Fracture mechanics analysis of steel bolted joints using a 3D global model based on peridynamics theory

Abstract The bolted joint is a crucial component of a steel structure, directly impacting the safety and reliability of the entire structure. At present, the linear elastic theory is used in the joint design of steel structures, but it fails to reflect the process of crack initiation and propagation clearly. The traditional methods of fracture mechanics, finite element method and extended finite element method are all based on differential calculation to analyze structural damage and failure. Still, the crack tip has a singularity and requires dynamic mesh division, and the precision of the local displacement field is insufficient. To this aim, the theoretical basis of peridynamics (PD) theory that uses an integral algorithm can be developed to solve and analyze problems, which would avoid the shortcomings of traditional methods. Therefore, in this paper, the 3D PD theory was introduced into the practical engineering field of bolted joints for the first time, and a new method was developed for the damage and failure analysis of these structural elements. To avoid directly considering the complex forces between the bolt and the hole wall, the PD physical model of the bolt and the base material as a whole was established, and the PD theoretical analysis program was developed to disperse the bolt and the base material into PD particles. By analyzing the interaction of PD particles under external load, the damage mechanism of bolts and base metal at different positions was analyzed. At the same time, PD analysis and finite element results are combined with actual structural failure forms to verify the accuracy of PD theoretical results. It provides a new theoretical basis and analysis tool for bolted connection design in the engineering field, which can help structural engineers to design more optimized bolted connections for steel structures.