SYNCHRONOUS PRE-TENSIONABLE SENSING SCREW WITH FIBER BRAGG GRATING DEVICES

摘要

An apparatus includes a sensing screw capable of providing synchronous both pre-drawing of fiber Bragg grating and pre-tightening of bolt with induced characteristics to detect feedback control of large scale public engineering structures or precise equipments to facilitate fabrication of precise elements to achieve more precise control and record fabrication processes. Through the sensing screw apparatus a precision system structure can be formed to meet expectation of improved product quality and comprehensive recording of complete production process and physical characteristics at important points of the production process. The invention can provide instant onsite status and accumulate data or make parameter pre-action to avoid error accumulation, thereby improve production yield or safety of large scale structures.

主权项

1. A synchronous pre-tensionable fiber sensing screw apparatus providing synchronous both pre-drawing of fiber Bragg grating and pre-tightening of bolt to serve as a fastening means equipped with a structure to sense strain characteristic values when subject to a force to display or output strain value, comprising:
a bolt including an embedded fiber Bragg grating; a first washer coupled on a bolt head portion to bear the force applied to the bolt and a coupling object; a second washer coupled on a nut to bear the force applied to the coupling object; a nut screwed helically on the bolt to form self-locking; a fiber with the fiber Bragg grating embedded in the bolt; and fastening and setting elements to fix sensing screw apparatus; wherein the bolt and the nut wrench the object to be fastened via a tightening torque to make transformation for sensing an extension length of the bolt caused by the axial strain of the bolt that becomes a sensing screw structure to measure output wavelength variations resulted from change of length of the fiber Bragg grating embedded axially on the axis of the bolt; the fastening means containing a pretightening force and the fiber Bragg grating in the bolt containing a pre-drawing amount to measure shifted Bragg wavelength, the two pre-drawing amounts being synchronously formed or formed by stages.