Multiscale mechanics of polydimethylsiloxane: A comparison of meso‐ and micro‐cyclic deformation behavior
Multiscale mechanics of polydimethylsiloxane: A comparison of meso‐ and micro‐cyclic deformation behavior
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DOI：
10.1002/app.55546
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发表时间：
2024-04
影响因子：
3
通讯作者：
Lihua Lou;Nicole Bacca;Marshall S. Ma;Pranjal Nautiyal;Thomas G. Bifano;Arvind Agarwal
中科院分区：
文献类型：
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作者：
Lihua Lou;Nicole Bacca;Marshall S. Ma;Pranjal Nautiyal;Thomas G. Bifano;Arvind Agarwal
尽管大量的静态和动态力学测量和建模散装聚二甲基硅氧烷（PDMS）试样，一个显着的差距存在于全面了解大周期，低应变条件下的动态力学，特别是对于微尺度样品。本研究整合了拉伸测试和纳米压痕技术，以比较散装PDMS样品和μ柱的动态力学响应。循环拉伸试验的结果表明，在最初的25次循环后，能量耗散率趋于稳定，其中在10%-20%的应变范围内进行了多达10，000次循环。这归因于应力松弛和应变硬化，通过最大应力的快速双相指数衰减以及弹性模量的增量增加来验证。与拉伸测试相比，μ柱的刚度降低0.82%，稳定约600次循环。同时，在最初的120个循环期间，接近距离增加了大约两倍，并且在达到平台之前，在前80个循环期间耗散能量增加了大约四倍。这种滞后滞后效应归因于合力的分布，包括顶部张力、底部压缩和底部倾斜。总体而言，本研究阐明了两种应用场景下PDMS的时间力学变形，增强了我们对PDMS力学行为的理解。
Despite plenty of static and dynamic mechanical measurements and modeling for bulk polydimethylsiloxane (PDMS) specimens, a notable gap exists in comprehensively understanding the dynamic mechanics under large cycle, low strain conditions, especially for microscale samples. This study integrates tensile testing and nanoindentation techniques to compare dynamic mechanical response for bulk PDMS samples and μ‐pillars. The results from cyclic tensile testing, which involved up to 10,000 cycles at a strain range of 10%–20%, indicate a stabilization of energy dissipation rate after the initial 25 cycles. This attributes to stress relaxation and strain hardening, validating by rapid dual‐phase exponential decay in maximum stress, coupled with an incremental increase in elastic modulus. In comparison to tensile testing, μ‐pillars exhibited a 0.82% reduction in stiffness, stabilizing ~600th cycle. Concurrently, there was an approximately twofold increase in approaching distance during the initial 120 cycles, and an approximately fourfold increase in dissipated energy over the first 80 cycles, before reaching a plateau. This lagging hysteresis effect attributes to the distribution of the resultant force, including top tension, bottom compression, and base tilt. Overall, this study illuminates temporal mechanical deformations in PDMS under two application scenarios, enhancing our understanding of PDMS mechanical behavior.