Quantitative detection and evaluation of Rayleigh ultrasonic wave for fatigue crack on turbine blade surface

Meng, Jiajian; Zhen, Yu; Zhang, Kaisheng; Zhang, Jianhai; Zhao, Hongwei; Li, Junrong

doi:10.1016/j.apacoust.2023.109558

Cited by 5 publications

(1 citation statement)

References 32 publications

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“…As turbines are exposed to harsh operating conditions, predicting their remaining service life is important to reduce the risk of fracture. Turbine blades are currently subjected to regular in-service inspections and non-destructive detection of cracks using ultrasonic (Kalambe et al, 2020;Mevissen and Meo, 2020;Wang et al, 2021;Meng et al, 2023;Qin et al, 2023) and radiation methods (Błachnio et al, 2021;Zhang et al, 2023;Chen et al, 2019). However, because the crack propagation rate is relatively high in some areas methods for predicting the remaining life of a plant before crack initiation are required.…”

Section: Introductionmentioning

confidence: 99%

Non-destructive estimation of three-dimensional creep strain based on non-linear inverse analysis using displacement

FUJII,

OGAWA

2024

Mechanical Engineering Journal

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In mechanical structures exposed to high temperatures, such as turbine blades for power generation, cracks are detected during in-service inspections. However, there is a risk of fracture owing to the relatively rapid rate of crack propagation, even when a large safety factor is in force. Therefore, a technique is required to estimate the creep-strain distribution before crack initiation and to predict the remaining service life. An inverse analysis method, based on the eigenstrain methodology, has been proposed to estimate the three-dimensional creep-strain distribution using non-destructively measured surface displacements. Three-dimensional creep-strain distributions can be estimated even when the relationship between the creep strain and displacement is non-linear. Through iterative calculations, this method converges to a solution with relatively high estimation accuracy, however, a method for estimating actual complex creep-strain distributions is needed. In this study, a method was proposed to improve the convergence of the iterative calculations. Its effectiveness was demonstrated by numerical analysis using a torsional geometry model that could be used to describe an actual turbine blade. Many unknown values were assumed so that relatively complex creep-strain distributions could be estimated. Convergence calculations were performed to improve the estimation accuracy through iterative calculations, even when displacement measurement errors were considered. The estimation accuracy was improved by using more actual measurements in the inverse analysis.

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