ELASTIC AND PLASTIC BUCKLING OF SPHERICAL SHELLS UNDER VARIOUS LOADING CONDITIONS by SHAHIN NAYYERI AMIRI B.Sc., University of Tabriz, 2000 M.Sc., University of Tabriz, 2003 M.Phil., University of Tabriz, 2006 M.Sc., Kansas State University, 2010 AN ABSTRACT OF A DISSERTATION submitted in partial fulfillment of the requirements for the degree DOCTOR OF PHILOSOPHY Department of Civil Engineering College of Engineering KANSAS STATE UNIVERSITY Manhattan, Kansas 2011