• Smart Structures and Systems
• /
• v.18 no.3
• /
• pp.569-584
• /
• 2016

This paper presents a method for stochastic modelling of fatigue crack growth and optimising inspection and maintenance strategy for the structural members of steel bridges. The fatigue crack evolution is considered as a stochastic process with uncertainties, and the Gamma process is adopted to simulate the propagation of fatigue crack in steel bridge members. From the stochastic modelling for fatigue crack growth, the probability of failure caused by fatigue is predicted over the service life of steel bridge members. The remaining fatigue life of steel bridge members is determined by comparing the fatigue crack length with its predetermined threshold. Furthermore, the probability of detection is adopted to consider the uncertainties in detecting fatigue crack by using existing damage detection techniques. A multi-objective optimisation problem is proposed and solved by a genetic algorithm to determine the optimised inspection and maintenance strategy for the fatigue affected steel bridge members. The optimised strategy is achieved by minimizing the life-cycle cost, including the inspection, maintenance and failure costs, and maximizing the service life after necessary intervention. The number of intervention during the service life is also taken into account to investigate the relationship between the service life and the cost for maintenance. The results from numerical examples show that the proposed method can provide a useful approach for cost-effective inspection and maintenance strategy for fatigue affected steel bridges.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2169-2170
• /
• 2011

This paper presents about the analysis on cost factor reduction using the life cycle cost model for motor block in the KTX-1. Until now, most life cycle cost of the system as a whole that has been studied. but in case of railway industry part, LCC studies are needed on the subsystem like a propulsion control system because subsystems are developed continuously localization. Therefore, In this paper presents cost breakdown structure for life cycle cost (LCC) estimation for localization development of propulsion control system (Motor Block) in high speed railway vehicle (KTX-1). Also to analysis LCC on motor block, it was analyzed physical breakdown structure (PBS) and preventive cost on propulsion control system in view of maintenance cost. Based on this, we describe life cycle cost on motor block of KTX-1.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.162-163
• /
• 2014

Operation and maintenance stage consists the largest portion of project life cycle cost. Appropriate management and analysis of such stages have massive effect on the total project cost. The effective prediction of optimized repair period is one of main factors in ㅌ management. However, it has been analyzed that the prediction of appropriate repair period revealed limitations in reliability. Therefore, this study suggests a methodology of repair period prediction by dividing finished projects into similar groups with same properties to be compared with the target project using quantitative variables.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.05a
• /
• pp.21-23
• /
• 2012

The process of building project for planning, designing, construction, maintenance, and waste disposal are related with each other. However, we have a difficulty for estimating building's LCC due not to be flexible each other. Therefore, we analyzed the boundary condition between the process of construction and maintenance, and analyzed the factor of segment. We also suggested the Link System for flexible relation.

• International Journal of Reliability and Applications
• /
• v.18 no.1
• /
• pp.1-8
• /
• 2017

In this paper, we study an extended warranty model under minimal repair-replacement warranty (MRRW) which is suggested by Park, Jung and Park (2013). Under MRRW policy, the manufacturer is responsible for providing the minimal repair-replacement services upon the system failures during the warranty period. And if the failure occurs during the extended warranty period, only the minimal repair is conducted. Following the expiration of extended warranty, the user is solely responsible for maintaining the system for a fixed length of time period and replaces the system at the end of such a maintenance period. During the maintenance period, only the minimally repair is given for each system failure. The main purpose of this article is to suggest the extended warranty and replacement model with MRRW. Given the cost structures incurred during the life cycle of the system, we formulate the expected cost and the expected length of life cycle to obtain the expected cost rate.

• Journal of Korean Society for Quality Management
• /
• v.30 no.3
• /
• pp.53-65
• /
• 2002

This paper studies an economic manufacturing quantity (EMQ) model with two types of failures and planned preventive maintenance of the production facility. One is a type I (major) failure which should be corrected by a failure maintenance and the other is a type H (minor) failure which can be minimally repaired without interrupting the production run. The objective is to determine the lot size and preventive replacement policy minimizing the long-run expected cost per unit time. We consider a control policy with a constant production lot size and preventive maintenance after completing n production runs. It is assumed that both preventive and failure maintenance times are random and the demand arriving during a stock-out period is lost. An expression for the expected cost per unit time is obtained in the general case. A special case is discussed and numerical results are provided.

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.312-317
• /
• 1998

Reliable maintenance scheduling of main equipments is a crucial problem in thermal power stations in order to skirt overall losses of power generation resulted from severe failures of the equipments. A reasonable method was proposed to determine the maintenance scheduling of whole pump system in thermal power stations in order to reduce the maintenance cost by keeping the present avail-ability of the pump system throughout the operation. The dimensional reduction method was used to solve problems encountered due to few data which involved many operational factors in failure rate of pumps. The problem of bandlimited nature of data with time was solved by extrapolating future failures from presently available actual data with an aid of Weibull distribution. The results of the analysis identified the most suitable maintenance intervals of each pump type accordingly and hence reduce the cost of unnecessary maintenance with an acceptable range in the overall system availability.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.215-217
• /
• 2013

The maintenance management in buildings has got more important by the increasing complexity of building sizes and use. Nowadays an expectation and a possibility of BIM technology become accepted as a new construction management method, therefore many studies and legal systems of it are being suggested actively. Although orders for BIM projects are supposed to be increasing, at present the BIM information accumulated from planning and design still doesn't have its continuity at the maintenance step after completion of construction in terms of LCC. It can't use the possibility that BIM originally has, and also causes some confusion in communication. This study analyzes and classifies required information in terms of BIM in the range of estimating repair costs of apartment buildings, as an example of a way to use BIM information at the maintenance step.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.533-542
• /
• 2016

The periodic maintenance of bridges is necessary once they have been constructed and its cost depends on various factors, such as their condition, environmental conditions and so on. To make a decision support system, it is essential to establish a basic reconstruction cost model. In this study, a regression model is suggested for calculating the reconstruction cost for typical cases and influential factors, depending on the type of bridge and its components, by analyzing the basic bridge specifications based on the data of the Bridge Management System (BMS). The details for each case were estimated in consideration of the cost calculation variables. The details for each case were estimated in consideration of the cost calculation variables. The cost model for the new construction of the superstructure, substructure and foundation and the temporary bridge construction and demolition costs were drawn from the regression analysis of the estimation results of typical cases according to the cost calculation variables. The reconstruction costs for different types of bridge were obtained using the cost model and compared with those in the literature. The cost model developed herein is expected to be utilized effectively in maintenance decision making.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.10
• /
• pp.2803-2809
• /
• 2009

For a successful construction project not only construction engineering and project management technology but also economic evaluation technique is required. Design and construction technologies are necessary to receive a project order. However, construction management technology which can be apply from the project initial phase to the project operation and management phase is required to create a benefit from the project. Construction management technology is one of the effective factors for project success. Economical and efficient cost management from the planning phase influences the project success. This study investigated cost flow and cost factors of domestic Sewage Treatment Plant project for systematic analysis of cost items following the entire project phase. Particularly, data modeling based on domestic Sewage Treatment Equipment maintenance cost DB was performed, and maintenance cost estimation trend line is suggested using Monte carlo Simulation Method to decrease uncertainty of actual results DB and for feasibility study. Korea Academia-Industrial cooperation Society. The Korea Academia-Industrial cooperation Society. The Korea Academia-Industrial cooperation Society. The Korea Academia-Industrial cooperation Society.