Mohamed Khalil

Toward a new definition of FMECA approach

It is well known that Failure Mode Effect Analysis methodology (FMEA) allows to reduce, and if it possible eliminate, the effects of potential failure modes starting from the first stage of the product design. By means of the Criticality Analysis (CA), implemented in FMECA, it is possible to select by means of risk indexes the most potential critical failures. In this paper the authors present the pros and cons of FMECA along the product development cycle based on the existing standards, recommending the most appropriate standard for each development stage. Additionally, the concept of fault mechanisms is introduced through a new hybrid approach to avoid drawbacks of current FMECA. In this way, it will be possible to observe the evolution of the Remaining Useful Life (RUL) of the system and define the maintenance strategy using the information provided by the suitable monitoring activity.

A condition monitoring tool based on a FMECA and FMMEA combined approach in Oil&Gas applications

A new approach that combines up both FMECA and FMMEA techniques has been analyzed and apply in the Oil&Gas field. This method guarantees its efficiency along the product/system development cycle and assures a proper maintenance scheduling according to the current condition of the product/system.

Outage data analysis and RAMS evaluation of the Italian overhead transmission lines

A serious failure of a power transmission line can generate substantial financial losses due to the power outage. Consequently, utilities have a clear incentive to assess the actual condition of strategically important transmission lines, with the aim to minimize the risk of failures, enhance the maintenance practices and plan the development of the transmission network. This work focuses on the analysis of forced outages data for high-voltage overhead transmission lines (OHTL) in the Italian network during the period from 2008 to 2014. After a brief survey of the Italian network, the analysis has been carried out as follows: after a preliminary identification of the outage causes for OHTL, a new factor, namely the Severity Factor, has been introduced with the aim to drive the prioritization of the failure causes and the enhancement of the maintenance activities. Finally, an evaluation of the reliability, availability, safety and maintainability (RAMS) of the Italian OHTL network has been performed.

Markov process reliability model for photovoltaic module encapsulation failures

This paper presents Markov reliability model of Photovoltaic module encapsulation. The model includes all the possible failures associated with the operation of PV module. The same procedure of modeling can be extended to other parts of Photovoltaic systems. Firstly, failure causes are identified in details to develop the model, and then all the possible states of the encapsulation during the service are considered. Finally a complete Markov process is attained to assess the probability of each state and estimate the encapsulation mean time to failure, probability density function of the time to encapsulation failure, hazard and survival functions of PV module encapsulation.