There are several potential causes and solutions for this issue:
1. The FEA model and the CFD model are positioned or oriented differently.
The two models must be located in the same place and in the same orientation. If they are not, then it is very difficult to ensure that conditions are accurately transferred. Note that the FEA model and CFD models do not have to include the same parts. In many cases, the CFD model includes a fluid region that is omitted from the FEA model. This is acceptable as long as the parts common to both are consistently orientated and positioned.
2. The FEA model and the CFD model use different length scales (units systems).
Check this one carefully. It is always a good practice to compare the length of an edge in the FEA model and the CFD model. If the edge is 0.0025 m in the FEA model and 2.5 mm in the CFD model, resolve the difference before proceeding. The easiest way is to change the length units in the CFD analysis.
3. No "dummy" boundary conditions were applied in the FEA model.
This is probably the situation that occurs most often. A key step in this process is to apply dummy boundary conditions to the FEA model prior to exporting the initial deck. These boundary conditions are essential because they tell Autodesk® Simulation CFD where to transfer the results to the FEA model. Without them, Autodesk® Simulation CFD has no idea where the loads should be applied to the FEA model.
The other purpose is to define what kind of boundary condition to apply--nodal temperatures or elemental pressures. Only temperatures and pressures can be transferred; other boundary condition types are ignored.
4. Initialization Data Was Mapped to the FEA File Instead of Calculated Temperature Results
In certain situations, temperature data mapped to the FEA file may reflect initial conditions used in the CFD model. If you open the new boundary conditions file, you will see that only boundary conditions and initial conditions were mapped over to some of the dummy BCs. This is because the CFD result sets were not available within the source file at the time when the FEA mapping was performed. This problem can be resolved by either closing and reopening the scenario or running 0 iterations from the last saved result set.