孔隙率对气凝胶力学性能的影响

建立了考虑孔隙率影响的气凝胶的本构方程，分析了孔隙率对其有效弹性模量、体积模量和气凝胶固体网络骨架上应力的影响，结果表明孔隙率越大，固体骨架承受的应力越大；有效弹性模量、体积模量随孔隙率的变化而变化；同时气凝胶干燥过程中，由于蒸发，孔中的液体不断被气体取代，导致作用在固体和液体上应力重新分布，容易造成干裂。

Effects of Porosity on Mechanical Properties of Aerogels

In this paper, the effective Young's modulus and effective bulk modulus of the mixture are defined. The constitutive equations of solid network of aerogels account of the effect of porosity are presented for analysis of the effects of porosity on the effective Young' s modulus, effective bulk modulus of the mixture and the stress of solid network of aerogels. The results show that the greater the porosity is, the greater the stress borne by solid skeleton and the less the stress borne by liquid in pores are; that the less the porosity is, the less the stress borne by solid skeleton and the greater the stress borne by liquid are. In the process of drying, gas - phase substitutes for liquid in pores unceasingly by evaporation , and the distribution of stress acted on both solid skeleton and liquid - phase is redistributed. The strain and volumetric strain of solid network of the aerogels are the functions of porosity of gels. The effective Young's modulus and effective bulk modulus vary with porosity.