Size Effects on Cavitation Instabilities
Size Effects on Cavitation Instabilities
复制标题
尺寸对空化不稳定性的影响
DOI：
10.1115/1.2074747
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
V. Tvergaard
中科院分区：
文献类型：
--
作者：
C. F. Niordson;V. Tvergaard
在金属-陶瓷系统中，对塑性流动的约束导致如此高的应力三轴性，从而可能发生空穴不稳定性。如果空穴半径在金属特征长度的数量级上，空穴增长的速率降低，并且在此分析了这种情况下空穴不稳定增长的可能性。将高阶应变梯度塑性理论的有限应变推广应用于幂律硬化材料，并对含球形孔洞的轴对称单胞进行了数值分析。在高应力三轴度的范围内，空泡不稳定性预测的常规塑性理论，这样的不稳定性也被发现的非局部理论，但梯度硬化的影响延迟发病的不稳定性。此外，在某些情况下，空化应力达到最大值，然后随着空隙增长到远高于特征材料长度的尺寸而衰减。
In metal-ceramic systems the constraint on plastic flow leads to so high stress triaxialities that cavitation instabilities may occur If the void radius is on the order of magnitude of a characteristic length for the metal, the rate of void growth is reduced, and the possibility of unstable cavity growth is here analyzed for such cases. A finite strain generalization of a higher order strain gradient plasticity theory is applied for a power-law hardening material, and the numerical analyses are carried out for an axisymmetric unit cell containing a spherical void. In the range of high stress triaxiality, where cavitation instabilities are predicted by conventional plasticity theory, such instabilities are also found for the nonlocal theory, but the effects of gradient hardening delay the onset of the instability. Furthermore, in some cases the cavitation stress reaches a maximum and then decays as the void grows to a size well above the characteristic material length.