Optical measurement on dynamic buckling behavior of stiffened composite panels under in-plane shear

- Full-field topography of stiffened composite panel was measured by FPP.
- Deflection evolvement reveals the buckling behaviors of panel under in-plane shear.
- FEM was used to predict buckling shapes and compared with optical experiments.

The buckling behavior and failure mode of a composite panel stiffened by I-shaped stringers under in-plane shear is studied using digital fringe projection profilometry. The basic principles of the dynamic phase-shifting technique, multi-frequency phase-unwrapping technique and inverse-phase technique for nonlinear error compensation are introduced. Multi-frequency fringe projection profilometry was used to monitor and measure the change in the morphology of a discontinuous surface of the stiffened composite panel during in-plane shearing. Meanwhile, the strain history of multiple points on the skin was obtained using strain rosettes. The buckling mode and deflection of the panel at different moments were analyzed and compared with those obtained using the finite element method. The experimental results validated the FEM analysis.