H NOPOUR - Ph.D. student,Department of Mechanical Engineering, Malek Ashtar University of Technology
A KABIRI ATAABADI - Asiatant professor Department of Mechanical Engineering, Malek Ashtar University of Technology
M.M SHOKRIEH - Professor Composites Research Laboratory, Center of Excellence in Experimental Solid Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, ۱۶۸۴۶-۱۳۱۱۴, Iran

In this research, buckling load optimization for variable and constant stiffness composite cylindrical shells with cut-out under external hydrostatic pressure has been performed. For this purpose, by considering the fiber angle at cylinder edges and mid-span as optimization variables and a linear variation of fiber angles between these two locations, the buckling load of the cylinder was optimized. Optimization process was done by linking a genetic algorithm code in python language with ABAQUS software. Results show that by increasing the cut-out diameter size, the buckling pressure enhancement percent of the variable stiffness cylinder in comparison with that of the constant stiffness cylinder was firstly constant and then increases. Furthermore, it has been observed that regardless of the distinction of the buckling load of the variable stiffness cylinder with that of the constant stiffness one, the constant stiffness cylinder is safer in terms of Tsai-Wu criterion near the cut-out region.

variable stiffness cylinder, buckling, external hydrostatic pressure, cut-out, optimization