About the Output Material Properties

Some of these material groups are only used by physics interfaces in the add-on modules and detailed information is in the applicable documentation.

This section describes all available property groups and the material properties that they contain. These material properties can be added to models from two Settings windows: the Material window and its subnodes’ Property Group windows.

The Basic group contains over 25 basic properties for use with all materials.

Materials

Basic Material Properties

These common material properties belong to the Basic property group.

•	When this information is accessed from the Basic>Property Group window, it is listed under Quantities>Output Properties and Variable is listed in the table.

•	When this information is accessed from the Material window, it is listed under Material Properties>Basic Properties and Name is listed in the table under Material Contents.

Table 9-2: Basic Material Properties

Property	Name/Variable	SI Unit
Absorption Coefficient	kappaR	1/m
Bulk Viscosity	muB	Pa·s
Characteristic Acoustic Impedance	Z	Pa·s/m
Coefficient of Thermal Expansion	alpha	1/K
Compressibility of Fluid	chif	1/Pa
Density	rho	kg/m3
Diffusion Coefficient	D	m2/s
Dynamic Viscosity	mu	Pa·s
Electrical Conductivity	sigma	S/m
Electron Mobility	mue	m2/(Vs)
Heat Capacity at Constant Pressure	Cp	J/(kg·K)
Isotropic Structural Loss Factor	eta s	1
Mass Flux	Mf	kg/(m2·s)
Mean Molar Mass	Mn	kg/mol
Permeability	kappa	m2
Poisson’s Ratio	nu	1
Porosity	epsilon	1
Ratio of Specific Heats	gamma	1
Relative Permeability	mur	1
Relative Permittivity	epsilonr	1
Resistivity	res	Ω·m
Scattering Coefficient	sigmaS	1/m
Seebeck Coefficient	S	V/K
Speed of Sound	cp	m/s
Storage	S	1/Pa
Surface Emissivity	epsilon rad	1
Thermal Conductivity	k	W/(m·K)
Young’s Modulus	E	Pa

The coefficient of thermal expansion (CTE) and the resistivity temperature coefficient have the SI unit 1/K. COMSOL Multiphysics translates this into the Fahrenheit temperature unit using an offset. This means that you do not get the expected results. Use caution when a model uses the coefficient of thermal expansion or the resistivity temperature coefficient and the unit system’s temperature is not kelvin.

The rest of the material properties are grouped by application area:

• Acoustics Material Properties • Electrochemistry Material Properties • Electromagnetic Models • Equilibrium Discharge • Gas Models • Piezoelectric Models • Piezoresistive Models

• Solid Mechanics Material Properties • Solid Mechanics Material Properties: Nonlinear Structural Materials Module • Solid Mechanics Material Properties: Fatigue Module • Solid Mechanics Material Properties: Geomechanics Material Model • Semiconductors Material Properties