Vol.12, No2, 2012, pp. 81–86
UDC 620.179.15

Effective dimensioning requires an effective experimental in situ analysis of the stress states of structures. Load monitoring is the first step for the calculation of residual lifetime, respectively the structural health under realistic conditions and special loads. For many decades already, stress analysis using strain gauges has been a proven and qualified method for analysing the loading conditions in structural mechanics. Strain gauges are particularly suited for determining such mechanical loads on structures or components, because they detect minimal structural deformations. Quality and reliability of the sensors determine the durability of the structural system. Even under the background of lightweight materials, fibre optical sensors are increasingly used today, amongst others due to:

• Low weight of the sensors, cables and data acquisition unit as well as assembling work load

• Fatigue behaviour of the sensors due to applied high mechanical strain.

Basic considerations and experimental investigations on fibre optic Bragg grating strain sensors is presented and a number of measuring effects that influence the strain transformation from specimen into the fibre optic sensors are discussed. The presentation is also to enforce the discussion between experts of different subjects and areas of expertise.

Keywords: fibre Bragg grating, structural test, strain sensing, fatigue