Effect of microcracking on the uniaxial tensile response of β-eucryptite ceramics: Experiments and constitutive model

A constitutive model for the nonlinear or “pseudoplastic” mechanical behavior in a linear-elastic solid with thermally induced microcracks is developed and applied to experimental results. The model is termed strain dependent microcrack density approximation (SDMDA) and is an extension of the modified differential scheme that describes the slope of the stress-strain curves of microcracked solids. SDMDA allows a continuous variation in the microcrack density with tensile loading. Experimental uniaxial tensile response of β-eucryptite glass and ceramics with controlled levels of microcracking is reported. It is demonstrated that SDMDA can well describe the extent of non-linearity in the experimental uniaxial tensile response of β-eucryptite with varying levels of microcracking. The advantages of the SDMDA are discussed in regard to tensile loading.

We develop a constitutive equation termed strain dependent microcrack density approximation (SDMDA) that models the uniaxial tensile behavior of β-eucryptite with various levels of microcracking. Model results are compared with experimental results on specimens that were heat treated to produce different levels of microcracking.110