低密度开孔泡沫蠕变松弛特性分析

利用三维Voronoi模型和有限元方法分析了胞壁材料具有粘弹特性的低密度开孔泡沫的蠕变和应力松弛行为.采用了三参量标准线性固体模型来描述胞壁材料的粘弹特性.所得结果表明.低密度开孔泡沫具有与其胞壁材料相同的松弛时间,当相对密度较低时(低于1%)开孔泡沫的松弛模量与胞壁材料的松弛模量和泡沫相对密度平方成正比.此外,计算结果还表明,低密度开孔泡沫在较小的初始应力条件下具有与其胞壁材料相同的延迟时间.其蠕变柔度与胞壁材料的蠕变柔度和泡沫相对密度平方倒数基本成正比.但随着初始应力值的增大,泡沫的延迟时间将会显著增加.

NUMERICAL ANALYSIS OF THE CREEP AND STRESS RELAXATION OF LOW DENSITY OPEN-CELL FOAMS

Three dimensional Voronoi model, in conjunction with the three-parameter standard linear model for the viscoelastic behavior of the cell wall material, is employed to simulate the creep and stress relaxation responses of low density open-cell foams. Obtained finite element results reveal that the foams have the same relaxation time as that of the solid of which the foams are made. The stress relaxation modulus of the foams with very low relative density is proportional to that of the solid and the square of the relative density. Numerical results on the creep analysis also show that the foams have the same delay time as that of the solid material of the foams and the creep compliance of the foams is proportional to that of the solid and the reciprocal of the square of relative densities at very low initial stress. With the increase of the initial stress, the delay time of the foams increases significantly.