Nikit Gupta’s scientific contributions

The electro mechanical impedance (EMI) technique facilitates capturing of incipient damage. Further advantage of EMI techniques ceases after damage severity increases from incipient to moderate level, which can be more realistically quantified by global vibration techniques. Lot of research has already been done in the field of structural health monitoring (SHM) of reinforced concrete (RC) structures. Concrete vibration sensor (CVS) is a new sensor developed at the Smart Structures and Dynamics Laboratory (SSDL) of IIT Delhi. CVS is a ready to use packaged sensor for dynamic response measurement of RC structures such as buildings and bridges. These sensors provide the additional advantages of higher longevity and negligible decay of the sensing element. Also, the use of low-cost adaptations for EMI technique provides a cutting edge for SHM. In this paper, the integrated application of the global vibration technique and the low-cost EMI technique is carried out on a lab-based RC. The specimen (a simply supported RC beam) has the provision to introduce controlled damage severity levels. Fourteen CVS are embedded inside a RC beam, while casting, to obtain the first curvature mode shape of the RC beam. The damage location is detected by comparing the curvature mode shapes of the undamaged and the damaged beams using global vibration technique. A mode shape curvature based algorithm is adopted for damage detection and severity assessment. The admittance signature in the frequency range 50-150 kHz of all CVS is acquired for low-cost EMI technique. In the EMI technique, the RMSD values are used to locate and quantify the damage. Both the global vibration technique and the EMI technique successfully locate and quantify the damage in the RC beam using CVS. These changes would then present necessary warnings for proper and timely coactive action.