Determination of linear and nonlinear viscoelastic properties

泡沫型粘弹性材料由于具有优异的吸能和耗能能力，在航空航天、船舶、汽车、医疗等领域被广泛应用于减振、降噪、减应力等领域。最近的研究表明，如果系统设计得当，它们也可以用于提高结构的抗爆能力。为了设计出最有效和最有效的防爆结构，必须知道每个部件的材料特性。对现有文献的回顾表明，泡沫型粘弹性固体的性质以及用来表征其性质的技术仍然没有得到充分的探索。通常，用于识别粘弹性材料的动态特性的技术是基于波的传播、自由振动和强迫振动。这些方法对于泡沫型粘弹性固体都有局限性。这是因为它们的性质取决于它们的密度和形状、环境温度、应力历史、应变历史和加载的性质。因此，这项研究的中短期目标是深入研究识别具有不同密度和非线性程度的泡沫型粘弹性固体的动态特性的技术，并开发该材料的数学模型。该项目的长期目标是利用该数学模型开发结构防爆系统。

Foam-type viscoelastic materials have been widely used to reduce vibration, noise, and stresses in aerospace, marine, automobile, and medical industries due to their superior ability to absorb and dissipate energy in different forms. Recent studies showed that they can also be used to enhance the blast resisting capacity of structures if the system is properly designed. To design the most efficient and effective blast protection structures, material properties of each component must be known. A review of the existing literature reveals that the properties of foam-type viscoelastic solids and the techniques used to characterize their properties are still not fully explored. In general, the techniques used to identify dynamic properties of viscoelastic materials are based on wave propagation, free vibration, and forced vibration. Each of these methods has limitations for foam-type viscoelastic solids. This is because their properties depend on their density and form, ambient temperature, stress-history, strain-history, and the nature of loading. Therefore, the short- to medium-term objectives of this study are to thoroughly investigate techniques to identify dynamic properties of foam-type viscoelastic solids having different densities and degrees of nonlinearlity and to develop a mathematical model of the material. The long-term objective of this project is the development of structural blast protection system using this mathematical model.