Document Type : Research Paper
Authors
1 Mechanical Engineering Department, University of Baghdad, Baghdad, Iraq
2 Mechanical Engineering Department, University of Baghdad, Baghdad, Iraq,
Abstract
Shell structures are liable to different kinds of defects and damage like cracking and corrosion which may destroy their structural safety and affect the service life. The cracks' effects are significant considerations in the design of cylindrical shell structures as they influence the vibration characteristics and safety. This present work is an experimental study on the free vibration analysis of a cylindrical shell involving circumferential surface crack. The influence of the ratio of shell’s radius to a shell’s thickness (R/h)of the shell structure, crack length in the shell, crack depth in the shell, crack location of the shell, and crack orientation in the shell are investigated under a clamped - clamped and simply supported boundary conditions at each end in the shell. Results showed that the minimum impact of the crack is at the angle of crack 75, and the circumferential fissure has more effect than a longitudinal fissure, In addition to this, under SS-SS, C-C the natural frequency will decrease if the fissure is located in the middle of the shell is greater than other locations. but when crack animated across in the ends of the limits the decrease in the natural frequency under C-C only. Results were compared with the literature there was a close agreement.
Keywords
[2] A. Roytman, and O. Titova, “An Analytical Approach to Determining the Dynamic Characteristics of a Cylindrical Shell with Closing Cracks,” J. Sound Vib., vol. 254 pp. 379–386, 2002.
[3] K.H. Ip, and P.C. Tse, “Locating damage in circular cylindrical composite shells based on frequency sensitivities and mode shapes,” Eur. J. Mech., vol. 21, pp. 615–628, 2002.
[4] M. Javidruzi, A. Vafai, J.F. Chen, and J.C. Chilton, “Vibration, buckling and dynamic stability of cracked cylindrical shells,” Thin-Walled Struct., vol. 42, pp. 79–99, 2004.
[5] A. Vaziri, and H. E. Estekanchi, “Buckling of cracked cylindrical thin shells under combined internal pressure and axial compression,” Thin-Walled Structures, vol.44, pp. 141–151, 2006.
[6] J. Xin, J. Wang, J. Yao, and Q. Han, “Vibration, buckling and dynamic stability of a cracked cylindrical shell with time varying rotating speed,” Mechanics based Design of Structures and Machines, vol. 39, pp. 461–490, 2011.
[7] T. Yin, and H.F. Lam, “Dynamic analysis of finite-length circular cylindrical shells with a circumferential surface crack,” J. Eng. Mech., vol.139 pp. 1419–1434, 2013.
[8] S. Moradi, and V. Tavaf, “Crack detection in circular cylindrical shells using differential quadrature method,” Int. J. of Pres. Vessels and Pipes, pp. 209–216, 2013.
[9] L. Sarker, Y. Xiang, X.Q. Zhu, and Y.Y. Zhang, “Damage detection of circular cylindrical shells by ritz method and wavelet analysis,” Electronic Journal of Structural Engineering, vol. 14, pp. 62–74, 2015.
[10] K. Moazzeza, H. Saeidi Googarchin, and S.M.H. Sharifi, “ Natural frequency analysis of a cylindrical shell containing a variably oriented surface crack utilizing line-spring model,” thin-walled structures, Vol. 125, pp. 63–75, 2018.
[11] R. D. Cook, “Concepts and applications of finite element analysis,” John Wiley and Sons 2nd ed, New York, 1981.
[12] V. V. Bolotin, “The dynamic stability of elastic systems,” Holden-Day, 1964.
[13] J. L. Sewall, and E. C. Naumann, “An experimental and analytical vibration study of thin cylindrical shells with and without longitudinal stiffeners,” NASA TN D-4705, 1968
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