基于有限元分析在接骨螺釘扭斷測(cè)試中的應(yīng)用

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Application of Finite Element Analysis in the Torque Fracture Testing of Bone Screws

FAN Sijie

（Shanghai Institute of Medical Device Testing）

Abstract： Objective： The paper aims todesign a fixture for testing the torsional fracture torque of metal bone screws with adiametergreaterthan or equal to 5mm ，and reduce the occurrence of slippage between the screwsand the fixture before the screwsfracture，therebyimproving the success rateofthe tests.Method：According to material mechanics formulas， it analyzesthereasons whythe fracture torque ofbone screws cannot be measured due to slippage phenomena.The finite elementnalysisisusedtostablshamodel，assignmaterialproperties，onductmeshgeneration，seaalysisstesand definecontactconstraintconditions，boundaryconditions，andloads.houghfniteelementanalysis，itanalyzestheuied clamping force （reaction force）when usinga thre-jaw chuck andafixture with edges athe same embedding depth to hold the screws，andconductscomparative tests onthe successrates oftwo clamping methods.Result： The finite element analysis shows that the fixture with edges is more labor-saving when holding screws，saving nearly halfof the clamping force.The successrateoftestsusingthethre-jawchuckislowerthanthatoftestsusingthefixture withedges tohold thescrews for torsionalfracture tests.Conclusion：Usingafixture withedges tohold screws fortorsional fracture testscanimprove the success rate of the tests.

Keywords： bone screws; finite element analysis; torsional fracture torque

圖6嵌入螺釘后徑向投影面積

綜上，具有棱邊的工裝夾具夾持時(shí)所需的加持力更小，應(yīng)更容易的嵌入螺釘中，相同的夾持力嵌入螺紋的深度更深，切向的面積A徑更大，螺紋被夾持部分可承受的最大切向力F切向max越大，螺紋越不容易被破壞發(fā)生打滑現(xiàn)象。（剩余2943字）