Sharif Digital Repository

The present research proposes a new method to establish a practical framework for extension of gas turbine life time. This method is based on an nine-step operational algorithm which is capable for different types of gas turbine. The essential inputs for this algorithm includes documents of inspection and knowledge of repair and maitenance experts. In this algorithm is used the Bayesian network probabilistic method. Therefore, based on the observations and the knowledge of experts, gas turbine Bayesian network is produced. According to this Bayesian network consequenses are created. Furthermore, making the steps of the algorithem more explicit, FTA and FMEA methods are used to creat the... 

In this thesis we illustrated PFMEA in VAMCO to evaluate effectiveness of applying this standard in this company ,though the results showed better situation but they were not significant then we launch to study the reasons of this matter and to help our survey we used other companies' knowledge via questionnaires and interviews,. After collection of data our conclusion proved that there were both problems in context and application. For solving these problems we investigated about experience of international esteemed companies and finally we decided to apply a new model in form of a software. For designing algorithm of this software we deeply focused on problems and use the recent... 

Most of designers, manufacturers and all of the agents involved in product development processes are using the failure modes and effects analysis to reduce the potential failure of new products. Risk priority number (RPN) is calculated by multiplying occurrences (O), severity (S) and detection (D). This value is used as FMEA performance measure. Although the value of the RPN gives a good sight to product design and development, but firstly it ignores relative importance of the risk factors, secondly it is difficult to calculate the RPN value where there is shortage of product failure records and thirdly it is difficult to express risk factors with crisp values. In the above conditions FMEA... 

This work presents a novel approach to redefine a safe aircraft based on systems engineering fundamentals. Its aim is to prescribe a “Safe-Functional-Aircraft” instead of currently used procedures that is based on “Physically-defined-Safe-Aircraft”. The current work is much more consistent with increasing number of flights. It basically suggest that any aircraft that can complete its mission should not declare emergencies due to any physical malfunction. With proper simulations, have investigated the feasibility of replacing a “physically safe” aircraft with an “operationally/functionally safe” one. The process makes use of well-known documents such as FTA and FMEA ; which are produced... 

In this thesis, bayesian network has been used in analyzing the failure of a structural component. The design life of a structural component of a system can be limited or unlimited depending on the working conditions considered by the designers. However, usually during the operation of an industrial system or device, a structural component of it fails prematurely, in other words, its actual life is less than the design life. In this case, the failure must be analyzed to find the causes and factors. The method of work is such that first, according to the problem and the type of failure, the required analyzes and studies are considered. Then, a number of samples of the components, whose... 

Reliability-centered maintenance (RCM) is one of the main maintenance methodologies that ensures the continuity of the organization's physical assets in order to meet the expectations of its stakeholders. Despite the widespread use of artificial intelligence in maintenance, the use of these tools to improve the RCM implementation process is a new issue. To this end, in this dissertation, using artificial intelligence and soft computing tools, an upgraded RCM system is introduced so that in addition to increasing the accuracy in the implementation of RCM processes, the time and cost required to implement these processes has reduced, and made it possible to record and store the knowledge of...