A novel adaptive global-local multiscale damage numerical analysis method of large-size CFRP structure based on nonlinear criterion

Large-size Carbon Fiber Reinforced Polymer (CFRP) composite thin-walled structures are critical components within aerospace structures. Due to the inherent multiscale characteristics of composite, quantitatively characterizing the multiscale properties and damage of CFRP structures is crucial for their structural design. However, traditional macroscopic Finite Element Methods (FEM) fail to capture critical microscopic damage mechanisms. Although concurrent multiscale methods can obtain multiscale mechanical states, they incur high computational cost when applied to large- size CFRP structures. To address these issues, this study proposed an adaptive global-local multiscale damage analysis method for large-size CFRP thin-walled structure. To achieve an optimal balance between computational accuracy and efficiency, an adaptive strategy based on the nonlinear criterion was introduced within the Finite Element Method-Fast Fourier Transform (FEM-FFT) concurrent multiscale framework. In this scheme, macroscopic elements exhibiting linear behavior were calculated using homogenized material properties, while elements entering the nonlinear damage stage were resolved by the concurrent multiscale method to accurately capture multiscale nonlinear damage behaviors. The validity of the proposed multiscale model was verified through specifically designed experiments on CFRP laminate and stiffened panel. The results demonstrated that the proposed method successfully captures the multiscale mechanical responses and damage states, providing an efficient and accurate tool for the mechanical and damage analysis of large-size CFRP thin-walled structures.