Model deformation measurement in ETW using the Moire technique

A non-intrusive Moire Interferometry system has been designed and installed to determine the instantaneous deformation of aircraft models during testing in the European Transonic Windtunnel. The present paper describes the principles of the Moire technique and the experimental set-up of the system. As high accuracy for the measurement of wing twist (< 0.1degrees) and wing bending (< 0.05 mm) is required, hardware and evaluation software have to be carefully designed. The influence of disturbing effects is discussed in detail, also the solutions to overcome these problems. Measurements of the wing twist of an A 380 type aircraft within the European HiReTT project are described, and results of selected test cases are presented and compared to other experimental and numerical methods.