Document Type : Research Paper

Author

Civil Engineering Dept., Enugu State University of Science and Technology, Agbani, Enugu State, Nigeria.

Abstract

The determination of free vibration frequencies of thin beams on Winkler foundations is important in their design to avoid resonant failures when the excitation frequency equals the least natural frequency. This article presents the determination of natural transverse vibration frequencies of Euler-Bernoulli beams on Winkler foundations using the Generalized Integral Transform Method (GITM). The problem is governed by a fourth-order partial differential equation (PDE) and boundary conditions dependent on the end restraints. The governing PDE is transformed into an algebraic eigenvalue problem for harmonic vibrations and harmonic response. Analytical solutions of the governing equations are difficult and complex. Hence, other solution methods are needed. The main merit of the GITM is the apriori selection of kernel functions as orthogonal functions of vibrating thin beams with equivalent boundary conditions. This prior selection of the kernel functions and their orthogonality properties simplify the resulting integral equation formulation to an algebraic problem in the GITM space. Eigenfunctions of freely vibrating thin beams with identical restraints are used in the GITM to construct the displacement function as infinite series in terms of unknown parameters. The solution of the algebraic equation yielded exact solutions to the candidate problem. Exact solutions for frequency parameters are obtained for the four cases of boundary conditions for the various values of foundation parameters considered. The effectiveness of the GITM in obtaining a simplification of the governing PDE and reducing the problem to an algebraic problem is illustrated.

Graphical Abstract

Highlights

  • Eigenfunctions of thin beam vibrations used as kernel functions
  • Generalized integral transform method converts governing equations to integral and then algebraic equations
  • Exact solutions obtained for an infinite spectrum of natural frequencies of beams on Winkler foundations
  • Method provides accurate solutions compared to previous approaches

Keywords

Main Subjects

  1. C. Ike, Point collocation method for the analysis of Euler-Bernoulli beam on Winkler foundation, Int. J. Darshan Inst. Eng. Res. Emerg. Technol., 7 (2018) 1 – 7.
  2. C. Ike, Timoshenko beam theory for the flexural analysis of moderately thick beams – variational formulation and closed-form solutions, Technica Italiana – Int. J. Eng. Sci., 63 (2019) 34-45. https://doi.org/10.18280/ti-ijes.630105
  3. Levinson, A new rectangular beam theory, J. Sound Vib., 74 (1981) 81-87. https://doi.org/10.1016/0022-460x(81)90493-4
  4. V. Krisha Murty, Towards a consistent beam theory, AIAA J., 22 (1984) 811–816. https://doi.org/10.2514/3.8685
  5. M. Ghugal, A single variable parabolic shear deformation theory for flexureand flexural vibration of thick isotropic beams, 3rd Int.Conf. Struct. Eng. Mech. Comput., 2007,77 – 78.
  6. S. Sayyad, Y.M. Ghugal, Single variable refined beam theories for the bending, buckling and free vibration of homogeneous beams, Appl. Comput. Mech., 10 (2016) 123 – 138..
  7. O. Mama, C.C. Ike, H.N. Onah, C.U. Nwoji, Analysis of rectangular Kirchhoff plate on Winkler foundation using finite Fourier sine transform method, IOSR J. Math.,13 (2017) 58 – 66.https://doi.org/10.9790/5728-1301065866
  8. Adair, K. Ismailov, M. Jaeger, Vibration of a beam on an elastic foundation using Variational Iteration Method, World Acad. Sci., Eng. Technol., Int. J. Aerosp. Mech. Eng., 12 (2018) 914 – 919.
  9. Balkaya, M.O. Kaya, A. Saglamer, Analysis of the vibration of an elastic beam supported on soil using the differential transform method, Arch. Appl. Mech., 79 (2009) 135 – 146. https://doi.org/10.1007/s00419-008-0214-9
  10. O. Agboola, J. A. Gbadeyan Free vibration analysis of Euler-Bernuilli beam using different transform methods. Nigerian Def. Acad. J. Sci.Eng.,7 (2013) 77-88. http://www.academyjsekad.edu.ng
  11. Kacar, H.T. Tan, M.O. Kaya, Free vibration analysis of beams on variable Winkler elastic foundation by using the Differential Transform Method, Math. Comput. Appl., 16 (2011) 772 – 783. https://doi.org/10.3390/mca16030773
  12. Boudaa, S. Khalfall, E. Bilotta, Influence of Soil-Structure Interaction on free vibrations of beam by the Spectral Element Method, Model.Civ. Environ. Eng., 16 (2021) 51 – 60.https://doi.org/10.2478/mmce-2021-0005
  13. Khnaijar, R. Benamar, A Discrete Model for Nonlinear Vibration of Beams resting on various types of elastic foundations, Adv. Acoust. Vib., 2017 (2017) 1-25.https://doi.org/10.1155/2017/4740851
  14. Yayli, A.M. Özgur, A. Suleyman, An efficient analytical method for vibration analysis of a beam on elastic foundation with elastically restrained ends, Shock Vib., 2014 (2014)1-7. https://dx.doi.org/10.1155/2014/159213
  15. A. Al-Azzawi ,K.A. Daud, Free vibration of non-prismatic beam on variable Winkler elastic foundation, IOP Conf. Ser.: Mater. Sci. Eng., 737, 2020, 012025. https://doi.org/10.1088/1757-899x/737/1/012025
  16. E. Motaghian, M. Mofid, J.E. Akin, A new Fourier series solution for free vibration of non-uniform beams, resting on variable elastic foundation, Scientia Iranica, Trans. A:Civ. Eng., 25 (2018) 2967-2979. https://doi.org/10.24200/sci.2017.4239
  17. Soltani , B. Asgarian, New hybrid approach for free vibration and stability analyses of axially functionally graded Euler-Bernoulli beams with variable cross-section resting on uniform Winkler-Pasternak foundation, Lat. Am. J. Solids Struct., 16 (2019) 1 – 25. http://dx.doi.org/10.1590/1679-78254665
  18. Coskun, The response of a finite beam on a tensionless Pasternak foundation subjected to a harmonic load, Eur. J. Mech. A/Solids, 22 (2013) 151 – 161. https://doi.org/10.1016/S0997-7538(03)00011-1
  19. N. Chen, Vibration of prismatic beam on an elastic foundation by the differential quadrature element method, Comput. Struct., 77 (2000) 1 – 9. https://doi.org/10.1016/S0045-7949(99)00216-3
  20. Mutman, S.B. Coskun, Free vibration analysis of non-uniform Euler beams on elastic foundation via Homotopy Perturbation Method, World acad. Sci., Eng.Technol., Int. J. Mech. Mechatron. Eng., 7 (2013) 1353 – 1358.
  21. Franciosi ,A. Masi, Free vibration of foundation beams on two-parameter elastic soil, Comput. Struct., 47 (1993), 419 – 426. https://doi.org/10.1016/0045-7949(93)90237-8
  22. Rahbar-Ranji, A. Shahbaztabar, Free vibration analysis of beams on a Pasternak foundation using Legendre polynomials and Rayleigh-Ritz method, Proceedings of Odessa Polytechnic University, 3 (2017) 20-31. https://doi.org/10.15276/opu.3.53.2017.03
  23. Zhou, A general solution to vibrations of beams on variable Winkler elastic foundation, Comput. Struct., 47 (1993), 88 – 90. https://doi.org/10.1016/0045-7949(93)90281-H
  24. C. Ike, Fourier sine transform method for the free vibration of Euler-Bernoulli beam resting on Winkler foundation, Int. J. Darshan Inst. Eng. Res. Emerg. Technol., 7 (2018) 1 – 6. https://doi.org/10.32692/IJDI-ERET/7.1.2018.1801
  25. C. Ike, Sumudu transform method for finding the transverse natural harmonic vibration frequencies of Euler-Bernoulli beams, ARPN J. Eng. Appl. Sci., 16 (2021) 903 – 911.
  26. C. Ike, M. E. Onyia, E. O. Rowland-Lato, Generalized integral transform method for bending and buclking analysis of rectangular thin plate with two opposite edges simply supported and other edges clamped, Adv. Sci. Technol. Eng. Syst. J., 6 (2021) 283-296. https://dx.doi.org/10.25046/aj060133
  27. C. Ike ,Generalized integral transform method for the bending analysis of clamped rectangular thin plates, J. Comput. Appl. Mech., 53 (2022) 599-625.