Determination of Maintenance Task on Tanker Vessel’s Marine Boiler Using Reliability Centered Maintenance (RCM) II Method

2021 ◽  
Vol 15 (5) ◽  
pp. 228
Author(s):  
Muhammad Badrus Zaman ◽  
Dwi Priyanta ◽  
Bagas Somporn Supriadi Putra
Keyword(s):  
Reliability Centered Maintenance ◽  
Marine Boiler

Probabilistic Prediction of Aviation Engine Critical Parts Lifetime

2006 ◽  
Author(s):  
Y. A. Nozhnitski ◽  
E. A. Lokshtanov ◽  
I. N. Dolgopolov ◽  
G. V. Shashurin ◽  
M. E. Volkov ◽  
...  
Keyword(s):  
Extreme Values ◽  
Low Cycle Fatigue ◽  
Statistical Processing ◽  
Probabilistic Prediction ◽  
Safe Life ◽  
Reliability Centered Maintenance ◽  
Risk Functions ◽  
Cyclic Durability ◽  
Statistical Determination

Lifetime of disks and other aviation engine parts critical for safe operation is currently probabilistically predicted using mainly two methods. One method to predict lifetime is to confirm lifetime to low-cycle fatigue (LCF) cracking of a part without initial defects. The other method to predict lifetime is to confirm lifetime for safe propagation of a crack from initial defects available in a part. Combination of the above stated methods along with usage of margins on cyclic durability that ensure the required nonfracture probability presents another more conservative approach. Confirmation of lifetime to LCF cracking of a part without initial defects is usually performed based on results of cyclic tests of parts. The safe life determination algorithms were developed in Central Institute of Aviation Motors (CIAM) that take into account a difference in test outcome (“failure”–“no failure”). The developed software makes possible to consider the admissible failure probability, use the actual cyclic durability spread characteristics of the parts involving both lognormal and Weibull durability distributions. This paper discusses the examples of application of the elaborated methods and software. To confirm lifetime for safe propagation of a crack from defects available in a part, a program of statistical determination of durability of powder alloy disks with random fields of ceramic inclusions was developed in CIAM. This program allows performing the partition of disks into typical elements, the generation of realizations of initial defects for each typical disk element and calculation of life realizations corresponding to them, the statistical processing of the obtained data made with usage of asymptotic theory of extreme values, and the determination of technical risk functions for a disk as a whole. While developing the software, the problems of crack initiation and its stable propagation from ceramic inclusions were sequentially decided. Example of the calculation made according to the developed program is given in this paper. The probabilistically-justified approaches to determine the safe life shall be supplemented with the methods of economical and ecological risk analysis. In this case these approaches may become a good support for arranging the engine service to Reliability Centered Maintenance.

scholarly journals Determination of Production Instrumentation Equipment Maintenance Intervals In the Paper Industry

2021 ◽  
Vol 4 (1) ◽  
pp. 23-31
Author(s):  
Nurma M. Hidayatulloh ◽  
Tedjo Sukmono
Keyword(s):  
Power Supply ◽  
Manufacturing Industry ◽  
Raw Materials ◽  
Paper Industry ◽  
Control Valve ◽  
Machine Failure ◽  
Reliability Centered Maintenance ◽  
Critical Components ◽  
Fmea Method

PT. XYZ is a manufacturing industry engaged in paper processing with afval raw materials. The problem faced is machine failure that occurs suddenly without predictability, this is because there is no scheduled maintenance (preventive main-tenance). The object of this research is focused on production instrumentation equipment. This study uses the Failure Mode and Effect Analyzer (FMEA) method to identify the causes of failure and the effects of these failures by determining the critical value of the component, namely the Risk Priority Number (RPN) which is the largest, then the Reliability Centered Maintenance (RCM) II Decision Worsheet method for determine maintenance intervals of production instrumentation equipment. Based on the results of RPN calculations in the FMEA method to determine the critical components of the Instrumentation equipment, namely the Control Valve, it can be seen that the highest total RPN value is found in three components, namely Restrictor with an RPN value of 390, Power Supply with RPN of 297, and also a Pilot Positioner. with an RPN value of 240. And with optimum maintenance intervals, among others, the Restrictor every 40 hours, the Power Supply every 41 hours, and the Pilot Positioner every 47 hours.

Bayesian Networks on Risk Analysis of a Regasification System on an Offshore Unit

2011 ◽  
Author(s):  
Adriana Miralles Schleder ◽  
Marcelo Ramos Martins ◽  
Gilberto Francisco Martha Souza
Keyword(s):  
Risk Analysis ◽  
Bayesian Networks ◽  
Failure Modes ◽  
Terrorist Attack ◽  
Fault Trees ◽  
Reliability Centered Maintenance ◽  
Considerable Impact ◽  
Cut Set ◽  
Maintenance Plan

Nowadays, LNG Import Terminals (where the storage and regasification process is conducted) are mostly onshore; the construction of these terminals is costly and many adaptations are necessary to abide by environmental and safety laws. Moreover, an accident in one of these plants might produce considerable impact in neighboring areas and population; this risk may be even worse due to the possibility of a terrorist attack. Under this perspective, a discussion is conducted about a vessel known as FSRU (Floating Storage and Regasification Unit), which is a storage and regasification offshore unit, that can work miles away from de coast and, owing to this, can be viewed as an option for LNG storage and regasification facilities. The goal is to develop a method for using Bayesian Networks in the Risk Analysis of Regasification System of the FSRU, which will convert Fault Trees (FT) into Bayesian Networks (BN) providing more accurate data. Using BN is possible to represent uncertain knowledge and local conditional dependencies. In addition, FT models the failure modes as independent and binary events while BN may model a larger number of states. It is worth noting that BN does not require the determination of cut sets; however, given a failure, it is capable of providing the probability of each possible cut set. This method will provide information to define, in a future study, a maintenance plan based on the Reliability Centered Maintenance. The results intend to clarify the applicability of BN on risk assessment and might improve the risk analysis of a Regasification System FSRU.

The Experimental Determination of a Condition Indicator for Condition Based Maintenance

2011 ◽  
Author(s):  
Seth E. Farrington ◽  
M. Paul Buttram ◽  
Charles Boyles
Keyword(s):  
Failure Analysis ◽  
Hazard Function ◽  
Mechanical Test ◽  
Condition Based Maintenance ◽  
Test Bed ◽  
Reliability Centered Maintenance ◽  
Two Factors ◽  
Condition Indicator ◽  
Set Up

The objective of this paper is to present the investigation of a condition indicator to be used for a bearing. Reliability centered maintenance is implemented from the findings of reliability failure analysis. Reliability centered maintenance is implemented through either condition based maintenance or time-directed maintenance. Reliability failure analysis is performed through the inspection of a failed component either from failures in the system in use or from controlled laboratory experiments. This paper details the design and set up of a mechanical test bed used to demonstrate reliability failure analysis for the determination of condition based maintenance. The test bed consists of an electric motor driving a loaded shaft with a bearing as the test article. The load on the shaft is supplied by a screw jack and monitored by a load cell. A two factor, two level experiment with three replications is run. The two factors are load and rpm. The test is run above and below the load ratings for the bearing at high and low rpm. Each of the tests was run for twenty four hours or until bearing failure. The temperature and vibration of the test bearing was monitored throughout the duration of each test, and the bearings are characterized for wear at the completion of the test. A failure model with hazard function is presented and evaluated.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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