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arXiv 1807.08170cond-mat.mtrl-sci
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弹塑性功能梯度材料的尺寸效应

Size effects in elastic-plastic functionally graded materials

Tittu V. Mathew, Sundararajan Natarajan, Emilio Martínez-Pañeda

摘要:

我们开发了一个应变梯度塑性公式的复合材料与空间变化的体积分数来表征功能梯度材料(FGMs)的尺寸效应。该模型基于应变梯度塑性力学理论,并通过线性均匀化方法确定有效性能。几个范例的边值问题进行了数值研究,以深入了解与塑性应变梯度和几何必要位错(GNDs)的强化效果。微尺寸的功能梯度箔的弯曲分析显示出显着的刚度响应与厚度减小。显微硬度测量从压痕揭示了一个显着的增加,随着压头尺寸减小。并且裂纹附近的大位错密度显著提高了开裂的FGM部件中的应力。我们全面评估了长度尺度参数和材料级配剖面的影响,以准确表征微尺度响应并识别功能梯度材料中GND相关性的机制。

英文摘要:

We develop a strain gradient plasticity formulation for composite materials with spatially varying volume fractions to characterize size effects in functionally graded materials (FGMs). The model is grounded on the mechanism-based strain gradient plasticity theory and effective properties are determined by means of a linear homogenization scheme. Several paradigmatic boundary value problems are numerically investigated to gain insight into the strengthening effects associated with plastic strain gradients and geometrically necessary dislocations (GNDs). The analysis of bending in micro-size functionally graded foils shows a notably stiffer response with diminishing thickness. Micro-hardness measurements from indentation reveal a significant increase with decreasing indenter size. And large dislocation densities in the vicinity of the crack substantially elevate stresses in cracked FGM components. We comprehensively assess the influence of the length scale parameter and material gradation profile to accurately characterize the micro-scale response and identify regimes of GNDs relevance in FGMs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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