Accession Number : AD0668477

Title :   APPLICATION OF THE PLATE TWIST TEST TO LAMINATED COMPOSITES.

Descriptive Note : Technical rept. Jun-Sep 67,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Whitney,James M.

Report Date : MAR 1968

Pagination or Media Count : 20

Abstract : The laminated plate theory is used to show that the applicability of the plate twist test for measuring shear modulus of laminated fiber-reinforced composites is limited to cross-ply layups and unsymmetric angle-ply layups. Numerical examples for symmetric plus or minus 45-degree boron-epoxy and glass-epoxy composites are used to illustrate the magnitude of the error generated when this test is used incorrectly. Results show errors of over 100% can occur. It is also concluded from laminated plate theory that the shear modulus for angle-ply composites can be considerably higher than the shear modulus of a unidirectional ply oriented at an angle of zero degrees to the plate axes. For example, the shear modulus of each layer of a plus or minus 45-degree boron-epoxy angle-ply composite containing 70% fiber by volume is approximately 3,500,000 PSI, while the composite shear modulus is 10,500,000 PSI. (Author)

Descriptors :   (*LAMINATES, TEST METHODS), COMPOSITE MATERIALS, REINFORCED PLASTICS, EPOXY RESINS, REINFORCING MATERIALS, GLASS TEXTILES, BORON, FIBERS, SHEAR STRESSES, MEASUREMENT

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE