预应力对基座振动特性的影响分析

Analysis of pre-stress influence on base vibration characteristic

设备安装引起的预应力会影响基座的振动特性。基座主要由梁板结构组成,该文首先从理论推导出发分析了预应力对简支梁、板固有频率及导纳的影响,并验证了有限元方法计算预应力结构振动特性的准确性;然后利用有限元方法计算了预应力对加筋板结构振动特性的影响,最后分别计算分析了设备安装对刚性台架上的淡水泵基座以及对实艇浮筏基座振动特性的影响。结果表明预加载荷对梁板结构低频振动特性影响较为显著;设备安装对刚性台架上的淡水泵基座低频导纳峰值频率处的影响较为明显,尤其是跨点导纳;设备安装对实艇浮筏基座导纳的影响可以忽略。

The pre-stress induced by installed machine will affect vibration characteristic of base. The base is mostly composed by beams and plates, the pre-slress influence on natural frequency and admittance of simply supported beam and plate is analyzed by theoretical derivation firstly, then the validity of using FEM to calculating pre--stressed structure vibration characteristic is confirmed, after that the pre--stress influence on stiffened plate is analyzed by FEM. The effect of installed machine on vibration characteristic of fresh water pump base fixed on rigid bench and floating raft base fixed on submarine is analyzed finally. The conclusion is that the effects of pre-stress on beam-plate assembly can＇t be neglected, especially when the frequency is Iowl The pre-stress effect on fresh water pump base is evident in the frequency of peak value, especially for the transmission admittance and pre--stress effect on the floating raft base can be neglected.