Developing a Standard Test Method for Overlap Shear Splices for Wet-Layup FRP Samples

Faculty Mentor(s)

Dr. Jeff Brown, Hope College

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This material is based upon work supported by the Hope College Engineering Department.


The objective of this research was to develop a standard test method for evaluating overlap splices in wet-layup FRP samples. Using Infrared-thermography IRT, high temperature variations during tests could indicate high stress levels, allowing IRT to be used as a potential analysis tool. Fiber-reinforced polymer [FRP] composites are commonly used to support civil structures that are in need of strengthening and support. Overlap splices become necessary when the span of rehabilitation is too large. Carbon fiber was used with Type A and B Tyfo® S Epoxy to develop overlap coupons that were applied to cyclic load tests. To analyze the temperature variation of the coupon samples, a FLIR® A325 infrared camera was used. The camera recorded 900-1800 frames at 30fps for each test. A sinusoidal curve was fitted to the temperature variations at a frequency of 1 Hz. This allowed the images to be developed into a single amplitude image using a Fourier transform. With the amplitude image, samples could be evaluated to determine where the high stresses occurred. Results showed that large temperature variation occurred at the kink of the overlap samples, indicating higher stress. In the future, more samples will be tested to support current results.

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