When components cannot be treated as homogeneous (such as when the structure is made of different materials or when the heat transfer is two- or three-dimensional), different approaches are needed to evaluate accurately their thermal resistance: numerical evaluations can be useful, but they need to be integrated by experimental validations.When components cannot be treated as homogeneous (such as when the structure is made of different materials or when the heat transfer is two- or three-dimensional), different approaches are needed to evaluate accurately their thermal resistance: numerical evaluations can be useful, but they need to be integrated by experimental validations.