脉冲风洞天平基础动力特征的简化计算方法

Simplified Calculation Method for Dynamic Characteristics of Pulse Wind Tunnel Balance Foundation

为了研究脉冲风洞天平基础在脉冲气动荷载作用下的动力响应特征,以某脉冲风洞为例,选择某典型气动荷载作用形式,建立了脉冲风洞天平基础在气动荷载作用下竖直方向、水平方向位移以及回转角度等动力特征的简化计算方法,并采用数值模拟的方法验证其可靠性.研究结果表明:天平基础在典型气动荷载作用下,竖直向最大振幅0.00175 mm,频率7.94 Hz,水平向最大振幅0.00283 mm,频率7.94 Hz,回转角度最大振幅0.00034°,频率7.94 Hz,典型气动荷载对天平基础振动影响较小,也未产生共振现象;基础振动最大振幅随气动荷载增大而增大,基础振动频率随气动荷载频率增大而增大;在气动荷载不变的条件下,基础振动的最大振幅与频率随尺寸的变大而变小,基础振动的最大振幅也随地基土性质的增强而减小,但地基土性质的变化对基础振动频率无影响.

In order to study the dynamic response characteristics of the pulse wind tunnel balance foundation under the action of pulse aerodynamic loads,a pulse wind tunnel was taken as an example,and a typical aerodynamic load action type was selected.As a result,a simplified calculation method for dynamic characteristics of the pulse wind tunnel balance foundation such as displacement of the vertical direction,displacement of the horizontal direction,and rotation angle was established,and its reliability was verified by numerical simulation.The results show that under the action of a typical aerodynamic load,the balance foundation has a maximum vertical vibration amplitude of 0.00175 mm and a frequency of 7.94 Hz;a maximum horizontal vibration amplitude of 0.00283 mm and a frequency of 7.94 Hz;a maximum amplitude of the rotation angle of 0.00034°and a frequency of 7.94 Hz.The typical aerodynamic load has little effect on the vibration of the balance foundation,and no resonance phenomenon occurs.Meanwhile,the maximum amplitude of foundation vibration increases with the increase in aerodynamic load,and the frequency of foundation vibration increases with the increase in aerodynamic load frequency;under the condition of constant aerodynamic load,the maximum amplitude and frequency of foundation vibration gradually decrease with the increase in size;the maximum amplitude of the foundation vibration decreases with the increase in foundation soil properties,but the change of foundation soil properties has no effect on the foundation vibration frequency.