Experimental Research On Inverse Piezoelectric Effect In Bone

Because the structure of bone is non homogeneous and anisotropic, it is very difficulty to fully understand the piezoelectric behaviors of bone only by measuring piezoelectric effect directly. The importance of the research on piezoelectricity of bone is based on the understanding of how the electric potentials generated by stress in bone influencing the osteocyte growth. With the development of technology, various new techniques have been developed, which can be employed to investigate the electromechanical behavior of bone.The purpose of this thesis is to investigate the converse piezoelectric properties of bone by measuring the deformation of bone beam specimens under an applied electric field using an image correlation. To realize this purpose, 7 thin beam specimens which are from bovine tibia are prepared. The beam specimen is supported as a cantilever at the thickniss of 1mm(0.8mm 0.6mm 0.5mm 0.3mm) and direct current voltages,ranging from 200V to 1000V,are applied to the electrodes step by step with each increment of 200V, which may induce a bending deformation in the specimen. The deflections or displacements of the cantilever beam in free end are measured by applying a high resolution digital microscope combined with digital image correlation technique.The results show that the applied voltages have great influence on the bone beams deformation, voltages are proportional to deflections with the thickniss of specimens being constant, and the relationship between the thickniss of specimens and deflections is negative with the applied voltages being constant. There is a great difference in the deflections of different specimens at the same applied voltage and thickniss.However, different specimens have the same trend between the applied voltages and deflections.The impact of electrodes polarity on the deformation is also explored. It is found that when the electrodes polarity are changed, the displacements are also changed and there is a great difference between the two states. We also found that there were many differences when we changed the direction of the switch of the experimental installation.