【摘要】 对非线性Duffing系统进行数值仿真,用Hilbert-Huang变换时频分析得到其非线性动力特征,进而识别出系统的非线性项系数。通过对带裂缝的钢筋混凝土梁的脉冲锤击试验测得跨中加速度响应进行Hilbert-Huang变换分析,得出响应的瞬时频率与瞬时振幅的关系图,从而识别出梁的非线性动力特征。结果表明该梁的振动形式与Duffing系统的振动类型极为相似,为三次非线性振动。这一结果为通过梁的非线性动力特征来识别损伤提供了一定的依据。更多还原

【Abstract】 The numerically simulated response of nonlinear Duffing system is analyzed by using Hilbert-Huang Transform and the nonlinear dynamical characteristics and nonlinear parameters are identified. Parallellly, the acceleration response of a cracked concrete beam in impact-excitation experiment is also analyzed by Hilbert-Huang Transform. Then, the relation diagram between instantaneous frequencies and instantaneous amplitudes is obtained and the nonlinear dynamical characteristics are identified. The results show that the vibration of the beam is similar to that of the Duffing system and is of cubic nonlinear property. The results are useful for detection of structural damage according to the nonlinear dynamical characteristics.更多还原