Time-variant reliability analysis of crane boom involving interval process and random parameters

Due to uncertainties such as loads and material degradation, the reliability of the crane boom changes over time. In this paper, a hybrid interval process and random model is used to characterize the uncertainty of crane boom. Considering that the reliability in actual engineering is often determined by a variety of failure modes, this paper considers three failure modes: strength failure, stiffness failure and stability failure. Because reliability analysis of crane boom involves time-consuming finite element analysis, a hybrid time-variant reliability analysis method based on the Kriging model is proposed to alleviate this issue. To reduce the computational complexity of the hybrid uncertain model, the equivalent uncertainty transformation method is employed. For the transformed model, an active learning method is utilized to construct a high-precision Kriging model, which can further reduce the analysis time. Based on the constructed Kriging model, the time-variant reliability results of the crane boom under multiple failure modes can be obtained by the Monte Carlo analysis. The proposed method is first verified by a cylindrical pressure vessel mathematical example and then applied on the reliability of crane booms.