SEDL / STP / STP787-EB / STP28497S

Durability/Life of Fiber Composites in Hygrothermomechanical Environments

Chamis, CC
Aerospace Structures and Composites Engineer, and Materials Engineer, NASA Lewis Research Center, Cleveland, Ohio

Sinclair, JH
Aerospace Structures and Composites Engineer, and Materials Engineer, NASA Lewis Research Center, Cleveland, Ohio

Pages: 15    Published: Jan 1982

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Abstract

Statistical analysis and multiple regression were used to determine and quantify the significant hygrothermomechanical (HGTM) variables which influence the tensile durability/life (cyclic loading, fatigue) of boron-fiber/epoxy-matrix (B/E) and high-modulus-fiber/epoxy-matrix (HMS/E) composites. The use of the multiple regression analysis reduced the variables from 15, assumed initially, to 6 or less with a probability of greater than 0.999. The reduced variables were used to derive predictive models for compression and intralaminar shear durability/life of B/E and HMS/E composites assuming isoparametric fatigue behavior. The predictive models were subsequently “generalized” to predict the durability/life of graphite-fiber/resin-matrix composites. The “generalized” model is of simple form, predicts conservative values compared with measured data, and should be adequate for use in preliminary designs.