Experimental and numerical analysis on concrete interface damage of ballastless track using different cohesive models

The Interface damage has become one of the most critical issues for ballastless tracks, which is a severe challenge to the rapid development of high speed railway. This paper presents experimental and numerical analyses on the concrete interface damage of ballastless track using different cohesive constitutive models and their implementation methods. The interface damage evolution characteristics of the ballastless track are investigated by combining damage mechanics method with finite element model, in particularly, the potential-based cohesive models are firstly used into the interface damage analysis of ballastless track by secondary development in software ABAQUS. Primarily, three types of cohesive constitutive model including a concise bilinear constitutive model and two potential-based cohesive constitutive models are implemented in ABAQUS through user-defined material subroutine, and then the interface damage simulation is completed by a DCB finite element model to verify the effectiveness of programmed cohesive constitutive subroutines. Subsequently, the experiment of concrete interface specimens is conducted by combining the concrete tensile test and the DIC full-field stress-strain test to obtain the mechanical properties and the constitutive relationship of the concrete interface. Finally, the interface damage evolution of a ballastless track with different cohesive constitutive models under temperature gradient load are investigated. The experimental results show that the exponential constitutive has the best agreement with the tested interface mechanical properties than other two types of cohesive law and the polynomial constitutive shows the worst match with test results. Moreover, the simulation results indicate that the interface failure of the track structure is a mix-mode damage process under temperature gradient load, and exponential cohesive model is recommended for the mix-mode damage analysis of track interface under quasi-static condition, whereas the polynomial cohesive model predicts asymmetrical damage distribution at the track interface due to its insufficient definition of the constitutive model. (C) 2020 Elsevier Ltd. All rights reserved.