Feasibility Assessment of Simultaneous Biaxial Test Methodology by Segmentation Approach for a Supersized Wind Turbine Blade Evaluation

Abstract

This paper outlines an innovative biaxial segment blade test methodology for large wind turbine rotor blades. Today, as a blade size is getting bigger, not only it is hard to find the test facility incorporating blade over 100 m, but also a blade test time and test cost required for certification according to IEC 6140023 are also increased, which could cause the delay of product entrance to wind energy market. The proposed biaxial segment test method mainly aims at improving the efficiency of the fatigue test because fatigue test takes up more than 70% of total test time and 60% of total test time approximately and is also intended to utilize existing test facilities through the segmentation of a large blade. For the feasibility assessment of the novel methodology, the virtual test model of the fatigue test configuration was constructed including virtual mass element, spring element, damping element, blade beam element, and kinematic lever-arm mechanism. Through the optimization process, it was found out that the proposed test methodology has a significant time saving up to 36% compared to conventional blade test method for 90 m blade test, which is even 17% further saving compared to uniaxial segment test. Also, the proposed methodology could save cost by 17% compared to traditional method. Among categories constituting the total cost calculated from 90 m blade case, electricity cost category related to hydraulic pumps necessary to maintain high forces was increased by 7% while labor and material costs reduced by 3% and 3% respectively compared to traditional test approach. The current study also showed that the biaxial segment test method is even more effective for a supersized wind blade. For the 115 m blade, the cost reduction rate was even higher by 5% than one of 90 m blade in addition to the utilization of the existing test facility.