Bend limiting stiffener and related methods

1. A bend restrictor device comprising:

at least two bend limiter units coupled together, wherein each bend limiter unit comprises a male end and a female end;

at least one stiffness ring having a first cumulative axial thickness and disposed in a female end of a first bend limiter unit; and

at least one stiffness ring having a second cumulative axial thickness and disposed in a female end of a second bend limiter unit, wherein the first and second cumulative axial thicknesses are different.

2. The bend restrictor device of claim 1 , wherein each bend limiter unit is generally cylindrical having a central bore therethrough.

3. The bend restrictor device of claim 2 , wherein the male end of a first bend limiter unit comprises a flange configured to engage an inner shoulder formed in the female end of the second bend limiter unit.

4. The bend restrictor device of claim 1 , wherein at least one bend limiter unit comprises two split halves fastened together.

5. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit comprises a different axial thickness from the at least one stiffness rind disposed in a female end of a second bend limiter unit.

6. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit comprises a thickness of between about one-quarter inch and about five inches.

7. The bend restrictor device of claim 1 , comprising at least three bend limiter units, wherein a number of stiffness rings disposed between adjacent pairs of the at least three bend limiter units is different.

8. The bend restrictor device of claim 7 , wherein each of the stiffness rings have a same axial thickness.

9. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit comprises a resilient thermoplastic material.

10. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit is configured to compress up to about 50% yield strength.

11. The bend restrictor device of claim 1 , wherein a maximum bend angle between the at least two coupled bend limiter units is about 20 degrees.

12. The bend restrictor device of claim 1 , wherein a maximum bend angle between the at least two coupled bend limiter units is about 5 degrees.

13. The bend restrictor device of claim 1 , wherein the at least two bend limiter units are configured to be installed onto a flexible pipe.

14. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit comprises two split halves, wherein each half is semi-circular in shape.

15. The bend restrictor device of claim 1 , wherein at least one bend limiter unit comprises two split portions fastened together, wherein the split portions are unequal.

16. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit comprises two split portions fastened together, wherein the split portions are unequal.

17. The bend restrictor device of claim 1 , wherein the at least one stiffness ring disposed in a female end of the first bend limiter unit comprises more than two split portions.

18. An apparatus comprising:

a flexible pipe used for subsea drilling operations;

at least three bend limiter units disposed on the flexible pipe, each bend limiter unit comprising:

a male end having a flange disposed on a distal end thereof; and

a female end having an inner shoulder disposed on a distal end thereof;

wherein the at least three bend limiter units are coupled together by inserting a male end of a first bend limiter unit into a female end of a second bend limiter unit; and

at least one stillness ring disposed between a flange of the first bend limiter unit and an inner shoulder of the second bend limiter unit, wherein a number of stiffness rings disposed between a first adjacent pair and a second adjacent air of the at least three bend limiter units is different.

19. The bend restrictor device of claim 18 , wherein the at least one stiffness ring is disposed within the female end of the second bend limiter unit.

20. A bend restrictor device comprising:

at least three bend limiter units coupled together, wherein each bend limiter unit comprises a male end and a female end; and

at least one stiffness ring disposed in a female end of at least one of the bend limiter units,

wherein a number of stiffness rings disposed between adjacent pairs of the at least three bend limiter wilts increases from a proximal end to a distal end.