Maintenance Philosophy Research Articles

Recent Development in Structural Damage Diagnosis and Prognosis

Prognostics and health management (PHM) integrates diagnostic and prognostic technologies, provides the ability to assess the current health status of a structural system, predict its future health status for a given time period, and predict its time-to-failure for cost-effective maintenance schedule. It deals with system fault and anomaly conditions by automatic detection, classification, and prediction of critical component failures. The development of an effective PHM system for a structural system relies on both the sensing technology and the associated diagnostic and prognostic algorithms. Many sensor technologies such as strain gages, thermocouples, and accelerometers are available for use in PHM. In the meantime, a broad variety of techniques are available for damage diagnosis and prognosis of engineering structures, including but not limited to physical, statistical, intelligent, heuristic, or hybrid methods. This paper provides a state-of-the-art review on the recent development in damage diagnostics and prognostics methods applied in civil, mechanical and energy structures over the past decade. In addition, this paper introduces the basic concepts of various maintenance philosophies including corrective, preventive, and predictive maintenance. Predictive maintenance approaches such as condition based maintenance (CBM) combine the best features of corrective and preventive maintenance while avoiding the disadvantages of both. Currently it has become a popular maintenance philosophy for most high-value engineering structural systems such as airplane and gas turbine. In view of the number of recent patent applications it is reasonable to speculate that the combination of CBM and PHM will ultimately not only become the core maintenance philosophy for high-value engineering structures, but also foster further groundbreaking development and commercialization of PHM in a broad range of engineering fields.

Coal seam gas production: the operational and maintenance challenges

Compared to conventional gas, coal seam gas (CSG) production introduces additional complexities in operation due to the remoteness, number and distribution of the producing wells, the quantity of associated water and the variability in characteristics of each well. The potential irregularity in gas production is further highlighted when integrating with relatively steady state downstream facilities such as LNG production and power generation. Margins are particularly sensitive to operating cost because of the remoteness and distributed nature of the producing assets. Cost effective and reliable production of gas to the flow tolerances needed downstream requires that operations management, ongoing field development, asset maintenance and regulatory compliance be systematic and highly integrated. Experience shows that for operations reliant on distributed and remote assets, including CSG, that the ratio of predictive/preventive to corrective maintenance correlates directly to surety of gas production, with little margin to compensate for less than required reliability or low maintenance productivity. For CSG production it is difficult to avoid significant lost production as a consequence of higher levels of unplanned asset downtime. The remoteness, number of assets and operating cost constraints simply makes it difficult to overcompensate for lower reliability. Corrective actions are significantly more expensive when compared with centrally located assets because of the heightened pressure to correct in the shortest possible time. Further, deterioration of the maintenance regime compounds the effect as the emerging backlog of critical issues reduces the ability of crews to keep up with the preventative maintenance programme. Achieving a reliable outcome in CSG operations is therefore more reliant on a robust operations and maintenance management arrangement that also effectively incorporates the ongoing discrete activities of drilling, well completions, start-up and abandonment. To achieve these outcomes operators must ensure: the early development of maintenance philosophies, systems and processes during the project phase that consider the frequency of field variations for life of asset; a well planned system start up, commissioning and transition into first production; and, a constant focus on efficient deployment of resources, fit for purpose reliability and maintenance routines, logistics support and sparing plans, use of appropriate remote monitoring technologies and an incorporated regulatory compliance management plan. In its presentation PSN will demonstrate, through case study examples from its operations supporting coal seam gas and gas production assets in the United States and distributed and remote assets for the Western Australian Water Corporation, the challenges and management focal points critical to effective CSG production. The case studies will demonstrate the benefits achieved by PSN’s operations and maintenance management approach in the following areas: operations and maintenance readiness; distributed asset management; managing field development and modifications; implementing high performance maintenance; environmental monitoring and compliance; resource utilisation models; and, workforce training and development

Characterizing System Health Using Modal Analysis

In support of the condition-based maintenance (CBM) philosophy, a theoretical framework and algorithmic methodology for obtaining useful diagnostic and prognostic data from small-scale electromechanical systems is developed. The methods are based on vibration and modal analyses of the physical components. To illustrate the concept of the derived process, an example circuit card is considered. Models are created using finite-element analysis (FEA) techniques and analyzed to determine fundamental mode shapes and vibration frequencies. Simulations are initially conducted on an unadulterated benchmark model. Various fault conditions and cracks that are typical of the modeled circuit card are inserted. Additionally, cracks of increasing length are introduced to simulate dynamic crack growth, representing a deteriorating system. The simulation results yielded vibration modes characteristic of undamaged, faulty, and deteriorating systems. The altered natural frequency response signatures derived from each test signal vector for systems with existing faults and under progressive cracking are compared with the normal operation benchmark signature. An <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> middotlog <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> ) correlation technique is utilized for discrimination. Application of the developed techniques proved useful in characterizing system health by identifying both faulty and deteriorating conditions of the example component.

Maintaining Naval Combatants in ABS Classification In‐Service

AbstractThe American Bureau of Shipping and the Naval Sea Systems Command have been working together over the last several years in a measured initiative to develop and apply classification Rules for naval vessels, and currently both littoral combat ship (LCS) programs and the DDG‐1000 program require that the vessels be built and delivered in class to the Naval Vessel Rules. In addition, the JHSV platform will be delivered in class with ABS. It has been decided that the LCS platforms will be retained in class as a part of their maintenance philosophy. If this is successful, then DD‐1000 will also be retained in class. The JHSV, as are all Military Sealift Command ships, will be retained in class in‐service. This paper reviews the background supporting this initiative, describes the concept of retention in class, outlines the approach adopted, and reviews the current status of application.

A Political Philosophy of Basic Income Maintenance: Stuart White’s Civic Minimum and Fair Reciprocity

A Political Philosophy of Basic Income Maintenance: Stuart White’s Civic Minimum and Fair Reciprocity

A risk based maintenance approach (for facilities complying with the US OSHA PSM regulation)

Every US OSHA 29 CFR1910.119 Process Safety Management regulated manufacturing facility is populated with equipment that requires appropriate maintenance to fulfill its role in manufacturing and to keep the facility operating in a safe and environmentally sound manner. However, not all equipment poses the same risks at failure when compared to those requirements. Therefore, from a risk perspective, not all equipment deserves the same level of maintenance attention. Proper categorization of risks and appropriate levels of maintenance attention help keep the facility operating safely by better allocating available resources where and when needed. This paper proposes an approach for establishing a hierarchy of maintenance attention based on various equipment failure risks. It does so by helping the reader to understand the difference between “Mechanical Integrity” and “Reliability” and the risks imposed by failure of either. A combination of different maintenance philosophies, such as preventive, predictive, and run-to-failure/breakdown, is discussed as possible approaches for allocating limited resources.

Precision Material Condition Assessments

AbstractOne of the key elements for cost effective and efficient maintenance of today's Navy is the use of material condition assessments as part of the overall Navy's Condition‐Based Maintenance (CBM) philosophy. Through the use of material condition assessments, maintenance managers are able to detect, mitigate, and prevent potential costly and operationally debilitating equipment or systems failures. All Type Commanders (TYCOMs) use CBM assessments to help manage maintenance. This has been accomplished for CNSF N432 by the consolidated visit process, which has an established track record of proven success and is continuing to evolve with new technology and emerging processes, especially in view of the need to “do more with less.” One of the advances made in the material condition assessment process is the increased ability to accurately target problem maintenance objects for assessment. Much like the improvements made in missile technology, whereby the detection and seeker accuracy have evolved to permit pinpoint targeting (thus allowing warheads to become smaller and overall less costly), the improved use of maintenance history data and engineered risk priority business rules allows the material condition assessment process to zero in on problem maintenance objects. Modern missiles can now zoom in on specific buildings as designated targets and no longer need to be as destructive as in the past in order to achieve desired results, thus saving the cost and necessity for larger missiles and warheads. Likewise, today's precision material condition assessments can zoom in on those components within systems that are causing failures and not expend time, effort, and funding on collateral assessments for non‐problem items. A process tool currently being used to provide the precision targeting for material condition assessments is the Maintenance Assessment Index (MAI). This paper will review the background of the MAI, the process by which precision material condition assessments are determined, and how that information is integrated with the consolidated visit process: Hull, Mechanical, and Electrical Readiness Assessment. Success of the MAI is measured by increasing the look‐to‐find and find‐to‐fix ratios executed during the visits. Good systems and components fall off the radar screen, while bad actors are specifically targeted. This paper will also cover the consolidated visit process from agenda building to task loading from the Integrated Class Maintenance Plan, from the use of work order management tools to metrics collection and measures analysis. The ability to adjust the targeting criteria of the material condition assessment has become a powerful weapon for the TYCOM's battle to accomplish more maintenance with fewer resources and yet ensure a high state of material readiness for the fleet.

A methodology to enhance equipment performance using the OEE measure

In recent years, a remarkable improvement has taken place in the maintenance management of physical assets and productive systems to reduce the wastage of energy and resources. The Overall Equipment Effectiveness (OEE) methodology is a proven approach to increase the overall performance of equipment. Focused improvement and autonomous maintenance are two important activities to enhance equipment performance. These activities aim to educate the participants in the concepts and philosophy of equipment maintenance and give them an opportunity to develop their knowledge and skills. The OEE of the machine needs to be higher for sustained capacity planning. In the present paper, a method is proposed to evaluate OEE by including a factor known as usability and a relation is developed to evaluate the earning capacity of six big losses with incremental improvement in OEE as an extension to the maturity of OEE. Furthermore, a framework is proposed for implementing the OEE methodology to enhance overall equipment performance. [Submitted 30 April 2007; Revised 12 October 2007; Accepted 17 December 2007]

Proposed Array-Based Deep Space Network for NASA

The current assets of the deep space network (DSN) of the National Aeronautics and Space Administration (NASA), especially the 70-m antennas, are aging and becoming less reliable. Furthermore, they are expensive to operate and difficult to upgrade for operation at Ka-band (321 GHz is shorthand for the allocated 31.8-32.3 GHz. GHz). Replacing them with comparable monolithic large antennas would be expensive. On the other hand, implementation of similar high-sensitivity assets can be achieved economically using an array-based architecture, where sensitivity is measured by G/T, the ratio of antenna gain to system temperature. An array-based architecture would also provide flexibility in operations and allow for easy addition of more G/T whenever required. Therefore, an array-based plan of the next-generation DSN for NASA has been proposed. The DSN array would provide more flexible downlink capability compared to the current DSN for robust telemetry, tracking and command services to the space missions of NASA and its international partners in a cost-effective way. Instead of using the array as an element of the DSN and relying on the existing concept of operation, we explore a broader departure in establishing a more modern concept of operations to reduce the operations costs. This paper presents the array-based architecture for the next-generation DSN. It includes system block diagram, operations philosophy, user's view of operations, operations management, and logistics like maintenance philosophy and anomaly analysis and reporting. To develop the various required technologies and understand the logistics of building the array-based low-cost system, a breadboard array of three antennas has been built. This paper briefly describes the breadboard array system and its performance.

A Philosophy of Maintenance? Engaging with the Concept of Software

Although reducing the costs of software maintenance has long been held as an important goal, few researchers have studied software maintenance — except in the context of software design. However, thinking in software design is itself muddled by the frequent confusion over the term ‘software’ and ‘programs’. In this paper we argue for a re-examination of the underlying philosophical foundations of programs, in order to establish software as a phenomenon in its own right. Once we understand the basic structure of software theories, we will be in a better position to understand how theories of software relate to theories of programs. This might finally provide the insight needed to achieve the long awaited reduction in the cost of software maintenance.

Active facility management strategy for containment of ILW using risk-based service life modelling of reinforced concrete to incorporate in-service cracking

An Intermediate Level Waste Store facility for on-site waste storage is under construction to contain arisings from historic operations of the Hunterston 'A' NPS, Ayrshire. This paper updates previous a durability design strategy for reinforced concrete structures used in long-term storage (>100 years) of nuclear waste that incorporates design-limit flexural cracking. The approach, utilising probabilistic modelling of deterioration and reliability methods, gives greater flexibility to the decision-making process for management of concrete structures depending on the balance chosen between acceptable risk and maintenance philosophy. The results are compared with contemporary UK Codes concerning durability of reinforced concrete.

Survival of the fittest [consumer goods manufacturing

To enable UK Fast Moving Consumer Goods manufacturers to survive against the global pressures from low-cost economies, and at home, from supermarket chains who wield absolute power, they must invest in automation and innovation. There is a need for a total productive maintenance philosophy in terms of providing equipment that will do the complete job and does not need specialist equipment. Energy management is becoming more and more a priority, especially in the UK. Waste reduction is, without a doubt, another priority for all consumer goods manufacturers and understanding that machine material interaction. Last but not the least is data capture - if manufacturers are going to address any cost issue then they have to know where it is coming from.

Data fusion/data mining-based architecture for condition-based maintenance

Condition-based maintenance (CBM) is a maintenance philosophy wherein equipment repair or replacement decisions are based on the current and projected future health of the equipment. The constituents and sub-processes within CBM include sensors and signal processing techniques that provide the mechanism for condition monitoring, and decision support models. Since past research has been dominated by condition monitoring techniques for specific applications, the maintenance community lacks a generic CBM architecture that would be relevant across different domains. This paper attempts to fulfil that need by proposing a combined data fusion/data mining-based architecture for CBM. Data fusion, which is extensively used in defence applications, is an automated process of combining information from several sources in order to make decisions regarding the state of an object. Data mining seeks unknown patterns and relationships in large data sets; the methodology is used to support data fusion and model generation at several levels. In the architecture, methods from both these domains analyse CBM data to determine the overall condition or health of a machine. This information is then used by a predictive maintenance model to determine the best course of action for maintaining critical equipment.

The Successful Implementation of TPM in Conjunction with EOM and 5S: A Case Presentation

Certainly, manufacturing plants are encountering resource constraints. Limited equipment resources require close attention to make them useful every moment. This demands a total participatory equipment maintenance environment. Total Productive Maintenance (TPM) philosophy demonstrates that potential ability. In conjunction with Ecology Oriented Management (EOM)and Japaneses 5Ss housekeeping-norms, TPM can offer the successful achievement of total maintenance and pertinent productive goals. This study presents a case example on how a blend of these three concepts renders the highest effective potential in maintenance arena that can excel over maintenance goals. The methodology of this study is two fold: literature survey and case investigations in a large-scale company.

Successful deployment of commercial ATE to an air force I-level (back-shop) repair facility

In today's world of constrained budgets, one of the problems the military faces is the challenge of trying to maintain organic maintenance capabilities. Historically, the US Air Force has desired to achieve an autonomous capability to maintain the equipment it uses. This has been achieved, traditionally, by setting-up three levels of maintenance: organizational; intermediate (back-shop); and depot. The I-level back-shops often utilize militarized automatic test equipment (ATE) and test program sets (TPSs) to test today's complex aircraft line replaceable units (LRUs). And even though this is still a cost-effective maintenance philosophy, it has become costly to develop militarized ATE. The Department of Defense (DoD) has been very active in trying to reduce the total ownership cost of ATE in the government inventory. One approach is to utilize commercial, instead of Mil-Spec, ATE. However, utilizing commercial ATE at an USAF back-shop is not without its tradeoffs and challenges as it represents a significant deviation from the way the USAF maintenance squadrons are accustomed to doing business. This paper documents the current success story of replacing the legacy C-17 I-level ATE with a commercial ATE.

Plant maintenance strategy: evidence from four British manufacturing firms

The nature of maintenance work has changed as a result of a huge increase in the number and variety of physical assets to be maintained, increasing automation and complexity, new maintenance techniques and changing views on maintenance organisation and responsibilities. Maintenance philosophy has evolved from reactive to preventive and later to a proactive approach. However, maintenance function is still largely seen as a “necessary evil” by many companies. What is their maintenance strategy in an increasingly competitive world? This paper first reviews the development of the maintenance philosophy. It then reports the case study findings of the maintenance strategies adopted by four large and medium‐sized British manufacturing and processing companies. The paper concludes that production pressure has forced these companies to resort to reactive maintenance, a technique which is counterproductive for the long‐term performance of the plant.

Creating mold-free buildings: a key to avoiding health effects of indoor molds.

In view of the high costs of building diagnostics and repair subsequent to water damage--as well as the large medical diagnostic and healthcare costs associated with mold growth in buildings--commitment to a philosophy of proactive preventive maintenance for home, apartment, school, and commercial buildings could result in considerable cost savings and avoidance of major health problems among building occupants. The author identifies common causes of mold growth in buildings and summarizes key building design and construction principles essential for preventing mold contamination indoors. Physicians and healthcare workers must be made aware of conditions within buildings that can give rise to mold growth, and of resulting health problems. Timely advice provided to patients already sensitized by exposure to molds could save these individuals, and their families, from further exposures as a result of inadequate building maintenance or an inappropriate choice of replacement housing.

Selecting the most efficient maintenance approach using fuzzy multiple criteria decision making

We assess the most popular maintenance approaches, i.e. strategies, policies, or philosophies, using a fuzzy multiple criteria decision making (MCDM ) evaluation methodology. We illustrate with two examples how the suggested evaluation methodology identifies the most informative approach. Using the fuzzy MCDM, it would be possible to select in advance, the most informative (efficient) maintenance approach. Consequently, this leads to less planned replacements , and failures would be reduced to approximately zero and higher utilization of component life can be achieved. Thus, the maintenance department could contribute more to the business objectives throughout participating effectively in adding value to the production activities.

ICONE11-36068 IMPROVEMENTS IN VALVE RELIABILITY DUE TO IMPLEMENTATION OF EFFECTIVE CONDITION MONITORING PROGRAMS

Modern diagnostic systems for motor-operated valves, pneumatic control valves and checkvalves have facilitated a shift in the maintenance philosophy for valves and actuators in nuclear power plants from schedule based to condition-based maintenance (CBM). This shift enables plant management to focus resources and schedule priority on the plant equipment that warrants attention thereby not wasting resources or increasing the human factors risk on equipment that has not degraded. The most recent initiatives combine condition monitoring with risk/safety insights to focus attention and resources on the right equipment at the right time consistent with each component's safety-significance. The activities of the ASME working groups responsible for nuclear O&M codes have kept pace with the technology and process improvements necessary to maximize the technical and economic benefits of condition based and risk informed maintenance. This paper discusses adoption of valve condition monitoring in the nuclear power industry, changes to ASME codes and standards during the 90's to facilitate adoption of condition monitoring technology for in-service testing and recent efforts to combine risk insights with condition monitoring strategies to achieve the highest level of valve reliability and nuclear safety without over inflating maintenance cost.

Converting tribology principles into measurable maintenance improvements at Sishen Iron Ore Mine

Sishen Iron Ore Mine in the Northern Cape province of South Africa utilises 72 primary equipment units to move 119Mt of materials per year, of which 32.5Mt of run‐of‐mine material are sent to the processing plant. The maintenance mission, philosophy and strategy of the Mine are outlined as a background to the discussion of the application of tribology principles. The evolution of Sishen’s tribology outlook is described up to the current position, where the vision for the future is: “no wear”. The current maintenance activities are discussed under the headings: contamination control, lubricants, growing awareness, flushing equipment, and breathers. The results achieved are described, together with the calculated return on investment. Finally, the requirements for success are outlined and possible pitfalls listed.