| Objective: This topic is designed to establish a normal human lumbosacral(L4-S1)three-dimensional finite element model,verify its effectiveness,and then a lumbar vertebrae(L4-S1)three-dimensional finite element model placed in a new axial screw composite After analysis,the displacement,stress and strain indicators of the analysis model are calculated under certain loads,verify its mechanical properties,and provide the new internal fixtures to perform the next improvement and provide relevant theoretical foundations.Methods:Using CT scan to obtain normal adult male lumbazte imaging data,the complete lumbosacral fracture(L4-S1)three-dimensional finite element model is constructed by three-dimensional finite element method and verify its effectiveness,and the implant axial screw composite is completed.On the basis of the lumbosacralial model,a finite element analysis is performed,Apply 500 N axial compression preload force(torque of 5N ยท m)on the upper surface of the L4 vertebrae,rotate a variety of motion states,such as flexion,reach,side bend,rotation,using the ANSYS 14.1 software to calculate the stress distribution of the L5-S1 vertebral bodies in various working conditions and the size of the displacement change,so that the objective scientific pair axial screw complex is Evaluation of biomechanics.Result:1.Successfully established effective lumbosacral vertebral threedimensional model(L4-S1),the lumbar spine surgical integrity consists of 155,971 elements and 37859 nodes,including 21,852 elements and4541 nodes of 21852 elements and 4541 nodes.2.Under certain load loading,when two different friction coefficients u = 0 or u = 0.5,the inner holder is less than the yield stress,and the axial screw is different from the stress distribution of the locking staple,where is locked.The maximum of the stress of the nail is smaller than the maximum stress of the axial screw,and the stress of the two is generally more distributed,and the stress is mainly distributed in the lock hole and surrounding of the lock nail,but the pressure of the concentration is still much lower than Yield pressure does not cause breakage due to stress concentration.3.At different working conditions,the displacement size of the axial screw composite is different,and the displacement value is small,and there is no yield deformation in the whole,thereby providing a significant displacement,thereby providing sufficient stiffness to ensure that the lumbar fusion segment is in a physiological load stability.Conclusion:1.Successfully established a lumbosacral type three-dimensional model(L4-S1)with axial screw composite(L4-S1).2.Under physiological loading,the internal fixator can provide sufficient strength and stiffness,with reliable safety and good biomechanical stability.3.In subsequent production,we need to improve process standards,improve material quality to enhance the weaknesses and lock nails on both sides of the internal fixator lock hole. |
