Analysis of center-notched, unidirectional composites

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6949701

Reedy, Jr., E. D.

A method for calculating the stresses in a notched, unidirectional monolayer is described which permits the modeling of a finite-dimensioned monolayer containing a centered notch transverse to the fibers. Elastic-work hardening constitutive relationships may be specified for the fibers and/or matrix. Notch growth under increasing load can be analyzed. Calculations demonstrate the utility of this analysis in determining how constituent properties affect notch-tip fiber stress concentrations. Calculations for unidirectional boron/aluminum indicate that stress concentrations are reduced by a matrix with: (1) sufficiently high yield strength to prevent large-scale yielding (uniform traction loading can cause large fiber stress concentrations when global yielding occurs); and (2) a low rate of work-hardening (to reduce stress concentrations). The analysis has also been applied to Kevlar 49 plain weave fabric/epoxy monolayers. Predicted matrix and fiber stress concentrations are localized in this material with nonlinear material response limited to the notch-tip region. This is different from the widespread yielding in as-fabricated, unidirectional boron/aluminum. 6 figures.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6949701
• Report Number(s): SAND-82-2255C; CONF-821132-1; ON: DE83002509
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360303* -- Composite Materials-- Mechanical Properties-- (-1987)
ALUMINIUM
ARAMIDS
BORON
COMPOSITE MATERIALS
ELEMENTS
EPOXIDES
FIBERS
HARDENING
LAYERS
MATERIALS
MATRIX MATERIALS
METALS
NOTCHES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
SEMIMETALS
STRAIN HARDENING
STRESS ANALYSIS
SYNTHETIC MATERIALS