Method of repairing a subsurface void or damage for a wind turbine blade
A procedure for repairing subsurface defects in a shell member laminate of a wind turbine blade includes detecting the location and boundary of the subsurface defect and drilling a fill hole from an external surface of the laminate into the defect proximate to a boundary of the defect. A vent hole is drilled from the external surface of the laminate into the defect proximate to an opposite boundary from the fill hole. A flowable bonding material is injected into the fill hole until the bonding material flows from the vent hole. The repair zone is reinforced with at least one mechanical fastener defined through the laminate either within the boundary of the defect or outboard of the boundary of the defect.
1. A procedure for repairing subsurface defects in a shell member laminate of a wind turbine blade, comprising:
detecting the location and boundary of the subsurface defect in the laminate;
drilling a fill hole from an external surface of the laminate into the defect proximate to a boundary of the defect;
drilling a vent hole from the external surface of the laminate into the defect proximate to an opposite boundary from the fill hole;
injecting a flowable bonding material into the fill hole until the bonding material flows from the vent hole; and,
reinforcing the repair zone with at least one mechanical fastener defined through the laminate either within the boundary of the defect or outboard of the boundary of the defect.
2. The repair procedure as in claim 1 , wherein the repair zone is reinforced with a plurality of the mechanical fasteners.
3. The repair procedure as in claim 2 , wherein the repair zone is reinforced with a plurality of the mechanical fasteners outboard of the boundary of the defect and at least one mechanical fastener within the boundary of the defect.
4. The repair procedure as in claim 1 , wherein the mechanical fastener is countersunk in the external surface of the laminate.
5. The repair procedure as in claim 1 , wherein the mechanical fastener is used to generate a clamping load on the laminate in the repair zone during curing of the bonding material.
6. The repair procedure as in claim 1 , wherein the mechanical fastener is not removed from the laminate and is maintained as a permanent component of the repair.
7. The repair procedure as in claim 1 , wherein the location and boundary of the defect are detected with non-destructive external inspection techniques.
8. The repair procedure as in claim 1 , further comprising drilling a plurality of the fill holes and vent holes to ensure a complete fill of the subsurface defect.
9. The repair procedure as in claim 1 , wherein the procedure is completed on-site with the wind turbine blade remaining on its respective hub and tower.
10. The repair procedure as in claim 1 , wherein the procedure is conducted for defects along the trialing edge of the wind turbine blade and the mechanical fastener extends through the pressure side shell member, the trailing edge bond line material, and the suction side shell member.