Damage Mechanics–Based Numerical Analysis of the Impact Fatigue Behavior of Helical Layered Steel Cables

The long-term structural integrity of steel cables is significantly compromised by cumulative damage and potential low-cycle fatigue failure caused by repeated impacts, but the complex dynamics of their helical layered structure makes impact fatigue analysis challenging. To address this, a damage mechanics–based numerical framework is developed. The proposed framework is built upon a refined numerical model that explicitly accounts for the structural features of helical cables and the dynamic effects of repeated impact loading and, when integrated with damage mechanics principles, provides an effective means of predicting fatigue damage and life. The close agreement between the simulations and experimental observations supports the use of the model for investigating the impact fatigue failure mechanisms of steel cables. The results reveal that the impact fatigue of steel cables progresses through the sequential fracture of wire layers in three stages: local depression, regional shearing, and overall fracture. Higher impact energy accelerates this process, while nonuniform damage markedly alters the subsequent tensile response compared with intact cables. The proposed damage model introduces a novel plastic strain evolution equation that effectively captures the unique damage characteristics of cables, enabling highly accurate life predictions across a range of impact scenarios. This study is expected to offer a generalized solution for the impact fatigue analysis of helical layered cables and fundamental insights into the associated failure mechanisms.