An innovative method to measure stress distribution of a wind turbine model by thermoelasticity

An innovative thermoelastic stress analysis method is proposed in order to study stress distribution on a wind turbine model. Thermoelastic stress analysis (TSA) allows to measure the superficial stress pattern of a mechanical component by observing temperature variations due to the application of a dynamic load on a body. To carry out thermoelastic stress analysis, an high resolution thermocamera has been used. Usually this measurement technique is applied when the observed object is fixed in respect to the thermocamera, i.e. it does not present rigid movement or large deformation under load application. In this work it’s shown how it is possible to compensate the movement of the component by using thermal markers during the thermographic acquisition and choosing a fixed Cartesian coordinate system in respect to the surface analysed. Results obtained are successfully post-processed by a self made software. This new technique has been applied to investigate stress distribution on a 1:100 scale wind turbine model tested in a subsonic closed circuit wind tunnel.