Residual Stresses Generation in Ultra-Thick Components for Wind Turbine Blades

摘要

The present paper investigates the generation of cure induced residual stresses during the cure stage of the Vacuum Assisted Resin Transfer Moulding (VARTM) process for the fabrication of ultra-thick components (i.e. 105 mm) for wind turbine blades manufacturing (i.e. root insert). The viscous-elastic material characterisation of the Airstone 780E epoxy resin mixed with the 785H Hardener has been undertaken and the corresponding coupled thermo-mechanical simulation has been implemented using a commercial FE solver. The finding points out that the level of residual stresses generated during the cure stage leads to a spring-in of about 1.3 cm when Manufacturer Recommended Cure Cycle is applied and that improvements in both spring-in and cure time can be obtained by applying different cure cycles.