Influence analysis of layered subsoil on vibration characteristics of balance foundation in the pulse wind tunnel
Since the pulsed wind tunnel balance foundation plays a supporting role in aircraft wind tunnel tests,in order to deeply study the influence of the layered subsoil on the vibration characteristics of the balance foundation,the impedance function of the balance foundation on a layered subsoil under impulse load is derived.A dynamic response equation of the foundation is established by using a simplified model,and the dynamic impedance function of the simplified model is equated with that of the foundation-foundation system.The dynamic response of the balance foundation on the laminated foundation under impulsive wind tunnel loading is obtained and verified by numerical simulation.The results show that the vertical amplitude,horizontal amplitude and slewing angle of the foundation gradually decrease with the increase of the loading frequency.The increase of the loading amplitude leads to the increase of the maximum amplitude of foundation vibration,while the vibration frequency remains unchanged.The increase of the shear modulus of the foundation results in the decreasing of the maximum amplitude of foundation vibration.The increase of the foundation dimensions leads to the obvious decreasing of the maximum amplitude of foundation vibration and the vibration frequency.In addition,the vertical vibration amplitude of the foundation increases with the decrease of foundation layer depth ratio,while the horizontal vibration amplitude and slewing angle decrease with the decrease of layer depth ratio.The increase of foundation shear wave velocity has less effect on the vertical vibration amplitude,while the effect on the horizontal vibration amplitude and slewing angle is more significant.
pulse wind tunnellayered subsoilbalance foundationvibration characteristicsimpedance function