Journal of Applied Science and Engineering

Published by Tamkang University Press

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Yi-Ren Wang This email address is being protected from spambots. You need JavaScript enabled to view it.1 and Tseng-Hwa Tsao1

1Institute of Aerospace Engineering Tamkang University Tamsui, Taipei, Taiwan 251, R. O. C.


 

Received: July 4, 2001
Accepted: August 10, 2001
Publication Date: September 1, 2001

Download Citation: ||https://doi.org/10.6180/jase.2001.4.3.04  


ABSTRACT


In this research, the mixed mode fracture of a pair of highly rotating metallic blades has been investigated at room temperature using single edge notched specimens. A set of 2-bladed rotor is driven by a 220 volt AC motor and the rotating speed is fixed at 850 rpm. The notch is located in various blade positions from blade root to tip. The correlation of notch cracks at blade leading edge and trailing edge is also studied. A simple theoretical model of a flapping Bernoulli-Euler-Beam like rotor blade model is established for analytic study. The experimental results show that the cracks grow faster in the case of the rotor blade with higher pitch angle. The analytic study of blade flapping motion also shows the importance of the aerodynamic force in rotating machines. It is suggested that the aerodynamic force should be included in solving the rotating fracture problems.


Keywords: Crack Growth, Fracture, Rotating Beam, Aerodynamic Force, Helicopter Rotor Blades


REFERENCES


  1. [1] Azhdari, A. and Nemat-Nasser, S., “Experimental and computational study of fracturing in an anisotropic brittle solid.” Mechanics of Materials, Vol. 28, pp. 247-262 (1998).
  2. [2] Azhdari, A., Nemat-Nasser, S. and Rome, J. “Experimental observations and computational modeling of fracturing in an anisotropic brittle crystal (Sapphire).” Int. J. of Fracture, Vol. 94, pp. 251-266 (1998).
  3. [3] Bluhm, J. I., “A slice synthesis of a three dimensional work of fracture.” Engineering Fracture Mechanics, Vol. 7, pp. 593-604 (1975).
  4. [4] Erdogan, F. and Arin, K., “A Sandwich plane with a part-through and a deboneding crack.” Engng Fracture Mech, Vol. 4, pp. 449-458 (1972).
  5. [5] Griffith, A. A., “The theory of rupture.” Proceeding of the First Institutional Congress of Applied Mechanics., pp. 55-63 (1925).
  6. [6] He, C. J., “Development and Application of a Generalized Dynamic Wake Theory for Lifting Rotors,” Ph. D. Thesis, School of Aerospace Engineering, Georgia Institute of Technology, U. S. A. (1989).
  7. [7] He, M. Y. and Evans, A. G., “Three dimensional finite element analysis of chevron-notched, three-point and four-point bend specimens.” Fracture Mechanics: Twenty-Symposium., Vol. 1, pp. 26-28 (1990).
  8. [8] Hwu, C., Kao, C. J. and Chang, L. E., “Delamination fracture criteria for composite laminates.” J. Composite Materials, Vol. 29, pp. 1963-1987 (1995).
  9. [9] Jenkins, M. G., Kobayashi, A. S., White, K. W. and Bradt, R. C., “A 3-D finite element analysis of a chevron-notched, three-point bend fracture specimen for ceramic materials.” Int. J. of Fracture, Vol. 34, pp. 281-295 (1987).
  10. [10] Joch, J., Zemankova, J. and Kazda, J., “Analysis of a chevron-notched four-point-bend specimens by the three dimensional finite-element method.” J. of the American Ceramic Society, Vol. 71, pp. 154-155 (1988).
  11. [11] Karunamoorthy, S. N., “Use of Hierarchical Elastic Blade Equations and Automatic Trim for Helicopter Vibration Analysis”, Ph. D. Thesis, Washington University, U.S.A. (1985).
  12. [12] Kolhe, R., Hui, C. Y., and Zehnder, A. T., “Effect of finite notch width on the fracture of chevron-notched specimens.” Int. J. of Fracture, Vol. 94, pp. 189-198 (1998).
  13. [13] Munz, D., Bubsey, R. T. and Shannon Jr., J. L., “Fracture toughness determination of Al2O3 using four-point-bend specimens with straight-through and chevron notches.” J. of the American Ceramic Sociey, Vol. 63, pp. 300-305 (1980).
  14. [14] Newman Jr., J. C., “A review of chevronnotched fracture specimens,” Chevronnotched Specimens, Testing and Stress Analysis: a Symposium (ASTM STP 855), (Edited by W. W. Freiman, J. H. Underwood and F. I. Baratta) American Society for Testing and Materials, Philadelphia, pp. 5-31, U.S.A. (1984).
  15. [15] Nikishkov, G. P. and Atluri, S. N., “Calculation of fracture mechanics parameters for an arbitrary three-dimensional crack,” Int. J. Numbe. Methods Eng., Vol.24, pp. 1801-1802 (1987).
  16. [16] Pang, H. L. J. and Leggat, R. H. “Twodimensional test case in linear elastic fracture mechanics,” Report R0020. National Agency for Finite Element Method and standards, Glasgow, U. K. (1990).
  17. [17] Rice, J. R. and Sih, G. C., “Plane problem of crack in dissimilar media,” J. Appl. Mech, pp. 418-423 (1965).
  18. [18] Sakata, M., Aoki, S., Kishimoto, K., and Takagi, R., “Distribution of crack extension force, the J-integral, along a through-crack-front of a plane,” Int. J. of Fracture, Vol. 23, pp. 187-200 (1983).
  19. [19] Schmitt, W. and Siegete, D., “Application of finite-element method to fracture problems,” Int. J. of Computer Applications in Technology, Vol. 5, pp. 118-126 (1992).
  20. [20] Shih, C. F., Moran, B. and Nakamura, T., “Energy release rate along a three-dimensional crack front in a thermally stressed body,” Int. J. of Fracture, Vol. 30, pp. 79-102 (1986).
  21. [21] Sinclair, G. B., “Asymptotic singular eigenfunctions for the three-dimensional crack,” Proc. of the Seventh Canadian Congress of Applied Mechanics, Sherbrooke, Quebec, pp. 295-296 (1979).
  22. [22] Wang, S. S. and Choi, I., “The interface crack behavior in dissimilar anisotropic composites under mixed-mode loading,” J. Appl. Mech, Vol. 50, pp. 179-183 (1983).
  23. [23] Wang, S. S. and Choi, I., “The interface crack between dissimilar anisotropic composites,” J. Appl. Mech., Vol. 50, pp. 169-178 (1983).
  24. [24] Wang, S. S., “An analysis of delamination in angle-ply fiber-reinforced composites,” J. Appl. Mech., Vol. 47, pp. 64-70 (1980).
  25. [25] Wang, Y. R., “The Effect of Wake Dynamics on Rotor Eigenvalues in Forward Flight,” Ph. D. Thesis, School of Aerospace Engineering, Georgia Institute of Technology, U.S.A. (1992).
  26. [26] Wu, S. X., “Compliance and stress intensity factor of chevron-notched three point-bend specimen,” Chevron-notched Specimens, Testing and Stress Analysis: a Symposium (ASTM STP 855), (Edit by W. W. Freiman, J. H. Underwood and F. I. Baratta) American Society for Testing and Materials, Philadelphia, U.S.A., pp. 176-192 (1984).
  27. [27] Yeh, J. R., “Fracture mechanics of delamination in ARALL laminates,” Engng Fracture Mech., Vol.30, pp. 827-837 (1988).