The establishment of the time interval between inspections for a cold standby system with component repair

The time interval between inspections of cold standby systems is a crucial decision to ensure the appropriated system reliability and the lowest costs possible. This paper presents a model developed to establish the optimal time interval between inspections for a two-unit cold standby system with component repair and subject to periodic inspection, considering reliability and costs. A Markov chain is used to define possible states, their transition probabilities and the mean time to system failure, as a function of the time interval between inspections. Given the mean time to system failure, the steady state availability is determined. Finally, the costs related to the system maintenance are established and a cost function is developed and optimized for the time interval between inspections. Numerical examples are presented and results for different system parameters are compared. Besides optimizing the time interval between inspections, the analyses also reveal the effect of repair time on system availability and mean time to system failure

Optimal maintenance of multi-component systems: a review

In this article we give an overview of the literature on multi-component maintenance optimization. We focus on work appearing since the 1991 survey "A survey of maintenance models for multi-unit systems" by Cho and Parlar. This paper builds forth on the review article by Dekker et al. (1996), which focusses on economic dependence, and the survey of maintenance policies by Wang (2002), in which some group maintenance and some opportunistic maintenance policies are considered. Our classification scheme is primarily based on the dependence between components (stochastic, structural or economic). Next, we also classify the papers on the basis of the planning aspect (short-term vs long-term), the grouping of maintenance activities (either grouping preventive or corrective maintenance, or opportunistic grouping) and the optimization approach used (heuristic, policy classes or exact algorithms). Finally, we pay attention to the applications of the models.literature review;economic dependence;failure interaction;maintenance policies;grouping maintenance;multi-component systems;opportunistic maintenance;maintencance optimization;structural dependence

The establishment of the time interval between inspections for a cold standby system with component repair

Abstract The time interval between inspections of cold standby systems is a crucial decision to ensure the appropriated system reliability and the lowest costs possible. This paper presents a model developed to establish the optimal time interval between inspections for a two-unit cold standby system with component repair and subject to periodic inspection, considering reliability and costs. A Markov chain is used to define possible states, their transition probabilities and the mean time to system failure, as a function of the time interval between inspections. Given the mean time to system failure, the steady state availability is determined. Finally, the costs related to the system maintenance are established and a cost function is developed and optimized for the time interval between inspections. Numerical examples are presented and results for different system parameters are compared. Besides optimizing the time interval between inspections, the analyses also reveal the effect of repair time on system availability and mean time to system failure

PERFORMANCE EVALUATION MODELING OF PRE-TREATMENT UNIT IN GAS PROCESSING PLANT

This paper presents a report for Final Year Project (FYP). The title of the research project is Performance Evaluation Modeling of Pre-Treatment Unit (PTU) in Gas Processing Plant which under manufacturing from mechanical field. The project is conducted at one of Gas Processing Plant which is Pre-treatment Unit (PTU). The project started with identification of critical component for PTU, construction of reliability block diagram (RBD) and reliability analysis based on RBD model. During the completion of the project, the researcher has been assisted by reliability engineer from PETRONAS Gas Berhad in verifying the RBD model. The outcome of this project is a model of reliability that could be used by plant management to evaluate the current reliability of the PTU. Besides, this research can analyze whether that equipment has achieved target plant reliability and identify the sub-component that reduces the overall reliability of the system. This paper includes introduction, literature review, methodology, result and discussion and conclusion. The report will include introduction, literature review and theory, methodology, result and discussion, conclusion and recommendation and reference

Optimizing a Multi-State Cold-Standby System with Multiple Vacations in the Repair and Loss of Units

A complex multi-state redundant system with preventive maintenance subject to multiple events is considered. The online unit can undergo several types of failure: both internal and those provoked by external shocks. Multiple degradation levels are assumed as both internal and external. Degradation levels are observed by random inspections and, if they are major, the unit goes to a repair facility where preventive maintenance is carried out. This repair facility is composed of a single repairperson governed by a multiple vacation policy. This policy is set up according to the operational number of units. Two types of task can be performed by the repairperson, corrective repair and preventive maintenance. The times embedded in the system are phase type distributed and the model is built by using Markovian Arrival Processes with marked arrivals. Multiple performance measures besides the transient and stationary distribution are worked out through matrix-analytic methods. This methodology enables us to express the main results and the global development in a matrix-algorithmic form. To optimize the model, costs and rewards are included. A numerical example shows the versatility of the model

Study of Space Station propulsion system resupply and repair Final report

Resupply and repair capabilities for orbital space station bipropellant propulsion syste

Phased mission reliability analysis of unmanned ship systems

With the development of unmanned ships, their use in production is becoming more and more common. However, the unmanned ship work cycle is long and the work environment is complex, and it is still very difficult to calculate the phased mission reliability without unmanned ship. We analyze the unmanned ship phased mission reliability based on the binary decision diagram. Moreover, redundancy is used as the unmanned ship reliability optimization scheme. Considering the resource limitation, and the capacity of unmanned ship, the redundancy allocation scheme of unmanned ship is established. The redundancy allocation scheme is solved by marginal optimization algorithm. Finally, a case study is established to analyze the effectiveness and practicality of the proposed method

Study of space shuttle environmental control and life support problems

Four problem areas were treated: (1) cargo module environmental control and life support systems; (2) space shuttle/space station interfaces; (3) thermal control considerations for payloads; and (4) feasibility of improving system reusability

Report on the design requirements for reactor power systems for manned earth orbital applications Final report

Reactor power systems design requirements for manned Earth orbital application

Profitability, reliability and condition based monitoring of LNG floating platforms: a review

The efficiency and profitability of Floating, Production, Storage and Offloading platform (FPSO) terminals depends on various factors such as LNG liquefaction process type, system reliability and maintenance approach. This review is organized along the following research questions: (i) what are the economic benefit of FPSO and how does the liquefaction process type affect its profitability profile?, (ii) how to improve the reliability of the liquefaction system as key section? and finally (iii) what are the major CBM techniques applied on FPSO. The paper concluded the literature and identified the research shortcomings in order to improve profitability, efficiency and availability of FPSOs