Monotonic Response of European High‐Strength Steel HR and HV Bolts Under Tension and Bending

Abstract

HR and HV bolts are two common European high‐strength steel bolt classes with different failure mechanisms: the first fractures at the threaded part, while the second experiences thread stripping, which reduces ductility. Most studies on their behavior rely on standard tensile tests; however, recent research indicates that a significant bending moment can occur alongside tensile force. This study examines the response of HR and HV bolts under combined tension and bending. It also proposes a continuum finite‐element modeling procedure to accurately simulate their behavior. The research begins by introducing a new constitutive law for a steel material and calibrating values for its mechanical backbone and ductile fracture parameters. Following the general bolt modeling procedure, a method for capturing thread stripping is detailed. The loading regimen is explained, and the bolt responses under tension and bending are analyzed. Results show that increasing the bending moment increases ductility without altering resistance in HV bolts. However, applying a bending moment decreases both the ultimate strength and ductility of HR bolts.