Due to flexibility of thin plates, high amplitude vibrations are observed when they are subjected to severe dynamic loads. Due to the extensive application of circular plates in industry, attenuating the undesired vibrations is of foremost importance. In this paper, adaptable vibration suppressors (AVSs) as a semi-active control approach, are utilized to suppress the vibrations in a free circular plate; under the concentrative harmonic excitation. Using mode summation method, mathematical model of the hybrid system, including the plate and an arbitrary number of vibration suppressors is analyzed. By developing a complex multiple-loops algorithm, optimum values for the AVSs’ parameters (stiffness and position) are achieved such that the plate deflection is comprehensively minimized. According to the results, AVSs act efficiently in suppressing the vibrations in resonance/non-resonance conditions. It is also observed that optimum AVSs reduce the plate deflection over a broad spectrum of excitation frequencies. Finally, since the algorithm is developed in a general user friendly style, AVSs’ design can be extended to other shapes of plates with various boundary conditions and excitations.