Cortazar-Noguerol Julen, Cortés Fernando, Sarría Imanol, Elejabarrieta María Jesús
Department of Mechanics, Design and Industrial Management, University of Deusto, Avda. de las Universidades 24, 48007 Bilbao, Spain.
Polymers (Basel). 2024 Jun 28;16(13):1844. doi: 10.3390/polym16131844.
Polymeric foams are widely used in engineering applications for vibration attenuation. The foams usually work preloaded and it is known that the dynamic properties and attenuation ability of these polymers depend on the preload. In this paper, experimental characterization of a polyurethane elastomeric foam is performed in a frequency range between 1 and 60 Hz, a temperature range between -60 and 30 °C and a preload range between 2 and 12 N, using a Dynamic Mechanical Analyzer. When going from the minimum to the maximum preload, results show the linear viscoelastic range increases 57%. In the frequency sweeps, the storage modulus increases 58% on average, while the loss factor remains unaffected by preload. Moreover, the glassy transition temperature of the material decreases for greater preloads. From the curve-fitting of a four-parameter fractional derivative model using the experimental data, a seven-parameter mathematical model is developed, reducing the number of parameters needed to describe the influence of frequency and preload on the dynamic properties of the material. Hence, it has been established that the relaxation time, relaxed modulus and unrelaxed modulus depend on the exponential of the squared prestress. In contrast, the fractional parameter does not depend on preload for the range under study.
聚合物泡沫广泛应用于工程领域的减振应用中。这些泡沫通常在预加载状态下工作，并且已知这些聚合物的动态特性和衰减能力取决于预加载。在本文中，使用动态力学分析仪在1至60Hz的频率范围、-60至30°C的温度范围以及2至12N的预加载范围内对聚氨酯弹性体泡沫进行了实验表征。从最小预加载到最大预加载，结果表明线性粘弹性范围增加了57%。在频率扫描中，储能模量平均增加58%，而损耗因子不受预加载的影响。此外，对于更大的预加载，材料的玻璃化转变温度会降低。通过使用实验数据对四参数分数阶导数模型进行曲线拟合，开发了一个七参数数学模型，减少了描述频率和预加载对材料动态特性影响所需的参数数量。因此，已经确定松弛时间、松弛模量和未松弛模量取决于平方预应力的指数。相比之下，在所研究的范围内，分数参数不依赖于预加载。
