Determination of linear and nonlinear viscoelastic properties

泡沫粘弹性材料由于具有吸收和耗散不同形式能量的优异性能，在航空航天、船舶、汽车、医疗等领域广泛应用于减振、减噪、减应力等领域。最近的研究表明，如果设计得当，它们也可以用来提高结构的抗爆炸能力。为了设计出最高效和最有效的防爆结构，必须了解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和用于表征其性质的技术仍然没有得到充分的探索。一般来说，用于识别粘弹性材料动态特性的技术是基于波传播、自由振动和强迫振动。对于泡沫型粘弹性固体，每种方法都有局限性。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、应变历史和载荷的性质。因此，本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动态特性的技术，并建立材料的数学模型。本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.