Accession Number : ADA303177

Title :   Influence of Layer Thickness of the Strength of Angle-Ply Laminates.

Corporate Author : VIRGINIA POLYTECHNIC INST BLACKSBURG

Personal Author(s) : Herakovich, Carl T.

PDF Url : ADA303177

Report Date : APR 1982

Pagination or Media Count : 34

Abstract : Experimental results are presented showing that the strength and toughness of finite-width angle-ply laminates can be increased significantly by using an alternating layer stacking sequence as opposed to a clustered configuration. The ultimate tensile stress of an alternating plus/minus theta aminate of the form ((+ or - theta))se as much as 1.5 times that of a clustered configuration of the form (theta sub 2/-theta sub 2)s. Further, the toughness of the alternating layer configuration can be as much as 2.7 times that of the clustered configuration. These differences are explained analytically through consideration of the influence of layer thickness on the magnitude of the interlaminar shear stress and by examination of failed specimens. It is shown that the two laminate configurations exhibit distinctly different failure modes for some fiber angles. Both laminates configurations exhibit catastrophic failure with the damage limited essentially to a small region defined by the length of a single crack across the width of the specimen, parallel to the fiber direction. Results are presented for T3OO/52O8 graphite-epoxy for fiber orientations of 10 deg, 30 deg, and 45 deg. (MM)

Descriptors :   *LAMINATES, *GRAPHITE EPOXY COMPOSITES, STRESS STRAIN RELATIONS, THICKNESS, TENSILE STRESS, CRACKS, DAMAGE ASSESSMENT, FIBER REINFORCED COMPOSITES, ORIENTATION(DIRECTION), TOUGHNESS, STRENGTH(MECHANICS), SHEAR STRESSES, FAILURE(MECHANICS), EPOXY RESINS.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE