Spherical indentation into elastoplastic materials: Indentation-response based definitions of the representative strain
Spherical indentation into elastoplastic materials: Indentation-response based definitions of the representative strain
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DOI：
10.1016/j.msea.2007.01.002
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发表时间：
2007-04
期刊：
影响因子：
6.4
通讯作者：
Yanping Cao;Xiuqing Qian;N. Huber
中科院分区：
文献类型：
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作者：
Yanping Cao;Xiuqing Qian;N. Huber
在开发利用深度传感仪器化压痕测试确定材料机械性能的系统方法时，关键问题是找到压痕响应与压痕材料性能之间的联系。对于幂律工程材料的球形压痕，我们表明可以通过使用代表应变的概念来解决这个问题。在本研究中，利用基于增量塑性理论和大变形公式的有限元分析，我们提出了四种基于压痕响应的代表应变定义。它们中的每一个都可以简单而明确地表达材料特性（即代表性应力，或折减模量和代表性应力）与球形压痕加载-卸载曲线给出的直接可测量量之间的关系。此外，还进一步研究了摩擦力对压痕载荷-深度曲线的影响。根据这项工作报告的结果，已经建立了许多使用球形压痕测试来识别弹塑性材料机械性能的新方法。进行了数值实验来验证所提出方法的有效性。还讨论了由表面粗糙度和压头柔量影响引起的实验不确定性，强调了在实践中应用新方法的注意事项。
In the development of a systematic method to determine the mechanical properties of materials using depth-sensing instrumented indentation tests, a key issue is to find the connection between the indentation response and the properties of the indented material. For spherical indentation into power law engineering materials, we showed that this problem can be solved by using the concept of the representative strain. In the present research, using finite element analysis based on the incremental plasticity theory and large deformation formulations, we proposed four indentation-response based definitions of the representative strain. Each of them leads to a simple and explicit expression of the relationship between the material properties (i.e., representative stresses, or reduced modulus and representative stresses) and the directly measurable quantities given by the spherical indentation loading–unloading curves. In addition, the effect of friction on the indentation load–depth curve is further investigated. Based on the results reported in this work, a number of novel approaches to identify the mechanical properties of elastoplastic materials using spherical indentation tests have been established. Numerical experiments were performed to verify the effectiveness of the proposed methods. Experimental uncertainties caused by the effects of the surface roughness and the indenter compliance are also discussed which highlights the precautions of applying the novel methods in practice.