An analysis of differently measured moduli of elasticity of media containing shape fabrics of pores and microcracks

摘要

Different experimental methods can provide different values for a particular effective modulus when applied to specimens made of heterogeneous materials. In this contribution we concentrate on investigating and comparison of effective moduli determined by means of both static deflection and resonance frequency of flexural vibration of bar-shaped samples made of material consisting of homogeneous matrix and shape fabrics of ellipsoidal pores and microcracks. The effect of shape characteristic of the pores themselves as well as of the parameters of pore distribution is investigated. We found that although the effective moduli determined by means of static deflection and by means of resonance frequency are usually the same even for quite heterogeneous bars, for materials with general fabrics of pores these moduli can differ from each other if there are non-homogeneities with a characteristic length comparable to the length of the sample.