Importance analysis of underframe connection system for the pantograph lower arm rod

This paper is aiming at the high severity and failure rates of the parts connected by the lower arm rod and the underframe of the electric multiple unit pantograph, and a variety of state problems presented in the process of performance degradation and repair. A method of importance analysis by using multi-valued decision diagrams and logical partial derivative is proposed. Firstly, the multi-valued decision diagrams are introduced into the importance analysis of the underframe connection system for the pantograph lower arm rod. Secondly, the mathematical model for every importance is established by utilizing the principle of logic differential theory, and component importance, as well as the corresponding state, is analyzed. The importance of Birnbaum, structure, fussell–vesely, reliability results and reliability decrease value are calculated for each component of underframe connection system for the pantograph lower arm rod. The influence of component state on system state is determined in the third part. This method serves as a reference for the reliability analysis, safety assessment and maintenance optimization of underframe connection system for the pantograph lower arm rod.