COMPUTATIONAL WELDING MECHANICS
Material Properties Summary
Properties can be provided for a material or alloy or for a specific phase in a material or alloy. If properties are provided for a specific phase, then the macroscopic or alloy material properties must be computed by a method such as the rule of mixtures, homogenization or a micro-macro model. Properties of a phase are a much more powerful strategy because it allows the properties to be computed as a function of microstructure evolution.
For CWM it is best that the properties be functions of temperature or specific enthalpy. Properties can be represented by tables, piecewise polynomials with ranges or can be quite complex functions. Gurson’s equation for yield stress as a function of porosity evolution is an example of a complex function.
Internally, the software works only in SI units, e. g., Pa, not MPa and not psi. Of course data could be accepted with other units and then immediately transform to SI units. We also transform data or results from SI units to other units when post processing and writing reports.
- Latent heats of phase transformation; each phase transformation can have an associated latent heat,
- Specific enthalpy as a function of temperature and microstructure,
- Specific heat preferably as a function of specific enthalpy but often provided as a function of temperature and microstructure,
- Thermal conductivity as a function of temperature and microstructure,
- Elasticity tensor; if a material is not isotropic, e. g., if a texture is present as in some cold rolled steel,
- Young’s modulus,
- Poisson’s ratio,
- Yield stress,
- Density or specific volume,
- Viscosity,
- Hardening modulus for rate independent plasticity,
- Softening modulus; a coefficient that defines the rate at which work hardened material softens, i. e., the yield stress decays as a function of temperature.
The structure with the following data can be viewed in 3D color with rotation, zoom and translation:
- Mesh. Part types. Loop over welds,
- Temperature,
- Displacement vector,
- Deformed structure,
- Phase fraction, for each phase,
- Stress. Each component, principal stresses, effective stress, maximum principal tensile stress, hydrostatic stress,
- Strain, Each component, principal strains, effective plastic strain, maximum principal tensile strain, hydrostatic strain, effective strain,
- Internal variables, effective plastic strain, hardening modulus.
