Identification of Critical Speeds of Turbine Blade Along with Stress Stiffing and Spin Softening Effects
SureshBabu G1, Raviteja Boyanapalli2, Raja Sekhara Reddy Vanukuri3, Prudhvi Gogineni4, Janakinandan Nookala5, Goutham Kumar Yarlagadda6, VinayBabu Gada7

1Mr. Suresh Babu G, Assistant Professor, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
2Mr. Raviteja Boyanapalli, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
3Mr. Raja Sekhara Reddy Vanukuri, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
4Mr. Prudhvi Gogineni, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
5Mr. GouthamKumar Yarlagadda, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
6Mr. Janakinandan Nookala, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
7Mr. Vinay Babu Gada, Department of Mechanical Engineering, KL University, Vijayawada (A.P), India.
Manuscript received on 15 April 2013 | Revised Manuscript received on 22 April 2013 | Manuscript Published on 30 April 2013 | PP: 122-126 | Volume-2 Issue-5, April 2013 | Retrieval Number: E0682042413/13©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: Turbo machinery blades pass through several natural frequencies during start up and shut down operations. That will cause the resonance and cumulative damage to the turbine blades. Hence it is important to identify critical speeds. Critical speed is theoretical angular velocity which extends natural frequency of a rotating object, such as shaft, propeller, lead screw or gear. As of the speed of the rotation approaches the objects natural frequency, the object begins to resonate which dramatically increases systematic vibration. The resulting resonance occurs regardless of orientation. In this project the natural frequencies of turbine blade are identified using FINITE ELEMENT modal analysis at different speeds with spin softening and stress stiffening effects. Then the critical speeds are obtained by plotting Campbell diagram.
Keywords: Softening Critical Speeds Frequencies Machinery Theoretical.

Scope of the Article: Theoretical and Applied Fracture Mechanics