Feasibility and performance study of 2400 mm sealed piezoelectric balance

To address the technical challenge of directly measuring the aerodynamic loads of large-sized and heavy aircraft models in hypersonic wind tunnel tests, this paper has developed a 2400 mm sealed piezoelectric gauge balance to meet the aerodynamic measurement requirements of large aircraft models. The piezoelectric gauge balance consists of two groups of force-sensitive elements (a total of 8), and adopts a sealed structure to protect the force-sensitive elements and avoid environmental damage, overcoming the problems of insufficient stiffness and susceptibility to temperature interference in traditional strain gauge balances. The 2400 mm large size fills the research gap of similar gauge balances. Based on the piezoelectric effect, a gauge balance structure composed of 8 three-component piezoelectric sensors is designed, and a piezoelectric coefficient matrix is established. Through simulation analysis, the structural strength of the piezoelectric gauge balance is evaluated. A calibration platform is built, and static and dynamic calibrations are carried out, analyzing performance such as linear error, repeatability, and inter-channel interference. Through decoupling matrix compensation, the inter-channel interference is reduced by up to 96.15 %. The measurement errors of the decoupled drag, lift and pitch moment directions are 0.015 %, 0.140 % and 0.065 %, respectively, and the maximum improvement effect reaches 106.5 %. Long-term effectiveness verification is conducted, and the life of the gauge balance is re-calibrated after 9 years, proving that the piezoelectric gauge balance has long-term effectiveness. A large-sized sealed piezoelectric gauge scheme is proposed, providing a new idea for wind tunnel force measurement of large aircraft models; the feasibility and long-term stability of the piezoelectric gauge balance in large-scale scenarios are verified, providing technical references for the development of related equipment.