Analysis of certain problems in continuous and discontinuous fiber composite materials

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5819775

Gillespie, Jr, J W

Experimental and analytical techniques show that, in continuous fiber-composite structures, the local instability of composite laminates in the vicinity of interlaminar defects strongly influence the compressive strength of the laminate. An approximate strain energy release rate formulation for Mode I fracture (G = G/sub IC/) provides accurate predictions for the onset of delamination growth for the defect geometries considered. Furthermore, the analytical model shows that for composite materials exhibiting high Mode I interlaminar fracture toughness (G/sub IC/), delamination growth will be dominated by the Mode II component of strain energy release. In the transfer molding of discontinuous fiber reinforced composite materials, the process induced fiber orientation will result in the point-wise variation of thermoelastic properties throughout the structure. An experimental study provides fundamental insight into the influence of process conditions on fiber orientation in a center-gated axisymmetric disk, transfer molded with a short glass fiber reinforced phenolic molding compound. The thermoelastic response of the annular disk is correlated with analytic, numerical integration and finite element predictions, which includes the variable elastic constants corresponding to the process induced fiber orientation.

• Research Organization: Delaware Univ., Newark (USA)
• OSTI ID: 5819775
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360301 -- Composite Materials-- Preparation & Fabrication-- (-1987)
360302* -- Composite Materials-- Structure & Phase Studies-- (-1987)
COMPOSITE MATERIALS
DEFECTS
FABRICATION
FIBERS
MATERIALS
MECHANICAL PROPERTIES
ORIENTATION