were conducted under various tensile speed for SM400B, SM490A, SM490B and SN490B steels. And critical strains to initiate ductile crack were evaluated. To estimate the stress - strain states during dynamic tensile test, the thermal mechanically coupled FE-analysis (MARC K7.2) were used. The results showed the strain rate effect on the critical strain to initiate ductile crack is small. And the results also suggested that if the load is controlled by displacement, the higher yield ratio steel is advantageous for the ductile crack initiation.