T-S Model Based Fault Tree Analysis on the Hoisting System of Rubber-Tyred Girder Hoister

Hoisting system is the key part of the girder hoister, and its reliability determines the stability and security of the girder hoister directly. Hoisting system consists of mechanical, electrical and hydraulic components. Owing to the multiple and complex failure modes and mechanisms of the components, the hoisting system's reliability evaluation is accomplished by Fault Tree Analysis (FTA) based on T-S model. Failure probabilities can be described as fuzzy possibilities and fault degrees are expressed in terms of fuzzy numbers, while events' relationships are described by T-S gates instead of conventional logic gates. A method to acquire knowledge about the premise and consequent events is given, in terms of fuzzy rules of T-S gates made up of fuzzy possibilities and fault degrees of components. Fuzzy possibilities of the intermediate events and the top event are computed by MATLAB, in terms of information about field experiences and expert data. Considering the influence of fault degrees to the system at the same time, it offers reference to find and improve relevant weaknesses of the system, thus the dependability of the whole hoisting system is improved.