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.