Accession Number : AD0287159

Title :   ON THE MECHANICAL BEHAVIOR AND FRACTURE MORPHOLOGY OF EPOXY RESIN

Corporate Author : ILLINOIS UNIV URBANA

Personal Author(s) : FELTNER,C.E.

Report Date : AUG 1962

Pagination or Media Count : 1

Abstract : Tensile specimens of irradiated and non- rradiated epoxy resin were broken by static loading using various strain rates and a study was made of the origin, development and characteristic patterns of the fracture surface markings. In nearly all cases fractures originated at inclusions or bubbles even when reasonable care was exercised in casting the resin. Epoxy resin exhibits 3 different types of stress-strain curve which have been termed normal, transition and premature. The slope of the stress-strain curve at fracture serves as an index of the degree of prematurity or normalcy of the fracture; positive and negative slopes being termed premature and normal, respectively. Examination of the corresponding fracture surfaces discloses that normal fractures are always accompanied by a considerable amount of slow crack extension while on the other hand little or no slow crack growth occurs in a premature fracture. Quantitatively, the relation between the fracture stress and the stable flaw size agrees reasonably well with the Griffith theory when the mirror is considered to be the Griffith flaw. Fractures started internally in some of the epoxy samples but at the edges of all of the others. In most respects the characteristic features of a fracture surface of epoxy resin are similar to those of other polymers such as polymethyl methacrylate. (Author)

Descriptors :   *EPOXY RESINS, *FRACTURE (MECHANICS), *NEUTRON REACTIONS, *PLASTICS, ACRYLIC RESINS, POLYMERS, RADIATION EFFECTS, SURFACE PROPERTIES, THEORY, THERMOSETTING PLASTICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE