BS in Materials Engineering
Materials Engineering Department
The mechanical properties of carbon fiber reinforced polymer (CFRP) hinges produced by Common Fibers (Kent, Washington) are a new technology with uncharacterized mechanical properties. Currently, Common Fiber’s hinges are utilized in wallets, but in order to expand the application of the hinges to structural components, complete characterization of the mechanical properties of the hinges is necessary. To address this problem, hinges developed by Common Fibers were tested utilizing the V-Notch rail shear test, ASTM D7078, to determine the shear strength of the hinges. Two layups, [+45/-45/0]s and [0/+45/-45/0]s were produced by Common Fibers for the experiment. Hinged and unhinged laminates of both layups were tested using the V-Notch rail shear test for maximum load producing load-extension curves. The results of the hinged and unhinged laminates were compared to characterize the shear behavior of the composite hinges. Comparison of hinged and unhinged composites revealed that the production of the hinge results in a reduction in shear strength from an average of 12.260 kN to as low as 1.568 kN. The load-extension curves display a pre-loading phase where the fibers in the hinge region undergo a period of relaxed extension until they are engaged in supporting the applied load. Observations of specimens after testing revealed splintering delamination as the failure mode along the interface between hinged and unhinged material parallel to the 450 oriented fibers.