Bone-crack detection by piezoeletric-electromechanical impedance method

There is a growing interest in the application of smart materials such as piezoelectric in the biomedical field. The work presented in this paper is an attempt to demonstrate the feasibility of bone-crack detection by using piezoelectric-electromechanical impedance (EMI) method, which has the advantages of low cost, portable and simplicity in measurement. A piezoelectric transducer known as PZT (lead zirconate titanate) was used for actuating and sensing simultaneously and as a means of coupling the electrical and mechanical impedance. The basis of this novel method is to monitor variation in the mechanical impedance of a structural element via electrical impedance of a piezoelectric transducer attached to the host structure. In this study, a PZT transducer was used to detect artificially induced cracks in a bone. EMI measurements were carried out using AD5933 evaluation board for frequency range between 0.04 kHz to 100 kHz. The results obtained from the experiment were analyzed by quantifying the damage index using root mean square deviation (RMSD) of the impedance signals before and after cracks were induced in the bone. The results from the study show the feasibility of the piezoelectric-EMI method to effectively detect physical changes in the bone due to the artificially induced cracks.