Comprehensive Mechanical Study Of Six-axis External Fixators For Orthopedic Rehabilitation

The six-axis external fixators for orthopedic rehabilitation has important significance in the field of orthopedic treatment because of its wide applicability,convenient process and high precision.However,the current research mainly focuses on the fracture deformity correction algorithm.For the mechanical research of the fixators,there are some shortcomings such as research scheme,the finite element simulation analysis quality,and force measuring device for connecting rod.In this paper,a force measuring device for connecting rod has designed,and a comprehensive mechanics research program for orthopedic rehabilitation fixators is proposed,which has certain reference significance for the comprehensive mechanical analysis of orthopedic rehabilitation fixators.The main work of the thesis includes the following aspects:Establish a six-axis external fixators for orthopedic rehabilitation model.Based on the analysis of the existing fixators size,the overall model of the orthopedic rehabilitation fixators is established by Solidworks;the CT data of the human skeleton is collected,the Mimics reconstruction and processing,the Geomagic surface optimization,and the accurate three-dimensional model of the Tibia and fibula was established.On this basis,the fixators,skeleton,and connector models were assembled to establish a reasonable orthopedic rehabilitation fixators model.Finite element analysis of external fixation fixators model.Firstly,the mechanical analysis of the steel needle structure is carried out,and the maximum force is calculated according to the shear strength theory.Then,the integrated orthopedic rehabilitation fixators model is combined meshing to establish a more accurate finite element model.Finally,the axial loading simulation is carried out,and the reaction force of the broken skeleton growing with the increase of the axial force.The lateral loading simulation is used to study the influence of different lateral force points on the bearing force.The torsional loading simulation is used to obtain the connecting rod.The tendency of stress to increase with torque.A set of connectors force measuring devices including a pneumatic control module,an experimental structure module and a sensor acquisition module are designed.The pneumatic control model realizes the output control of the air pressure through the upper computer program,and provides the power source for the cylinder;the experimental structure module designs a corresponding frame and clamps to achieve the positioning and clamping of the orthopedic rehabilitation fixators;the sensor acquisition module mainly selects the appropriate sensor to be installed at the connectors,and is amplified by the amplifier,and converted by the single-chip microcomputer to achieve the reading of the force of the connecting rod and calibrate the writing slope characteristic of the sensor.Comprehensive mechanical study of the six-axis external fixators for orthopedic rehabilitation.On the basis of the design of the connector force device,an axial compression test,a lateral pressure test,and a torsional pressure test were performed.It is concluded that the trend of the force change of the connector is related to the initial force form of each link,the force line of each link and the angle between the force.The maximum increase is related to the distance between the point of action of the connector and the angle of the force line.During the lateral loading process,the equivalent lateral force value is applied,and the structural stability of the loading at the blank is better than that at the joint.