DOI QR코드

DOI QR Code

Resonance Frequency Analysis of A Baseball Bat by Impact Angle

가진 각도에 따른 야구배트의 공진주파수 분석

Park, Sun-Hyang;Chung, Woo-Yang;Jung, Hwan-Hee;Lee, Sang-Joon
박선향;정우양;정환희;이상준

  • Received : 2015.07.21
  • Accepted : 2015.09.08
  • Published : 2015.11.25

Abstract

Wood is an anisotropic material that shows the changes in hardness, quality and dimensions depending on the types of cells on three cross sections, size, array and so on. It can also be used in different ways according to its use, which requires a meticulous research, in order to maximize the utilization by understanding the nature and use; and by clarifying the theory and technologies. The research on relationship among wood's physical properties, density, and elasticity of modulus have been studied in Korea and abroad, but those studies were based on correlation gained through standardized specimen. Rather, the study on complete product is rare. Moreover, the previous reports are mostly concentrating on vibration mode and batting, though the wood's physical properties as a material have not been in the main focus. Therefore, this study will carried out for analyzing MOE through figuring material property out and comparing frequency adapting to the Canadian HardMaple bat. For comparison of material properties, we studied the annual ring and density of the bat; calculated the MOE with resonance frequency and formula (ASTM C1259); and verified the repulsive force of this material. As a result, the relevance of the resonance frequency and annual ring is weak, and in comparison in the grain direction in wood, the MOE value is higher when the grain direction in wood is excited horizontally than when is excited vertically, because the material is repulsive when grain direction is horizontal.

Keywords

Canadian Hardmaple;resonance frequency;modulus of elasticit

References

  1. ASTM C1259. 2008. Standard Test Method for Dynamic Young Modulus, Shear Modulus, and Poisson's Ratio for Advanced Ceramics by Impulse Excitation of Vibration.
  2. Brody, H. 1990. "Models of baseball bats". American Journal of Physics. 58(8): 756-758. https://doi.org/10.1119/1.16378
  3. Forest Products Laboratory. 2010. Wood Handbook.
  4. Korean Standard Association. 2011. Determination of average width of annual rings for wood. KS F 2202.
  5. Nathan, A.M. 2002. Characterizing the performance of baseball bats. American Association of Physics. Teacher 71(2): 134-143.
  6. Park, S.J, Lee, W.Y., Lee, H.H. 1990. Identification and wood structure, Hyangmunsa: 127.
  7. Rod Cross. 1998. The Sweet spot of a baseball bat. American Association of Physics. Teacher 66(9): 772-779.
  8. Russel, D.A. 2006. Bending Modes, Damping and Sensation of sting in Baseball bats. Engineering of sport 6: 11-16.
  9. Van Zandt, L.L. 1991. The Dynamical Theory of the Baseball Bat. American Association of Physics. Teacher 67(11): 175-181.
  10. Yue, X., Dong, C., Wang, X., Chang, Z. 2010. Computation Simulation and Model Analysis on "Sweet Spot" of Bar. ICCASM.

Acknowledgement

Supported by : 국립산림과학원