Fatigue Failure by In-line Flow-induced Vibration and Fatigue Life Evaluation

Odahara, Satoru; Murakami, Yukitaka; Inoue, M.; Sueoka, Atsuo

doi:10.1299/jsmea.48.109

Cited by 10 publications

(5 citation statements)

References 11 publications

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“…However, there has been a renewed interest in streamwise VIV since the failure of the Monju reactor, in which design engineers failed to consider the risk of streamwise VIV, which occurs at a lower freestream velocity (Nakamura et al, 2001;Okajima et al, 2004). There has also been an interest in how the freedom to move in the streamwise direction affects the overall response of structures with multiple degrees-of-freedom (DOF) Williamson, 2003, 2004) and the resulting fatigue damage (Odahara et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The role of the separation point in streamwise vortex-induced vibrations

Cagney

Balabani

2019

Journal of Fluids and Structures

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Structures in crossflow are susceptible to vortex-induced vibrations (VIV) when the vortex-shedding becomes synchronised with the structural vibration. Strategies to control VIV often include modifying the separation point on the cylinder surface, such as adding helical strakes, although there remains disagreement regarding the mechanism by which these work. We explore the role of the separation point on VIV acting in the streamwise (drag) direction, by performing high-speed Particle-Image Velocimetry (PIV) measurements of the wake and the structural displacement of a range of cylinders with different cross-sectional shapes, including circular (no fixed separation points), equilateral triangles (fixed separation points) and elliptical cylinders (which act as an intermediate case). None of the non-circular cylinders are found to exhibit VIV, despite having approximately the same experimental conditions (mass ratio, structural damping, Reynolds number range, etc.) as the circular cylinders, which undergo VIV. The phase-averaged PIV measurements of the near wake of the circular cylinder are used to calculate the separation angle throughout the shedding cycle for different wake modes, and it is shown that all the wake modes that are associated with VIV require a periodic movement of the separation point. In contrast, the variation in the separation angle was negligible for the von Kármán vortex street observed behind near-stationary circular cylinders and for all non-circular cylinders. The experiments illustrate the great sensitivity of the wake mode and streamwise VIV to modifications of the separation point and demonstrate that even a moderately elliptical cylinder (major to minor axis ratio of 1.54) is sufficient

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Section: Introductionmentioning

confidence: 99%

The role of the separation point in streamwise vortex-induced vibrations

Cagney

Balabani

2019

Journal of Fluids and Structures

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“…Therefore, the difference of two damage curves indicate that the fatigue damage D at failure become a different value for the various shapes of Fig. 12 The strain waves at first stage of test with no crack [5], [12]. The Japan Society of Mechanical Engineers strain histograms.…”

Section: 3 Variation Of Crack Size With the Increase In The Value Of ...mentioning

confidence: 99%

“…Fig 12. The strain waves at first stage of test with no crack[5],[12]. f no : Natural frequency at first stage of test.…”

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confidence: 99%

ICONE19-43186 Fatigue Failure by In-line Flow-induced Vibration : Fatigue Crack Detection and Fatigue Life Evaluation

Odahara¹,

Inoue

2011

ICONE

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The phenomenon of fatigue failure due to In-line flow-induced vibration has been investigated. In the experimental program an induced-vibration experimental set-up involving water flow was developed. This apparatus was used to produce fatigue failure resulting from In-line flow-induced vibration. The fatigue test cylinders were made of medium carbon steel. A small hole was drilled onto the test cylinder surface to localize the fatigue cracking process. A strain histogram recorder was used to acquire the service strain histogram and also to detect any variation in natural frequency. The cumulative fatigue damage, D, as defined by the Modified Miner Rule, was determined by using the strain histogram of the early portion of the test record. The value of D was close to unity in the case of In-line vibration. In contrast, the value of D obtained in a previous investigation for the case of the Cross-flow vibration ranged approximately from 0.2 to 0.8.

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“…To face these threats, it is necessary to increase the safety of operation of energy cycles including steam turbine type 18K370 [1][2][3]. The work regimes for load of control stage are different, so we have to rely upon more accurate calculation tools [3,16] including predicting further safe operation of steam turbine rotors after the calculated working time [14] as well as the increased expenditure and even entry into resonance resulting from the non-stationary operating conditions [17,18]. Another aspect is the interaction of fatigue and creep [12,13].…”

Section: Introductionsmentioning

confidence: 99%

“…Another aspect is the interaction of fatigue and creep [12,13]. The new computational tools such FSI (Fluid Solid Interaction) allow determining the fluid -solid interactions [3,6,16,18]. Of particular importance is the transfer of information on the interface (with working medium -construction) which represents the connection, and at the same time the boundary condition, between the CSD (Computational Solid Dynamic) and CFD (Computational Fluid Dynamic).…”

Section: Introductionsmentioning

confidence: 99%

Issues to improve the safety of 18K370 steam turbine operation

Bzymek¹,

Badur

Ziółkowski

2017

E3S Web Conf.

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Abstract. The paper presents the process of improving the safety and reliability of operation the 18K370 steam turbines Opole Power Plant since the first failure in 2010 [1], up to install the on-line monitoring system [2]. It shows how the units work and how to analyse the contol stage as a critical node in designing the turbine. Selected results of the analysis of the strength of CSD (Computational Solid Dynamic) and the nature of the flow in different operating regimes -thanks to CFD (Computational Fluid Dynamic) analysis have been included. We have also briefly discussed the way of lifecycle management of individual elements [2,3]. The presented actions could be considered satisfactory, and improve the safety of operating steam turbines of type 18K370.

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Fatigue Failure by In-line Flow-induced Vibration and Fatigue Life Evaluation

Cited by 10 publications

References 11 publications

The role of the separation point in streamwise vortex-induced vibrations

The role of the separation point in streamwise vortex-induced vibrations

ICONE19-43186 Fatigue Failure by In-line Flow-induced Vibration : Fatigue Crack Detection and Fatigue Life Evaluation

Issues to improve the safety of 18K370 steam turbine operation

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