An Anisotropic Bilinear Cohesive Zone-Based Damage Evolution Model with Experimentally Calibrated Parameters for Mode I Cracking in Chinese Fir

This study investigates the crack damage evolution in Chinese fir using an anisotropic bilinear cohesive zone-based constitutive model. The crack initiation and propagation processes were numerically modeled and simulated, and the results were validated through double cantilever beam (DCB) fracture tests. By exploiting the bijective relationship between the equivalent linear elastic fracture mechanics (LEFM) resistance curve (R-curve) and the cohesive softening law, the bilinear cohesive parameters were inversely identified from experimental data. The simulation results show good agreement with experimental observations in terms of crack path, propagation rate, and failure mode. The accuracy of the maximum load simulation results for mode I fracture of wood beams is 96.8%. These results further demonstrate the accuracy and applicability of the proposed cohesive zone model in describing crack propagation behavior in Chinese fir and provide a reliable theoretical and numerical framework for predicting fracture performance in timber structures.