两种运动平台下晃荡冲击荷载的实验研究

An experimental study of slamming impact load on two platforms

由液体晃荡引起的冲击荷载主要与外部激励(激励频率和激励幅值)和装载率相关。大尺度物理模型实验通过运动平台在室内复现液舱的运动,进而实现在室内对储液舱内晃荡载荷的研究。因此,平台的运动能力、运动的精确性对液体冲击载荷的实验结果非常关键。为了研究不同类型运动平台的运动性能及其对储液舱内冲击载荷的影响,文中以大比尺二维矩形舱为模型,分别在单自由度运动平台和六自由度运动平台开展系统的液体晃荡冲击实验。实验结果表明:仅考虑水平运动,单自由度平台的精度要高于六自由度平台;在个别工况下,两个平台下冲击荷载时程和特征值的对比结果出现了一定差别,但是晃荡冲击荷载的整体趋势基本一致。通过评价单自由度和六自由度两种类型的运动平台在液体晃荡研究领域应用的适用性。

Impact loads caused by liquid sloshing are related to the filling level and excitation parameters（such as excitation amplitude and period） of the tank. The large-scale sloshing model experimental method is the most reliable approach to study impact loads, which can realize tank motion in the laboratory by the test rig. Hence, the performance and accuracy of the employed test platform is very important. In order to investigate the performance and the effect of single degree-of-freedom（1 dof） platform and hexapod test rig on slamming impact pressure, this paper focuses on a comparatively experimental study in a large-scaled two-dimensional rectangular tank. A series of sloshing tests was designed and conducted with the same regular sway excitation, measurement set-up and filling level. The results show that the 1dof platform has higher accuracy for lateral motion. Furthermore, there exist significant discrepancies on pressure time history and pressure characteristic values under some conditions. Even though, the general trend of impact pressure is the same. These experimental results can give an indicator for choosing test rig for large-scaled sloshing model experiments.