Simulating real world systems or applications often requires an analyst to address multiple physical phenomena, simultaneously. This is sometimes referred to as multiphysics or multidiscipline simulation. Simply put, it is the science that emerges from the recognition that physical phenomena do not act in isolation, but rather in conjunction with one another.
Thermal-structural effects are a typical example of multiphysics, where heat transfer through a medium affects its structural behavior differently than if heat transfer were absent. Take an automotive exhaust manifold for instance, where heat propagates throughout the structure due to contact with exhaust gases. The heat flux creates a unique temperature profile on the manifold, which then affects its structural behavior by causing the metal to expand differently across the geometry.
Mapping can be an effective and computationally efficient technique for conducting multiphysics analysis. Results from one physics solution are ‘mapped’ onto the model of another physics solution. In our example above, this would involve imposing the temperature profile from a heat transfer simulation onto a structural analysis model. This allows the analyst to understand the structural behavior of the manifold, while accounting for its dependency on thermal effects.
The following video illustrates the mapping of temperature results from a thermal solution to a structural analysis model in NX CAE. The process is seamless, despite the two geometries having meshes that are quite distinct. Note how the mapping procedure is a numerical solution, with the solver computing the equivalent temperature map for the structural analysis model based on the map in the thermal analysis model. This ensures that the temperature information is transferred with a high degree of accuracy. Another feature I like is the option to automatically create a Nastran solution complete with the mapped temperature profile – a little luxury that can go a long way when you have lots of cases to evaluate. Click on the video to commence playback.