An Efficient Nano Sensor for Strain Sensing and Defect Detection in Engineering Components

This work demonstrates the application of PVDF/CNT composite as strain sensor and defect detector. The PVDF/CNT films were prepared by solution/filtration method and were bonded directly onto specimens by nonconductive adhesive. The two electrodes were connected on to PVDF/CNT films with silver conducting epoxy to reduce contact resistance. Conventional Strain gauge is also attached to other end of the specimen for comparison. For testing purpose 9CR 1MO material is considered and cut into dog bone shaped structures according to ASTM standards. Tensile load is applied by subjecting the specimen in a servo hydraulic test frame .Calibration curves were plotted with change in voltage versus the strain obtained in test specimen. The result shows that there is linear change in voltage across the film when subjected to tension. The defect detection is done using electronic measurement technique. The results shows that the presence of defect was marked by high value of resistance on that particular region and the resistance value was low in non-defective region.