Proposing rhombus shape non-linear connection by seismic approach on the "pendulum column" isolator considering buckling effect in its piers

An Earthquake is a natural phenomenon that causes the destruction of structures. For many years, various methods have been proposed to control this phenomenon. In modern times, a new method called active and passive control has been developed. Isolator systems are among the methods to control the structure's response. Instead of increasing the strength and capacity of the structure, these systems react to earthquakes. In this paper, a nonlinear rhombus shaped spring combined with the pendulum column isolation system was introduced that caused the piers to be flexible. The behavior of this isolator with flexible bases has been investigated. The studied system mathematical equations were derived, solved with MATLAB software, and compared with ABAQUS results. Later on, the isolator system was investigated under different earthquakes, and FFT analysis was performed on the results. The results demonstrate that this mechanism is suitable as an isolator because it reduces earthquake effects. It was observed that in the flexible piers form, the period was increased. The flexible piers have an effective role - in the response of the system-by reducing the system's stiffness considerably. Among the different damping ratios, those with ratios greater than 10% showed better results.