Papers by Author: Sheng Wang Hao

Abstract: The microstructural heterogeneity and stress fluctuation play important roles in the failure process of brittle materials. In this paper, a generalized driven nonlinear threshold model with stress fluctuation is presented to study the effects of microstructural heterogeneity on continuum damage evolution. As an illustration, the failure process of cement material under explosive loading is analyzed using the model. The result agrees well with the experimental one, which proves the efficiency of the model.

Abstract: Pattern competition and selection of strain localization were observed in rocks under uniaxial compression. The localization may be the trigger mechanism and an effective precursor of eventual rupture in brittle media. It is found that usually two high strain zones form before the eventual rupture. The rapidly increasing strain and strain rate within one of the high strain zones will lead to the eventual rupture of the specimen, and in the meantime, the strain and strain rate in the other high strain zone decrease rapidly. The digital speckle correlation method (DSCM) was used to measure the surface deformation fields.

Abstract: Contact pressure of porous Al2O3 probed by nanoindentation was investigated by dimensional analysis with special attention paid to scaling effects in the mechanical behavior. It was found that, for sample containing small grains and interconnected pores, the contact pressure is manifest dominated by bonding strength of the porous alumina. Whereas the samples with coarse grain and various porous structures exhibit higher contact pressures and smaller residual deformations, which can be attributed to the mechanical response of the solid-phase under current limited peak loads.