OICC Press Journal of Solid Mechanics 2008-7683 9 5 2017 12 30 Investigating the Effect of Stiffness/Thickness Ratio on the Optimal Location of Piezoelectric Actuators Through PSO Algorithm 832 848 EN S Jafari Fesharaki Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran S.Gh Madani Department of Mechanical Engineering, Faculty of Engineering, University of Kashan, Kashan, Iran S Golabi Department of Mechanical Engineering, Faculty of Engineering, University of Kashan, Kashan, Iran Journal Article 2017 12 30 This article has studied the effect of ratio of stiffness and thickness between piezoelectric actuators and host plat has been explored on optimal pattern for placement of piezoelectric work pieces around a hole in thin isotropic plate under static loading to reduce stress concentration. The piezoelectric actuators reduce directly or indirectly the stress concentration by applying positive and negative strains on the host plate. For this purpose, various modes as the thickness/stiffness ratios of the plate to the piezoelectric patches as ≥1 or ≤1 were considered. Then, a Python code was developed using particle swarm optimization algorithm in order to achieve the best model of piezoelectric actuators around the hole for maximum reduction in stress concentration factor. Also, the maximum stress concentration on the top and bottom of the hole was moved to another point around the edge by changing the location of piezoelectric patches. The results obtained from software solutions were confirmed by experimental tests.