Strain fields in adhesively bonded patch repairs of damaged Metallic beams

The repair of notched metal I-beams was tested in a four-point bend test. Patches can be well designed by focusing on the interaction between the adhesive joint behavior and the notch tip in the metal. Identifying the onset of nonlinear behavior in the adhesive joint is important to characterize damage development and the limits of use. The onset of nonlinear behavior could be identified by changes in the strain field in the patch close to the adhesive measured experimentally with distributed fiber-optic sensing and analyzed by FE-analysis.