Nonlinear Restoring Force Identification of Strongly Nonlinear Structures by Displacement Measurement

Abstract Strongly nonlinear structures have attracted a great deal of attention in energy harvesting and vibration isolation recently. However, it is challenging to accurately characterize the restoring force using analytical modeling or cyclic loading tests many realistic conditions due uncertainty installation parameters other constraints, including space size dynamic disturbance. Therefore, displacement-measurement surface identification approach presented for obtaining force. Widely known quasi-zero stiffness, bistable, tristable are designed cantilever-beam system with coupled rotatable magnets illustrate strongly properties application isolation. Based on derived physical model structures, least-squares parameter fitting proposed obtain The comparison between acceleration integration displacement differentiation methods describing discussed. Besides, influence noise level accuracy investigated. In experimental conditions, various geometrical utilized analyze identified curve measured force–displacement trajectory. Finally, results verify effectiveness displacement–measurement method