Experimental Research On Inverse Piezoelectric Effect In Bone

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. Because the structure of bone is anisotropic and non homogeneous, it is very difficulty to fully understand the piezoelectric behavior of bone only by measuring piezoelectric effect directly. With the development of technology, various new techniques have been developed, which can be employed to investigate the electromechanical behavior of bone. Based on the principle of piezoelectricity the piezoelectric materials will deform proportionally to an external electric field, which is called converse piezoelectric effect. Therefore it is also an effective way to understand the piezoelectric properties through measuring the converse piezoelectric properties.The goal of this thesis is to investigate the converse piezoelectric properties of bone by measuring the deflection of bone beam specimens under an applied electric field using an image correlation. To realize this purpose, thin beam specimens from bovine tibia are prepared and conductive adhesive are painted on both sides of the specimen as electrodes. The beam specimen is supported as a cantilever and direct current voltages from 500 to 1500V are applied to the electrodes, which may induce a bending deformation in the specimen. The displacements or deflections of the cantilever beam in free end are measured by applying a high resolution digital microscope combined with digital image correlation technique.Define the direction parallel to electric field is X direction, and the direction perpendicular to Electric field is Y direction. X direction of all specimens' displacements has a large increasing in first 10 minutes load voltage.The increasing of displacement will be close to 0 after unload voltage. Y direction of all specimens' displacements is small.