Reliability Analysis of Repairable Systems Subject to System Modifications

Author(s):  
Z. H. Jiang ◽  
L. H. Shu ◽  
B. Benhabib

Abstract This paper approaches environmentally conscious design by further developing a reliability model that facilitates design for reuse. Many reliability models are not suitable for describing systems that undergo repairs performed during remanufacture and maintenance because the models do not allow the possibility of system reconfiguration. In this paper, expressions of reliability indices of a model that allows system reconfiguration are developed to enable life-cycle cost estimation for repairable systems. These reliability indices of a population of repairable systems are proven theoretically to reach steady state. The expressions of these indices at steady state are obtained to gain insight into the model behavior, and to facilitate life-cycle cost estimation.

1999 ◽  
Vol 121 (4) ◽  
pp. 614-621 ◽  
Author(s):  
Z. H. Jiang ◽  
L. H. Shu ◽  
B. Benhabib

Environmentally conscious design is approached through analysis and further development of a reliability model that facilitates design for reuse of products. Many reliability models may not he suitable for describing systems that undergo repairs performed during remanufacture and maintenance since they do not allow for the possibility of system reconfiguration. In this paper, expressions of reliability indices of a model that allows system modifications during repair are derived. These reliability indices that describe a population of repairable systems are theoretically proven to reach steady state, supporting the simulation results of the model. This model can be used to estimate life-cycle replacement requirements for systems that are remanufactured, thereby facilitating decisions during system design and use. An example illustrates the application of the model to a relevant industry.


Author(s):  
Wai M. Cheung ◽  
Linda B. Newnes ◽  
Antony R. Mileham ◽  
Robert Marsh ◽  
John D. Lanham

This paper presents a review of research in the area of life cycle costing and offers a critique of current commercial cost estimation systems. The focus of the review is on relevant academic research on life cycle cost from 2000 onwards. In addition to this a comparison of the current cost estimation systems is presented. Using the review findings and industrial investigations as a base, a set of mathematical representations for design and manufacturing costs and the introduction of the critical factors is proposed. These are considered in terms of the operational, maintenance and disposal costs to create a method for ascertaining the life cycle cost estimate for complex products. This is presented using as an exemplar, research currently being undertaken in the area of low volume and long life electronic products in the UK defence sector. The benefit of the method proposed is that it aims to avoid the inflexibility of traditional approaches which usually require historical and legacy data to support the cost estimation processes.


2014 ◽  
Vol 903 ◽  
pp. 408-413 ◽  
Author(s):  
FRESELAM Mulubrhan ◽  
Ainul Akmar Mokhtar ◽  
Masdi Muhammad

This paper presents a mathematical model to estimate the life cycle cost (LCC) of heat exchanger and pump. Maintenance cost, down time cost and acquisition costs are calculated. The main uncertainty in calculating these costs are prediction of number of failure and cumulative down time. Number of failure is determined using failure and repair time density function. According to the characteristic that the cumulative failure probability observed, a Weibull distribution model is used. The scale and shape parameters of the Weibull are extracted from the published data. The results of the study show that 71.3% loss in the reliability of heat exchanger and 34.2% reliability loss in pump could lead to 66.2 % increment of the total cost. The reliability of the system decreases because of number of failures will increase each year, and this failure leads to unavailability of the system.Therefore in order to achieve higher system effectiveness and reduce the total LCC, the reliability of the systems need to be increased through proper maintenance policies and strategies. The results of the study could assist the managers to make decision with high degree of accuracy.


2017 ◽  
Vol 5 (2) ◽  
pp. 15 ◽  
Author(s):  
Stanislav Szabo ◽  
Ivan Koblen

<p align="LEFT">The paper in the introductory part underlines some aspects concerning the importance of Aviation Technology Life Cycle Management and informs on basic international standards for the processes and stages of life cycle. The second part is focused on definition and main objectives of system life cycle management. The authors subsequently inform on system life cycle stages (in general) and system life cycle processes according to ISO/IEC/IEEE 15288:2015 standard. Following the fact, that life cycle cost (LCC) is inseparable part and has direct connection to the life cycle management, the paper contains brief information regarding to LCC (cost categories, cost breakdown structure, cost estimation a.o.). Recently was issued the first part of Aviation Technology Life Cycle Management monograph (in Slovak: ”Manažment životného cyklu leteckej techniky I”), written by I.Koblen and S.Szabo. Following this fact and direct relation to the topic of article it is a part of article briefly introduced the content of two parts of this monograph (the 2nd part of monograph it has been prepared for the print). The last part of article is focused on issue concerning main assumptions and conditions for successful application of aviation technology life cycle management in aviation companies, aerospace industry organizations as well as from the relevant stakeholders side.</p>


Author(s):  
C-y Tung ◽  
M H Wang

Increasing awareness of environmental burdens has led companies and designers to initiate design for the environment (DFE) programmes, which consider the design of products from the ‘cradle to grave’ and is also known as ‘life-cycle design’. In this paper, the use of a novel environmental performance technique to be used at the early stage of product design is presented. This technique, which is to be used as a framework for green product design, is demonstrated in this paper by evaluating the environmental performance between plastic and steel fuel tanks. The fuel tank comparison can be divided into five steps. In the first four steps, a modified house of quality (HOQ) is used to analyse the performance of fuel tanks in terms of requirements of environmentally conscious design. The final step is an overall assessment that synthesizes the results from the previous four analyses. As a result, the comprehensive environmental effects in the whole life cycle of fuel tanks are captured in the early stage of design.


Author(s):  
Travis Moody ◽  
Robert Provine ◽  
Samantha Todd ◽  
Nicholas Tyler ◽  
Thomas R. Ryan ◽  
...  

Author(s):  
Kei Kurakawa ◽  
Kumiyo Nakakoji ◽  
Takashi Kiriyama

Abstract We have developed the Green Browser to support a team of designers to collaboratively construct and share the product life cycle information for environmentally conscious design. We developed the ReqC model (Requirement-Centered Model) and the GLC model (Green Life-Cycle Model) for structuring design information in the Green Browser. The system allows the design team to construct the GLC model by chunking discourse and assigning types. It provides a visual presentation of the concept and scenario, and allows the user outside the team to share the model across different computer environments. We used Java2 and CORBA for system implementation. To test implementation of the system, we built a GLC model by using data collected in an industrial design project.


Manufacturing ◽  
2003 ◽  
Author(s):  
Yasushi Umeda

This paper describes the outline of “life cycle design” course the author teaches and illustrates some experiences and findings with results of questionnaires to attendees of the lecture. “Life cycle design” is a half-year course to third-year students at Tokyo Metropolitan University, Japan. The main subject is environmentally conscious design focusing on life cycle thinking. This course intends to establish general and correct viewpoints toward relationship between manufacturing industry and the environmental issues, which are indispensable knowledge as mechanical engineers, rather than to educate environmental specialists. Results of questionnaires indicate that this course succeeded in increasing students’ interest in this area and awareness of importance of the environmental issues. However, some students feel bewildered because of wide variety of topics and, therefore, lack of a central theory.


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