scholarly journals U.S. Navy Experience with SSS (Synchro-Self-Shifting) Clutches

2010 ◽  
Vol 132 (08) ◽  
pp. 54-55
Author(s):  
Morgan Hendry ◽  
Michael Zekas B.
Keyword(s):  
Gas Turbines ◽  
Motor Drives ◽  
Propulsion Systems ◽  
Electric Motor Drives ◽  
Mean Time Between Failures ◽  
Repair Strategy ◽  
Time Between Failures ◽  
The Us ◽  
Us Navy ◽  
Mean Time

This article discusses the experience of the US Navy with Synchro-Self-Shifting (SSS) clutches. The US Navy has nearly 40 years of experience using SSS clutches in main reduction gears of gas-turbine-driven ships and propulsion systems with combinations of gas turbines and diesel engines or electric motors, and in steam-turbine propulsion plants for use with electric motor drives. Over 900 SSS clutches have been installed in 14 different classes of US Navy ships, with some having been in service for over 30 years. SSS clutches have accumulated approximately 15,278,000 hours of operation. Mean Time Between Failures in Hours for US Navy clutch applications is relatively high (271,550 hours) based on the operational hours accumulated and the total number of failures that have occurred. The maintenance and repair strategy used for US Navy SSS clutches is similar to a Performance Based Logistics arrangement, where the Navy maintains a rotatable pool of ready-for-issue clutches, and in the event of a problem or failure, the clutch is changed out with an available spare.

Hidden Advantages and Strategic Leaps for CODAG, CODELAG, CODELOG and Hybrid Propulsion Systems

2020 ◽  
Author(s):  
Morgan L. Hendry ◽  
Nicholas Bellamy
Keyword(s):  
Gas Turbines ◽  
Electric Propulsion ◽  
High Speed ◽  
Plant Design ◽  
Propulsion Systems ◽  
Hybrid Propulsion ◽  
Low Speed ◽  
Depth Analysis ◽  
Us Navy ◽  
Mean Time

Abstract Navies worldwide are increasingly considering and adopting propulsion plants with electric propulsion for cruise and ship silent operation, and gas turbines for boost propulsion for high speed. These propulsion plants, often referred to as hybrid propulsion, utilize water jets, controllable pitch propellers, or fixed pitch propellers, and have design and overall configuration to fit into naval ships with various size hulls such as would be the case with corvettes, frigates, destroyers, cruisers, etc. Therefore, size, weight, and space of the propulsion plant is important, but equally important is limiting associated machinery which must be used with a particular hybrid propulsion plant design selected. In addition, propulsion design engineers, in conjunction with naval architects, shipyards and navies, must consider fuel efficiencies, machinery efficiencies, weight of all the associated machinery, placement in the hull, first time cost, and life cycle maintenance with associated cost when selecting the configuration of the propulsion system’s associated machinery. Manning levels are dictated by these parameters and in the end, it must be realized that the purpose of the ship mission can be compromised if reliability is not high and premature failures occur. This paper is a more in depth analysis of hybrid propulsion systems for naval ships of various sizes, and analysis of the associate machinery emphasizing ship weight and space savings, fuel savings, cost savings, mean time between failures and mean time to repair which results in lower manning requirements and increased mission readiness. By the time this paper is published, more than 250 SSS Clutches will be installed in US Navy Arleigh Burke Destroyers, 32 are operating in low speed propeller shafts of British Navy Type 23 ships, 2 in the Japanese Navy’s Asuka Class and 16 in low speed propeller shafts of Royal Korean Navy FFX Batch II frigates. At the time of abstract submission, all three programs referenced above have cumulatively had zero defects attributable to SSS Clutch material, function, design, or quality. While the US Navy are given occasional reminders of why alternative clutch designs remain ineffective, unreliable and remarkedly inefficient, other nations’ vertically tiered supply chains and inexperienced engineers are shielded from similar issues.

Review of Technological Advancements and HSE-Based Safety Model for Deep-Water Human Occupied Vehicles

2014 ◽  
Vol 48 (3) ◽  
pp. 25-42 ◽  
Author(s):  
Narayanaswamy Vedachalam ◽  
Gidugu Ananada Ramadass ◽  
Malayath Aravindakshan Atmanand
Keyword(s):  
Deep Water ◽  
Capital Expenditure ◽  
Mean Time Between Failures ◽  
Safety Integrity Level ◽  
Geological Surveys ◽  
Time Between Failures ◽  
High Resolution Bathymetry ◽  
Safety Systems ◽  
Mean Time ◽  
Safety And Environment

AbstractThis paper reviews the latest advancements in subsea technologies associated with the safety of deep-water human occupied vehicles. Human occupied submersible operations are required for deep-water activities, such as high-resolution bathymetry, biological and geological surveys, search activities, salvage operations, and engineering support for underwater operations. As this involves direct human presence, the system has to be extremely safe and reliable. Based on applicable IEC 61508 Standards for health, safety, and environment (HSE), the safety integrity level requirements for the submersible safety systems are estimated. Safety analyses are done on 10 critical submersible safety systems with the assumption that the submersible is utilized for 10 deep-water missions per year. The results of the analyses are compared with the estimated target HSE requirements, and it is found that, with the present technological maturity and safety-centered design, it is possible to meet the required safety integrity levels. By proper maintenance, it is possible to keep the mean time between failures to more than 9 years. The results presented shall serve as a model for designers to arrive at the required trade-off between the capital expenditure, operating expenditure, and required safety levels.

scholarly journals A Statistical State Analysis of a Marine Gas Turbine

Actuators ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 54 ◽  
Author(s):  
Suzana Lampreia ◽  
Valter Vairinhos ◽  
Victor Lobo ◽  
José Requeijo
Keyword(s):  
Gas Turbine ◽  
Point Of View ◽  
Operating Conditions ◽  
Environmental Data ◽  
Statistical Point ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Intervention Plan ◽  
Mean Time

This paper describes the analysis, from a statistical point of view, of a maritime gas turbine, under various operating conditions, so as to determine its state. The data used concerns several functioning parameters of the turbines, such as temperatures and vibrations, environmental data, such as surrounding temperature, and past failures or quasi-failures of the equipment. The determination of the Mean Time Between Failures (MTBF) gives a rough estimate of the state of the turbine, but in this paper we show that it can be greatly improved with graphical and statistical analysis of data measured during operation. We apply the Laplace Test and calculate the gas turbine reliability using that data, to define the gas turbine failure tendency. Using these techniques, we can have a better estimate of the turbine’s state, and design a preventive observation, inspection and intervention plan.

Comparison of the Mean Time Between Failures for Two Systems Under Short Tests

2009 ◽  
Vol 58 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Y.H. Michlin ◽  
G.Y. Grabarnik ◽  
E. Leshchenko
Keyword(s):  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Two Systems ◽  
The Mean ◽  
Mean Time

A warranty based bilateral multi-issue negotiation approach

2015 ◽  
Vol 22 (7) ◽  
pp. 1247-1280 ◽  
Author(s):  
Prashant M. Ambad ◽  
Makarand S. Kulkarni
Keyword(s):  
Real Life ◽  
Spare Parts ◽  
Negotiation Process ◽  
Design Stage ◽  
Automated Negotiation ◽  
Content Type ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Target Values ◽  
Mean Time

Purpose – The purpose of this paper is to propose a warranty-based bilateral automated multi-issue negotiation approach. Design/methodology/approach – A methodology for bilateral automated negotiation process is developed considering the targets such as warranty attractiveness, warranty cost, mean time between failures, spare parts cost to the end user over the useful life of the life. The negotiation methodology is explained using different cases of negotiation. The optimization for each negotiation step is carried out using genetic algorithm with elitism strategy. Findings – The result after optimization indicates that the desired target values are achieved and manufacturer obtained desired profit margin. Practical implications – Application of automated negotiation model is illustrated using a real life case of an automobile engine manufacturer. The proposed approach helps the manufacturer of any product to develop a methodology for carrying out the negotiation process. The approach also results into taking warranty-related decisions at the design stage. Originality/value – This paper contributes in proposing a generalized methodology for warranty-based negotiation in which the negotiation is carried out between the manufacturer and the customer.

scholarly journals DEGRADATION ANALYSIS OF PROBABILISTIC PARALLEL CHOICE SYSTEMS

2014 ◽  
Vol 21 (03) ◽  
pp. 1450012
Author(s):  
AVINASH SAXENA ◽  
SHRISHA RAO
Keyword(s):  
Complete System ◽  
System Failure ◽  
Time To Failure ◽  
Probabilistic Choice ◽  
Mean Time Between Failures ◽  
System Parameters ◽  
Time Between Failures ◽  
Degradation Analysis ◽  
Mean Time ◽  
Selection Of

Degradation analysis is used to analyze the useful lifetimes of systems, their failure rates, and various other system parameters like mean time to failure (MTTF), mean time between failures (MTBF), and the system failure rate (SFR). In many systems, certain possible parallel paths of execution that have greater chances of success are preferred over others. Thus we introduce here the concept of probabilistic parallel choice. We use binary and n-ary probabilistic choice operators in describing the selections of parallel paths. These binary and n-ary probabilistic choice operators are considered so as to represent the complete system (described as a series-parallel system) in terms of the probabilities of selection of parallel paths and their relevant parameters. Our approach allows us to derive new and generalized formulae for system parameters like MTTF, MTBF, and SFR. We use a generalized exponential distribution, allowing distinct installation times for individual components, and use this model to derive expressions for such system parameters.

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