Thermodynamic Phase Field Models for Fracture and Inelasticity
Abstract
A geometrically nonlinear phase field theory accounting for dissipation, rate effects, nonlinear thermoelasticity, fracture, and other structural changes is constructed in the context of continuum thermodynamics. Order parameters represent fractures, solid-solid phase transformations, deformation twinning, or slip of partial dislocations. Pressure-dependent strength commensurate with frictional resistance is enabled in novel kinetic equations for dynamic fracture with irreversibility constraints. Linearization suitable for moderate volume changes but small deviatoric elastic strain and rotation is undertaken. The theory is applied to study deformation and failure of polycrystalline boron carbide (B4C), titanium diboride (TiB2), and a B4C-TiB2 ceramic composite. Solutions are derived and evaluated numerically for uniaxial stress tension and compression, uniaxial strain compression, and planar shock compression. The latter analysis yields relationships among viscosity coefficients, gradient regularization lengths, and characteristics of steady waveforms. Results give new insight into high-rate deformation mechanisms in these materials. This report includes and enlarges content of a recent journal publication by the author.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2021
- Accession Number
- AD1149573
Entities
People
- John D. Clayton
Organizations
- United States Army Research Laboratory