Material model

Material Model

• Materials can be parametrized either through material files (m6-format) or via implemented functions in class Material

• Materials can be parametrized for heat and moisture transport, or for heat transport alone (metals, plastic etc.)

• Material parametrization availability is indicated via the Material::m_flags variable, which is set either by flags WATER_TIGHT, VAPOR_TIGHT, AIR_TIGHT in the material data file or in the init() function for built-in materials

• Unless WATER_TIGHT and VAPOR_TIGHT are set together, materials are expected to have a moisture storage function available, otherwise the solver treats the materials as moisture-tight and the moisture content of these materials will always be zero.

Moisture Storage

• The moisture retention function Ol(pC) must be present (either as spline or as implemented function). In the case of spline data, the function is linearly interpolated using pC as interpolation x-variable.

Liquid Transport

• The liquid conductivity lgKl(Ol) must be present (either as spline or as implemented function). In the case of spline data, the function is linearly interpolated using log10(Kl) as interpolation y-variable.

Vapour Transport

• The vapor permeability Kv(Ol) must be provided. If not implemented as built-in material, the function can be parametrized in two ways:
  1. a spline lgKv(Ol) is provided in the material file, in which case the spline is linearly interpolated using log10(Kv) as interpolation y-variable
  2. a mu-value is given, in which case the function is generic Kv = delta_v/mu * (1-Ol/Oeff)