Numerical evaluation of nonbonded piezo sensor for biomedical diagnostics using electromechanical impedance technique

• Published in: International journal for numerical methods in biomedical engineering Vol. 35; no. 2; pp. e3160 - n/a
• Main Authors: Srivastava, Shashank, Bhalla, Suresh
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.02.2019
• Subjects: Animals; Biocompatibility; Biomedical materials; Bonding; Bone and Bones - metabolism; Bone density; Bones; Change detection; Condition monitoring; Configurations; Damage detection; Damage localization; damage quantification; Electric Impedance; Electromagnetic interference; electromechanical impedance technique; Finite Element Analysis; Finite element method; Imaging, Three-Dimensional; Impedance; Irritation; Localization; Mathematical models; Models, Biological; Muscles; numerical analysis; osteomalacia; Osteoporosis; Osteoporosis - diagnosis; Pain; piezo sensors; Rats; Rats, Sprague-Dawley; Sensors; Skin; Skin - metabolism; Structural health monitoring; osteomalacia; damage quantification; electromechanical impedance technique; osteoporosis; numerical analysis; piezo sensors
• ISSN: 2040-7939; 2040-7947; 2040-7947
• DOI: 10.1002/cnm.3160

Directly bonded piezo sensor, conventionally employed in the electromechanical impedance (EMI) technique, although a proven candidate for structural health monitoring, is severely constrained in its application in the biomedical field due to its bonding requirement. In contrast, nonbonded piezo sensor (NBPS) provides a viable platform to assess the condition of human bones, tissues, and other biomedical subjects using the EMI technique without inflicting pain or irritation to the skin. The name NBPS was coined to emphasize that there was no direct bonding between the PZT patch and the live subject; instead, the PZT patch was bonded to a supporting medium, which maintains the mechanical interaction between the PZT patch and the subject. However, there are several aspects in the analysis of NBPS configuration that cannot be addressed completely through experimental study due to measurement constraints, cost, and time. For example, experimentally changing the density of bone continuously to study the osteoporosis effect is a tedious task warranting large number of specimens. This paper presents a detailed parametric study based on finite element method covering condition monitoring of human bones using the NBPS configuration. It is for the first time that 3D analysis for specimen identification and damage detection in bones using NBPS has been carried out. In addition to the validation of the numerical model against the previously established experimental studies involving bones, quantification of the extent of damage and its localization has been investigated. The density changes due to osteoporosis in bones are comprehensively investigated by the NBPS including the quantification aspect of osteoporosis/damage. Definite acquisition of bone signature and detection of physiological changes in bones are achieved even with the presence of skin, muscle, and fat layers on the bone. This novel work elaborates on 3D finite element analysis for bone specimen identification, its damage detection, and quantification using nonbonded piezo sensor based on electromechanical impedance technique. In addition to the validation of the numerical model against the previously established experimental studies involving bones, crack propagation and its localization has been investigated. Definite acquisition of bone signature and detection of physiological changes in bones are achieved even with the presence of skin, muscle, and fat layers on the bone.