The computational modeling of instrumented indentation tests used to characterize material properties is challenging. It is mainly due to the computational techniques demanded to couple the complex physical mechanisms involved, such as, for example, the time-dependent inelastic material response to loads during contact. Therefore, this work aims to simulate the mechanical response of the poly vinylidene fluoride (PVDF) during a micro-indentation test considering a viscoplastic material model, and a prescribed load approach, using the finite element method. Further, model validation is performed based on experimental data measured during the contact between the indenter and the PVDF. Numerical analyses were performed using COMSOL Multiphysics finite element software considering the loading scheme of the experimental tests of 800 mN/min rate during loading and unloading, and a 400 mN constant load, held by 30 s. Finally, a viscoplastic Chaboche constitutive model is presented considering two cases: (1) a perfectly plastic behavior, and (2) a nonlinear isotropic hardening behavior based on Voce and Hockett–Sherby exponential laws. While the latter models exhibit some discrepancy in capturing the experimental behavior, the former one has shown excellent agreement with the load-depth curves obtained experimentally, achieving the best fitting for the set of Chaboche parameters: \(A=1\,{\mathrm{{s}}}^{-1}, {n}=4.62\) and \(\sigma _\mathrm{{ref}}=132\) MPa. Moreover, several phenomenological features of viscoplastic behavior such as rate dependence, plastic flow (or creep) and stress relaxation were accurately provided by the Chaboche model when describing the behavior of the PVDF material.

用于表征材料性能的仪器压痕测试的计算模型具有挑战性。这主要是由于需要将涉及的复杂物理机制耦合在一起的计算技术，例如，接触过程中随时间变化的非弹性材料对载荷的响应。因此，这项工作旨在利用有限元方法，在考虑粘塑性材料模型和规定载荷方法的情况下，模拟微压痕试验中的聚偏二氟乙烯（PVDF）的机械响应。此外，基于压头和PVDF接触期间测得的实验数据进行模型验证。使用COMSOL Multiphysics有限元软件进行了数值分析，考虑了在加载和卸载期间以800 mN / min的速度进行实验测试的加载方案，并在30 s内保持了400 mN的恒定载荷。最后，考虑了两种情况，提出了粘塑性Chaboche本构模型：（1）完全塑性行为，（2）基于Voce和Hockett-Sherby指数定律的非线性各向同性硬化行为。尽管后一种模型在捕获实验行为方面表现出一些差异，但前一种模型与通过实验获得的载荷深度曲线显示出极好的一致性，从而实现了对Chaboche参数集的最佳拟合：（1）完全塑性行为，（2）基于Voce和Hockett-Sherby指数定律的非线性各向同性硬化行为。尽管后一种模型在捕获实验行为方面表现出一些差异，但前一种模型与通过实验获得的载荷深度曲线显示出极好的一致性，从而实现了对Chaboche参数集的最佳拟合：（1）完全塑性行为，（2）基于Voce和Hockett-Sherby指数定律的非线性各向同性硬化行为。尽管后一种模型在捕获实验行为方面表现出一些差异，但前一种模型与通过实验获得的载荷深度曲线显示出极好的一致性，从而实现了对Chaboche参数集的最佳拟合：\（A = 1 \，{\ mathrm {{s}}} ^ {-1}，{n} = 4.62 \）和\（\ sigma _ \ mathrm {{ref}} = 132 \）  MPa。此外，Chaboche模型在描述PVDF材料的行为时，准确地提供了粘塑性行为的一些现象学特征，例如速率依赖性，塑性流动（或蠕变）和应力松弛。