Doctor of Philosophy, University of Akron, 2014, Mechanical Engineering

The response of single-curvature composite panels under external blast was studied. For the single-curvature composite shells under external pressure pulse loading, Lagrange’s equations of motion were established to determine the shell response and the Budiansky-Roth criterion was used to examine the instability. The predicted transient shell response compared very well with FEA results from ABAQUS Implicit, and the predicted buckling loads also agreed with experiments on steel arches. Under various load durations, buckling was impulsive, dynamic and quasi-dynamic. Thicker composite shells were more likely to fail by first-ply failure rather than buckling. It was shown that the composite lay-up could be adjusted to increase the buckling resistance of the shell. For the single-curvature composite sandwich panels under external pressure pulse loading, a multi-layered approach was used to distinguish facesheets and core deformations. Core compressibility and transverse shear through the thickness were accounted for using linear displacement fields through the thickness. Equations of motion for the facesheet transient deformations were again derived from Lagrange’s equations of motion, and predicted solutions using this approach compared very well with FEA results from ABAQUS Implicit. In the case of core undergoing elastic deformations only, both facesheet fracture during stable deformation response and local dynamic pulse buckling of facesheets were considered as possible modes of failure in the curved sandwich panel. It was found that local facesheets buckling is more likely to occur than facesheet fracture in thin and deeply curved sandwich panels. The facesheet laminate lay-up could also be adjusted to improve the local buckling resistance of the curved sandwich panel. In the case of the core undergoing elastic-plastic deformations, a parametric study showed that blast resistance of the curved sandwich panel can be increased by allowing cores to un (open full item for complete abstract)

Committee: Michelle Hoo Fatt Dr. (Advisor); Xiaosheng Gao Dr. (Committee Member); Gregory Morscher Dr. (Committee Member); Ernian Pan Dr. (Committee Member); Kevin Kreider Dr. (Committee Member) Subjects: Mechanical Engineering