Thermal strain is computed when coefficient of thermal expansion is specified and a temperature load is applied in a structural analysis. To specify the coefficient of thermal expansion, you must set Thermal Strain Effects to Yes in the Details of the part or body objects before initiating a solve.

Each component of thermal strain is computed as:

Where:

  - thermal strain in one of the directions x, y, or z.

  - Secant coefficient of thermal expansion defined as a material property in Engineering Data (see "Chapter 2.4 Linear Material Properties" in the Element Reference of the Mechanical APDL application Help for more information about the secant function).

  - reference temperature or the "stress-free" temperature. This can be specified globally for the model using the Reference Temperature field of Static Structural or Transient Structural analysis types. Optionally you can also specify the reference temperature as a material property for cases such as the analysis for cooling of a weld or solder joint where each material has a different stress-free temperature.