Brittle fracture: Variation of fracture toughness with constraint and crack curving under mode I conditions |
| |
Authors: | Y J Chao S Liu B J Broviak |
| |
Institution: | (1) Department of Mechanical Engineering, University of South Carolina, 29208 Columbia, SC |
| |
Abstract: | The effect of constraint on brittle fracture of solids under predominantly elastic deformation and mode I loading conditions
is studied. Using different cracked specimen geometry, the variation of constraint is achieved in this work. Fracture tests
of polymethyl methacrylate were performed using single edge notch, compact tension and double cantilever beam specimens to
cover a bread range of constraint. The test data demonstrate that the apparent fracture toughness of the material varies with
the specimen geometry or the constraint level. Theory is developed using the critical stress (strain) as the fracture criterion
to show that this variation can be interpreted using the critical stress intensity factorK
Cand a second parameterT orA
3,whereT andA
3are the amplitudes of the second and the third term in the Williams series solution, respectively. The implication of this
constraint effect to the ASTM fracture toughness value, crack tip opening displacement fracture criterion and energy release
rateG
Cis discussed. Using the same critical stress (strain) as the fracture criterion, the theory further predicts crack curving
or instability under mode I loading conditions. Experimental data are presented and compared with the theory. |
| |
Keywords: | Brittle fracture Constraint effect fracture toughness T-stress |
本文献已被 SpringerLink 等数据库收录! |
|