SEDL / STP / STP808-EB / STP36202S

Compressive Behavior of Unidirectional Fibrous Composites

Sinclair, JH
Materials Engineer and Aerospace Structures and Composities Engineer, Lewis Research Center, National Aeronautics and Space Administration, Cleveland, Ohio

Chamis, CC
Materials Engineer and Aerospace Structures and Composities Engineer, Lewis Research Center, National Aeronautics and Space Administration, Cleveland, Ohio

Pages: 20    Published: Jan 1983

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Abstract

The longitudinal compressive behavior of unidirectional fiber composites was investigated by using the Illinois Institute of Technology Research Institute (IITRI) test method with thick and thin test specimens. The test data obtained are interpreted by means of stress/strain curves from back-to-back strain gages, examination of fracture surfaces by scanning electron microscope, and predictive equations for distinct failure modes including fiber compression failure, Euler buckling, delamination, and flexure. The results show that longitudinal compressive fracture is induced by a combination of delamination, flexure, and fiber tier breaks. No distinct fracture surface characteristics can be associated with unique failure modes. An equation is described that can be used to extract the longitudinal compressive strength from the longitudinal tensile and flexural strengths of the same composite system.