连续突风频域响应过程的时域等效模拟方法

目的在时域中模拟连续突风响应,比较常见的功率谱密度函数的时域数值模拟方法。方法构建民用飞机大展弦比单机翼突风响应计算模型,针对CCAR25规定的大气紊流功率谱密度函数,进行连续突风随机载荷计算,并直接为频谱分配随机相位,经傅立叶逆变换得到与连续突风随机计算使用的功率谱密度函数等效的突风时域激励,进行离散突风载荷分析,并与连续突风响应计算结果进行对比。结果比较机翼的弯矩、剪力及扭矩,离散突风载荷分析得到的弯剪扭载荷值与连续突风载荷分析得到的弯剪扭载荷值的偏差不超过3%。结论在功率谱密度函数等效的基础上,利用随机相位构造时域突风激励的方法快捷有效,能直观地显示随机突风激励下载荷响应的时域情况,便于进行时域中的非线性分析。

Time Domain Equivalence Simulation Method in Continuous Gust Frequency Response Process

The work aims to construct the calculation model of gust response of single wing with high aspect ratio of civil aircraft, and calculate the random load of continuous gust according to the power spectral density function of atmospheric turbulence specified by CCAR25, so as to simulate the continuous gust response in time domain. The common time domain numerical simulation methods of power spectral density function were compared and random phase was directly assigned to spectrum. The gust time domain excitation equivalent to the power spectral density function used in the random calculation of continuous gust was obtained by inverse fourier transform to carry out discrete gust load analysis and compare the continuous gust response calculation results. The results indicated that based on the equivalence of power spectral density function, the method of constructing time domain gust excitation by random phase was fast and effective, which could visually display the time domain of load response under random gust excitation and facilitate nonlinear analysis in time domain. Comparing the bending moment, shear force and torque of the wing, the deviation between the bending, shearing and torsional loads obtained by discrete gust load analysis and those obtained by continuous gust load analysis was less than 3%.