Reliability prediction model of bolted connection based on uncertainty

During the service of bolts, their preload exhibits a random decreasing trend due to external loads, affecting contact stiffness and connection reliability. System uncertainties can also lead to preload variations within the same group of bolts. In this paper, we use the Wiener process to model this preload decrease, incorporating drift and wave coefficients to capture temporal variability and system uncertainty. This approach accounts for monotonic preload reduction and random fluctuations, enabling accurate calculations. By integrating the time-varying preload uncertainty into the bolted structure’s contact stiffness model, we establish a limit state function for structural failure and assess the reliability of the bolted connection over time.