Delamination initiation in postbuckled dropped-ply laminates

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:7164184

Davila, C G

The compression strength of dropped-ply, graphite-epoxy laminated plates for the delamination mode of failure is studied by analysis and corroborated with experiments. The nonlinear response of the test specimens is modeled by a geometrically nonlinear finite-element analysis. The methodology for predicting delamination is based on a quadratic interlaminar stress criterion evaluated at a characteristic distance from the ply drop-off. The details of the complex state of stress in the region of the thickness discontinuity are studied using three-dimensional solid elements, while the uniform sections of the plate are modeled with quadrilateral shell elements. A geometrically nonlinear transition element was developed to couple the shell elements to the solid elements. Uniaxial compression testing of dropped-ply, graphite-epoxy laminated plates confirmed that delamination among the interfaces above and/or below the dropped plies is a common mode of failure initiation. The compression strength of specimens exhibiting a linear response is greater than the compression strength of specimens with the same layup exhibiting geometrically nonlinear response.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)
• OSTI ID: 7164184
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CARBON
CARBON FIBERS
COMPOSITE MATERIALS
COMPRESSION STRENGTH
ELEMENTAL MINERALS
ELEMENTS
EPOXIDES
FAILURE MODE ANALYSIS
FAILURES
FIBERS
GRAPHITE
INTERFACES
LAYERS
MATERIALS
MECHANICAL PROPERTIES
MINERALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PLATES
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS