基于减小轴向力测量干扰的高精度测力天平研制

针对目前风洞试验技术的发展对风洞天平测量精度的更高需求，研制一台六分量杆式高精度轴向力测量天平，应用新型轴向力测量元件结构形式，并采用有限元方法对其进行了优化和改进。轴向力结构设计采用将测量元件置于天平轴线上的"设计中心位置"的方式，并通过在测量梁上设置铰链以及轴向力测量梁的非对称设计，最终使各气动载荷分量对轴向力的干扰应变输出近乎为零，彻底解决了杆式应变天平轴向力的测量干扰问题。同时，该设计还改善了天平各分量载荷作用在轴向力测量梁上交错复杂的应力分布状态，提高了天平的长期稳定性。天平校准和标模试验结果表明，该天平轴向分量具有较高的测量精、准度，可满足现代风洞试验的高精度轴向力测量需求。

Development of a six-component wind tunnel balance with lower interference on axial force measurement

The demand of the higher measurement precision and accuracy of a strain-gauge balance is proposed with the development of the wind tunnel experiment, especially for the axial force measurement. A six-component wind tunnel balance with lower interference on axial force is developed in this paper, aiming to obtain a higher precision and accuracy on the axial force measurement. A promising new type of axial force component structure is developed and the finite element method (FEM) is employed to optimize the structure of the design. The axial component design, different from a traditional one, eliminates the interference strain output on axial component from the other aerodynamic forces by placing the axial component in the position of the balance design center with the balance axis just passing through it. In addition, the interference strain output is also eliminated by setting a rectangular "hinge" between the measurement beams of the axial component as well as making the measurement beams offset from the design center along the balance axis. Furthermore, the strain-stress condition of the strain-gauge of axial component performs more satisfying, which improves the stability and the lifetime of the balance. The results of balance calibration and the standard model test show that there is almost no interference on the axial force, and the balance has an approving high precision and accuracy on the axial force measurement, which can meet the high measurement requirement of the modern wind tunnel experiment.