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Experimental and Analytical Analysis of Mechanical Response and Deformation Mode Selection in Balsa Wood

  • Murat VuralEmail author
  • Guruswami Ravichandran

Abstract

This study investigates the influence of relative density and strain rate on the compressive response of balsa wood as a sandwich core material commonly used in naval structures. Compressive strength, plateau stress and densification strain of balsa wood along the grain direction is investigated over its entire density spectrum ranging from 55 to 380kg/m3 at both quasi-static (10−3 s−3) and dynamic (103 s−3) strain rates using a modified Kolsky (split Hopkinson) bar. Scanning electron microscopy is used on recovered specimens subjected to controlled loading histories to identify the failure mode selection as a function of density and strain rate. The results indicate that compressive strength of balsa wood increases with relative density though the rate of increase is significantly larger at high strain rates. The failure of low-density specimens is governed by elastic and/or plastic buckling, while kink band formation and end-cap collapse dominate in higher density balsa specimens. Based on the experimental results and observations, several analytical models are proposed to predict the quasi-static compressive strength of balsa wood under uniaxial loading conditions. Results also show that the initial failure stress is very sensitive to the rate of loading, and the degree of dynamic strength enhancement is different for buckling and kink band modes. Kinematics of deformation of the observed failure modes and associated micro-inertial effects are modeled to explain this different behavior. Specific energy dissipation capacity of balsa wood was computed and is found to be comparable with those of fiber-reinforced polymer composites.

Notes

Acknowledgment

The support of the Office of Naval Research (Dr. Y. D. S. Rajapakse, program Manager) is gratefully acknowledged. GR acknowledges the support of the DoD MURI at the California Institute of Technology on Mechanics and Mechanisms of Impulse Loading, Damage and Failure of Marine Structures and Materials through the Office of Naval Research.

References

  1. 1.
    Gibson LJ, Ashby MF (1997) Cellular Solids:Structure and Properties. Cambridge University Press, CambridgeGoogle Scholar
  2. 2.
    Ashby MF, Evans A, Fleck NA, Gibson LJ, Hutchinson JW, Wadley HNG (2000) Metal Foams:A Design Guide. Butterworth-Heinemann, OxfordGoogle Scholar
  3. 3.
    Vural M, Ravichandran G (2003) Microstructural aspects and modeling of failure in naturally occurring porous composites. Mech Mater 35:523–536CrossRefGoogle Scholar
  4. 4.
    Knoell AC (1966) Environmental and physical effects of the response of balsa wood as an energy dissipator. JPL Technical Report No. 32–944, California Institute of Technology, Pasadena, CAGoogle Scholar
  5. 5.
    Soden PD, McLeish RD (1976) Variables affecting the strength of balsa wood. J Strain Anal 11(4):225–234CrossRefGoogle Scholar
  6. 6.
    Easterling KE, Harrysson R, Gibson LJ, Ashby MF (1982) On the mechanics of balsa and other woods. Proc Roy Soc London A383:31–41Google Scholar
  7. 7.
    Silva AD, Kyriakides S (2007) Compressive response and failure of balsa wood. Int J Solids Struct 44:8685–8717CrossRefGoogle Scholar
  8. 8.
    Daigle DL, Lonborg JO (1961) Evaluation of certain crushable materials. JPL Technical Report No. 32–120, California Institute of Technology, Pasadena, CAGoogle Scholar
  9. 9.
    Reid SR, Peng C (1997) Dynamic uniaxial crushing of wood. Int J Impact Eng 19(5–6):531–570CrossRefGoogle Scholar
  10. 10.
    Vural M, Ravichandran G (2003) Dynamic response and energy dissipation characteristics of balsa wood:experiment and analysis. Int J Solids Struct 40(9):2147–2170CrossRefGoogle Scholar
  11. 11.
    Vural M, Ravichandran G (2004) Failure mode transition and energy dissipation in naturally occurring composites. Composites Part B —Eng 35(6–8):639–646CrossRefGoogle Scholar
  12. 12.
    Hahn JJ (1981) Wood-based composites. In:Wangaard FF (Ed.) Wood:Its Structure and Properties. Pennsylvania State University, University Park, PA, pp. 401–427Google Scholar
  13. 13.
    Dinwoodie JM (1975) Timber —a review of the structure-mechanical property relationship. J Microscopy 4(1):3–32Google Scholar
  14. 14.
    Oguni K, Tan CY, Ravichandran G (2000) Failure mode transition in unidirectional E-glass/ vinylester composites under multiaxial compression. J Compos Mater 34(24):2081–2097CrossRefGoogle Scholar
  15. 15.
    Kolsky H (1949) An investigation of mechanical properties of materials at very high rates of loading. Proc Roy Soc London B62:676–700Google Scholar
  16. 16.
    Chen W, Lu F, Zhou B (2000) A quartz-crystal-embedded split Hopkinson pressure bar for soft materials. Exp Mech 40(1):1–6CrossRefGoogle Scholar
  17. 17.
    Ravichandran G, Subhash G (1994) Critical appraisal of limiting strain rates for compression testing of ceramics in split Hopkinson pressure bar. J Am Ceram Soc 77(1):263–267CrossRefGoogle Scholar
  18. 18.
    Maiti SK, Gibson LJ, Ashby MF (1984) Deformation and energy absorption diagrams for cellular solids. Acta Metal 32(11):1963–1975CrossRefGoogle Scholar
  19. 19.
    Mamalis AG, Robinson M, Manolakos DE, Demosthenous GA, Ioannidis MB, Carruthers J (1997) Review:Crashworthy capability of composite material structures. Compos Struct 37:109–134CrossRefGoogle Scholar
  20. 20.
    Timoshenko S (1936) Theory of Elastic Stability. McGraw-Hill, New York, pp. 324–418Google Scholar
  21. 21.
    Wangaard FF, (1950) The Mechanical Properties of Wood. Wiley, New YorkGoogle Scholar
  22. 22.
    Mark RE (1967) Cell Wall Mechanics of Tracheids. Yale University Press, New HavenGoogle Scholar
  23. 23.
    Cave ID (1968) The anisotropic elasticity of the plant cell wall. Wood Sci Tech 2(4):268–278CrossRefGoogle Scholar
  24. 24.
    Zhang J, Ashby MF (1992) The out-of-plane properties of honeycombs. Int J Mech Sci 34(6):475–489CrossRefGoogle Scholar
  25. 25.
    McFarland RK (1963). Hexagonal cell structures under post-buckling axial load. AIAA J 1(6):1380–1385CrossRefGoogle Scholar
  26. 26.
    Wierzbicki T (1983) Crushing analysis of metal honeycombs. Int J Impact Eng 1(2):157–174CrossRefGoogle Scholar
  27. 27.
    Cave ID (1969) The longitudinal Young's modulus of Pinus radiata. Wood Sci Tech 3(1):40–48CrossRefGoogle Scholar
  28. 28.
    Rosen VW (1965) Mechanics of composite strengthening. In:Fiber Composite Materials, American Society of Metals, Metals Park, Ohio, pp. 37–75Google Scholar
  29. 29.
    Argon A (1972) Fracture of composites. In:Herman, H (Ed.), Treatise on Materials Science and Technology, vol.1. Academic Press, New York, pp. 79–114Google Scholar
  30. 30.
    Budiansky B (1983) Micromechanics. Comp Struct 16(1):3–12CrossRefGoogle Scholar
  31. 31.
    Goldsmith W, Sackman JL (1992) An experimental study of energy absorption in impact on sandwich plates. Int J Impact Eng 12(2):241–262CrossRefGoogle Scholar
  32. 32.
    Wu E, Jiang W-S, (1997) Axial crush of metallic honeycombs. Int J Impact Eng 19(5–6):439–456CrossRefGoogle Scholar
  33. 33.
    Zhao H, Gary G (1998) Crushing behavior of aluminium honeycombs under impact loading. Int J Impact Eng 21(10):827–836CrossRefGoogle Scholar
  34. 34.
    Baker WE, Togami TC, Weydert JC (1998) Static and dynamic properties of high-density metal honeycombs. Int J Impact Eng 21(3):149–163CrossRefGoogle Scholar
  35. 35.
    Harrigan JJ, Reid SR, Peng C (1999) Inertia effects in impact energy absorbing materials and structures. Int J Impact Eng 22:955–979CrossRefGoogle Scholar
  36. 36.
    Deshpande VS, Fleck NA (2000) High strain rate compressive behavior of aluminium alloy foams. Int J Impact Eng 24:277–298CrossRefGoogle Scholar
  37. 37.
    Calladine CR, English RW (1984) Strain-rate and inertia effects in the collapse of two types of energy absorbing structure. Int J Mech Sci 26:689–701CrossRefGoogle Scholar
  38. 38.
    Zhang TG, Yu TX (1989) A note on a velocity sensitive energy absorbing structure. Int J Impact Eng 8:43–51CrossRefGoogle Scholar
  39. 39.
    Tam LL, Calladine CR (1991) Inertia and strain-rate effects in a simple plate-structure under impact loading. Int J Impact Eng 11:349–377CrossRefGoogle Scholar
  40. 40.
    Su XY, Yu TX, Reid SR (1995a) Inertia-sensitive impact energy-absorbing structures Part I:Effects of inertia and elasticity. Int J Impact Eng 16:651–672CrossRefGoogle Scholar
  41. 41.
    Su XY, Yu TX, Reid SR (1995b) Inertia-sensitive impact energy-absorbing structures Part II:Effects of strain-rate. Int J Impact Eng 16:673–689CrossRefGoogle Scholar
  42. 42.
    Karagiozova D, Jones NA (1995) A note on the inertia and strain-rate effects in Tam and Calladine model. Int J Impact Eng 16:637–649CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Mechanical, Materials and Aerospace Engineering DepartmentIllinois Institute of TechnologyChicagoUSA
  2. 2.Graduate Aeronautical LaboratoriesCalifornia Institute of TechnologyPasadenaUSA

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