Enhanced core rigidity classifier method (RJS 2.0): A comprehensive approach to properly measure elastic properties of sandwich structures

The primary RJS Method consists of a suggestive criterion for the qualitative and quantitative classification of the core rigidity relevance in sandwich panels based on the structure's ability to achieve pure bending behaviour. It also includes a set of assumptions that address the influence of the dimensions of the specimen on the elastic properties measured by three-point bending tests. The method allows for characterising the flexural modulus of sandwich panels through a homogenisation concept and comparing theoretical and experimental values to assess the amount of shear deformations occurring. Some limitations of the method were reported, such as the restriction to three-point bending tests and symmetrical sandwich structures (those composed of faces of the same thickness and composition). Additionally, the possible contribution of the rigidity of the face-to-core adhesives was not addressed when estimating the overall rigidity of a sandwich panel. Moreover, a direct link between the qualitative and quan