Reliability and maintainability

R. J. Murry and B. E. Mitchell, Proceedings ofMnnual Reliability and Maintainability Symposium (BMPMS), 24—27 Jan. 1994, Anaheim, Calif. 

Society of Automotive Engineers, Reliability and Maintainability Guideline for Manufacturing Machine andEquipment, SAE Order No. M-110, Society of Automotive Engineers (SAE), Warrendale, Pa., 1993. 

Dhillon, B. S. 1980 Mechanical Reliability Interference Theory Models. In Proceedings Annual Reliability and Maintainability Symposium, 462-467. 

Leitch, R. D. 1990 A Statistical Model of Rough Loading. In Proceedings 7th International Conference on Reliability and Maintainability, Brest, France, 8-12. 

Schatz, R., Shooman, M. and Shaw, L. 1974 Application of Time Dependent Stress-Strength Models of Non-Electrical and Electrical Systems. In Proceedings Reliability and Maintainability Symposium, 540-547. 

Abemethy, R. B, Weibull Analysis for Improved Reliability and Maintain ability for the Chemical Industries, 3rd International Conference and Exhi bition on Improving Reliability in Petroleum Refineries and Chemical Plants, Organized by Gulf Publishing Co. and Hydrocarbon Processing, Houston, TX, November 1994. 

The GIDEP Reliability-maintainability Data Bank (RMDB) has failure rates, failure modes, replacement rates, mean time between failure (MTBF) and mean time to repair (MTTR) on components, equipment, subsystems and systems. The RMDB includes field experience data, laboratory accelerated life test data, reliability and maintainability demonstration test results. The... 

The RMDB consists of two mayor sections computer data storage and retrieval system, and backup microfilm data bank file. The computer data storage and retrieval system is used for die standard reliability and maintainability data listing, special calculations, and searches. This data bank system has been established to facilitate remote terminal access compatible with the GIDEP remote terminal programs. The microfilm data bank file is used for storage and distribution of supplier s documents, failure analysis curves, description of methods used in the collection of the data, and additional background information too extensive to include in the computer data bank. 

Smith, A. M. and I. A. Watson, 1980, Common Cause Failures A Dilemma in Perspective. Reliability and Maintainability Conf. pp 127-142. 

The requirements of the automotive industry are more demanding than some other industries. Automotive products have to be safe, reliable, and maintainable, protect the occupants, and have minimal impact on the environment in their manufacture, use, and disposal. The automotive sector is a very competitive market and as a consequence costs have to be optimized. There is little margin for excessive variation, as variation causes waste and waste costs money and time. Therefore several methods have evolved to reduce variation. Among them are SPC, FMEA, MSA, and many other techniques The automotive industry believes that the more their suppliers adopt such variation reduction techniques the more likely it will be that the resultant product will be brought to the market more quickly and its production process be more efficient. 

Design validation may take the form of qualification tests which stress the product up to and beyond design limits - beta tests where products are supplied to several typical users on trial in order to gather operational performance data, performance trials, and reliability and maintainability trials where products are put on test for prolonged periods to simulate usage conditions. 

Smith, D. J. Reliability and Maintainability in Perspective, Macmillan, New York, 1985. 

Welker, E. L. and M. Lipow. Estimating the Exponential Failure Rate from Data with No Failure Events. Proceedings of the 1974 Annual Reliability and Maintainability Symposium. Los Angeles, January 29-31, 1974 (IEEE Catalog No. 74CH08201ROC). 

Verify long-term, continuous operability, reliability, and maintainability (i.e., operation of the full length of the test without unintended shutdown)... 

Also, technology reliability and maintainability will need to be established - as with other emerging technologies. This means the full range of technology risks must be clearly understood as early as possible. The more significant risks must be reduced and the information communicated to potential customers for those technologies. 

The general framework presented here on the model development side, the issues of knowledge representation in the form of systematie eomposition, ontology, and quantity representaion was involved. On the model analysis side issues involving the automatie evaluation and presentation of simulation results. The plant simulation model should mirror the behaviour of a eomplex plant subjeet to eonstraints in feedstoek, produets, equipment eapaeities, operational parameters, and utilities eonsumptions. The life eyele eoneept may lead to a reliable and maintainable tool. 

Program. Based on IMS technology, the ICAM upgrades the CAM with improved reliability and maintainability. It is a handheld device for real-time detection of low levels of nerve and mustard vapors and is capable of both day and night operation. More than 6,000 ICAMs have been procured to date. 

R M 2000, the Air Force Reliability and Maintainability Action Plan does not discuss the unique problems (and potential) of expert systems, particularly those which rely on the massive "knowledge bases" which can now be delivered on optical disc. Nor have they addressed the problems (and potential) associated with parallel processing, neural networks and "systems that learn". 

Achieve integrated operation of the complete system and conduct a nominal two-year test program to determine reliability and maintainability... 

On-Line Instrumentatlon-General Considerations. Rapid response time and the ability to sample large quantities of material constitute the principal design criteria for on-line instruments in the coal preparation industry. Other important factors include cost, reliability, and maintainability however these are common to on-line instrumentation in any industry. 

DhiUon, B. S., and Reiche, H., Reliability and Maintainability ManagemerU, Van Nostrand Reinhold, New York, 1983. 

Reliability and maintainability Machines and systems will be specified, designed, retrofitted, and installed with greater reliability and ease of maintainability. 

Reliability and Maintainability Activities during the System Life Cycle... 

Reliability and maintainability activities should span the entire life cycle of the system. Figure 1 shows the major points of reliability practice in a typical system life cycle (AMC 1968). The activities given in the exhibit are briefly explained here. There is a continuous feedback, and designs go through several cycles of the reliability program activities. 

The need for a reliability and maintainability program must be anticipated right from the beginning. The need for such programs cannot be overemphasized. These programs are justified based on specific system requirements in terms of life-cycle cost and other operational requirements. As already mentioned, the effectiveness of a system is determined by its reliability and maintainability characteristics. 

Availability is defined as the probability that a system is operating satisfactorily at any point in time. Availability considers only the operating time and downtime, thus excluding the idle time. Therefore, it is a measure of the ratio of operating time of the system to the operating time plus the downtime. Availability is a function of both the reliability and maintainability of the system. 

The conceptual system selected in step 3 is designed. Reliability and maintainability of this design are assessed. Various methodologies, such as design review, failure mode and effect analysis, fault tree analysis, and probabilistic design approach, can be applied at this step. Reliability is a design parameter and must be incorporated in the system at the design step. 

The system in the field is continuously evaluated to determine whether the original reliability and maintainability goals are met by the system. For this purpose a reliability monitoring program and field data-collection program must be established. 

The properties of some life distributions that are used in reliability and maintainability discipline are given below. 

To analyze and measure the reliability and maintainability characteristics of a system, there must be a mathematical model of the system that shows the functional relationships among all the components, the subsystems, and the overil system. The reliability of the system is a function of the reliabilities of its components. A system reliability model consists of some combination of a reliability block diagram or cause-consequence chart, a definition of all equipment failure and repair distributions, and a statement of spare and repair strategies (Kapur 1996a). All reliability analyses and optimizations are made on these conceptual mathematical models of the system. 

The allocation process is approximate, tind the system effectiveness parameters, such as reliability and maintainability apportioned to the subsystems, are used as guidelines to determine design feasibility. If the allocated parameters for a system ceinnot be achieved using the current technology, then the system must be modified and the allocations reassigned. This procedure is repeated until an allocation is achieved that satisfies the system requirements. 

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