Wind turbine rotor blade and a method for mounting a wind turbine rotor blade

1. A wind turbine rotor blade comprising:

a first blade section;

a second blade section; and

a plurality of pre-stressed tensioning elements for connecting the first blade section and the second blade section with each other, the plurality of pre-stressed tensioning elements arranged in indentations that are provided in spar caps of the wind turbine rotor blade, wherein the wind turbine rotor blade is split at an interface thereof in a longitudinal direction into the first blade section and the second blade section;

wherein the first blade section is arranged closer to a root of the wind turbine rotor blade than the second blade section, further wherein a length of the at least one pre-stressed tensioning element is larger than half of a chord length of the wind turbine rotor blade at the interface;

wherein the at least one pre-stressed tensioning element extends deeper into the first blade section than into the second blade section.

2. The wind turbine rotor blade according to claim 1 , wherein the length of the plurality of pre-stressed tensioning elements corresponds half times to five times the chord length.

3. The wind turbine rotor blade according to claim 1 , wherein 6/10- 9/10, of the length of the plurality of pre-stressed tensioning elements extends into the first blade section.

4. The wind turbine rotor blade according to claim 1 , wherein the plurality of pre-stressed tensioning elements each comprise a carbon fiber reinforced material.

5. The wind turbine rotor blade according to claim 1 , wherein the plurality of pre-stressed tensioning elements each comprise two fixing sections being provided at opposite ends thereof.

6. The wind turbine rotor blade according to claim 5 , wherein the two fixing sections comprise external threads.

7. The wind turbine rotor blade according to claim 1 , wherein the second blade section comprises a fixing member being embedded in fiber material of the second blade section and wherein plurality of pre-stressed tensioning elements engages with the fixing member for connecting the first blade section and the second blade section with each other.

8. The wind turbine rotor blade according to claim 1 , wherein the first blade section comprises a fixing device with an insert being embedded in fiber material of the first blade section and a removable nut and wherein the plurality of pre-stressed tensioning elements engages with the nut for connecting the first blade section and the second blade section with each other.

9. The wind turbine rotor blade according to claim 1 , comprising a sealing element being arranged between the first blade section and the second blade section.

10. The wind turbine rotor blade according to claim 9 , wherein the first blade section and/or the second blade section is provided with a notch for receiving the sealing element.

11. The wind turbine rotor blade according to claim 1 , wherein the plurality of pre-stressed tensioning elements is charged with a tensile force so that at the interface only compression forces act on shells of the first blade section and the second blade section.

12. The wind turbine rotor blade according to claim 1 , wherein the length of the plurality of pre-stressed tensioning elements corresponds once to four times the chord length.

13. The wind turbine rotor blade according to claim 1 , wherein the length of the plurality of pre-stressed tensioning elements corresponds twice to three times the chord length.

14. A method for mounting a wind turbine rotor blade, comprising the steps of:

a) providing a first blade section;

b) providing a second blade section, wherein the wind turbine rotor blade is split at an interface thereof in a longitudinal direction into the first blade section and the second blade section and wherein the first blade section is arranged closer to a root of the wind turbine rotor blade than the second blade section;

c) providing a plurality of pre-stressed tensioning elements for connecting the first blade section and the second blade section with each other, the plurality of pre-stressed tensioning elements arranged in indentations that are provided in spar caps of the wind turbine rotor blade, wherein a length of the plurality of pre-stressed tensioning elements is larger than half of a chord length of the wind turbine rotor blade at the interface; and

d) connecting the first blade section and the second blade section with each other by means of the plurality of pre-stressed tensioning elements, so that the plurality of pre-stressed tensioning elements is charged with a tensile force for pre-stressing it and so that the plurality of pre-stressed tensioning elements extends deeper into the first blade section than into the second blade section.

15. A wind turbine rotor blade comprising:

a first blade section;

a second blade section; and

at least one pre-stressed tensioning element for connecting the first blade section and the second blade section with each other, the at least one pre-stressed tensioning element is centrally arranged in a web of the wind turbine rotor blade, wherein the wind turbine rotor blade is split at an interface thereof in a longitudinal direction into the first blade section and the second blade section;

wherein the first blade section is arranged closer to a root of the wind turbine rotor blade than the second blade section, further wherein a length of the at least one pre-stressed tensioning element is larger than half of a chord length of the wind turbine rotor blade at the interface;

wherein the at least one pre-stressed tensioning element extends deeper into the first blade section than into the second blade section.

16. The wind turbine rotor blade according to claim 15 , wherein the length of the at least one pre-stressed tensioning element corresponds half times to five times the chord length.

17. The wind turbine rotor blade according to claim 15 , wherein 6/10- 9/10 of the length of the at least one pre-stressed tensioning element extends into the first blade section.

18. The wind turbine rotor blade according to claim 15 , wherein the at least one pre-stressed tensioning element comprises a carbon fiber reinforced material.

19. The wind turbine rotor blade according to claim 15 , wherein the at least one pre-stressed tensioning element comprises two fixing sections being provided at opposite ends thereof.

20. A method for mounting a wind turbine rotor blade, comprising the steps of:

a) providing a first blade section;

b) providing a second blade section, wherein the wind turbine rotor blade is split at an interface thereof in a longitudinal direction into the first blade section and the second blade section and wherein the first blade section is arranged closer to a root of the wind turbine rotor blade than the second blade section;

c) providing at least one pre-stressed tensioning element for connecting the first blade section and the second blade section with each other, the at least one pre-stressed tensioning element is centrally arranged in a web of the wind turbine rotor blade, wherein the at least one pre-stressed tensioning element is larger than half of a chord length of the wind turbine rotor blade at the interface; and

d) connecting the first blade section and the second blade section with each other by means of the at least one pre-stressed tensioning element, so that the at least one pre-stressed tensioning element is charged with a tensile force for pre-stressing it and so that the at least one pre-stressed tensioning element extends deeper into the first blade section than into the second blade section.