Electromechanical Properties Analysis Of Influence Bone Remodeling

Bone can feel its external environment, and to respond to changing external environment, this process is called bone remodeling. It is now generally believed that the main factors affecting bone remodeling have bone stress, fluid pressure, fluid shear stress and the streaming potential. Therefore, researching electromechanical properties of bone when bone subjected to dynamic loads, it is not only the premise step to understand the stress and electrical stimulation of bone growth and absorb, but also the basis theoretical to achieve and treatment of bone remodeling. Studying electromechanical properties of bone, relationship between bone growth and force and electricity, it can help us to understand the mechanisms of bone growth and reconstruction from the microscopic point of view. It has a wide range of applications in medicine and can help to raise various bone metabolic diseases research and present new bone metabolism disorders treatment program. This paper takes this as the starting point study fluid pressure distribution in the bone, fluid shear stress and streaming potential in canalicules when bone subjected to dynamic loads. The main contents of this paper are:We establish an annular cylinder model of single osteon. We consider a single osteon subjected to axial cyclic loading, and consider the effects of blood pressure oscillations in Haversian canal. The pore fluid pressure and flow velocity in osteon and blood pressure has been linked; this is one of the innovations of the paper. Solid skeleton is seen as transversely isotropic porous material, and the liquid and the solid matrix is seen as compressible. We analyzed the pore fluid pressure and fluid flow velocity distribution in osteon using porous elastic theory, and we obtained the analytical solution of the pore fluid pressure and fluid flow velocity in osteon and analyze the influence of axial strain amplitude, axial load frequency and permeability on pore fluid pressure and flow velocity.We research the fluid flow characteristics in canalicules, fluid shear stress, electric field distribution and streaming potential when single osteon subjected to an external cyclic axial loading and blood pressure. In this paper we innovationly consider the bone cells in canalicules and electro viscous effect and research the fluid shearing stress on bone cell projection surface. The fluid in canaliculus is seen as incompressible. Using the Navier-Stokes equations of incompressible fluid, we obtained the fluid flow velocity distribution in canaliculus, fluid shear stress distribution and streaming potential in canalicules and analyze the influence of axial strain amplitude, axial load frequency and permeability on the fluid flow velocity distribution in canaliculus, fluid shear stress distribution and streaming potential in canalicules.According to the governing equations of the electric field and fluid, using COMSOL Multiphysics and through the MEMS module in COMSOL to establish the model of the multi-physical field, we calculate the steady streaming potential of a microscopic model of cancellous bone at a certain pressure. We analyzed the influence of parameters of pressure, Zeta potential and ion concentration on the streaming potential of the model.According to the four kinds of microstructure of cancellous bone, we print out a magnified size model through the 3D printer. Then, we use the drop- weight impact test to study the dynamic mechanical properties of cancellous bone structure models with different microstructures under the impact load, and with a high-speed camera records the destruction characteristics of different models by the impact force.