Acta Mechanica Solida Sinica

, Volume 23, Issue 4, pp 353–360

# Experimental and Theoretical Investigation of the First Fold Creation in Thin Walled Columns

• G. H. Liaghat
• H. Moslemi Naeini
• A. H. Behravesh
Article

## Abstract

In this paper, a theoretical formula is presented to predict the instantaneous folding force of the first fold creation in square and rectangular columns under axial loading. The rectangular column is a small and single model of honeycombs with square or rectangular cells. Calculations are based on the analysis of the Basic Folding Mechanism (BFM). For this purpose, sum of the dissipated energy rate under bending around horizontal and inclined hinge lines and the dissipated energy rate under extensional deformations was equal to the work rate of the external force on the structure. The final formula obtained in this research, reasonably predicts the instantaneous folding force of single-cell square and rectangular honeycombs instead of the average value. Finally, according to the calculated theoretical relation, the instantaneous folding force of the first fold creation in a square column was sketched versus folding distance and compared to the experimental results, which showed a good correlation.

## Key words

dissipated energy rate first fold creation instantaneous folding force thin walled column

## References

1. [1]
Hanssen, A.G., Langseth, M. and Hopperstad, O.S., Optimum design for energy absorption of square aluminium columns with aluminium foam filler. International Journal of Mechanical Sciences, 2001, 43: 153–176.
2. [2]
Zhao, H., Elnasri, I. and Abdennadher, S., An experimental study on the behaviour under impact loading of metallic cellular materials. International Journal of Mechanical Sciences, 2005, 47: 757–774.
3. [3]
Niknejad, A., Liaghat, G.H., Behravesh, A.H. and Moslemi, N.H., Theoretical investigation of the instantaneous folding force during the first fold creation in a square column. In: International Conference on Applied Mechanics and Mechanical Engineering, Bangkok, 2008.Google Scholar
4. [4]
Wierzbicki, T. and Abramowicz, W., On the crushing mechanics of thin-walled structures. Journal of Applied Mechanics, 1983, 50: 727–734.
5. [5]
Abramowicz, W. and Wierzbicki, T., Axial crushing of multicorner sheet metal columns. Journal of Applied Mechanics, 1989, 56: 113–120.
6. [6]
Liaghat, G.H. and Alavinia, A., A comment on the axial crush of metallic honeycombs by Wu and Jiang. International Journal of Impact Engineering, 2003, 28: 1143–1146.
7. [7]
Liaghat, G.H., Daghiani, H.R., Sedighi, M. and Alavinia, A., Dynamic crushing of honeycomb panel under Impact of cylindrical projectile. Amirkabir Journal, 2002, 53: 68–79.Google Scholar
8. [8]
Liaghat, G.H., Sedighi, M., Daghiani, H.R. and Alavinia, A., Crushing of metal honeycomb structures under quasi-static loads. Tehran University Journal, 2003, 37: 145–156.Google Scholar
9. [9]
Zamani, J., Soleimani, M., Darvizeh, A. and Liaghat, G.H., Numerical analysis of full folding of thin-walled structures with square cross-section by LS-DYNA. In: 14th International Conference on Mechanical Engineering, Iran, 2006.Google Scholar
10. [10]
Alavinia, A. and Liaghat, G.H., Investigation of properties and quasi-static analysis of honeycombs. In: 12th International Conference on Mechanical Engineering, Tehran, Iran, 2004.Google Scholar
11. [11]
Alavinia, A. and Liaghat, G.H., Dynamic crushing of thin-walled columns under Impact of projectile. In: 12th International Conference on Mechanical Engineering, Tehran, Iran, 2004.Google Scholar
12. [12]
Zamani, J. and Liaghat, G.H., Effect of honeycomb main properties under impact loads. In: 10th International Conference on Mechanical Engineering, Iran, 2002.Google Scholar
13. [13]
Yasui, Y., Dynamic axial crushing of multi-layer honeycomb panels and impact tensile behavior of the component members. International Journal of Impact Engineering, 2000, 24: 659–671.
14. [14]
Nakamoto, H., Adachi, T. and Araki, W., In-plane impact behavior of honeycomb structures randomly filled with rigid inclusions. International Journal of Impact Engineering, 2009, 36: 73–80.
15. [15]
Niknejad, A., Liaghat, G.H., Behravesh, A.H. and Moslemi Naeini, H., Experimental investigation of the maximum axial force in the folding process of aluminum square columns. In: International Conference on Manufacturing Systems Engineering, Rome, Italy, 2009.Google Scholar
16. [16]
Niknejad, A., Liaghat, G.H., Moslemi Naeini, H. and Behravesh, A.H., Investigation of the folding angle variations during the folding progress in the columns. Trends in Applied Sciences Research, 2010, 5(1): 56–63.
17. [17]
Zhang, X., Cheng, G. and Zhang, H., Theoretical prediction and numerical simulation of multi-cell square thin-walled structures. Thin-Walled Structures, 2006, 44: 1185–1191.
18. [18]
Santosa, S., Wierzbicki, T., Hanssen, A.G. and Langseth, M., Experimental and numerical studies of foam-filled sections. International Journal of Impact Engineering, 2000, 24: 509–534.

© The Chinese Society of Theoretical and Applied Mechanics and Technology 2010