Large Deformation Bending of Thin Composite Tape Spring Laminates

The bending stiffness of a thin carbon and glass fiber composite tape spring for deployable space structures was measured and compared to analytical predictions. Testing consisted of subjecting the laminate to bending in a large deformation four point bending test fixture. Bending stiffnesses in the D11 and D22 directions as well as failure curvatures were measured. Coupons failed in a fiber tensile mode at a bending strain of 2.2%. Modified micromechanics and classical lamination theory analysis were used to predict laminate stiffness properties. Test results were 10% less than predicted values.