Study of Stability in the Hyperbolic Paraboloid

This experimental investigation covers the buckling behavior under uniform vertical load of a right square hyperbolic paraboloid. Results are secured by observation of the behavior of small scale plastic models fabricated from polyvinyl chloride. The study focuses on defining the form buckling takes in the hyperbolic paraboloid and the influence of edge member properties on the magnitude of the shell buckling load and the ultimate load. Results indicate buckling may be identified by a knee in the load-deflection curve of points on the shell surface. Geometric imperfections are shown to affect the magnitude of the buckling load. A significant conclusion of these experiments is that the initiation of shell buckling is mainly dependent on axial stiffness of the edge members. Finally, strain gage readings and observation of loaded shells indicate the formation of a tension field along the direction of the tension diagonal in the post-buckling region.