A finite element creep crack growth model for Waspaloy

Götting, M.; Rösler, Joachim

doi:10.1016/j.compstruc.2006.08.052

Cited by 8 publications

(6 citation statements)

References 12 publications

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“…Historically, it is used for a large variety of high temperature applications including turbine blades [29,30]. For the sake of simplicity, the room temperature density and poisson's ratio of Waspaloy are considered constant independent of temperature, with values of 8.20 g cm −3 and 0.3 [30,31], respectively. As the thermal conductivity and elastic modulus are known to considerably vary with temperature, temperature-dependent data are used.…”

Section: Materials and Systemmentioning

confidence: 99%

“…As the thermal conductivity and elastic modulus are known to considerably vary with temperature, temperature-dependent data are used. Table 1 summarises the thermal conductivity (k) values, and figure 2(a) shows the temperature dependence of yield strength, ultimate tensile strength and elastic modulus as generated using literature data [29][30][31]. Similar to most metals [32][33][34], Waspaloy exhibits a strong drop in strength above 900 K where a substantial change in mechanical behavior can be expected.…”

Section: Materials and Systemmentioning

confidence: 99%

“…First is the generation of the mechanical material behavior. Using existing data of Waspaloy IN713LC [29][30][31], ideally elastic-plastic stress-strain curves for different temperatures are developed as shown in figure 2(b). Hereby, the elastic material behavior is constructed using the temperature-dependent elastic modulus up to the yield strength from figure 2(a).…”

Section: Theoretical Analysis Data Generation and Model Validationmentioning

confidence: 99%

See 2 more Smart Citations

Numerical assessment of blade deflection and elongation for improved monitoring of blade and TBC damage

Dyke

Nganbe

2021

Eng. Res. Express

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The reliability of turbine blades is largely maintained by damage tolerance approach based on monitoring and pre-set periodic inspections. This can result in unnecessary downtimes, premature part retirement and unforeseeable failures. Therefore, there is growing interest in systems that can reliably detect damages in real‐time. However, many current sensors are based on blade tip clearance and time of arrival. The first primarily correlates with relatively predictable long-term creep deformation and ensuing blade elongation, while the second can be related to blade deflection. Therefore, this research comparatively assesses the two parameters. For this purpose, TBC defects, representative for coating spallation, and notches, representative for blunted blade cracks, are investigated. Overall, the results suggest that the measurement of changes in axial deflection could show higher sensitivity to cracks and TBC defects, and therefore, constitutes a potential alternative for continuous monitoring with respect to unforeseeable rapidly growing blade damage. Moreover, TBC spallation seems more difficult to immediately detect as the ensuing changes in blade tip position are small. However, they cause changes in deflection that can switch from negative to positive as they are located closer to the blade root, which may allow to assess their location during monitoring. In contrast, critical cracks located close to the blade root can cause measurable changes in blade deflexion, potentially making their timely detection and continuous monitoring possible.

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Section: Materials and Systemmentioning

confidence: 99%

Section: Materials and Systemmentioning

confidence: 99%

Section: Theoretical Analysis Data Generation and Model Validationmentioning

confidence: 99%

See 1 more Smart Citation

Numerical assessment of blade deflection and elongation for improved monitoring of blade and TBC damage

Dyke

Nganbe

2021

Eng. Res. Express

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“…The damage is implemented using open crack. There are a number of methods to model crack in structures (Friswell and Penny, 2002;Owolabi et al, 2003;Go¨tting and Ro¨sler, 2007;Ayhan, 2011;Khorram et al, 2013). A simplified model of open crack by Sinha et al (2002) is adopted in this paper.…”

Section: Application For Crack Detection In Cantilever Beammentioning

confidence: 99%

Local variation detection in MDOF system using wavelet based transmissibility and its application in cracked beam

Dong

Peng

et al. 2015

Journal of Vibration and Control

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Since the local stiffness or damping variation happens when damage occurs in engineer structures, it is useful to detect the local variation as a way for structural damage inspection. As a vibration based approach, transmissibility has attracted considerable interest because of its convenience and effectiveness in damage detection. However, using the traditional Fourier transform, it should be very careful to select the frequency bands in transmissibility calculation. Inappropriate choice of frequency band could cause a complete inaccurate result. For unknown damage detection, it is difficult to select the frequency band which eigen-frequency should be included. This paper proposes a novel method using wavelet based transmissibility for local variation detection. Benefiting from the ability in subtle information acquisition of wavelet transform, it is useful in reducing the influence of frequency bands to the indicators. Analytical derivation using wavelet balance method and numerical studies of a multiple degree of freedom (MDOF) system are carried out to verify the effectiveness of the proposed method. In the last section, the method is applied for detecting crack position in cantilever beam with analysis of its sensitivity to frequency bands and measurement inaccuracies.

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“…The local variation is implemented using open crack. There are a number of methods to model crack in structures [29][30][31][32][33]. A simplified model of open crack by Sinha et al [34] is adopted in this paper.…”

Section: Model Descriptionmentioning

confidence: 99%

A New Transmissibility Based Indicator of Local Variation in Structure and Its Application for Damage Detection

Peng

Dong

et al. 2015

Shock and Vibration

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The presence of damage in engineering structures could usually cause local variation in stiffness or damping, and therefore it is meaningful to detect the variation as early as possible for protecting the engineering structure from serious damage. In the study, a novel method is developed to detect and locate the local variation in stiffness and damping for structures based on transmissibility. Some important properties of transmissibility are first analytically revealed and, further, a variation detection indicator is proposed to locate the variation. The effectiveness of the proposed method is verified by numerical studies and the usefulness of it is demonstrated by application for detecting crack position in beam structures. The results show that the proposed new method has better performance than the three conventional transmissibility based methods when considering different frequency bands and noise.

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A finite element creep crack growth model for Waspaloy

Cited by 8 publications

References 12 publications

Numerical assessment of blade deflection and elongation for improved monitoring of blade and TBC damage

Numerical assessment of blade deflection and elongation for improved monitoring of blade and TBC damage

Local variation detection in MDOF system using wavelet based transmissibility and its application in cracked beam

A New Transmissibility Based Indicator of Local Variation in Structure and Its Application for Damage Detection

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