International Journal of Aeronautical and Space Sciences

The Korean Society for Aeronautical and Space Sciences (한국항공우주학회)
권호 표지
DOI QR코드

DOI QR Code

Shape Optimization of Damaged Columns Subjected to Conservative and Non-Conservative Forces

  • Jatav, S.K. (Department of Aerospace Engineering, Indian Institute of Technology) ;
  • Datta, P.K. (Department of Aerospace Engineering, Indian Institute of Technology)
  • Received : 2013.10.10
  • Accepted : 2014.01.15
  • Published : 2014.03.30
Download PDF
⟨ Previous Next ⟩

Abstract

This paper deals with the development of a realistic shape optimization of damaged columns that are subjected to conservative and non-conservative forces, using the Genetic Algorithm (GA). The analysis is based on the design of the most optimized shape of the column under the constraint of constant weight, considering the Static, Vibrational, and Flutter characteristics. Under the action of conservative and non-conservative longitudinal forces, an elastic column loses its stability. A numerical analysis based on FEM has been performed on a uniform damaged column, to compute the fundamental buckling load, vibration frequency, and flutter load, under various end restraints. An optimization search based on the Genetic Algorithm is then executed, to find the optimal shape design of the column. The optimized column references the one having the highest buckling load, highest vibration frequency, and highest flutter load, among all the possible shapes of the column, for a given volume. A comparison is then made between the values obtained for the optimized damaged column, and those obtained for the optimized undamaged column. The comparison reveals that the incorporation of damage in the column alters its optimal shape to only a certain extent. Also, the critical load and frequency values for the optimized damaged column are comparatively low, compared with those obtained for the optimized undamaged column. However, these results hold true only for moderate-intensity damage cases. For high intensity damage, the optimal shape may not remain the same, and may vary, according to the severity of damage.

Keywords

References

  1. Bolotin, V. V., "Non-conservative problems of the Theory of Elastic Stability", Oxford: Pergamon Press, Oxford, 1963.
  2. Evan-Ivanowski, "Resonant Oscillations in Mechanical systems", Elsevier, New York, 1976.
  3. Elishakoff, I., "Controversy associated with the so called follower forces", Applied Mechanics reviews, Vol. 58, No. 2, 2005, pp. 117-142. https://doi.org/10.1115/1.1849170
  4. Sugiyama, Y., Langthjem, M. and Ryu, B., "Realistic follower forces", J. Sound Vib, Vol. 225, No. 4, 1999, pp.779- 782. https://doi.org/10.1006/jsvi.1998.2290
  5. Datta, P. K., and Biswas, S., "Aeroelastic behaviour of Aerospace structural elements with follower forces: A review", Int' l J. of Aeronautical & space Sci, Vol. 12, No. 2, 2011, pp. 134-148. https://doi.org/10.5139/IJASS.2011.12.2.134
  6. Hanaoka, M., and Washizu, K., "Optimum Design of Beck's column", Comp Struct, Vol. 11, 1980, pp. 473-480. https://doi.org/10.1016/0045-7949(80)90054-1
  7. Langthjem, M. A., and Sugiyama, Y., "Optimum design of Beck's column with a constraint on the static buckling load", Struct. Optim, Vol. 18, 1999, pp. 228-235. https://doi.org/10.1007/BF01223304
  8. Ishida, R., and Sugiyama, Y., "Proposal of Constructive algorithm and discrete shape design of the strongest column", AIAA J, Vol. 33, No.3, 1995, pp. 401-406. https://doi.org/10.2514/3.12591
  9. Sugiyama, Y., and Katayama, T., Ryu, B. and Horii, R., "Optimal shaped design of cantilevered columns subjected to a follower force", Proceedings of The 1993 Asia-Pacific Vibration Conference, Kitakyushu, Japan, pp. 1746-1751.
  10. Sugiyama, Y., Langthjem, M. A., Iwama, T. Kobayashi, M., Katayama, M., and Yutani, H., "Shape optimization of cantilevered columns subjected to a rocket based follower force and its experimental verification", Struct. Multidisc. Optim, Vol. 46, 2012, pp. 829-838. https://doi.org/10.1007/s00158-012-0796-2
  11. Rahul, R., and Datta, P. K., "Static and Dynamic instability characteristics of thin plate like beam with internal flow subjected to in-plane harmonic load", Int'l J. of Aeronautical & Space Sci, Vol. 14, No.1, 2013, pp. 19-29. https://doi.org/10.5139/IJASS.2013.14.1.19
  12. Cook, R. D., Malkus, D. S., and Plesha, M. E., Concepts and applications of finite element analysis, Wiley, New York, 1989.
  13. Pradhan, S., and Datta, P. K., "Dynamic instability characteristics of a free-free missile structure under a controlled follower force", Aircraft Engineering and Aerospace Technology, Vol. 78, No. 6, 2006, pp. 509-514. https://doi.org/10.1108/00022660610707184
  14. Pratihar, D. K., Soft Computing, Narosa Publishing House, New Delhi, 2008.