A Numerical–Experimental Approach for Multi‐Matrix Fiber‐Reinforced Plastics Characterization Using Finite Element Model Updating

This study presents a numerical–experimental approach for characterizing continuous multi‐matrix fiber‐reinforced polymers (MM‐FRPs). Characterizing the mechanical behavior of MM‐FRPs remains a challenge, especially regarding viscoelastic effects, despite the enhanced design flexibility provided by combining stiff and soft matrices. The proposed methodology integrates harmonic mechanical testing with finite element model updating (FEMU) to overcome this gap. Two types of specimens were fabricated using tailored fiber placement and tailored matrix placement. One of the samples featured an epoxy matrix, while the other one incorporated a hybrid epoxy/polyurethane matrix. Both specimen types were subjected to bending tests at multiple frequencies. To deal with the distinct material phases, a high‐fidelity finite element model was developed. The FEMU process was then employed to calibrate material parameters by minimizing the discrepancy between the experimental and numerical force–displacement curves. Key results demonstrate that the hybrid specimen exhibits pronounced viscoelastic behavior with significant energy dissipation, whereas the reference specimen behaves predominantly elastically. The good alignment between simulated and experimental results validates the effectiveness of the FEMU approach for accurately identifying the complex properties of advanced composite systems.