Fluid Transport into Crazes under Triaxial Stress.
CASE WESTERN RESERVE UNIV CLEVELAND OHIO DEPT OF MACROMOLECULAR SCIENCE
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The penetration coefficient of silicon oil 500 cS into PS during tensile deformation was determined under a range of superposed hydrostatic pressure of 1 to 1200 bars. At atmospheric pressure, the liquid front, driven by a relatively high capillary pressure, was found to lag behind the dry craze tip front. The penetrability was observed to increase as a steep linear function of the pressure up to 80 bars at which the liquid front was forced to reach the craze tip front. At higher pressures, a stage of suppressed penetrability was observed which was associated with a substantial decrease in the craze size and density. The suppressed penetrability is explained on the basis of pressure-induced void reduction competing with its pumping component. An effective axial strain analysis is presented to explain such a reduction. The effect of pressure on the maximum stress at the tip of a flaw, in conjunction with the distribution of surface defects, is found to account for the suppressed craze density at elevated pressures. Author
- Fluid Mechanics