Design for Reliability of Complex System with Limited Failure Data; Case Study of a Horizontal Drilling Equipment

In this paper, a methodology is developed for reliability evaluation of electromechanical systems. The method is applicable in early design phase where there is only limited failure data available. When experimental failure data is scarce, generic failure data are searched from some related reliability data banks. In this method, Reliability Block Diagrams (RBD) is used for modeling the system reliability. Monte Carlo Simulation technique is employed to simulate the system for reliability and availability calculation. Current methodology contains the reliability importance analysis and reliability allocation to optimize the reliability. Evaluating reliability of complex systems in reverse engineering (competitive) design phase is one of the applications of this method. As a case study, a horizontal drilling equipment is used for assessment of the proposed method. According to the results, motor sub-system and hydraulic sub-system are the critical elements from reliability point of view. A comparison of the results is done with the results of reliability evaluation for a system with more failure and maintenance data available. Benchmark of the results indicates the effectiveness and performance quality of presented method for reliability evaluating of systems.