负刚度非线性系统的回复力曲面参数辨识方法

Aiming at the difficulty in identifying the restoring force of a nonlinear oscillator with negative stiffness, a time-domain nonparametric identification method based on restoring force surface is proposed. The numerical processing schemes of displacement differentiation and acceleration integration are compared and analyzed. A method for drawing three-dimensional restoring force surface diagrams of four typical negative stiffness oscillators and extracting stiffness and damping restoring forces by experimental data is given. This approach shows that the identification accuracy of the polynomial stiffness force and the damping force coefficient can reach more than 95% in the numerical simulation of the four negative stiffness vibrators. Frequency sweep experiment is carried out on the multi-stable oscillators at different acceleration levels by building an experimental platform. Following the designing idea, the restoring force surface of the multi-stable state vibrator is constructed. The surface recognition result coincides with the measured restoring force surface, which verifies the effectiveness of the complex force surface method in identifying the negative stiffness nonlinear oscillators, and this method is also applicable to the nonlinear analysis in the fields of energy harvesting and vibration control.