Optical and infrared monitoring techniques applied to the defects detection after indentation of jute/hemp fibre hybrid laminates

This work compares the experimental results obtained by Infrared Thermography (IRT), Digital Speckle Photography (DSP) and Holographic Interferometry (HI) used as nondestructive testing techniques after static indentation on jute/hemp (50 wt. % total fibre content) hybrid laminates, for the detection of damage caused by loading. Samples have been either indented to 50% of their ultimate load or to failure. The variability of their properties was quite considerable, as measured both from the indentation load and the integration of data from the optical and infrared techniques mentioned above.