SOME PROPERTIES OF CRAZE GROWTH-RATE DIST RIBUTION-FUNCTIONS

For tensile drawing of polymer samples at a constant strain rate and u nder a constant load, general properties of craze growth rate distribu tion functions are analyzed. The concept of normalized distribution fu nction is introduced, where the normalization implies the reduction of experimental distribution functions to similar scales along the coord inate axes. The normalized distribution functions are characterized by a set of common features. For the form factor of the normalized distr ibution functions, the corresponding analytical expressions are advanc ed. Analysis shows that the craze growth rate distributions are functi ons of time and may be obtained only by prolonged observations of a se t of crazes; craze growth rate distribution functions are bimodal, and this bimodal character is controlled by two different modes of craze nucleation: craze nucleation at the defects related to the history of polymer samples and craze nucleation at the stress-induced defects.