Contact Nonlinearity in Indenter–Foam Dampers
Contact Nonlinearity in Indenter–Foam Dampers
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压头中的接触非线性 – 泡沫阻尼器
DOI：
10.1115/1.4054054
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Eriten, Melih
中科院分区：
文献类型：
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作者：
Liu, Lejie;Yerrapragada, Karthik;Henak, Corinne R.;Eriten, Melih
在本文中，对压头泡沫阻尼器的非线性响应进行了表征。这些阻尼器由压在用润湿液体膨胀的开孔泡沫上的压头组成。最近，作者确定了这些阻尼器中阻尼的主要机制是关节软骨中的孔隙粘弹性（PVE）松弛，这是自然界振动衰减的最佳解决方案之一。作者之前的工作包括在小振动（即线性状态）下对压头泡沫阻尼器进行动态力学分析。当前的研究以类似阻尼器在较大应变下的动态响应为特色，以研究非线性状态。特别是，本文中测试的压头泡沫阻尼器由用蓖麻油膨胀的开孔聚氨酯泡沫组成。使用平端圆柱形压头将谐波位移施加到膨胀且预压缩的泡沫上。然后分析测量的力和相应的磁滞（力-位移）循环，以量化阻尼性能（通过特定阻尼能力）和非线性（通过谐波比）。通过实验研究了应变和应变率对阻尼能力和谐波比的影响。非线性的主要来源被认为是压头-泡沫界面处的剥离（并通过剥离指数进行量化）。由线性粘弹性泡沫和速率相关的粘合界面（粘合强度有限的滑块元件）组成的代表性模型解释了观察到的剥离趋势，从而解释了非线性动态响应。还讨论了在未来压头泡沫阻尼器设计中抑制这些非线性的可能补救措施。
In this paper, the nonlinear response of indenter–foam dampers is characterized. Those dampers consist of indenters pressed on open-cell foams swollen with wetting liquids. Recently, the authors identified the dominant mechanism of damping in those dampers as poro-viscoelastic (PVE) relaxations as in articular cartilage, one of nature’s best solutions to vibration attenuation. Those previous works by the authors included dynamic mechanical analyses of the indenter–foam dampers under small vibrations, i.e., linear regime. The current study features the dynamic response of similar dampers under larger strains to investigate the nonlinear regime. In particular, the indenter–foam dampers tested in this paper consist of an open-cell polyurethane foam swollen with castor oil. Harmonic displacements are applied on the swollen and pre-compressed foam using a flat-ended cylindrical indenter. Measured forces and corresponding hysteresis (force–displacement) loops are then analyzed to quantify damping performance (via specific damping capacity) and nonlinearities (via harmonic ratio). The effects of strain and strain rates on the damping capacity and harmonic ratio are investigated experimentally. The dominant source of the nonlinearity is identified as peeling at the indenter–foam interface (and quantified via peeling index). A representative model consisting of a linear viscoelastic foam and rate-dependent adhesive interface (slider element with limiting adhesive strength) explains the observed trends in peeling and thus nonlinear dynamic response. Possible remedies to suppress those nonlinearities in future designs of indenter–foam dampers are also discussed.