软式平流层飞艇气弹模型相似参数分析

软式平流层飞艇具有较大的尺寸，基于风洞试验探讨其气弹响应特性时，需要缩比模型取代全尺寸模型。缩比模型的试验结果能否准确地预测原型结构的位移响应，与相似性设计直接相关。该文以设定的某软式平流层飞艇为原型对象，基于量纲分析法推导了模型的相似准则；建立软式平流层飞艇的有限元模型，对不同相似比对应的缩比模型进行了自振及风振响应分析，获得对应的振动频率与位移响应；统计确定了各相似准则对结构振动频率及位移响应的影响程度；对影响程度较大且无法满足相似条件的偏差进行了评估，且给出相应的补偿修正。结果表明：风速偏差的影响可以忽略；蒙皮面密度对位移响应的影响可以忽略；蒙皮张拉刚度及压差的相似偏差，对振动频率及位移响应都有较大的影响。

SIMILARITY PARAMETER ANALYSIS OF AEROELASTIC MODEL FOR NON-RIGID STRATOSPHERIC AIRSHIP

For the wind tunnel tests to investigate the aeroelastic characteristics of non-rigid stratospheric airships, scale models are needed to replace the full-scale model due to its large size. Whether the test results of the scale models can accurately predict the displacement response of the prototype structure is directly correlative to the similarity design. In this paper, a non-rigid stratospheric airship was taken as the prototype object and the similarity criterions of the model were deduced based on a dimensional analysis. The finite element model of the non-rigid stratospheric airship was established, and the natural vibration and wind-induced responses of scale models with different similar ratios were analyzed. The corresponding vibrational frequency and displacement response were obtained. The influence degrees of each similarity criterion on vibrational frequency and displacement response were statistically determined. The similarity deviations that do not meet the similarity requirements and have a greater influence degree were evaluated, and the corresponding compensation corrections were obtained. The study demonstrates that the similar deviation of wind velocity can be ignored. The similar deviation of membrane surface density on the displacement response can be ignored. The similar deviations of membrane tensile stiffness and differential pressure appreciably affect the vibrational frequency and displacement response.