Energy-based criteria for identification of impact-induced interfacial damage of longitudinally connected slab ballastless track structure

Interfacial damage as a potential threat affects the stability of the longitudinally connected slab ballastless track structure (LCSBTS). In most related research, the interfacial damage of LCSBTS is identified in terms of stiffness degradation, which makes it difficult to explore the role of energy in the development of the interfacial damage. As an alternative, a set of energy-based criteria rooted in a bilinear cohesive zone model was proposed, together with a new damage indicator that evaluates the loss of interfacial fracture energy. The proposed criteria were utilized in the simulation of the interfacial damage of LCSBTS subjected to wheel impact. Results show that, the energy-based damage indicator describes the growth of the interfacial damage at a slower speed than the stiffness-based damage indicator, better coordinating with the variation of the interfacial fracture energy. Under wheel impact, interfacial damages are most likely to occur out of a peanut-shaped region surrounding the impact point where shear stress surpasses tension stress. However, by considering a coupling action of the positive temperature gradient, severe interfacial damages appear around the center of the track slab where tension stress surpasses shear stress and interfacial damages caused by shear stress are located near the longitudinal edges of the track slab. •Energy-based criteria for interpreting the interfacial damage are proposed.•A new indicator for evaluating the delamination resistance of the interface is proposed.•The dominant factor accounting for the interfacial damage is interpreted from the energy point of view.•The spatial and temporal variations of the interfacial damage subjected to wheel impact are analyzed.•Effects of considering a coupling action of temperature and wheel impact on the interfacial damage are investigated.