Replacement Of System Components Research Articles

Representation of replacement rules in the form of a matrix

Purpose – The purpose of this paper is to represent replacement policies (rules) in the form of a matrix. Visualization of replacement rules is useful for maintenance records. Matrix representation is more effective than the verbal description usually provided, as it allows better understanding of the specifics of the different replacement rules without careful research of their mathematical models. Design/methodology/approach – This approach employs mathematical models to investigate the simple conditions (requirements) for replacement of system component with illustrative examples. When comparing the different replacement rules a cost structure is applied to takes into account the nature and technology of disassembly assembly actions for the repair unit. Findings – Representation of replacement rules in the matrix form is useful when describing planned replacement models, opportunity replacement models, group replacement models and others, as well as computer modeling of the renewal process. Forming simple conditions for the replacement of system components ensures the total average repair cost is minimized. These conditions can be applied in the early stages of creating a maintenance program for the machine. Practical implications – Replacement matrices can be specified in a technical manual for maintenance of machines to achieve reliable operation and to reduce repair costs. Replacement matrices can be put into practical use for maintenance records and may be included in the maintenance procedures library of CMMSs. Developed in the paper, the replacement matrix, the conditions for replacement of system components and the cost structure will help engineers to make decisions at the time of repair for assembly units. Originality/value – Proposed in the paper is a new approach to the visualization of the replacement rules and cost structure which simplifies the analysis of options for repair actions. The proposed technique contributes to the record of maintenance actions and the decision making process for replacement.

Analysis of mechanical systems with adaptable functions for the evaluation of functional coupling and component importance

Mechanical systems with adaptable functions are versatile in functionalities and compact in physical structure than ordinary ones, hence are useful in many industrial and agricultural applications. One aspect of design analysis for these systems is the analysis of functional coupling degree among the adaptable functions, because this is a measurement of how compact and material-effective (thus cost-effective) the systems are. Existing work on functional coupling is mainly oriented to multiple-function systems rather than adaptable-function systems, where the former owes multiple functions without the need of adjustment or replacement of system components. The purpose of this paper is to investigate the methodologies for the evaluation of functional coupling and component importance of adaptable-function systems, so as to provide support for the development of this kind of mechanical systems. To this end, the function-component dependency is investigated first by exploiting the methods for design change propagation, whereby a change possibility matrix is proposed and calculated, and a function-component incidence matrix is developed. Based on the incidence matrix, the functional coupling degree is evaluated to measure the coupling between individual functions, and a comprehensive coupling degree is evaluated to measure the functional coupling of the entire system. These results are then used for the evaluation of component utilization and component importance. Finally, a design case of an adaptable-function juicing machine is studied to illustrate the proposed methods as well as the related concepts.

Demonstrating the capabilities of IEEE SIMICA standards in support of the DoD ATS framework in a net-centric maintenance environment

The Software Interface for Maintenance Information Collection and Analysis (SIMICA) is a family of IEEE standards that are consistent with the objectives of the automatic test system (ATS) Framework Working Group?s (FWG) [1] Maintenance Test Data and Services (MTDS) requirement of the U. S. Department of Defense (DoD). It has been developed by the Diagnostic Maintenance Committee (DMC) of IEEE SCC20. SIMICA, IEEE Std 1636 ? 2009 [2], is an implementation independent specification for a software interface between information systems containing diagnosis and maintenance data. SIMICA addresses the collection, exchange, and analysis of the data. Two approved trial use standards were the focus of a demonstration which took place at AUTOTESTCON in 2010. This demonstration showed the utilization of these standards in the documentation of maintenance actions associated with the removal, repair, and replacement of system components required to maintain and support an operational system. The demonstration also showed utilization of the standards in the test results that allow for the recording of the test execution and observations. This paper outlines the processes and the application of the standards needed to share information in a net-centric environment and demonstrates this capability.

Water Distribution Systems: A Spatial and Cost Evaluation

Problems associated with maintaining and replacing water supply distribution systems are reviewed. Some of these problems are associated with public health, economic and spatial development of the community, and costs of repair and replacement of system components. A repair frequency analysis has been completed for distribution system maintenance events (leaks and breaks). The economic implication of various replacement strategies and the effect of water quality (corrosivity) on water loss and system cost are examined. This analysis is based on the data acquired from tne large (260 mgd; 11.39 m³/s) and one smaller (20 mgd; 0.88 m³/s) water utility. As this study shows, once a length of pipe begins to require maintenance, its maintenance rate increases exponentially. Maintenance costs soon exceed the costs of replacement. Therefore establishing a timely maintenance and replacement program is extremely important from an economic and public health viewpoint.