An Analytical Approach and Optimization of Curvature Gauge

The 'curvature gauge' is sensor for the monitoring of deflection of structures under mechanical loading in applications in which strain gauges have traditionally been used. The sensitive zone of the curvature gage is precision machined into the plastic optical fibre on grinding or milling machines. The cut-out produced removes a part of the fibre core and introduces a loss of light propagating along. The extent of such loss is related to the bendradius of the fibre. In this work we present an analytical approach of this sensor. The operation of this curvature gauge is now explained and estimated in order to optimise it and improve its performances. The results are shown that relate the relative light-loss to the fibre curvature for different parameters (its depth, length, number of cuts, bend radius and pitch of cuts). Proposed model allows a quantitative optimization of curvature gauge without the necessity for making of the thousands of sensors with slightly different parameters in order to accomplish a similar objective experimentally