Strain measurement characteristics of distributed fiber optic sensors in the temperature range of in-service aircrafts.

Abstract

Fiber-optic distributed sensing system is effective for structure health monitoring because of its flexibility, explosion proof and characteristic of distributed strain measurement. We are planning experiments of measuring the distributed strain of an aircraft by the fiber-optic distributed sensing system. Before the experiments, we must investigate the strain measurement characteristics of distributed fiber optic sensors in the temperature range of in-service aircrafts. Especially, the method for temperature compensation has much influence on measurement. Therefore, we conducted four point bending tests in multiple low temperatures. We bonded fiber optic sensors on the specimen by using an epoxy resin. As a result of the experiments, we found a problem with the method for temperature compensation we have been applying in the past. Therefore, we applied another method for temrerature compensation and evaluated strain measurement characteristics of distributed fiber optic sensors in the temperature range of in-service aircrafts by comparing with the value of the strain gauges.