Polyurethane Vertebrae Bend Restrictor

A vertebrae bend restrictor (VBR) is designed to protect a subsea control line umbilical from bending stresses that can occur during normal offshore installation and operation. It offsets the action of applied loads which could kink or buckle the internal conduits of an umbilical, cable, flexible riser pipe or MUX line.

The vertebrae have omni-directional freedom until the locking bend radius (LBR) is reached where the ball and socket of the VBR are fully engaged. The LBR of each VBR is the radius at which the lock, or “lock up,” occurs. At that point the segments of the VBR will lock on each other increasing the effective stiffness of the cable it protects to withstand specified loads applied to the device without violating the specified minimum bend radius (MBR). The VBR will accommodate lines 0.5inch (13 mm) to 16 inches (406 mm) in diameter and is made from either polyurethane or steel depending on the need.