Materials
The bending stiffener body is manufactured from moulded polyurethane elastomers specifically developed, qualified and tested over many years.
We have a range of materials to suit different applications, all of which are extremely tough, durable and suitable for extended service in arduous subsea and topside applications.
Polyurethane elastomer is used because of its low modulus and high elongation at break. A comparison between the stress vs strain properties of steel and a typical polyurethane elastomer is illustrated in the graph below [graph p.6 bending stiffeners brochure]
We have invested significantly in the development of new materials and the conduct of qualification programmes to demonstrate their suitability for use in such an apllication. Typical test requirements are:
- Fatigue resistance
- Creep resistance
- Tensile strength
- Tear resistance
- Temperature dependency
- Ageing in air and seawater
- UV resistance
If an adjacent cathodic protection system is present, the steel interface component of a bending stiffener is usually fabricated from high strength structural grade carbon steel. Alternatively it can be produced using more exotic corrosion resistant materials.