An in situ fatigue-CZM for unified crack initiation and propagation in composites under cyclic loading

摘要: Abstract In this paper, a non-Paris-law-based, unified fatigue cohesive zone model (CZM) that can predict both crack initiation and propagation in composites with or without starter cracks stress concentrators has been formulated validated. The CZM incorporates normal shear S–N curves for pre-initiation strength degradation, simple power-laws post-initiation damage accumulation rate computed directly from the situ traction–separation history. A unique procedure to determine loading profiles an efficient cycle jump strategy have also developed. It demonstrated, through direct comparisons against experimental results, proposed successfully ensuing pre-cracked as well crack-free specimens. Furthermore, become sufficiently long linear elastic fracture mechanics (LEFM) conditions be dominant, correctly Paris laws under pure mixed mode conditions.