Phase field analysis of crack propagation in bolts: effects of stress intensity factor and loading rate

Abstract Bolts are critical components in engineering structures, and their fracture behavior directly influences the safety and reliability of these structures. Although bolt fracture has been extensively studied, many studies have overlooked the complexity of crack growth under different stress intensity factors ( K ) and loading rates, which are common in real engineering applications. Therefore, a new approach is needed to account for these complex fracture behaviors and more accurately predict crack growth in bolts under these conditions. In this paper, the phase field method is employed to perform finite element simulations of the bolt tensile fracture process and to reconstruct its fracture behavior. Furthermore, the effects of varying stress intensity factors ( K ) and loading rates on the mechanical properties of the bolt during tensile fracture are systematically investigated. It is found that a higher stress intensity factor enhances the bearing capacity of bolts and delays crack propagation, while a higher loading rate accelerates crack propagation and increases the peak value of the fracture failure load. Through numerical simulations, the crack propagation path is accurately predicted, demonstrating the effectiveness and applicability of the phase field method in addressing bolt fracture problems. This study provides valuable theoretical guidance for bolt structural design via phase field simulation, particularly in predicting crack propagation paths, thereby offering more precise analysis tools for future engineering applications.