Accession Number : ADA304409

Title :   Craze Initiation Criterion in Glassy Polymers Under High Pressure.

Descriptive Note : Technical rept.,

Corporate Author : CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE

Personal Author(s) : Moet, Abdelsamie ; Palley, Igor ; Baer, Eric

PDF Url : ADA304409

Report Date : 11 MAY 1979

Pagination or Media Count : 20

Abstract : The initiation of crazes in glassy polymers is accounted for by a single criterion according to which crazing occurs when the maximum stress at the tip of a flaw (sigma sub max) reaches a critical value. This criterion can explain the initiation of crazes in polymethylmethacrylate and polystyrene tested in tension under superposed hydrostatic pressure. A single value of sigma sub max for each of the two polymers has been calculated max and found to be independent of the applied hydrostatic pressure whether or not the polymer was exposed to the pressure-transmitting fluid. Our analysis predicts that relatively small stress-concentrations suffice for craze initiation even under remote compressive stress states (negative first stress invariant). The predicted stress concentrations are in reasonable agreement with experimentally determined values. (MM)

Descriptors :   *POLYSTYRENE, *POLYMETHYL METHACRYLATE, *CRAZING, POLYMERS, TENSILE STRESS, HIGH PRESSURE, GLASS, CRACK PROPAGATION, DEFECTS(MATERIALS), COMPRESSIVE PROPERTIES, HYDROSTATIC PRESSURE, STRESS CONCENTRATION.

Subject Categories : Plastics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE