Tensile stress acoustic constants of unidirectional graphite/epoxy composites

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Journal of Reinforced Plastics and Composites; (USA)

DOI:https://doi.org/10.1177/073168449000900203· OSTI ID:6976056

Prosser, W H ^[1]

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1. NASA, Langley Research Center, Hampton, VA (USA)

Previously, the stress acoustic constants (SACs) of unidirectional graphite/epoxy composites were measured to determine the nonlinear moduli of this material. These measurements were made under compressive loading in order to obtain the sufficient number of values needed to calculate these moduli. However, because their strength in tension along fiber directions can be several times greater, most composites are used under tensile loading. Thus, it is important to characterize the nonlinear properties of these materials in tension as well. The SACs which are defined as the slope of the normalized change in ultrasonic natural velocity as a function of stress were measured in a unidirectional laminate of T300/5208 graphite/epoxy. Tensile load was applied along the fiber axis with the ultrasonic waves propagating perpendicular to the fiber direction. Changes in velocity were measured using a pulsed phase locked loop ultrasonic interferometer with the nominal frequency of the ultrasonic waves being 2.25 MHz. 6 refs.

• OSTI ID: 6976056
• Journal Information: Journal of Reinforced Plastics and Composites; (USA), Journal Name: Journal of Reinforced Plastics and Composites; (USA) Vol. 9; ISSN 0731-6844; ISSN JRPCD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CARBON
CARBON FIBERS
COMPOSITE MATERIALS
ELASTICITY
ELEMENTAL MINERALS
ELEMENTS
EPOXIDES
FATIGUE
FIBERS
GRAPHITE
MATERIALS
MECHANICAL PROPERTIES
MINERALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
REINFORCED MATERIALS
REINFORCED PLASTICS
SOUND WAVES
SYNTHETIC MATERIALS
TENSILE PROPERTIES
ULTRASONIC WAVES
WAVE PROPAGATION