This guide discusses coupled-field solutions available in Mechanical APDL. For details on coupled-field solutions in other Ansys products see their product specific documentation, for example Maxwell Coupling and Ansys System Coupling.

A coupled-field analysis, also known as a multiphysics analysis, is a combination of analyses from different engineering disciplines (physics fields) that interact to solve a global engineering problem. When the input of one field analysis depends on the results from another analysis, the analyses are coupled.

Some analyses can have one-way coupling. For example, in a thermal stress problem, the temperature field introduces thermal strains in the structural field, but the structural strains generally do not affect the temperature distribution; therefore, there is no need to iterate between the two field solutions.

More complicated cases involve two-way coupling. For example, a piezoelectric analysis handles the interaction between the structural and electric fields; that is, it solves for the voltage distribution due to applied displacements, or vice versa. In a fluid-structure interaction problem, the fluid pressure causes the structure to deform, in turn causing the fluid solution to change; such a problem requires iterations between the two physics fields for convergence.

Coupling between fields occurs either by direct or load-transfer coupling. Coupling across fields can be complicated because different fields may be solving for different types of analyses during a simulation. For example, in an induction heating problem, a harmonic electromagnetic analysis calculates Joule heating, used in a transient thermal analysis to predict a time-dependent temperature solution. The induction heating problem is complicated further because the material properties in both physics simulations are highly temperature-dependent.

Some applications in which coupled-field analysis may be required are pressure vessels (thermal-stress analysis), fluid-flow constrictions (fluid-structure analysis), induction heating (magnetic-thermal analysis), ultrasonic transducers (piezoelectric analysis), magnetic forming (magneto-structural analysis), and micro-electromechanical systems (MEMS).