Structural member bend radius and shape sensor and measurement apparatus

Structural member bend radius sensor apparatus comprises three fibre Bragg grating (FBG) strain sensors provided within three optical fibres . The optical fibres and the FBGs are embedded within a part-cylindrical shaped carrier member . The fibres are provided at three spaced locations across the shaped carrier member so that, in use, the three respective FBG strain sensors will be located at three different angular positions around the circumference of the structural member (pipe) . Structural member shape measurement apparatus comprises four bend radius sensor apparatus provided at four bend radius measurement positions along the pipe . The four bend radius sensor apparatus shown share their optical fibres , and a single shaped carrier member . The shape measurement apparatus further comprises FBG interrogation apparatus