Linear micropolar elastic crack-tip fields under mixed mode loading conditions
Linear micropolar elastic crack-tip fields under mixed mode loading conditions
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DOI：
10.1023/b:frac.0000049492.13523.5a
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发表时间：
2004-10-01
影响因子：
2.5
通讯作者：
Tsakmakis, C
中科院分区：
文献类型：
--
作者：
Diegele, E;Elsässer, R;Tsakmakis, C
微极弹性定律提供了一种可能性来描述材料的本构性质，其中内部长度尺度可能变得重要。它们的特征是存在偶应力和非对称的Cauchy应力张量。除了经典的位移场，运动学变量增加了所谓的微旋转场及其梯度，后者在理论中引入了内部长度尺度。对于各向同性线性微极弹性材料，导出了Ⅰ型和Ⅱ型裂纹尖端附近的渐近场解。结果表明，这些解的行为与Huang等人（1997 a）研究的所谓偶应力理论的解相似，或与Chen等人（1998）推导的多孔材料的解相似。特别地，奇异场具有奇异性阶r（-1/2），并且由一些振幅因子控制，具有经典线弹性理论中的应力强度因子的意义。本文用有限单元法计算了有限宽边裂纹试样的应力强度因子，研究了材料参数对应力强度因子的影响。
Micropolar elasticity laws provide a possibility to describe constitutive properties of materials for which internal length scales may become important. They are characterized by the presence of couple stresses and nonsymmetric Cauchy stress tensor. Beyond the classical displacement field, the kinematical variables are augmented by a so-called microrotation field and its gradient, the latter introducing an internal length scale in the theory. For an isotropic, linear micropolar elastic material, the near-tip asymptotic field solutions for mode I and mode II cracks are derived. It is shown that these solutions behave similar to those according to the so-called couple stress theory, which has been investigated by Huang et al. (1997a), or similar to those derived for cellular materials by Chen et al. (1998). In particular, the singular fields have an order of singularity r(-1/2) and are governed by some amplitude factors, having the meaning of stress intensity factors as in the classical linear elastic theory. The effect of material parameters on the stress intensity factors is studied by applying the finite element method to calculate the values of the stress intensity factors for an edge-cracked specimen of finite width.