摘要 |
The present invention features an apparatus that provides an indication of tensioning strain when it is tensioned with respect to a workpiece, comprising either a bolt, stud or fastener together with an embedded fiber optic Bragg Grating sensor. For example, the bolt has a head at one end, threads at the other end and a central bore with a bore wall drilled into at least one end thereof. The bolt responds to a tensioning force applied on the head of the bolt, for providing a tensioning strain force applied inwardly on the wall of the central bore. The fiber optic Bragg Grating sensor is arranged inside the central bore of the bolt and bonded, for example by epoxy, to the central bore wall. The fiber optic Bragg Grating sensor responds to the tensioning strain force, and further responds to a light signal, for providing a fiber optic Bragg Grating sensor light signal containing information about a sensed tensioning strain force on the bolt when the threads are tensioned to the workpiece.
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