1999 Volume 42 Issue 2 Pages 265-271
Carbon/Carbon(C/C) composites have attractive mechanical properties such as superior specific strength and high elastic modulus at high temperature exceeding 2000°C in an inert atmosphere. However, mainly due to lack of knowledge of design criteria, C/C composites have not been used in primary heat resistant structures. For example, almost no unified explanation has been given about the fracture behavior of C/C composites. The objective of this paper is to examine the adequacy of the linear elastic fracture mechanics(LEFM) as the fracture criterion of notched C/C composites. Thus the LEFM was tried to be applied to fracture behavior in tensile tests of double-edge-notched and compact tension specimens and in four-point bending tests of single-edge-notched specimens. It was found that the results of three kinds of fracture tests can be consistently and rationally explained in terms of the LEFM concept with the aid of R-curve behavior if the pre-crack length is long enough to be able to neglect the notch tip radius. From fractographic observation it was found that R curve behavior of C/C composites was mainly attributed to the fiber-bridging effect near the notch tip.
JSME international journal. Ser. 1, Solid mechanics, strength of materials
JSME international journal. Ser. A, Mechanics and material engineering
JSME international journal. Ser. 3, Vibration, control engineering, engineering for industry
JSME international journal. Ser. C, Dynamics, control, robotics, design and manufacturing