风洞天平动态特性多阶惯性补偿技术研究

Investigation of wind tunnel balance dynamic characteristics' multi-order inertial compensation

  • 摘要: 在高超声速风洞测力试验过程中,冲击载荷或动态载荷激励测力系统结构振动,天平输出信号中包含了振动干扰量,可通过动态补偿方法进行改善,但现有方法处理方式单一,精度受限。根据测力系统结构特点,将测力系统简化为带集中质量的悬臂梁模型,应用振动理论方法,得到了该系统的自由振动解析结果。在自由振动特性研究中,考察了各个振型对测力的干扰以及各个振型加速度分布规律,提出了天平"多阶惯性补偿方法",并得到了理论补偿系数;进而利用有限元仿真和小波变换后处理方法,对该方法进行了仿真验证。结果表明,相比传统方法,该方法有效提高了天平动态性能。

     

    Abstract: The structural vibration of the aerodynamic measurement system can be actuated by impulse loads or dynamic loads in aerodynamic measurement tests of hypersonic wind tunnels. Therefore, the useful data and the vibration noise are mingled. The accuracy of the present balance dynamic compensation method is poor since the processing method is over simplified. We simplify the force measurement system to a cantilever beam with an end mass determined by its structural characteristics, and obtain its analytical solutions for free vibration. Study of the free vibration is focused on the impacts of different vibration shapes on force measurement, and the distribution disciplines of acceleration of different vibration shapes. We put forward a new compensation method named 'multi-order inertial compensation method', and obtain the corresponding theoretical compensation coefficients. What's more, we validate this method by finite element analysis and wavelet analysis. The results show that the multi-order inertial compensation method significantly improves the dynamic characteristics of the balance compared with conventional method.

     

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