Use the Thermal Expansion subnode to add an internal thermal strain caused by changes in temperature.
The Volume reference temperature Tref is the temperature at which there are no thermal strains. As a default, the value is obtained from a
Common model input. You can also select
User defined to enter a value or expression for the temperature locally.
The current Temperature T of the alloy is defined in the parent
Shape Memory Alloy node.
Select an Input type to specify how the thermal strain is defined. The default is
Secant coefficient of thermal expansion, in which case the thermal strain is given by
here, α = ξAαA + ξMαM is the volume average secant coefficient of thermal expansion, and
ξA and
ξM are the austenite and martensite volume fractions. The default
Secant coefficient of thermal expansion for Austenite αA and
Secant coefficient of thermal expansion for Martensite αM use values
From material.
When Input type is
Tangent coefficient of thermal expansion, the thermal strain is given by
where αt = ξAαtA + ξMαtM is the volume average tangential coefficient of thermal expansion. The default
Tangent coefficient of thermal expansion for Austenite αtA and
Tangent coefficient of thermal expansion for Martensite αtM use values
From material.
When Input type is
Thermal strain, enter the
Thermal strain for Austenite dLA and the
Thermal strain for Martensite dLM as function of temperature explicitly. Then the temal strain of the alloy is computed from
dL = ξAdLA + ξMdLM.
In all three cases, the default is to take values From material. Select
User defined to enter a value or expression for the coefficient of thermal expansion or thermal strain.
Physics tab with Shape Memory Alloy node selected in the model tree:
