Finite Element Analysis And Experimental Verification Of Human Spine

The finite element molding of L4-L5segments of human lumbar is analyzed by afinite element software, Ansys Workbench to get theoretical stress value of its jointisthmus; The joint isthmus' strain in region of theoretical analysis is measured inbiomechanics experiment of human lumbar to prove the reliability of finite elementanalysis result which in different motion state of human lumbar by comparison to aboveof value.In the process of study, Firstly, the finite element molding of intervertebraldegeneration is analyzed under vertical load to get stress nephogram and that of stresswith light degeneration, moderate degeneration, severe degeneration of intervertebral andcomplete discectomy, the results show that the decrease of lumbar stability and theincrease of structural force of lumbar posterior are caused by the light degeneration, andthe recovery of lumbar stability, the decrease of posterior structural force, the increase ofstiffness with moderate degeneration, severe degeneration are caused by buffer capacity oflumbar. As the degree of intervertebral degeneration increase, the carrying capacity offibrous ring is increasing; Secondly, on the base of the finite element analysis of previousabout human lumbar, The human lumbar's motion states of normal stand,left or rightbending, front or back flexion-extension are simulated by applied vertical load on finiteelement model to get the stress of joint isthmus; At last the experiment speciments, pigbone, is fixed in designed clamping device, reading the value strain of experimentspeciments, joint isthmus, in the above three motion states, the picture of load-strain isdrawed by MATLAB with the numerical analysis method on the collected data, and thengetting the trend of change on load-strain after liner fitting, converting the theory stressvalue above to the strain value by use the distorted energy density theory(the forth strengththeory).Based on the theory of mathematical statistics, the stress value of lumbar jointsisthmus from the experiment is compared with the strain value of theory calculation to getthe above two normal distribution graphics, the trend of data distribution of both aresimilar, and the calculating result of error under previous conditions are:5.8%,6.7%and7.4%respectively, it meet the allowable range of error and supply the theoretical supportof study on human lumbar of clinical medicine.