Reliability modeling of a spool valve considering dependencies among failure mechanisms

Fan, Mengfei; Zeng, Zhiguo; Kang, Rui; Zio, Enrico

doi:10.1201/b19094-579

Cited by 4 publications

(4 citation statements)

References 1 publication

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“…As a matter of fact, the failure of the sealing of a spool valve is caused by internal leakage [31], whose mechanism shall be taken into account in order to conduct the reliability analysis [11]. The leakage between contacting surfaces in valves is likely to be influenced by the direction of the surface anisotropy or lay [3,23].…”

Section: Highlights Abstractmentioning

confidence: 99%

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Failure-based sealing reliability analysis considering dynamic interval and hybrid uncertainties

Sun¹,

Yang²,

Ren³

et al. 2021

Eksploatacja i Niezawodność – Maintenance and Reliability

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In the reliability analysis of a sealing structure, radial clearance of the contact surface is usually regarded as a failure criterion, and the sample size is usually quite small, which brings great challenges to uncertainty quantification. Therefore, this paper proposes a reliability analysis method based on the leakage mechanism of the sealing. With the application of dynamic interval, the proposed method can be used to deal with problem of degradation in small sample to evaluate reliability. Moreover, the dynamic reliability with the mixture of the probabilistic and non-probabilistic variables can be obtained using the proposed method. An illustrative numerical case study of a spool valve is conducted in order to validate the proposed method and the implemented reliability sensitivity analysis. The proposed method is of great help in evaluating and predicting reliability with small degradation sample and hybrid uncertainties.

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Section: Highlights Abstractmentioning

confidence: 99%

“…In formula (11), c(n) varies with the stroke and is modelled with a dynamic interval process. The reliability decreases monotonically with the increase of c. Therefore, the dynamic reliability interval of the sealing can be obtained using the following formulas:…”

Section: Fig 1 Schema Of a Spool Valve And Clearance [44]mentioning

confidence: 99%

Failure-based sealing reliability analysis considering dynamic interval and hybrid uncertainties

Sun¹,

Yang²,

Ren³

et al. 2021

Eksploatacja i Niezawodność – Maintenance and Reliability

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“…The outlet pressure (9) gauge and outlet thermometer (10) (used to test the device outlet temperature of CH11) are integrated into the outlet integration block. The flow gauge (11) and data recorder (14) are also accessed through this system. The device was connected to the hydraulic system, as shown in Figure 4.…”

Section: Design Of the Experimental Devicementioning

confidence: 99%

“…The size of a clearance should be set with regard to the following: the clearance should be small enough to prevent internal leakage, yet big enough to provide the sufficient space needed to ensure smooth action [6,7]. Barriers to achieving ideal clearance include factors such as roughness variation [8][9][10][11], particle pollution [12][13][14][15][16][17] and thermal deformation of valve orifices. Thermal deformation occurs when viscous heating generated by fluids increases the temperature of the valve orifice.…”

Section: Introductionmentioning

confidence: 99%

Optimization Algorithm and Joint Simulation to Micro Thermal Deformation Using Temperature Measurement in the Orifice of Hydraulic Valve

et al. 2020

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When exposed to viscous heating, hydraulic valve orifices experience thermal deformation, which causes spool clamping and actuator disorder. Quantitative research on thermal deformation can help reveal the micro-mechanism of spool clamping. In this study, miniature thermocouples are embedded into a valve orifice with an opening size of 1 mm to measure temperature distribution. An optimization algorithm based on measurement data (M-OA) for the thermal deformation of the valve orifice is proposed. The temperature and thermal deformation of the valve orifice are calculated through Fluent and Workbench joint simulation, with the measurement data serving as boundary conditions. Results show that, for a valve orifice with a valve wall length of 18 mm, when the temperature of the sharp edge is at 60 °C, thermal deformation measures 7.7 μm via observation and 7.62803 μm via M-OA, indicating that the M-OA method is reliable. The results of the joint simulation can be accepted because measurements of temperature reached an accuracy rate of 95%, and that of deformation reached 82.7%. A large drop in pressure led to a rapid increase in temperature, causing serious thermal deformation of the valve orifice. With an inlet pressure of 3 MPa, the temperature of the sharp edge reached 72.9 °C within 110 min, and radial thermal deformation can reach 8.3 μm. Such deformation poses great risk of spool clamping for a spool valve of Φ36 mm.

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A stochastic hybrid systems based framework for modeling dependent failure processes

et al. 2017

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In this paper, we develop a framework to model and analyze systems that are subject to dependent, competing degradation processes and random shocks. The degradation processes are described by stochastic differential equations, whereas transitions between the system discrete states are triggered by random shocks. The modeling is, then, based on Stochastic Hybrid Systems (SHS), whose state space is comprised of a continuous state determined by stochastic differential equations and a discrete state driven by stochastic transitions and reset maps. A set of differential equations are derived to characterize the conditional moments of the state variables. System reliability and its lower bounds are estimated from these conditional moments, using the First Order Second Moment (FOSM) method and Markov inequality, respectively. The developed framework is applied to model three dependent failure processes from literature and a comparison is made to Monte Carlo simulations. The results demonstrate that the developed framework is able to yield an accurate estimation of reliability with less computational costs compared to traditional Monte Carlo-based methods.

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Reliability modeling of a spool valve considering dependencies among failure mechanisms

Cited by 4 publications

References 1 publication

Failure-based sealing reliability analysis considering dynamic interval and hybrid uncertainties

Failure-based sealing reliability analysis considering dynamic interval and hybrid uncertainties

Optimization Algorithm and Joint Simulation to Micro Thermal Deformation Using Temperature Measurement in the Orifice of Hydraulic Valve

A stochastic hybrid systems based framework for modeling dependent failure processes

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