Fiber Bragg grating expansion sensor for detecting material expansion during lamination in e.g. wind turbine blade, has fiber section covered with plastic tube, where length and outer and inner diameters of tube satisfy specific conditions

摘要

The sensor has an optical fiber (1) having outer diameter (d) of 0.01 mm to 0.9 mm and comprising a Bragg grating (2) in a predesignated fiber section, where length (l) of the Bragg grating amounts to 2 mm to 20 mm. The fiber section with the Bragg grating is covered with a resilient plastic tube (3a) into which the fiber section slides. The tube has length (L) of 2 mm to 50 mm, outer diameter (D1) of 0.05 mm to 1.9 mm and inner diameter (D2) of 0.011 mm to 1.3 mm, where the length and outer and inner diameters satisfy specific conditions, where the sensor is formed as a measuring strip.