Fundamental Research On Design And Property Analysis Of3D Dynamic Model Of Lumbar Vertebrae Of Adults

The research on spine-related diseases is a new discipline. Spine-related diseases result from the change of the spine caused by force unbalance and inflammation of peripheral soft tissues. Spine diseases are very common and have a high incidence especially among low aged people. The prevention and treatment of spinal diseases are paid more attention. As the most effective stress analysis method in theoretical biomechanics, finite element method has advantages compared with experimental biomechanics.In this paper, a new method is proposed to build the lumbar vertebrae model of human spine. The3D geometric model of L3to L5spine is built according to spinal anatomy data. The stress analysis is performed by using FEM software ANSYS. The solid model of the lumbar vertebrae is processed by3D printing method. The main contents are listed as follows.(1) The establishment of L3-L5geometric model of the lumbar vertebrae. Based on the lumbar vertebrae shape data of adult male persons obtained from anatomy literature, the structure of the lumbar vertebrae is built by Solidworks. The structure includes vertebrate, intervertebral disc and small joints. The three parts are combined and assembled to make sure that intervertebral disc and vertebrate are closely attached and that bending forward angle of the model is in agreement with physiological bending angle. This is benificial for exerting loads and constraints in subsequent FEM analysis.(2) The establishment of FEM model of the lumbar vertebrae. The3D geometric model built in Solidworks is imported into ANSYS for pretreatment. The material properties of each part of the lumbar vertebrae are set differently. The elastic modulus shows a trend of gradient variation.(3) Mechanical properties analysis of L3-L5lumbar vertebrae. Different forces are exerted onto the model using ANSYS. Stress and strain conditions are obtained using ANSYS. In this paper, stress is simulated when the lumbar vertebrae is in various conditions. The condition includes upright, lateral flexion and forward bending. The conclusions reached are as follows. The maximum deformation of vertebrate is1.107mm when axial pressure of1umbar vertebrae is500N.The maximum deformation of vertebrate increases w ith axial pressure.Lateral angle displacement of L3vertebrate is1.2°when later al moment of lumbar vertebrae is2.5Nm. The maximum pressure of interverte bral disc is2.78Mpa and the maximum deformation of vertebrate is6.87mm w hen the load on the lumbar vertebrae is10Kg and the forward-bending angle is30°.Stresses of intervertebral disc and deformation of vertebrate increase with the forward-bending angle. (4) The model process and mechanical properties test. The PLA/ABS solid model of the lumar vertebrae is processed using3D printer and test is performed. The simulation results are compared with previous experimental data to confirm the precision of the analysis.The research results of this paper provide a reference for spinal bio-mechanics research and theoretical basis for the application of man-made skeletons to surgical operation of the spine. Also the results help to develop new3D materials such as compound materials to promote the research on treatment of spine-related diseases.