Tehdyt toimenpiteet
Electrostatic - Thermal coupling
The device modeled is a thermal actuator which is deformed by heating it with a static current. The electric power loss in the structure is transformed into heat due to Ohmic resistance (Joule heating). The heating depends on the electric conductivity and on the volume current density.
The electric-thermal problem is coupled since the electric conductivity of the material depends on the temperature. The boundary conditions for the temperature are somewhat unrealistic because the heat radiation is omitted. The coupled equations are solved in sequential manner. The model and all the equations are three-dimensional.
After the convergence of electric-thermal problem is achieved the temperature field is used as a load for linear stress analysis and the displacements of the actuator are solved. The displacements can be also be included into the coupled problem by solving the static current again with deflected structure and iterating all three solvers until convergence is reached. In this case, however, the results differed less than one percent compared to just one stress analysis step.
The example is an Ansys Tutorial case. The results of Elmer compared to Ansys Multiphysics software differ by 2 percent in temperature solution and by 3 percent in the displacement.