An experimental and theoretical study of the bending behavior of Kevlar 49/epoxy beams and rings

Conference · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6293998

Guess, T R; Reedy, Jr, E D

The basic lamina properties were determined by testing unidirectionally reinforced specimens in tension and compression. Results indicate that unidirectional Kevlar 49/epoxy composites manifest nearly linear elastic response in tension and yield-like behavior in fiber-directed compression. The measured compressive yield strength is roughly 20% of the tensile ultimate strength. We also tested 3.2 and 12.7 mm thick, quasi-isotropic beams in tension, compression, short beam shear, and four-point bending, and 457 mm diameter, 12.7 mm thick, quasi-isotropic rings in diametral compression. All specimens were fully instrumented with strain gages to provide a detailed record of their deformation. As anticipated, the flexural response of laminated Kevlar 49/epoxy beams and rings exhibit nonlinearity. For this reason, a material model which includes compressive yield behavior was examined. In this model, a Kevlar 49 lamina is assumed to respond in a linear elastic manner to all loads except compression in the fiber direction. In fiber-directed compression, it is assumed to behave in an elastic-perfectly plastic manner. Laminate response is determined from the postulated lamina behavior in a manner analogous to that used in classical laminated plate theory. This constitutive model was used in conjunction with the ABAQUS finite element code to analyze the tested specimens. Comparison of predicted results with experimental data corroborates the model's ability to reproduce much of the observed nonlinear behavior.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6293998
• Report Number(s): SAND-86-2983C; CONF-871082-1; ON: DE87010430
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ARAMIDS
BENDING
COMPOSITE MATERIALS
COMPRESSION
CYLINDERS
EPOXIDES
FIBERS
FLEXURAL STRENGTH
LAYERS
MATERIALS
MECHANICAL PROPERTIES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
PLATES
RINGS
STRUCTURAL BEAMS
SYNTHETIC MATERIALS