Life Cycle Cost through Reliability

This work presents a novel approach using dependability of sub-assemblies to compute the life cycle cost of complex products (i.e. products that are technologically more complex than average or have a higher life expectancy) This work is composed of two parts, first a retrospective on life cycle cost and its challenges, then a description of the approach using reliability as the key element. This approach combines the usage of already well-known components or sub-assemblies alongside new, innovative ones in order to compute the life cycle cost of the system. This work is currently conducted as a PhD thesis and as industrial support

Reliability characterization of a piezoelectric actuator based AVC system

Reliability and Maintainability analyses are becoming an increasing competitive advantage in machine tool design. In particular, the goal of machine tools for Ultra High Precision Machining is to guarantee high specified performances and to maintain them over life cycle time. A structured reliability approach applied to such complex and innovative systems must be integrated in the early phase of the design. In this paper, the reliability characterization of an adjustable platform for micromilling operations is presented. The platform is intended to improve the surface finishing of the workpiece, through a broadband Active Vibration Control device based on high performance piezoelectric multilayer actuators. The study intends to assess the capability of the system to maintain along the life cycle the appropriate reduction of the chattering vibrations without any shape error. By dividing the system through a morphological-functional decomposition, the critical elements are detected and their reliability issues are extensively discussed. Their lifetimes are described through opportune distributions and models. The study is completed by the quantitative reliability prediction of the overall system. Finally, a sensitivity analysis is performed and reliability allocation implications are evaluated to determine the effect of every component on the system reliability characteristics and life cycle cost

Preliminary design of the redundant software experiment

The goal of the present experiment is to characterize the fault distributions of highly reliable software replicates, constructed using techniques and environments which are similar to those used in comtemporary industrial software facilities. The fault distributions and their effect on the reliability of fault tolerant configurations of the software will be determined through extensive life testing of the replicates against carefully constructed randomly generated test data. Each detected error will be carefully analyzed to provide insight in to their nature and cause. A direct objective is to develop techniques for reducing the intensity of coincident errors, thus increasing the reliability gain which can be achieved with fault tolerance. Data on the reliability gains realized, and the cost of the fault tolerant configurations can be used to design a companion experiment to determine the cost effectiveness of the fault tolerant strategy. Finally, the data and analysis produced by this experiment will be valuable to the software engineering community as a whole because it will provide a useful insight into the nature and cause of hard to find, subtle faults which escape standard software engineering validation techniques and thus persist far into the software life cycle

Evaluation of the HARDMAN comparability methodology for manpower, personnel and training

The methodology evaluation and recommendation are part of an effort to improve Hardware versus Manpower (HARDMAN) methodology for projecting manpower, personnel, and training (MPT) to support new acquisition. Several different validity tests are employed to evaluate the methodology. The methodology conforms fairly well with both the MPT user needs and other accepted manpower modeling techniques. Audits of three completed HARDMAN applications reveal only a small number of potential problem areas compared to the total number of issues investigated. The reliability study results conform well with the problem areas uncovered through the audits. The results of the accuracy studies suggest that the manpower life-cycle cost component is only marginally sensitive to changes in other related cost variables. Even with some minor problems, the methodology seem sound and has good near term utility to the Army. Recommendations are provided to firm up the problem areas revealed through the evaluation

Generating project value through design for reliability : on the development and implementation of a potential value framework

The current trend to economically exploit deepwater hydrocarbon reserves is to reduce the capital expenditure; accomplished by deploying subsea equipment. The financial benefit afforded is offset by the risk of high operational costs associated with failure. Recognition of the life cycle cost implications of subsea reliability have led to the development of the reliability strategy. This strategy adopts a risk based approach to design for reliability where only analyses (and their subsequent recommended actions) perceived to add to whole project value are implemented. While life cycle costing has been developed to address through life cost, analyses are traditionally considered a source of cost accumulation rather than value creation. This thesis proposes a potential reliability value decision making framework to assist in the design for reliability planning process. The framework draws on the existing concepts of life cycle costing to explicitly consider the through life value of investing in reliability analyses. Fundamental to the framework are the potential reliability value index and an associated value breakdown structure intended as central decision support for decentralised decision making. Implementation of the framework is reliant on synergies within the project organization; including relationships between organizations and project functions. To enhance synergy between functions and dismantle some of the recognised barriers to implementing the reliability strategy an organizational structure, for projects, guided centrally by the reliability value framework is proposed. This structure requires the broadening of each project functions’ skill set to enable the value added implementation of the strategy’s activities. By widening the scope of application, the reliability analysis toolkit becomes the central guidance of the design process and awareness of the causes of unreliability and how they can be avoided increases. As this capability improves so the cost-efficiency with which reliability is managed in design (introduced as the reliability efficiency frontier) also increases.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Analisa Ekonomis Peralatan Pulverizer untuk Optimalisasi Keandalan Pltu dengan Simulasi Monte Carlo dan Pendekatan Analisa Biaya Siklus Hidup (Studi Kasus: Pltu X)

To improve and maintain the reliability of PLTU X (FTP-1) power supply using coal fuel it is necessary to improve the reliability of the equipment especially on the crucial equipment which one of the pulverizer equipment for it is necessary to process the procurement of equipment components (stock warehouse) to maintain if possible a malfunction or malfunction occurs. The author intends to make three alternative procurement process that is through OEM procurement process, Non OEM / reverse engineering and recondition.This journal will analyze a financial feasibility study to ascertain whether the procurement has economic value and the asset will be used effectively and efficiently over the life of the benefit using the LCCA cost analysis approach. In this paper, historical data on pulverizer damage is obtained from the HDKP Rapsodi Settlement application to be verified and processed using minitab 17 applications to obtain the weibull shape factor (β) and scale factor / characteristic life (ï¨) and the data as monte carlo simulation input. So we get mean time to failure (MTTF) / age of pulverizer component. To analyze the threealternatives and determine which alternatives are most profitable for 10 years with a life cycle cost analysis approach.Based on the analysis of quantitative calculation data, the life of pulverizer mills (MTTF) procurement process OEM for 10,108 hours / 1.2 years, non-OEM / reverse engineering for 16,899 hours / 2 years and recondition for 5,323 hours / 0.7 years and the results of approach life cycle cost analysis was obtained cost savings of 35.22 billion per unit pulverizer mills for 10 years with reverse engineering procurement process compared to OEM

Probabilistic optimization of fatigue maintenance for welded components in steel bridges based on LEFM and LCCM

In this paper a probabilistic-based method for fatigue maintenance optimization of steel bridge’s welded joints, combined with linear elastic fracture mechanics (LEFM), the structure reliability, and life cycle cost method(LCCM) is proposed. The probabilistic analysis method can be used with the fatigue maintenance of steel bridges. Weld cracks are classified by its size and maintenance decisions, and are made according to its size classification. Maintenance cost is divided into inspection, repair and failure costs, according to the life cycle cost method. The maintenance optimization strategy is transformed to minimize the expected lifetime total costs with the constraints of the minimum acceptable reliability index to attain the most cost-optimal inspection and repair for the balanced costs between risk and safety. An example concerning the transverse stiffeners of welded components in the main girder of suspension bridge is investigated through the research of some parameters sensitivity. Among all the parameters, the inspection cost is the most remarkable. The optimal time interval of repair will delay based on the increase of the inspection cost. The optimal time interval of repair will advance based on the increase of repair cost. A discount rate can drastically change the value of the total cost, but when the probability of failure is very small, the increase of failure cost has little effect on the optimal time interval of repair. The method presented in this paper can be conducted using the similar maintenance of steel structures

Target costing in construction: a comparative study

Target costing is an approach for the development of new products in the automobile industry, aimed at reducing their life-cycle costs while ensuring quality, reliability and other client requirements, by examining all possible ideas for cost reduction at the product planning, research and development and prototyping phases. Prior studies have attempted to adapt the manufacturing target costing process to the project-based nature of the construction industry. This paper aims to provide insights for future target costing implementations in the public sector projects. A qualitative comparison of three studies is performed through the lens of a set of target costing influencing factors. Similarities and differences revealed in the comparison suggest that factors related to supplier-base strategy and to the nature of customer are potentially relevant to future target costing implementations in public sector projects

Reliability-Informed Life-Cycle Warranty Cost Analysis: A Case Study on a Transmission in Agricultural Equipment

In agricultural and industrial equipment, both new and remanufactured systems are often available for warranty coverage. In such cases, it may be challenging for equipment manufacturers to properly trade-off between the system reliability and the cost associated with a replacement option (e.g., replace with a new or remanufactured system). To address this problem, we present a reliability-informed life-cycle warranty cost (LCWC) analysis framework that enables equipment manufacturers to evaluate different warranty policies. These warranty policies differ in whether a new or remanufactured system is used for replacement in the case of product failure. The novelty of this LCWC analysis framework lies in its ability to incorporate real-world field reliability data into warranty policy assessment using probabilistic warranty cost models that consider multiple life cycles. First, the reliability functions for the new and remanufactured systems are built as the time-to-failure distributions that provide the best-fit to the field reliability data. Then, these reliability functions and their corresponding warranty policies are used to build the LCWC models according to the specific warranty terms. Finally, Monte Carlo simulation is used to propagate the time-to-failure uncertainty of each system, modeled by its reliability function, through each LCWC model to produce a probability distribution of the LCWC. The effectiveness of the proposed reliability-informed LCWC analysis framework is demonstrated with a real-world case study on a transmission used in some agricultural equipment

Concepts for Life Cycle Cost Control Required to Achieve Space Transportation Affordability and Sustainability

Cost control must be implemented through the establishment of requirements and controlled continually by managing to these requirements. Cost control of the non-recurring side of life cycle cost has traditionally been implemented in both commercial and government programs. The government uses the budget process to implement this control. The commercial approach is to use a similar process of allocating the non-recurring cost to major elements of the program. This type of control generally manages through a work breakdown structure (WBS) by defining the major elements of the program. If the cost control is to be applied across the entire program life cycle cost (LCC), the approach must be addressed very differently. A functional breakdown structure (FBS) is defined and recommended. Use of a FBS provides the visibifity to allow the choice of an integrated solution reducing the cost of providing many different elements of like function. The different functional solutions that drive the hardware logistics, quantity of documentation, operational labor, reliability and maintainability balance, and total integration of the entire system from DDT&E through the life of the program must be fully defined, compared, and final decisions made among these competing solutions. The major drivers of recurring cost have been identified and are presented and discussed. The LCC requirements must be established and flowed down to provide control of LCC. This LCC control will require a structured rigid process similar to the one traditionally used to control weight/performance for space transportation systems throughout the entire program. It has been demonstrated over the last 30 years that without a firm requirement and methodically structured cost control, it is unlikely that affordable and sustainable space transportation system LCC will be achieved