SEDL / STP / STP497-EB / STP27750S

The Influence of Local Failure Modes on the Compressive Strength of Boron/Epoxy Composites

Suarez, JA
Grumman Aerospace Corp., Bethpage, N. Y.

Whiteside, JB
Grumman Aerospace Corp., Bethpage, N. Y.

Hadcock, RN
Grumman Aerospace Corp., Bethpage, N. Y.

Pages: 20    Published: Jan 1972

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Abstract

The compressive strengths of boron/epoxy laminates are developed theoretically and verified by tests on coupons, honeycomb sandwich columns, and honeycomb sandwich beams. Filament fracture occurs at high stress levels but laminate strengths are limited by overall and local instability. The effects of normal (interlaminar) shear stiffness on laminate stability are found to be significant. Layer instability, sandwich face wrinkling, and sandwich face dimpling are investigated. Associated with sandwich face wrinkling are laminate local instability, separation from core (bond tensile failure or honeycomb core tensile failure), core crushing, and core shear failure. Consistent assumptions of initial laminate waviness provide good correlation between analyses and tests.