Introduction

Three types of materials are defined within the platform: fluid materials, solid materials, and thermal interface materials (TIM). A material can be assigned to a solid region, fluid region, or interface by selecting an existing option from the material list or by defining a new one.

The material library is managed through the Library page, which contains a repository of predefined materials as well as the ability to create custom materials. Predefined materials are locked and cannot be edited, whereas custom materials are fully configurable.

All the predefined materials with constant properties are defined at Standard Temperature Pressure (STP) conditions. The STP conditions correspond to a temperature of 273.15

K

or 0

°C

and a pressure of 100

kPa

or 1

bar

. The properties of each type of material are given below:

Material summary

Property		Material type			Input Format
Name	Unit	Solid	Fluid	TIM	Input Format
Density $\rho$	$kg/m^3$				Solid: Constant Fluid: Constant, Polynomial, Tabulated
Dynamic viscosity $\mu$	$kg/(m\cdot s)=Pa\cdot s$				Fluid: Constant, Polynomial, Tabulated
Specific heat capacity $C_p$	$J/(kg\cdot K)$				Solid: Constant Fluid: Constant, Polynomial, Tabulated
Absorption coefficient $\alpha$	$m^{-1}$				Solid: Constant
Thermal conductivity $\kappa$	$W/(m\cdot K)$				Solid/TIM: Constant Fluid: Constant, Polynomial, Tabulated
Coefficient of thermal expansion $\beta$	$K^{-1}$				Fluid: Constant, Polynomial, Tabulated
Thickness $R_d$	$m$				TIM: Constant
Resistivity	$\Omega \cdot m$				Solid: Constant
Thermal resistance $R_{th}$	$K/W$				TIM: Constant

How to Add Materials

How to input temperature-dependent material properties?

Solid and thermal interface material (TIM) properties must be defined as strictly constant values. Fluid properties, however, can be configured as temperature-dependent. When defining a fluid, the chosen input method must be identical across all of its properties (i.e., mixing constant, polynomial, and tabulated inputs for a single fluid is not supported).

Constant Value: A single parameter value evaluated at a reference temperature:
$\kappa = 100$
Polynomial Function: An array of up to 8 coefficients representing a polynomial function of temperature:
$\kappa = [1,2,3,4,5,6,7,8]$
This array represents the coefficients of a polynomial:
$\kappa = 1+2T+3T^2+4T^3+5T^4+6T^5+7T^6+8T^7$
Tabulated Data: A nested list containing distinct temperature values and their corresponding parameter values:
$\kappa = [[273,100],[283,100],[293,120],[303,120]]$

Example of a constant input — Example of a material with constant properties.

Example of a polynomial input for kappa — Example of a material with polynomial data.

Example of a tabulated input for kappa — Example of a material with tabulated properties.

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Important
When creating a fluid, the input for all properties should be identical. This means that either all properties are constant, or tabulated or polynomial, mixing them is not accepted.