Repair analysis

Savage EB, Ferguson TB Jr, DiSesa VJ, et al. Use of mitral valve repair analysis of contemporary United States experience reported to the Society of Thoracic Surgeons National Cardiac Database. Ann Thorac Surg 2003 75 820—5. 

Improved failure and repair analysis A CMMS provides the means to track work order and equipment history data related to types of repairs, frequencies, tmd causes for failure. It allows maintenance to have key information on failure trends that leads to eliminating toot causes of failures and improving overall equipment reliability. 

R. Hasten, M.C. Heijden, J.M.J. Schutten. Joint optimization of level of repair analysis and spare parts stocks. European Journal of Operational Research, 222 (2012), pp. 474 - 483. 

P.K. Narotam, S. Jose, N. Nathoo, C. Taylon, Y. Vora, Collagen matrix (DuraGen) in dural repair analysis of a new modified technique. Spine 29(24), 2861-2867 discussion 2868-2869 (2004)... 

Smal, T. Furch, J. 2011. Expedient Repairs Analysis of Possibihties and Needs. Advanced in Military Technology, no. 4. ISSN 1802-2308. 

Narotham, P.K., Jose, S., Nathoo, N., Taylon, C., and Vora, Y. (2004) Collagen matrix (Duragen )in dural repair analysis of a newly modified technique. Spine, 29, 2861-2867. 

The first results of computer-based assessment system application show that the benefits are obvious for repaired (without heat treatment) welds and complex defect configurations defect with height local increasing, group of defects, case analysis of defects interference and possible joining. 

Often repair of the found defects is extremely undesirable. Therefore, for discontinuities which are potentially hazardous, it is very important to have a onfirmation of their stability. In this case monitoring of potentially hazardous discontinuities is well supported by automated UT systems and based on the comparative analysis results, the actual data from examination of a section of the welded joint of a (hydrogen) separator are given in Figures 5,6. 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

Markov model A mathematical model used in reliabihty analysis. For many safety apphcations, a discrete-state (e.g., working or failed), continuous-time model is used. The failed state may or may not be repairable. 

The press had been designed with a capacity to deliver 280 kN press force and to work at a production rate of 40 lids per minute. Calculations to determine the distribution of forming loads required indicated that the press capacity was adequate to form the family of steel lids to be produced on the machine. One of the major areas of interest in the design was the con-rod and pin (see Figure 4.66). The first option considered was based on a previous design where the con-rod was manufactured from cast iron with phosphor bronze bearings at the big and small ends. However, weaknesses in this approach necessitated the consideration of other options. The case study presents the analysis of the pin and con-rod using simple probabilistic techniques in an attempt to provide in-service reliable press operation. The way a weak link was introduced to ensure ease of maintenance and repair in the event... 

More inclusive is Table 3.3.1 -3 which is appropriate at depth into the analysis. The major headings in this table address major hazardous subject areas,. iccideni mitigation, protection and repair. I or example, under the first major heading, "Storage of Raw Materials, Products, Intermediates," listed are confinement measures, release nicclumi.sms (valves), procedures for safe operation and limitations that must be observed for safety. 

Since dependency analysis is not needed, we can go on to the BUILD program. Go to FTAPSUIT and select 5 "Run Build." It asks you for the input file name including extender. Type "pv.pch," It asks you for name and extender of the input file for IMPORTANCE. Type, for examle, "pv.ii . It next asks for the input option. Type "5" for ba.sic event failure probabilities. This means that any failure rates must be multiplied by their mission times as shown in Table 7.4-1. (FTAPlus was written only for option 5 which uses probabilities and error factors. Other options will require hand editing of the pvn.ii file. The switch 1 is for failure rate and repair time, switch 2 is failure rate, 0 repair time, switch 3 is proportional hazard rate and 0 repair time, and switch 4 is mean time to failure and repair time.)... 

In one incident, the laboratory staff were asked to analyze the atmosphere in a tanker to see if any hydrocarbon was present. The staff regularly analyzed the atmosphere inside LPG tank trucks to see if any oxygen was present. Owing to a misunderstanding they assumed that an oxygen analysis was required on this occasion and reported over the phone that "none had been detected." The worker assumed that no hydrocarbon had been detected and sent the tank truck for repair. Fortunately the garage carried out their own check analysis. 

Reliability Analysis of Pumps for Uranium Chemical Process, Operating life repair frequency and cost data service ... 

Repair and maintenance records were analyzed to determine failure rates and distribution of failure modes. Preliminary findings are reported which include the Weibull distribution characteristics. Failure mode distributions are approximate. Overall mean-time-between-failure is given for the kiln, leach tank, screwfeeder, tank pump, tank gearbox, and kiln gearbox. The study was confined to an analysis of unscheduled repairs and failures. 

The data are very comprehensive with direct applications to reliability, risk, and event analysis of nuclear power plants. Information has been assembled on failure frequency, modes, repairs, and maintenance. Rate Information is based on demands calculated. The time period covered varies from the early 1970 s to the present. Using real time access, the output format if the event can be varied by selection of 20 generic and detailed categories. 

The failure rates and times-to-restore developed used a variety of data sources and data construction methodologies and are presented in Section 2. The principal methodology used is a kind of failure mode analysis for each component several principle modes of failure are analyed by characteristics including frequency of occurence, repair time, start-up time, and shut-down time. From these an average failure rate is developed and expressed as failures per million hours and mean time between failure(MTBF). 

Raw data The original records from which reliability data are extracted the facility records of equipment failure, repair, outage, and exposure hours or demands that require analysis and encoding in order to be placed into data elements. 

Based on the survey, the actual costs normally associated with the maintenance operation were reduced by more than 50 per cent. The comparison of maintenance costs included the actual labor and overhead of the maintenance department. It also included the actual materials cost of repair parts, tools and other equipment required to maintain plant equipment. The analysis did not include lost production time, variances in direct labor or other costs that should be directly attributed to inefficient maintenance practices. 

Vibration analysis, a key predictive maintenance tool, can be used to determine whether or not the repairs corrected existing problems and/or created addition abnormal behavior before the system is re-started. This eliminates the need for the second outage that many times is required to correct improper or incomplete repairs. 

A central problem in complex materials systems of any kind involves testing to deteet flaws, analysis to predict their effect on remaining service life of the system, and repair strategies to overcome them. For the structural materials discussed in this chapter, these problems are uneharted territory in need of exploration by chemical engineers. 

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