Remaining useful life

The aim is to predict the future state of a coating by timely electrochemical measurements. These predictions could then be used to determine the remaining useful life, or the optimal time until recoating. A secondary aspect is that the results of these analyses may be useful in screening out poorly performing coatings from early measurements. 

The remaining useful life evaluation routine (RULER) is a useful monitoring program for used engine oils. The RULER system is based on a voltammetric method (Jefferies and Ameye, 1997 Kauffman, 1989 and 1994). The data allows the user to monitor the depletation of two additives ZDDP and the phenol/amineH+ antioxidant. The RULER results were compared to other standard analytical techniques, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), total base number (TBN), total acid number (TAN), and viscosity to determine any correlation between the techniques (Jefferies and Ameye, 1997 and 1998). The test concluded that the RULER instrument can... 

Thin-layer chromatography (TLC) has been used for estimating the remaining useful life of engine oil including depletion of the multifunctional additive ZDDP. It was found that the soot from the oil did not interfere with the spot intensity since these particles did not travel with the mobile phase. The TLC technique has the potential to be a good supporting technique for estimation of chemical additives depletion (Brook et al., 1975 Coates, 1971). This technique is comparatively easy, very cheap, does not need sophisticated and expensive instruments and takes less than an hour. 

Remaining useful life Linear Nonlinear Nonlinear... 

The Dow Freeport in-service inspection procedures are similar to those reported earlier in this chapter. The Dow out-of-service (internal) inspection includes ultrasonic thickness measurements at all benchmark locations. Other test methods include shear wave ultrasonics, eddy current, and radiography. Engineers use ultrasonic thickness readings to project the remaining useful life of the vessel and to determine when the next internal inspection should be scheduled. 

Kaufman, R. E., and Rhine, W. E. 1988. Development of a Remaining Useful Life of a Lubricant Evaluation Technique. Part I Differential Scanning Calorimetric Techniques. Fubr. Eng., 44,154-161. 

The rate of depreciation for the sum-of-the-year s digits method is a fraction. The numerator of this fraction is the remaining useful life of the property at the beginning of the tax year, while the denominator is the sum of the individual digits corresponding to the total years of life of the project. Thus, with a project life, r, of 10 years, the sum of the year s digits will be 10-l-94-8-l-7-l-6-)-5- -4-1-3-1-2-I-1 =55. The depreciation rate the first year will be 10/55 = 0.182. If the initial cost of the facility is 7, the depreciation for the first year will be 0.1827, 9/55 = 0.1647 for the second year, and so on until the last year. The SYD method will recover 100% of the investment at the end of r years. A shift from SYD to straight-line depreciation cannot be made once the SYD method has been started. 

Antioxidant Condition by RULER , ASTM D6810 and D6971 The RULER0 is a portable instrument for determining the remaining useful life of machinery fluids based on their oxidative resistance levels. The instmment was developed to function with petroleum, synthetic hydrocarbon, ester-based and biodegradable lubricants. 

Level 4 Predicting the remaining useful life of the structure. 

An example is represented by the node System prognosis . Potentially, the node can represent the remaining life second by second but in this application the node has only four states. One of them is the state OK that means that the chiller operates in a correct way. The other three are some time intervals that represent a discretization of the remaining useful life before the failure occurrence. The interval choice has been made from the maintenance point of view considering the restriction of the test bed unit. 

The second graph reports the probability distribution for the states of the node System prognosis . The state OK probability suffers an important decrease between the fourth and fifth interval that corresponds to the moment which the incipient has been detected. Moreover, the probabihty trends of the node states reflect with a shght delay the real time to failure giving a good prediction of the remaining useful life of the system. 

ABSTRACT Life extension has for a long time been an important and highly discussed issue in the nuclear and aviation industries and has recently attracted considerable attention in the subsea oil and gas industry. Though it is practical and advisable to learn from previous experiences, it is essential and prudent to imderstand the industry specific nuances and to tailor the strategies and frameworks accordingly. The paper proposes a framework for remaining useful life prediction for subsea equipment. The primary aim of this paper is to discuss the various factors that influence the remaining useful life. 

Jardine et al. (2006) define two main prediction types in machine prognostics. The most obvious and widely used type of prognosis is To predict how much time is left before a failure occurs (or, one or more faults), given the current machine condition and past operation profile . The time left before observing a failure is usually called remaining useful life and the acronym RUL is sometimes used. 

Farrar and Lieven (2006) define damage prognosis as the estimate of an engineered system s remaining useful life . They also introduce the concepts usage monitoring and structural health monitoring. 

The main factors influencing the decision about the remaining useful life are illustrated by the influence diagram in Figure 2. 

As shown in Figure 2, the factors influencing the remaining useful life of a system are (i) the technical health of the system at time t denoted by 0(j, (ii) the expected operational conditions and the planned interventions as predicted at time h, denoted by 0(t ), and (iii) the future expected environmental conditions 8(h), as predicted at time h. 

The remaining useful life is a random variable Tr measuring the time from t imtil the system is deemed to be no longer useful. The distribution of fy depends... 

Under these assiunptions, the mean remaining useful life (MRL) of the system at time t is (Rausand and H0yland2OO4)... 

Liao, H., W. Zhao and H. Guo (2006). Predicting remaining useful life of an individual unit using proportional hazards model and logistic regression model. In Reliability and Maintainability Symposium, 2006. RAMS 06. Annual, pp. 127-132. 

Xue, E, P. Bonissone, A. Varma, W. Yan, N. Eklund and K. Goebel (2008, April). An instance-based method for remaining useful life estimation for aircraft engines. Journal of Failure Analysis cmd Prevention 8(2), 199-206. 

Finally, with regard to condition based maintenance (CBM) of engineering systems it is important to detect the initiation of incipient faults, to assess the current health of a system and to predict the remaining useful life (RUL) of a component that has become faulty. As bond graph modelling enables the systematic generation of ARRs for FDI, it can also support failure prognosis. 

By using thresholds and a decision procedure, fault diagnosis can provide an indication of the onset of an incipient fault that may lead to a failure. If a model of the anticipated degradation of parameters is available, the time evolution of monitored parameters or features can be extrapolated. The time from the starting point of a fault until the projected parameter value intersects with a user defined alarm threshold is then an estimation of the remaining useful life. The prediction of the RUL is affected by uncertainties in the monitored parameters, by the choice of the degradation model, uncertainties in its parameters and uncertainties in the failure alarm thresholds. As... 

Prognosis Failure prognosis means the ability of an early detection and isolation of incipient faults that may lead to a component failure, to determine the progression of the fault and to predict the remaining useful life (RUL), i.e. the time to failure given the current state of a system. 

Does the current maintenance plan address the expected (or remaining) useful life Yes No... 

A second method, the RULER (remaining useful life evaluation routine) method [3], was used as a cross-check of TAN and TBN of samples as received. The method agreed to 1 mg KOH/g of oil with values obtained by an outside laboratory. 

Chen, N. Tsui, K.L. 2013. Condition monitoring and remaining useful life prediction using degradation signals revisited. HE Transactions 45(9) 939-952. 

Li, X.-Y, Liu, L., He, B. Jiang, T.-M. 2013. Accelerated Degradation Test and Particle Filter Based Remaining Useful Life Prediction. Chemical Engineering Transactions 33 343-348. 

Liao, H. Tian, Z. 2013. A framework for predicting the remaining useful life of a single unit under time-varying operating conditions. HE Transactions 45(9) ... 

Liao, L. Kottig, F. 2014. Review of Hybrid Prognostics Approaches for Remaining Useful Life Prediction of Engineered Systems, and an Application to Battery Life Prediction. IEEE Transactions on Reliability 63(1) 191-207. 

Saha, B., Goebel, K. Christophersen, J. 2009a. Comparison of prognostic algorithms for estimating remaining useful life of batteries. Transactions of the Institute of Measurement and Control 31(3-4) 293-308. 

Si, X.-S., Wang, W, Hu, C.-H. Zhou, D -H 2011. Remaining useful life estimation— A review on the statistical data driven approaches. European Journal of Operational Research 213(1) 1-14. 

Sikorska, J.Z., Hodkiewicz, M. Ma, L. 2011. Prognostic modelling options for remaining useful life estimation by industry. Mechanical Systems and Signal Processing 25(5) 1803-1836. 

Vaidya, P. Rausand, M. 2011. Remaining useful life, technical health, and life extension. Proceedings of the Institution of Mechanical Engineers. Part O Journal of Risk and Reliability 225(2) 219-231. 

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