Quantitative assessment and prediction of contact area development during spherical tip indentation of glassy polymers
Quantitative assessment and prediction of contact area development during spherical tip indentation of glassy polymers
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DOI：
10.1080/14786430802123224
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发表时间：
2008-03
影响因子：
1.6
通讯作者：
C. Pelletier;J. D. den Toonder;L. Govaert;N. Hakiri;M. Sakai
中科院分区：
文献类型：
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作者：
C. Pelletier;J. D. den Toonder;L. Govaert;N. Hakiri;M. Sakai
本文描述了聚碳酸酯在压痕过程中接触区的发展。使用仪表式压痕显微镜对接触面积进行了现场测量，并与弹塑性本构模型的数值模拟结果进行了比较。模型中的参数是通过宏观试验获得的。对具有不同热历史和不同速度的样品进行了压痕试验。对于所有情况，数值模型正确地预测了压痕过程中接触区域的发展。随着应变率的增加，在相同的压痕深度下，接触面积减小。在相同的压痕深度下，样品的退火导致较小的接触面积。数值模拟还表明，压头周围的堆积是由局部化效应引起的，因此是由压痕材料的应变软化特性促进的。另一方面，应变硬化将倾向于促进下沉。最后，我们对压痕过程中的载荷松弛进行了模拟。结果表明，约40%的总松弛可能归因于塑性效应。
This paper describes the development of the contact area during indentation of polycarbonate. The contact area was measured in situ using an instrumented indentation microscope and compared with numerical simulations using an elasto-plastic constitutive model. The parameters in the model were obtained using macroscopic tests. Indentations were performed on samples with different thermal histories and at different speeds. For all cases, the numerical model correctly predicted the development of the contact area during indentation. For increasing strain rates, the contact area decreased at equal indentation depths. Annealing the samples resulted in a smaller contact area at equal indentation depth. Using only numerical simulation, it was also shown that pile-up around the indenter resulted from localization effects and was, thus, promoted by strain-softening properties of the indented material. Strain hardening, on the other hand, will tend to promote sink-in. Finally, we performed simulations of load relaxation during indentation. The results indicate that about 40% of the total observed relaxation may be assigned to plastic effects.