Experimental and numerical investigation of Permanent Magnet Coupler Damper (PMCD) for adaptive energy dissipation in structural systems

With the increasing demand for advanced energy dissipation systems in structural engineering, mainly due to seismic activity and dynamic loads, there is a need for innovative solutions that offer improved performance and adaptability. This paper introduces a novel Permanent Magnet Coupler Damper (PMCD), which combines magnetic coupling damping with a rack and gear mechanism to generate controlled damping forces subjected to inerter building applications. The PMCD is designed to address challenges related to nonlinearity, complexity, and environmental sensitivity found in traditional dampers. First, the PMCD's force and torque are theoretically analyzed using an analytical model to predict the geometrical parameters of the magnets. A finite element method (FEM) analysis is performed using COMSOL Multiphysics to optimize the device's performance, focusing on air gap variation, pole number, and temperature effects. A physical prototype of the PMCD is then manufactured and tested experimentally to compare with the analytical and FEM results. The results show that the damping force exhibits a linear relationship with the velocity at speeds below 0.16 m/s, transitioning to a nonlinear behavior at higher velocities. The maximum damping force increases with reduced air gap and pole number, demonstrating the tunability of the PMCD design. Additionally, a 25 % increase in damping force is observed as the temperature decreases from 40°C to −40°C, highlighting the novel impact of temperature-dependent magnetization retention and enhanced magnetic properties on energy dissipation. This adaptability to varying environmental conditions underscores the PMCD's potential as an innovative solution for effective energy dissipation in structural systems.