Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
권호 표지

Experimental Investigations of Relationships between Resonance Frequencies and Elastic Moduli of Composite Materials by Impulse Excitation Method

Impulse Excitation Method에 의한 복합재료의 공진 주파수와 탄성계수 관계에 대한 실험적 고찰

  • Kim, Hyeong-Sam (Department of Mechanical Engineering, Myongji University) ;
  • Lee, Jae-Hyeok (Department of Mechanical Engineering, Myongji University) ;
  • Lee, Dong-Sik (Department of Mechanical Engineering, Myongji University) ;
  • Park, Se-Man (Department of Mechanical Engineering, Myongji University)
  • 김형삼 (명지대학교 공과대학 기계공학과) ;
  • 이재혁 (명지대학교 공과대학 기계공학과) ;
  • 이동식 (명지대학교 공과대학 기계공학과) ;
  • 박세만 (명지대학교 공과대학 기계공학과)
  • Published : 1998.09.01
Download PDF
⟨ Previous Next ⟩

Abstract

The Usages of composite materials have been steadily on the rise in the industries of automobiles, air crafts, shipbuilding and other structures for transportations. Commonly required in those industries are light weight and high strength of the structures. Consequently, serious efforts in research have been focused on searching for light materials and on developments and characterizations of advanced substitutes including various kinds of composite materials. In this investigation, transversely isotropic composite materials are chosen and formed into two kinds of beams; Euler-Bernoulli beam(thin team) and Timoshenko beam(thick beam) for determinations of elastic constants. As an experimental technique Impulse Excitation Method is utilized to measure resonance frequencies of the beams of the composite materials in vibration tests. Elastic constants are evaluated from measured resonance frequencies for the two types of beams to observe and establish possible existence of effects of rotary inertia and shear deformations.

결량화 되고 고강도의재료를 요하는 자동차, 항공기, 선박, 각종 구조물 등 여러 분야에서 복합재료의 사용은 증가되어 왔고, 그에 따라 연구가 활발히 진행되고 있다. 본 연구에서는 Impulse Excitation Method을 통해 Transversely Isotropic한 재료의 공진 주파수를 측정함으로써 복합재료의 탄성계수를 구하였다. Timoshenko Beam Equation식에 나타나는 회전관성효과와 전단변형을 고려하였을 때와 고려하지 않았을 때 재료의 탄성계수에 변화가 어떻게 나타나는 가를 관찰하였다.

Keywords

References

  1. Journal of Applied Mechanics v.33 The Shear Coefficient in Timoshenko's Beam Theory G.R.Cowper
  2. British Journal of Applied Physics v.1 A Study of errors due to shear and rotary inertia in the determination of Young's modulus by flexural vibrations G.R.Cowper
  3. Proceedings of the American Society for Testing Materials v.45 Equations for computing elastic constants from flexural and torsional resont frequencies of vibration of prisms and cylinders G.Pickett
  4. Journal of Sound and Vibration v.31 no.4 Improved Resonant Bar Techniques For The Measurement Of Dynamic Elastic Moduli And A Test Of the Timoshenko Beam Theory I.G.Ritchie
  5. Mechanical Vibrations Singiresu,S.Rao.
  6. Journal of Research of the National Bureau of Standards v.60 no.5 Comparison of Theoretical and Empirical Relations Between the Shear Modulus and Torsional Resonance Frequencies for Bars of Rectangular Cross Section S.Spinner;R.C.Valore,Jr
  7. Journal of research of the National Bureau of Standard-A. Physics and Chemistry v.644 no.2 A Comparison of Experimental and Theoretical Relations Between Young's Modulus and the Flexural and Longitudinal Resonance Frequencies of Uniform Bars S,Spinner;T.W.Reichard;W.E.Tefft
  8. Proceedings of ASTM v.45 A Method for Determining Mechanical Resonance Frequency and for Calculationg Elastic Modulus from These Frequencies S.Spinner;W.E.Tefft
  9. J. Appl. Mech. v.28 The Effects of Rotary Inertia and of a Shear Deformation on the Frequency and normal mode equations of uniform Beams with simple and conditions T.C.Huang
  10. Vibration Problem in Engineering(3rd.) Timoshenko,S.P.
  11. J. Composite Materials v.4 Young's and Shear Moduli of Unidirectional Composites by a Resonant Beam Method T.J.Dudek