Finite Element Modelling Of Blade Thermoelastic Stress Analysis Results

Thermoelastic stress analysis (TSA) is a non-destructive method that is used to assess structural stress. It is based on the ability to measure stress induced thermal emissions during cyclic loading with an infrared camera. It has potential applications for the monitoring of wind turbine blades certification tests. In this work, conducted as part of the UK SuperGen Wind consortium, finite element (FE) analyses are conducted to evaluate the potential correlation with TSA outputs. Such correlation of FE and TSA for composite blade structures is key for the interpretation of TSA results and thus for the application of thermoelasticity to wind turbine blades. A flexible parametric structural model for wind turbine blades is presented, based on a Python script and the ABAQUS solver. Typical wind turbine blade geometry, which can be tailored by the user, enables the generation of a regular mapped mesh. The application of industry standard materials and layups is also enabled, as well as various loading types. It is then shown through a particular case study using a 4.5m long blade that the main characteristic stresses of the loaded structure are reasonably well represented by both the FE and TSA techniques and that some manufacturing defects can be detected at an early stage by TSA measurements. This is encouraging and suggests that the use of TSA should be pursued by the wind energy sector.