Abstract
Shell structures are used for roofs of gymnasiums and exhibition halls, and the structures are subjected to seismic and wind forces which are dynamic. Therefore it is very important to analyze the vibration of the shells to design the structures safely. However this vibration analysis method is negative. This paper presents a method to reduce the displacements and stresses of shells applying the control of fuzzy theory which is called fuzzy control and adjusting the ratios of dampers.