What is the difference between conducting thick plates and contact resistances?
Conducting thick plates have both in-plane and normal (to the plane) conduction.They are modeled and meshed in 3D.
Contact resistance plates have normal conduction only, and are meant for plates with very small thickness.
They are modeled in 2D (planar surface mesh only) and use an effective thickness to calculate thermal resistance.
For additional information, refer following section:
Icepak 12.1 User Guide -> Plates -> Thermal Model Type