功率流测量以及振动能量参数估计试验研究

摘要

A test rig was built to measure power flow and estimate vibrational energy here.Both force signal and acceleration signal of the same location and direction of one point could be simultaneously captured by inserting an impedance head sensor between a vibration source and a receiver.Subsequently,the power flow entering the foundation was calculated with the time domain average method,the fundamental wave frequency domain method and the second harmonic wave frequency domain method,respectively.Experimental investigation showed that the harmonic vibration of the system should be controlled if the exciting frequency of the vibration source is the fractional double frequency of modal frequencies of the system.Because a negative value was inevitable in measurement processes of power flow,the cause of the negative power flow was explained with the theory of multi-DOF vibration.Due to the difficulty of measurement,the vibrational energy of the foundation was estimated via the driving point impedance and the mobility technique.Finally,the relationship between power flow and vibrational energy was examined with the loss factor of the system.%搭建了功率流测量以及能量参数估计试验平台，分析了功率流不同计算方法对功率流传递规律的影响，建立了功率流和振动能量参数间的关系。通过在振源和接受体之间插入阻抗头传感器，获得同点同方向的力和加速度信号，分别应用时域平均法、基波频域法和二次谐波频域法计算功率流。研究表明当激振频率为各阶模态频率分倍频时，其谐波振动需要加以控制。负功率流是功率流测量中不可避免的现象，本文从多自由度振动的角度揭示负功率流的成因。针对能量参数难以测量的难题，分别运用驱动点阻抗和导纳法估计振动能量，并通过系统损耗因子验证了功率流和能量参数间的关系。