Investigating the Mechanical Behavior of Embedded Bolt Structure in Wind Turbine Blades Through Subcomponent Test

ABSTRACT Root failure is one of the critical failure modes of wind turbine blades. This paper investigates the mechanical behavior of the embedded bolt structure (EBS) in wind turbine blades under tensile force through subcomponent tests. The specimens were subjected to ultimate static and fatigue loads using a specially designed rig for the subcomponent test. At the same time, a finite element model of the EBS was developed to predict the test results and analyze the failure process. The finite element simulation showed good agreement with the test results. The simulation and test results indicate that the debonding of the interface between the glass fiber bundle, the pultruded GFRP, and the GFRP laminate leads to the failure of the EBS. Under different stress amplitudes, the specimens exhibited the same failure mode. The shear strength of the adhesive determines the ultimate and fatigue tensile strength of the EBS. Improving the diameter of the bolt sleeve and the shear strength of the adhesive can enhance the EBS to better mechanical properties.