Fatigue of notched steel hollow sections under sinusoidal cyclic loading

Abstract

This paper presents the numerical modelling of the fatigue of notched steel hollow sections under sinusoidal cyclic loading. Steel hollow sections are commonly used as structural components, particularly for beams, columns, girders, trusses and bracing. The biggest concern is flaws or minor cuts that create notches in the steel hollow sections. The presence of a notch could degrade the strength properties and consequently lead to severe disadvantages in fatigue life. The fatigue assessment was carried out using the finite element program WELSIM. SHS50×50×3.0 was selected for the three-dimensional model. The sinusoidal cyclic loading was applied with a minimum force of 1.665 kN and a maximum force ranging from 5.550 kN to 16.65 kN. Variables such as notch depth and amplitude ratio were simulated to acquire the stress range and the number of cycles. The results showed that the stress range for unnotched specimens is 46.258 MPa to 164.93 MPa; for notched specimens, it is 52.273 MPa to 189.89 MPa. It was found that the presence of a notch leads to an increase in the stress range and a decrease in the number of cycles. The unnotched specimens can withstand the number of cycles from 1.83×106 to infinity. Meanwhile, the number of cycles for notched specimens ranges from 1.20×106 to 8.36×107. At each amplitude ratio, except for A = 0.10, the number of cycles is insignificant.