Effect of Preload on Tensile Fracture of Variable Cross-Section Bolts: Experiment and Simulation

High-strength bolts are widely used in structural connections, and the preload affects failure behavior of bolts. In this paper, a variable cross-section bolt (VCSB) with weakened strength to induce fracture is designed. Quasi-static tensile experiments different torque values were performed on VCSB. The torques 0, 430, 610, 820 N·m applied VCSB connection structures before test. load–displacement curves obtained by test could be divided into three stages: initial elastic phase, yield rapidly necking phase. As increased, stiffness phase increased from 101.21 kN/mm 270.64 displacement DC decreased 10.54 mm 8.42 mm. Finite element models developed simulate process under loads. difference between FB simulation results within 2%. simulations carried out adjusting prestress 0 650 MPa. show that value force has no effect VCSB, but greatly influences FC connection.