Investigating Imperfect Inspection of Avionics System and its Relationship with Availability Percentage

2012 ◽  
Vol 225 ◽  
pp. 534-539
Author(s):  
Aisyah Razana Mahayudin ◽  
Mohamed Tarmizi Ahmad ◽  
Fairuz Izzuddin Romli ◽  
Amzari Zhahir
Keyword(s):  
Preventive Maintenance ◽  
Discrete Event ◽  
Operating Conditions ◽  
Simulation Methods ◽  
Corrective Maintenance ◽  
Event Simulation ◽  
Operational Life ◽  
System Maintenance ◽  
Maintenance Policies ◽  
Maintenance Process

System maintenance is necessary to prolong the operational life of a system. There are four types of maintenance policies which are corrective, preventive, scheduled and predictive (conditioning based maintenance). However, this paper focuses on preventive maintenance and corrective maintenance policies. In general, the goal of preventive maintenance is to retain the system at its good operating conditions before the occurrence of any failure while corrective maintenance is done as a result of the system’s operating failure. This paper investigates the effects of maintenance activities for Engine Indication and Flight Instruments subsystems of the avionics system of a general aircraft. The simulation of the maintenance process is done using Monte Carlo and Discrete Event simulation methods for different preventive maintenance interval (PMI).

Selection of Maintenance Strategies in an Operating Theatre

2021 ◽  
pp. 1-35
Author(s):  
María Carmen Carnero ◽  
Andrés Gómez
Keyword(s):  
Preventive Maintenance ◽  
Predictive Maintenance ◽  
Operating Theatre ◽  
Sterile Water ◽  
Repairable Systems ◽  
Corrective Maintenance ◽  
Water Power ◽  
Suitable Combination ◽  
Multicriteria Model ◽  
Maintenance Policies

The aim of this chapter is to select the most suitable combination of maintenance policies in the different systems that make up an operating theatre: air conditioning, sterile water, power supply, medicinal gases, and operating theatre lighting. To do so, a multicriteria model will be developed using the Measuring Attractiveness by a Categorical Based Evaluation Technique (MACBETH) approach considering multiple decision centres. The model uses functional, safety, and technical-economic criteria, amongst which is availability. Mean availability for repairable systems has been measured to assess this criterion, using Markov chains from the data obtained over three years from the subsystems of a hospital operating theatre. The alternatives considered are corrective maintenance; preventive maintenance together with corrective maintenance by means of daily, weekly, monthly, and yearly programmes; periodical predictive maintenance together with corrective maintenance; and corrective together with preventive and predictive maintenance.

scholarly journals Combining system-theoretic process analysis and availability assessment: A subsea case study

2019 ◽  
Vol 233 (4) ◽  
pp. 520-536 ◽  
Author(s):  
Juntao Zhang ◽  
Hyungju Kim ◽  
Yiliu Liu ◽  
Mary Ann Lundteigen
Keyword(s):  
Process Analysis ◽  
Discrete Event ◽  
Hazard Identification ◽  
Operating Conditions ◽  
Stochastic Petri Nets ◽  
Control Loops ◽  
Event Simulation ◽  
Maintainability Analysis ◽  
Availability Assessment ◽  
Software Intensive

Hazard identification methods are important tools to verify that the system is able to operate according to specifications under different operating conditions. Unfortunately, many of the traditional methods are not adequate to capture possible dysfunctional behavior of complex systems that involve highly coupled parts, non-linear interactions and software-intensive functionalities. The rather recent method named system-theoretic process analysis (STPA) is one promising candidate to improve the coverage of hazard identification in complex and software-intensive system. Still, there is no guideline for utilizing system-theoretic process analysis output to evaluate the potential of loss, which is important for basis of decision-making about system configuration and equipment selection. The focus of this article is to place an interface between system-theoretic process analysis and reliability, availability and maintainability (RAM) analysis. The approach named STPA-RAM model is proposed to translate feedback control loops into stochastic Petri nets for discrete event simulation. The proposed approach is demonstrated with a simple case related to subsea design concept. The major conclusion is that STPA-RAM model extends the application of system-theoretic process analysis, while also improving and as such reducing completeness uncertainty and model uncertainty, associated with input data and information for reliability, availability and maintainability analysis.

scholarly journals Optimizing two-dimensional renewable warranty policies for sensor embedded remanufactured products

2017 ◽  
Vol 10 (2) ◽  
pp. 145 ◽  
Author(s):  
Ammar Alqahtani ◽  
Surendra M. Gupta
Keyword(s):  
Preventive Maintenance ◽  
Discrete Event ◽  
Two Dimensional ◽  
Experimental Conditions ◽  
Specific Product ◽  
Event Simulation ◽  
Recovery System ◽  
The Cost ◽  
Warranty Policies ◽  
The Impact

Purpose: Remanufactured products, in addition to being environment friendly, are popular with consumers because they can offer the latest technology with lower prices in comparison to brand new products. However, some consumers are hesitant to buy remanufactured products because they are skeptical about the quality of the remanufactured product and thus are unsure of the extent to which the product will render services when compared to a new product. A strategy that remanufacturers may employ to entice customers is to offer warranties on remanufactured products. To that end, this paper studies and scrutinizes the impact of offering renewing warranties on remanufactured products. Specifically, the paper suggests a methodology which simultaneously minimizes the cost incurred by the remanufacturers and maximizes the confidence of the consumers towards buying remanufacturing products.Design/methodology/approach: This study uses discrete-event simulation to optimize the implementation of a two-dimensional renewing warranty policy for remanufactured products. The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order (ARTO) system. The experiments used in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system so as to observe the system behavior under various experimental conditions. In order to determine the optimum strategy offered by the remanufacturer, various warranty and preventive maintenance scenarios were analyzed using pairwise t-tests along with one-way analysis of variance (ANOVA) and Tukey pairwise comparisons tests for every scenario.Findings: The proposed methodology is able to simultaneously minimize the cost incurred by the remanufacturer, optimize the warranty price and period, and optimize the preventive maintenance strategy resulting in increased consumer confidence.Originality/value: This is the first study that evaluates in a quantitative and comprehensive manner the potential benefits of offering warranties with preventive maintenance on remanufactured products.

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