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IMPROVED WEIGHT FUNCTIONS FOR STRESS INTENSITY FACTORS OF SEMI ELLIPTICAL CRACK IN STEAM TURBINE ROTOR SYSTEM
Authors:
Damarla Kiran Prasad1
, Kavuluri Venkata Ramana2, Nalluri Mohan Rao3
1 Gudlavalleru Engineering College, Gudlavalleru, India-521356
2 K. L. University, Vaddeswaram, India-522302
3 Jawaharlal Nehru Technological University Kakinada, Kakinada, India-533001
Received: 26.01.2019.
Accepted: 29.03.2019.
Available: 31.03.2019.
Abstract:
This paper presents weight function approach with piece wise polynomial interpolation function to determine the stress intensity factors at the surface and deepest points of a semi elliptical crack induced at the blade mounting locations of the rotor system. Initially, the mathematical model representing tapered rotating disc is solved and the equations for radial stress are obtained. Using the compatibility conditions, these equations are applied to plot the stress distribution at blade mounting locations in steam turbine rotor system. In the second part, weight functions with five and six terms are derived separately at the surface and the deepest points of semi elliptical crack to determine the stress intensity factors. The coefficients of these functions are determined assuming piece wise polynomial stress distribution along the crack. This weight function approach is applied to a semi elliptical crack at blade mounting locations by considering the stresses at discrete points of the crack obtained in first part and the stress intensity factors (SIFs) are determined. The results obtained are validated with the influence coefficient approach.
Keywords:
Stress intensity factor, blade mounting locations, steam turbine rotor, weight function approach, piece wise polynomial interpolation function
References:
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[2] J. Predan, V. Močilnik, N. Gubeljak, Stress Intensity Factors for Circumferential SemiElliptical Surface Cracks in a Hollow Cylinder Subjected To Pure Torsion. Engineering Fracture Mechanics, 105, 2013: 152-168.
http://doi.org/10.1016/j.engfracmech.2013.03.033
[3] M. K. Ramezani, J. Purbolaksono, A. Andriyana, S. Ramesh, I. S. Putra, Empirical Solutions for Stress Intensity Factors of a Surface Crack in a Solid Cylinder Under Pure Torsion. Engineering Fracture Mechanics, 193, 2018: 122-136.
http://doi.org/10.1016/j.engfracmech.2018.02.015
[4] X. Y. Zhang X. F. Li, Transient Thermal Stress Intensity Factors for a Circumferential Crack in a Hollow Cylinder Based on Generalized Fractional Heat Conduction. International Journal of Thermal Sciences, 121, 2017: 336-347.
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[5] J. M. Alegre, I. I. Cuesta, Stress Intensity Factor Equations for Internal Semi-Elliptical Cracks in Pressurized Cylinders. Journal of Pressure Vessel Technology, 133 (5), 2011: No.054501. http://doi.org/10.1115/1.4002613
[6] A. R. Shahani, M. M. Shodja, A. Shahhosseini, Experimental Investigation and Finite Element Analysis of Fatigue Crack Growth in Pipes Containing a Circumferential Semi-Elliptical Crack Subjected to Bending. Experimental Mechanics, 50 (5), 2010: 563-573. http://doi.org/10.1007/s11340-009-9229-6
[7] A. Zareei, S. M. Nabavi, Calculation Of Stress Intensity Factors for Circumferential SemiElliptical Cracks With High Aspect Ratio in Pipes. International Journal of Pressure Vessels and Piping, 146, 2016: 32-38.
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[8] D. Li, H. Yang, Y. Lu, Engineering Numerical Analysis of SIF and Security Service Evaluation on Thin- Walled Pipeline’ S Semi-Elliptical Crack in NPS Under Heat-Stress Coupling Load. Procedia Engineering, 27, 2012: 1582- 1587.
http://doi.org/10.1016/j.proeng.2011.12.624
[9] A. Benhamena, B. B. Bouiadjra, A. Amrouche, G. Mesmacque, N. Benseddiq, Three Finite Element Analysis of Semi-Elliptical Crack in High Density Poly-Ethylene Pipe Subjected to Internal Pressure. Materials and Design, 31 (6), 2012: 3038-3043. http://doi.org/10.1016/j.matdes.2010.01.029
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[11] D. G. Hattingh, M. N. James, M. Newby, R. Scheepers, P. Doubell, Damage Assessment And Refurbishment of Steam Turbine Blade/Rotor Attachment Holes. Theoretical and Applied Fracture Mechanics, 83, 2016: 125-134.
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0)
Volume 10
Number 1
March 2025
Last Edition
Volume 10
Number 1
March 2025
How to Cite
D.K. Prasad, K.V. Ramana, N.M. Rao, Improved Weight Functions for Stress Intensity Factors of Semi Elliptical Crack in Steam Turbine Rotor System. Applied Engineering Letters, 4(1), 2019: 24–32. https://doi.org/10.18485/aeletters.2019.4.1.4
More Citation Formats
Prasad, D.K., Ramana, K.V., & Rao, N.M. (2019). Improved Weight Functions for Stress Intensity Factors of Semi Elliptical Crack in Steam Turbine Rotor System. Applied Engineering Letters, 4(1), 24–32. https://doi.org/10.18485/aeletters.2019.4.1.4
Prasad, Damarla Kiran, et al. (2019). “Improved Weight Functions for Stress Intensity Factors of Semi Elliptical Crack in Steam Turbine Rotor System. Applied Engineering Letters,“ vol. 4, no. 1, 2019, pp. 24–32. https://doi.org/10.18485/aeletters.2019.4.1.4
Prasad, Damarla Kiran, Kavuluri Venkata Ramana, and Nalluri Mohan Rao. 2019. “Improved Weight Functions for Stress Intensity Factors of Semi Elliptical Crack in Steam Turbine Rotor System.” Applied Engineering Letters, 4 (1): 24–32. https://doi.org/10.18485/aeletters.2019.4.1.4.
Prasad, D.K., Ramana, K.V., and Rao, N.M. (2019). Improved Weight Functions for Stress Intensity Factors of Semi Elliptical Crack in Steam Turbine Rotor System. Applied Engineering Letters, 4(1), 24–32. doi: 10.18485/aeletters.2019.4.1.4.
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IMPROVED WEIGHT FUNCTIONS FOR STRESS INTENSITY FACTORS OF SEMI ELLIPTICAL CRACK IN STEAM TURBINE ROTOR SYSTEM
Authors:
Damarla Kiran Prasad1
, Kavuluri Venkata Ramana2, Nalluri Mohan Rao3
1 Gudlavalleru Engineering College, Gudlavalleru, India-521356
2 K. L. University, Vaddeswaram, India-522302
3 Jawaharlal Nehru Technological University Kakinada, Kakinada, India-533001
Received: 26.01.2019.
Accepted: 29.03.2019.
Available: 31.03.2019.
Abstract:
This paper presents weight function approach with piece wise polynomial interpolation function to determine the stress intensity factors at the surface and deepest points of a semi elliptical crack induced at the blade mounting locations of the rotor system. Initially, the mathematical model representing tapered rotating disc is solved and the equations for radial stress are obtained. Using the compatibility conditions, these equations are applied to plot the stress distribution at blade mounting locations in steam turbine rotor system. In the second part, weight functions with five and six terms are derived separately at the surface and the deepest points of semi elliptical crack to determine the stress intensity factors. The coefficients of these functions are determined assuming piece wise polynomial stress distribution along the crack. This weight function approach is applied to a semi elliptical crack at blade mounting locations by considering the stresses at discrete points of the crack obtained in first part and the stress intensity factors (SIFs) are determined. The results obtained are validated with the influence coefficient approach.
Keywords:
Stress intensity factor, blade mounting locations, steam turbine rotor, weight function approach, piece wise polynomial interpolation function
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0)
Volume 10
Number 1
March 2025
Last Edition
Volume 10
Number 1
March 2025