Probabilistic failure rate model of a tidal turbine pitch system

Ewing, Fraser J.; Thies, Philipp R.; Shek, Jonathan; Ferreira, Claudio Bittencourt

doi:10.1016/j.renene.2020.06.142

Cited by 10 publications

(6 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Let 𝜆 𝑖 be the failure rate of component i during the normal life phase of the bathtub curve under the independent failure. Assuming that the product lifespan obeys the exponential distribution during this period [10,18], the failure probability 𝐹 𝑖 of component i can be expressed as:…”

Section: Conventional Optimal Modelmentioning

confidence: 99%

Optimal allocation of reliability improvement target based on multiple correlation failures and risk uncertainty

Jia¹,

Yan²,

Kang³

et al. 2023

Eksploatacja i Niezawodność – Maintenance and Reliability

View full text Add to dashboard Cite

Optimal allocation of the reliability improvement target is essential for the system optimization design. In order to solve the problems that the optimization model is with loss of generality and the validity of the optimal solution is weakened, an optimal allocation method is proposed by considering multiple correlation failures and risk uncertainty in this paper. Two new concepts are presented, such as independent failure results in basic risk, and correlation failure leads to disturbance risk. A risk assessment machinery of “actual risk = basic risk + disturbance risk” is proposed. The action mechanisms of the three correlation failures are studied based on the cooperation game theory, and the generalized risk models are given under probability measure. Considering the improvement cost, the expectation and the variance of the reduction of system risk, a multi-objective optimal allocation model is developed, which is solved by using the PSO algorithm. Finally, the proposed optimal allocation is implemented at the 2-stage NGW planetary reducer, and the results show that it is more efficient and feasible for engineering practice.

show abstract

Section: Conventional Optimal Modelmentioning

confidence: 99%

Optimal allocation of reliability improvement target based on multiple correlation failures and risk uncertainty

Jia¹,

Yan²,

Kang³

et al. 2023

Eksploatacja i Niezawodność – Maintenance and Reliability

View full text Add to dashboard Cite

show abstract

“…Equation ( 16) was integrated numerically using the results for the axial trust shown in Figure 4 that yielded P m = 820 kN. The rating life, Equation (13), accounts only for fatigue failure of a properly manufactured rolling bearing, which operates under conventional operating conditions, i.e., when the bearing is properly mounted, protected from foreign matter, adequately lubricated and not exposed to extreme temperature or excessive loads [36]. However, the actual operating conditions of a bearing may differ from the conventional ones.…”

Section: Evaluation Of the Failure Rate Of The Main Bearingmentioning

confidence: 99%

“…Since there are significant uncertainties associated with the influence factors and the technique itself, it was suggested, in the context of mechanical components of a HATT, to treat these factors and, subsequently, the resulting failure rate as random variables [12]. This probabilistic approach to failure rates was further developed and implemented for components of a pitch system of a HATT in [13]. In this work, the influence of specific characteristics of components of the pitch systems on their failure rates was taken into account.…”

Section: Introductionmentioning

confidence: 99%

“…The method is based on the approach proposed in [12,19], i.e., the base failure rates, relevant influence factors and, subsequently, resulting failure rates are treated as random variables. In addition, the method addresses the issues mentioned above in connection to [13], i.e., (i) the influence factors account for the site-specific operating and environmental conditions of a HATT, and (ii) the probabilistic distributions of the failure rates can be updated using new data on the HATT's performance collected during its operational life. The latter is based on a Bayesian approach that uses data for similar components from other industries to construct the prior distribution of the base failure rate for a component.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Updatable Probabilistic Evaluation of Failure Rates of Mechanical Components in Power Take-Off Systems of Tidal Stream Turbines

2021

View full text Add to dashboard Cite

This paper presents a method for the probabilistic evaluation of the failure rates of mechanical components in a typical power take-off (PTO) system of a horizontal-axis tidal stream turbine (HATT). The method is based on a modification of the method of the influence factors, when base failure rates, relevant influence factors and, subsequently, resulting failure rates are treated as random variables. The prior (i.e., initial) probabilistic distribution of the failure rates of a HATT component is generated using data for similar components from other industries, while taking into account actual characteristics of the component and site-specific operating and environmental conditions of the HATT. A posterior distribution of the failure rate is estimated numerically based on a Bayesian approach as new information about the component performance in an operating HATT becomes available. The posterior distribution is then employed to obtain the updated mean and lower and upper confidence limits of the failure rate. The proposed method is illustrated by applying it to the evaluation of the failure rates of two key components of the PTO system of a typical HATT—main seal and main bearing. In particular, it is shown that uncertainty associated with the method itself has a major influence on the failure rate evaluation. The proposed method is useful for the reliability assessment of both PTO designs of new HATTs and PTO systems of operating HATTs.

show abstract

“…First, the number of load cycles in the dynamic rotor load simulation history is counted, then, the component fatigue is calculated and accumulated, and finally, test loads are derived, regarding the criterion of fatigue-equivalence [8]. The significance of the entire process is based on the correct selection of the critical component [11]. If the critical component is not known, the described process must be repeated for each possibly critical component, including the execution of experimental investigations.…”

Section: Introductionmentioning

confidence: 99%

Development of test methodologies for experimental lifetime investigations of tidal turbines

Rapp

Jacobs

Bosse

et al. 2021

Forsch Ingenieurwes

View full text Add to dashboard Cite

As a regenerative energy source, tidal energy can significantly contribute to greenhouse gas reduction, even though the potentially achievable energy output is lower than that of wind or solar energy. The decisive advantage of tidal turbines lies in the simply and reliably predictable energy output. However, their commercial use has so far been impeded by the fact that on the one hand complex mechanical systems are required to convert energy of tidal currents and on the other hand multi-axial loading conditions caused by turbulent ocean currents act on the turbine. For this reason, field tests on prototypes are an essential part of the development strategy to ensure operational reliability. However, in-field tests do not allow for accelerated lifetime testing, so that test bench experiments are becoming an increasingly important alternative. Today, established procedures for testing the turbines main bearings and gearing system are already available, both for setting up the required test configuration and for determining the corresponding test loads. However, the use of advanced calculation methods, such as the finite element method for stress calculation, requires a deep understanding of the examined components and hinders the transfer of the approaches to other components.To simplify the process of test loads determination, a general methodology is presented, which relies exclusively on standardized empirical calculation rules. Doing this, fatigue equivalent loads can be determined for any component in a simple process. It was shown that the achieved reduction in complexity opens further potential for test acceleration, since several components can be tested simultaneously.

show abstract

Probabilistic failure rate model of a tidal turbine pitch system

Cited by 10 publications

References 7 publications

Optimal allocation of reliability improvement target based on multiple correlation failures and risk uncertainty

Optimal allocation of reliability improvement target based on multiple correlation failures and risk uncertainty

Updatable Probabilistic Evaluation of Failure Rates of Mechanical Components in Power Take-Off Systems of Tidal Stream Turbines

Development of test methodologies for experimental lifetime investigations of tidal turbines

Contact Info

Product

Resources

About