(a) Specimen 1 in test rig
(b) Local bulging of the compressed, initially delaminated skin on the right-hand side of the sandwich column at its midlength
(c,d) Core-skin shear crimping (failure) of the delaminated region.
FROM:
Manickam Narayanan (Dept. of Aerospace Engineering, Mechanics and Engineering Science, University of Florida, Gainesville, Florida, USA ), “Finite element analysis of debonded sandwich beam under compression”, M.S. thesis, December 1999
ABSTRACT: This thesis highlights research aimed at predicting the compressive failure of sandwich beams with interfacial delaminations. A nonlinear finite element analysis was performed to simulate axial compression of the debonded sandwich beams. The load-deflection diagrams were generated for a variety of specimens used in a previous experimental study. The energy release rate at the crack tip was computed using the J-integral, and plotted as a function of the displacement and load. A detailed stress analysis was performed and the critical stresses in the face sheet and the core were computed. Further, the core was modeled as a elastic, perfectly plastic material and a nonlinear post-buckling analysis was performed. For this model, load-deflection curves, energy release rate plots and von Mises stress plots were generated. By comparing the experimental failure load and the finite element analysis results, the conclusions were reached and the scope of future research in this project was defined.
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