Effect of displacement-rate on the indentation behavior of an aluminum foam
Effect of displacement-rate on the indentation behavior of an aluminum foam
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DOI：
10.1016/s0921-5093(02)00608-1
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发表时间：
2003-04-25
期刊：
影响因子：
6.4
通讯作者：
Ramamurty, U
中科院分区：
文献类型：
--
作者：
Kumar, PS;Ramachandra, S;Ramamurty, U
实验研究了闭孔泡沫铝在1.5 x 10(-2)至5 x 10(3) mm s(-1)不同刺入速度下的深压痕响应。使用两种类型的压头几何形状：平端冲头（FEP）和球形端冲头（SEP）。将获得的压痕试验结果与不同应变率下进行的单轴压缩试验的结果进行比较。实验结果表明，使用 FEP 获得的压痕载荷-位移响应与单轴压缩下观察到的相似。在所有情况下，材料的塑性强度和单位变形体积吸收的能量随着位移率对数的增加而线性增加。压痕样本的横截面图显示，变形仅局限于压头正下方的材料，横向扩展非常小，这是泡沫塑性泊松比接近于零的结果。 FEP 压痕情况下计算的致密化应变与单轴压缩中观察到的结果相似，但明显低于 SEP 压痕中观察到的结果。从压痕数据中提取的剪切强度和能量与文献中报道的非常吻合。 (C) 2002 Elsevier Science B.V. 保留所有权利。
The deep indentation response of a closed-cell aluminum foam under different rates of penetration, ranging from 1.5 x 10(-2) to 5 x 10(3) mm s(-1), was experimentally investigated. Two types of indenter geometries were utilized: a flat-ended punch (FEP) and a spherical-ended punch (SEP). Indentation test results obtained are compared with the results under uniaxial compression tests conducted with varying strain rates. Experimental results show that the indentation load-displacement response obtained using the FEP is similar to that observed under uniaxial compression. In all the cases, the plastic strength and the absorbed energy per unit deformed volume of the material increases linearly with increasing logarithm of displacement rate. Cross-sectional views of the indented specimens show that the deformation is confined only to the material directly beneath the indenter with very little lateral spread, a consequence of the near-zero plastic Poisson's ratio of the foam. The computed densification strain in the case of FEP indentation is similar to that observed in uniaxial compression, but significantly lower than that observed in SEP indentation. The shear strength and energy, extracted from the indentation data, agree well with those reported in the literature. (C) 2002 Elsevier Science B.V. All rights reserved.