周期结构空腹梁的动态特性研究

Dynamic characteristics of a periodic hollow beam

设计了一种内部周期性挖空的梁,它在中高频具有良好的带通和带阻特性,带阻频率范围内的弹性波不能传播。空腹梁由周期单元串联而成,把周期单元分解成薄梁和刚性联接杆等子结构,推导了Timoshenko梁纵向、弯曲振动导纳,给出了刚性联接杆振动导纳,利用传递矩阵法计算得到了周期结构空腹梁的力传递率和带隙位置。数值模拟计算表明,当激励频率在周期结构的阻带之内时,周期结构空腹梁上的位移响应和传递到基础的力响应将大大衰减。

A hollow beam with its inner periodically excavated was designed to gain excellent band-pass and bandstop characteristics in a mid and higher frequency domain.The hollow beam was composed of two Timoshenko beams periodically connected with n rigid joints.The longitudinal vibration mobility of a rod and the bending vibration mobility of a Timoshenko beam were derived,the vibration mobilities of rigid joints were given.The force transfer rate and locations of band gaps of the periodic hollow beam were calculated with the transfer matrix method.Numerical simulation results showed that the displacement responses of the periodic hollow beam and the force transmitted to the base of the beam are greatly attenuated when the excitation frequencies are located within the stop bands of the periodic hollow beam.