Advanced Turboprop Propulsion System Reliability and Maintenance Cost

1977 ◽  
Author(s):  
Philip C. Stolp ◽  
James A. Baum
Keyword(s):  
System Reliability ◽  
Propulsion System ◽  
Maintenance Cost

Optimizing the Cost and Reliability of Shared Anchors in an Array of Floating Offshore Wind Turbines

2021 ◽  
Author(s):  
Michael Devin ◽  
Bryony DuPont ◽  
Spencer Hallowell ◽  
Sanjay Arwade
Keyword(s):  
Optimization Algorithm ◽  
System Reliability ◽  
Failure Modes ◽  
The United States ◽  
Offshore Wind ◽  
Bayesian Optimization ◽  
Maintenance Cost ◽  
Offshore Wind Turbine ◽  
Trade Offs ◽  
Floating Offshore Wind Turbines

Abstract Commercial floating offshore wind projects are expected to emerge in the United States by the end of this decade. Currently, however, high costs for the technology limit its commercial viability, and a lack of data regarding system reliability heightens project risk. This work presents an optimization algorithm to examine the trade-offs between cost and reliability for a floating offshore wind array that uses shared anchoring. Combining a multivariable genetic algorithm with elements of Bayesian optimization, the optimization algorithm selectively increases anchor strengths to minimize the added costs of failure for a large floating wind farm in the Gulf of Maine under survival load conditions. The algorithm uses an evaluation function that computes the probability of mooring system failure, then calculates the expected maintenance costs of a failure via a Monte Carlo method. A cost sensitivity analysis is also performed to compare results for a range of maintenance cost profiles. The results indicate that virtually all of the farm's anchors are strengthened in the minimum cost solution. Anchor strength is in- creased between 5-35% depending on farm location, with anchor strength nearest the export cable being increased the most. The optimal solutions maintain a failure probability of 1.25%, demonstrating the trade-off point between cost and reliability. System reliability was found to be particularly sensitive to changes in turbine costs and downtime, suggest- ing further research into floating offshore wind turbine failure modes in extreme loading conditions could be particularly impactful in reducing project uncertainty.

scholarly journals Reliability Guarantee Strategy for Complex System Based on Cost-Benefit Importance

2020 ◽  
Vol 38 (6) ◽  
pp. 1316-1321
Author(s):  
Cheng Wang ◽  
Jianxin Xu ◽  
Zhenming Zhang ◽  
Hongjun Wang
Keyword(s):  
Complex System ◽  
System Reliability ◽  
Cost Benefit ◽  
Maintenance Cost ◽  
Critical Systems ◽  
Preventive Replacement ◽  
Equipment Safety ◽  
Operation Process ◽  
The Cost ◽  
Component Replacement

In order to ensure the long-term stable and economic operation of complex system, the system operation process is described and the problems is solved, and a system reliability model and an optimization model for component replacement are constructed. Based on the theory of marginal utility and importance measures, a reliability guarantee strategy for complex system based on cost-benefit importance is presented, which aims to find a component preventive replacement sequence with minimum maintenance cost on the constraints of system reliability lower threshold and running time. When the system reliability drops to a preset threshold, the cost-benefit importance of each component is calculated, the component with the greatest cost-benefit importance to replace is selected, and then iterate until the operation task is completed to form an optimal component replacement sequence. The feasibility of the present strategy is verified by taking a complex system which can be equivalent to a series-parallel system as an example. The present strategy has certain reference significance of ensuring the reliable operation of some high-end equipment safety-critical systems.

Maintenance optimization of reconfigurable systems based on multi-objective Birnbaum importance

2020 ◽  
pp. 1748006X2090198
Author(s):  
Chenyang Ma ◽  
Wei Wang ◽  
Zhiqiang Cai ◽  
Jiangbin Zhao
Keyword(s):  
Genetic Algorithm ◽  
System Reliability ◽  
System Performance ◽  
Cost Effective ◽  
System Structure ◽  
Maintenance Cost ◽  
Reconfigurable Systems ◽  
Maintenance Optimization ◽  
Multi Objective ◽  
Better Than

Reconfigurable systems can meet the changing requirements of system performance by several approaches, such as adjusting the system structure, improving the component performance, and reassigning components. However, it is also challengeable to find a cost-effective maintenance scheme by integrating these maintenance approaches. This article investigates the multi-objective maintenance optimization problem for reconfigurable systems with the consideration of maintenance cost and system reliability. First, the multi-objective maintenance optimization model is established to maximize the system reliability and minimize the total maintenance cost considering the constraints on budget and system performance. Second, a multi-objective Birnbaum importance is proposed to quantify the contribution of the individual component to the system reliability. The multi-objective Birnbaum importance–based non-dominated sorting genetic algorithm II is developed to obtain the optimal maintenance scheme with the maximum system reliability and minimum maintenance cost. Finally, the performance of multi-objective Birnbaum importance–based non-dominated sorting genetic algorithm II is proved by three numerical experiments. Experiment 1 verifies the advantage of multi-objective Birnbaum importance compared with Birnbaum importance to improve the system reliability in direct maintenance. Experiment 2 shows that the effectiveness of multi-objective Birnbaum importance is much better than that of the Birnbaum importance to enhance the performance of non-dominated sorting genetic algorithm II in comprehensive maintenance. Experiment 3 illustrates that the performance of multi-objective Birnbaum importance–based non-dominated sorting genetic algorithm II is better than that of other multi-objective algorithms combining with multi-objective Birnbaum importance.

Reliability and maintenance modeling for competing failures with intermission considered

2019 ◽  
Vol 233 (5) ◽  
pp. 898-907
Author(s):  
Jingyi Liu ◽  
Yugang Zhang ◽  
Bifeng Song
Keyword(s):  
System Reliability ◽  
Rest Period ◽  
Maintenance Cost ◽  
Reliability Model ◽  
Maintenance Policy ◽  
General Applicability ◽  
Industrial Systems ◽  
Soft Failure ◽  
Long Run ◽  
Degradation Failure

There are many industrial systems experiencing multiple dependent competing failure processes, in detail degradation failure (soft failure) and catastrophic failure (hard failure). Earlier research studied failure behaviors and system reliability during operational period, but did not consider the intermission period. Some industrial systems are not always operating continuously while with intermissions or rest period. The degradation and random shock processes are different between operating period and intermissions, which caused it more challenging and complicated to establish reliability model. In this article, a new reliability model for multiple dependent competing failure processes is developed with intermission considered. The system reliability can be analyzed based on the proposed model more practically. Besides, a preventive replacement maintenance policy is studied by minimizing the average long-run maintenance cost with intermission periods considered. Finally, the availability and general applicability of presented model are demonstrated by a case in different parameter settings.

scholarly journals Comparative of Feasibility Study Between Diesel Mechanical Propulsion System and Combination of Diesel Engine and Electric Motor Propulsion System on Offshore Patrol Vessel (OPV) 80 m

2018 ◽  
Vol 177 ◽  
pp. 01011
Author(s):  
Eddy Setyo Koenhardono ◽  
Amiadji
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Feasibility Study ◽  
Electric Motor ◽  
Propulsion System ◽  
Feasibility Analysis ◽  
Maintenance Cost ◽  
Load Factor ◽  
Economic Exclusion ◽  
Electrical Propulsion

The modern offshore patrol vessel is designed to carry out various missions in the management of economic exclusion zones, thus having some speed of service. For example, the speed for slow patrol is 10 knots, regular patrols 18 knots and chasing 22 knots. This condition requires a flexible propulsion system, which is combination of mechanical and electrical propulsion system. The application of this propulsion system to the OPV can increase the load factor of the propulsion system, resulting in lower fuel consumption than when using a mechanical propulsion system. Based on feasibility analysis results, the choice of combination of mechanical and electrical propulsion system is more advantageous than mechanical propulsion system, although investment and maintenance cost is higher. Therefore, patrol boats should use combination of mechanical and electrical propulsion system.

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