Abstract
Fatigue crack propagation has been studied in polycarbonate as a function of specimen thickness and molecular weight. It was found useful to estimate the relative contribution of the shear lips and the plane strain crazing mode to fatigue crack propagation. In addition to measuring the width of the shear lips, the craze in the central region of the crack tip was examined in an optical microscope. The shear lip contribution was found to be particularly important at high values of the range of the stress intensity factor ΔK, and was appreciable in all but the thickest specimens and the lowest values of ΔK.
As in the case of fracture toughness, the fatigue crack propagation behaviour of polycarbonate is greatly affected by the molecular weight of the polymer. This is due to changes in both the shear lip contribution and the plane strain craze contribution. Because of the complicated nature of the failure mode it is suggested that the application of the Paris equation to the fatigue crack propagation of polycarbonate will be of limited significance.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
E. H. Andrews, “Testing of Polymers” Vol. 4, edited by W. E. Brown (Wiley, New York, 1969).
J. A. Manson and R. W. Hertzberg, C.R.C. Reviews in Macro. Sci. 1 (1973) 433.
P. C. Paris, in “Proceedings of the 10th Sagamore Army Materials Research Conference”, edited by J. J. Burke, N. L. Reed, V. Weiss (Syracuse University Press, 1964) p. 107.
S. Arad, J. C. Radon and L. E. Culver, Polymer Eng. Sci. 12 (1972) 193.
G. L. Pitman and I. M. Ward, Polymer 20 (1979) 895.
J. S. Harris and I. M. Ward, J. Mater. Sci. 8 (1973) 1655.
J. S. Harris, Ph.D. Thesis, Leeds (1973) p. 61.
J. H. Golden and E. A. Hazell, J. Polymer Sci. A1 (1963) 1671.
J. H. Golden, B. L. Hammant and E. A. Hazell, J. Appl. Polymer Sci. 12 (1968) 557.
R. P. Kambour, A. S. Holik and S. Miller, General Electric Technical Information Series, No. 77CRD 125 (June, 1977) p. 1.
G. M. Jacoby, ASTM STP453 (1969) p. 147.
M. D. Skibo, R. W. Hertzberg, J. A. Manson and S. L. Kim, J. Mater. Sci. 12 (1977) 531.
B. Gross and J. E. Srawley, NASA Report No. E 5701 (1967).
G. C. Martin and W. W. Gerberich, J. Mater. Sci. 11 (1976) 231.
H. R. Brown and I. M. Ward, Polymer 14 (1973) 469.
R. A. W. Fraser and I. M. Ward, ibid. 19 (1977) 220.
J. R. Rice, “Fracture — An Advanced Treatise”, edited by H. Liebowitz (Academic Press, New York, 1968) Ch. 3.
F. A. McClintock, “Fracture of Solids” (Wiley, New York, 1963).
R. W. Herztberg, J. A. Manson and M. D. Skibo, Polymer. Eng. Sci. 15 (1975) 252.
J. C. Radon and L. E. Culver, Polymer 16 (1975) 539.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Pitman, G., Ward, I.M. The molecular weight dependence of fatigue crack propagation in polycarbonate. J Mater Sci 15, 635–645 (1980). https://doi.org/10.1007/BF00551728
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00551728