超声速气流中复合材料壁板的动力学分析及其控制

超声速飞行器外表具有大量的蒙皮壁板结构,其在巡航过程中会受到气动、热、声及机械等载荷的联合作用.本文针对超声速气流中的复合材料壁板结构,基于一阶剪切变形理论(First-Order Shear Deformation Theory,FSDT)和超声速活塞理论,推导得到了复合材料壁板的气热弹动力学的能量泛函,并运用Hamilton原理变分求得系统的控制方程,利用牛顿迭代法结合Newmark法,求解获得了壁板的临界颤振动压和时域动力学响应.通过变参数计算,分析了不同参数对于壁板动力学响应的影响.最后,应用非线性能量阱(Nonlinear Energy Sink,NES)对复合材料壁板的动力学响应进行颤振控制,结果表明,NES可以有效降低壁板的颤振极限环振幅,从而极大提高超声速飞行器的可靠性和寿命.

DYNAMIC ANALYSIS AND CONTROL OF COMPOSITE PLATES IN SUPERSONIC AIRFLOW

With 2.0 MW horizontal axis wind turbines as the research object, self-designed wind turbine model was tested by force balance in a boundary layer wind tunnel. The wind load characteristics including wind force coefficient, power spectrum and coherence of fluctuating wind at the hub of wind turbine with a 0 ° or 90 ° pitch angle in A, B terrain categories were studied. The results show that the mean and fluctuating wind force coefficients of wind turbine hub increase or decrease obviously with the wind direction. The average value of mean wind force coefficients in all wind directions in B terrain category is about 80% of that in A terrain category. Compared with 0 ° pitch angle, the mean wind force coefficient in the y-axis decreases by 67% and that in the x-axis increases by 108% with 90 ° pitch angle. There is a sharp peak caused by the balance model resonance at the reduced frequency 0.6 on the fluctuating wind power spectrum. The resonance response caused by the insufficient stiffness of the balance model system can be eliminated by using the semi-rigid model wind spectrum correction method.