This paper proposes a new isotropic hyperelastic model for polymer foam, which explicitly models the micromechanical influence of changes in porosity. The foam is treated as a matrix of compressible solid material with evacuated pores that cause soft response for low pressures. In its general form, the strain energy of the foam depends on the strain energy of the solid material and on the porosity, which is taken to be a function of the total dilatation. This function adds only two material constants. One is the stress free porosity and the other controls the magnitude of the low pressure response of the foam. In contrast with other formulations, the proposed model naturally transitions to the response of the solid as the porosity approaches zero in hydrostatic compression.

中文翻译：

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包括孔隙度微观力学的软聚合物泡沫超弹性模型

本文提出了一种新的聚合物泡沫各向同性超弹性模型，该模型明确模拟了孔隙率变化对微观力学的影响。泡沫被视为具有真空孔的可压缩固体材料的基体，可对低压产生软响应。在其一般形式中，泡沫的应变能取决于固体材料的应变能和孔隙率，孔隙率被视为总膨胀的函数。此函数仅添加两个材料常数。一个是无应力孔隙率，另一个控制泡沫低压响应的大小。与其他公式相比，当静水压缩中孔隙率接近零时，所提出的模型自然过渡到固体的响应。