Synergistic Multiscale Analysis on the Bending Fatigue of Aerogel-Cored Stitched Sandwich Composites Available to Purchase

Bending fatigue in aerogel-cored stitched sandwich composites (ACSSCs) is a critical issue for their application in thermal protection systems (TPSs) in the context of reusability requirements. This study pioneers the introduction of a synergistic multiscale approach in the investigation of the bending fatigue behavior of ACSSCs using cost-effective finite element simulations, addressing the challenge of primarily relying on experimentation for the life prediction of ACSSCs. The multiscale method employs the node-based submodeling technique, enabling flexible selection of local analysis regions in complex structures and achieving the interaction between the local damage and the global structural response, combining the advantages of both. Initially, multiscale models for the stitched core within the ACSSC panel were established, which ensured calculation accuracy through convergence verification. Subsequently, the fatigue damage models for the components based on their fatigue life curves were established. The fatigue damage amplification technique was proposed to enhance computational efficiency in the fatigue simulation. Bending fatigue simulations were performed to predict the fatigue lives of ACSSC panels under varying vibration conditions. Finally, bending fatigue tests were conducted to verify the accuracy of the simulations. The results indicated that the predicted fatigue failure modes agreed well with the experimental observations. Moreover, the lives predicted closely matched experimental results, falling within a scattering band of ±2.44. Thus, the proposed method can effectively anticipate fatigue behavior in the ACSSC structures. In addition, this article examined the beneficial impact of stitching on enhancing the fatigue life of the sandwich structure.