ESTiG, Instituto Politécnico de Bragança, 5300-252, Bragança, Portugal.
MEtRICs, Mechanical Engineering Department, Campus de Azurém, University of Minho, 4800-058, Guimarães, Portugal; CMEMS, Minho University, Guimarães, Portugal; CIMO, Instituto Politécnico de Bragança, 5300-252, Bragança, Portugal.
J Mech Behav Biomed Mater. 2023 Dec;148:106164. doi: 10.1016/j.jmbbm.2023.106164. Epub 2023 Oct 7.
The examination of hyperelastic materials' behavior, such as polydimethylsiloxane (PDMS), is crucial for applications in areas as biomedicine and electronics. However, the limitations of hyperelastic models for specific stress scenarios, with stress concentration, are not well explored on the literature. To address this, firstly, three constitutive models were evaluated (Neo-Hookean, Mooney-Rivlin, and Ogden) using numerical simulations and Digital Image Correlation (DIC) analysis during a uniaxial tensile test. The samples were made of PDMS with stress concentration geometries (center holes, shoulder fillets, and edge notches). Results of ANOVA analysis showed that any of the three models can be chosen for numerical analysis of PDMS since no significant differences in suitability were found. Finally, the Ogen model was chosen to obtain the stress concentration factors for these geometries, a property which characterize how discontinuities change the maximum stress supported by an element. Our study provides new values for variables needed to analyze and design hyperelastic elements and produce a foundation for understanding PDMS stress-strain behavior.
对超弹性材料（如聚二甲基硅氧烷（PDMS））行为的研究对于生物医学和电子学等领域的应用至关重要。然而，超弹性模型在特定应力情况下（如应力集中）的局限性在文献中并未得到充分探讨。为了解决这个问题，首先，我们使用数值模拟和数字图像相关（DIC）分析在单轴拉伸试验中评估了三种本构模型（Neo-Hookean、Mooney-Rivlin 和 Ogden）。样品由具有应力集中几何形状的 PDMS 制成（中心孔、肩部圆角和边缘缺口）。方差分析结果表明，任何一种模型都可以选择用于 PDMS 的数值分析，因为没有发现它们在适用性方面存在显著差异。最后，选择 Ogden 模型来获得这些几何形状的应力集中因子，该因子表征不连续性如何改变元件承受的最大应力。我们的研究为分析和设计超弹性元件所需的变量提供了新的值，并为理解 PDMS 应力-应变行为奠定了基础。
