A Statistical Physics Analysis of Rock and Concrete Damage Response
Abstract
In our thermodynamic approach, crack densities have been treated as a hierarchy of order parameters operating at successively smaller scales (from macroscopic down to microcrack scales). The formulism renormalize surface energy densities due to interaction between microcracks, yields by thermodynamic self- consistency effective elastic constants (similar to those in effective medium approximations) and stress intensity factors (SIF) in cracked solids and provides thermodynamic definitions for observables (like R-curves and SIF). The fracture behavior under fixed grip or constant stress conditions has been studied numerically. Above a critical strain the material attains an equilibrium non-zero crack density that approaches the percolation threshold asymptotically with increasing strain. The effects of crack crack interactions of anisotropic crack-density and of pre-existing pores have also been studied. Crack propagation in ceramic materials, subject to microcrack formation and coalescence, has been examined with models that differ in the relative time scale involved in the internal relaxation processes and the external loading rate. It was found that when the external loading rate is high, a rising R-curve is obtained, which is primarily due to microcrack shielding.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 1991
- Accession Number
- ADA240310
Entities
People
- R. Englman
- Z. Jaeger
Organizations
- Israel Atomic Energy Commission