Investigation of mobile ultrasonic propagation imager as a tool for composite wind blade quality control

Abstract

According to the statistical reports, almost 50% of wind blade failures are due to manufacturing defects. Therefore, reliable nondestructive testing (NDT) methods are required to create a standard for blade manufacturing quality control that reduces maintenance costs and catastrophic accidents. Applying conventional NDT methods is currently impossible without major modifications; this would also be time-consuming because wind turbine blades are large, thick and heterogeneous composite structures. This study proposes an in-process quality control (IPQC) method based on an ultrasonic propagation imaging (UPI) system. The UPI system is based on laser-induced ultrasound and has the capabilities of noncontact, fast, curved structural and real-time inspection results. These capacities have the potential to be applied to IPQC in blade manufacturing and assembly in a Smart Blade Factory. To provide a proof-of-concept for Smart Blade Factory based on the UPI system as an IPQC tool, a 750-kW actual blade section was tested, and the inspection results were presented based on a multiple-defect visualization platform. Debonding, inclusion and void defects in a wind blade made of glass fiber reinforced plastic and PVC grid panels were studied. The inspection results proved high feasibility for the application of the UPI system to IPQC in blade manufacturing.