Accession Number : AD0775729

Title :   Fracture Graphite Fiber Reinforced Composites.

Descriptive Note : Technical rept. Apr 72-Apr 73,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s) : Mandell,John F. ; Wang,Su-Su ; McGarry,Frederick J.

Report Date : JUL 1973

Pagination or Media Count : 179

Abstract : The fracture of thin, prenotched graphite/ epoxy laminates is studied analytically and experimentally. The analytical portion of the study is concentrated on a three- dimensional finite element analysis of the crack problem in anisotropic laminates featuring a two-stage solution employing a hybrid model multilayered element. The case of a four ply (45 degree/-45 degree/-45 degree/45) laminate is analyzed, and results are presented for the distribution of in- plane stresses and interlaminar shear stresses about a sharp crack tip. A two- dimensional analysis is also employed to provide K-calibrations for fracture specimens used in the experimental program. Experiments are performed to investigate the applicability of classical fracture mechanics, the characteristics of crack tip damage during loading, and the final modes of crack propagation for representative ply configurations of graphite/epoxy laminates. The development of the subcritical zone into a final catastrophic fracture mode is also described. (Author, modified-PL)

Descriptors :   *Fiber reinforced composites, Composite materials, Graphite, Epoxy resins, Fiber reinforcement, Matrix materials, Fracture(Mechanics), Laminates, Stresses, Crack propagation, Numerical analysis

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE