Coupling of isogeometric higher-order RZT and parametric HFGMC frameworks for multiscale modeling of sandwich laminates: Theory and experimental validation

A novel isogeometric plate formulation based on {3,2}-order refined zigzag theory (RZT) is developed and coupled with the parametric high fidelity generalized method of cells (HFGMC) to perform multiscale structural analysis on sandwich structures. The HFGMC model enables the prediction of all material constants for the face sheets in sandwich laminate directly from fiber and matrix constituents, eliminating the need for standard mechanical tests. Moreover, the higher-order RZT formulation includes thickness-stretch effects in kinematic variables and generates all three-dimensional stress components, facilitating the direct transfer of stiffness matrices from the micro to macro levels, thus serving as a consistent multiscale framework. Besides, the high computational efficiency of the multiscale model is ensured by leveraging isogeometric analysis for interpolating the kinematic variables of RZT. Experimental studies are performed on uniaxial and cross-ply sandwich laminates for verification of the developed multiscale approach where a universal testing machine (UTM), strain gauges, acoustic emission (AE) sensors, and digital image correlation (DIC) technique are used for data collection. UTM and strain gauges are used to generate stress-strain curves whereas AE ensures the linear-elastic region of the testing, and DIC reveals the full-field experimental deformations. Comparing numerical and experimental results, higher accuracy and superior capabilities of the present multiscale model are revealed as compared to the linear RZT, shear deformation theory, where three-dimensional reference numerical solutions support the results of the present model. Overall, it is numerically and experimentally confirmed that the current methodology can serve as a generalized consistent multiscale analysis technique for modeling sandwich structures.