The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper...The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper. The optimum of gradient distribution is obtained by way of the FEM analyses.展开更多
In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoi...In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.展开更多
Tibiotalar arthrodesis(TTA)is a common surgical method for post-traumatic arthrosis and primary osteoarthrosis of ankle.Internal screw fixation exhibits such advantages of higher fusion rate and fewer complications th...Tibiotalar arthrodesis(TTA)is a common surgical method for post-traumatic arthrosis and primary osteoarthrosis of ankle.Internal screw fixation exhibits such advantages of higher fusion rate and fewer complications that it has become the mainstream surgical procedure in clinics.However,there are still disputes over the choice of screw type,number and nailing method.In this study,a 3D model of tibiotalar joint was established based on CT data.Two representative types of screws were modeled according to their real objects.Preprocessing was done in Hypermesh 2017,and the finite element simulations of different surgical schemes and postoperative ankle joint movements were performed via Abaqus 2016.The stress distribution in tibiotalar joints and screws,interarticular displacement,and screw deformation were extracted for comparative analyses.The results show that:(1)the three-screw fixation scheme with smaller displacements and higher contact pressure is superior to the two-screw one;(2)the relative displacements of the tibia and talus of full-thread screw under all loads were reduced by approximately 50%compared with those of lag screw,showing better stability;(3)the 60scheme is more favorable for joint fusion and more stable under vertical load,while the 75has the best bending resistance;(4)the stress and strain distributions in screws indicate that the screw break is most likely to happen near its contact region with the bone inlet,the maximum stress reaches 212.2 MPa.This study is of great significance for the selection and optimization of the surgical plan.展开更多
基金supported by the National Natural Science Foundation of China(59875091)
文摘The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper. The optimum of gradient distribution is obtained by way of the FEM analyses.
文摘In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.
基金The work was supported by National Natural Science Foundation of China[Grant Nos.11772240,11720101002,11542001,11502175]Jiangsu Natural Science Foundation[Grant No.BK20150381]+1 种基金the Fundamental Research Funds for the Central University,Translational Medicine and Interdisciplinary Research Joint Fund of Zhongnan Hospital of Wuhan University[Grant No.ZNJC201927]the Innovative Group Development Program at School of Civil Engineering,Wuhan University。
文摘Tibiotalar arthrodesis(TTA)is a common surgical method for post-traumatic arthrosis and primary osteoarthrosis of ankle.Internal screw fixation exhibits such advantages of higher fusion rate and fewer complications that it has become the mainstream surgical procedure in clinics.However,there are still disputes over the choice of screw type,number and nailing method.In this study,a 3D model of tibiotalar joint was established based on CT data.Two representative types of screws were modeled according to their real objects.Preprocessing was done in Hypermesh 2017,and the finite element simulations of different surgical schemes and postoperative ankle joint movements were performed via Abaqus 2016.The stress distribution in tibiotalar joints and screws,interarticular displacement,and screw deformation were extracted for comparative analyses.The results show that:(1)the three-screw fixation scheme with smaller displacements and higher contact pressure is superior to the two-screw one;(2)the relative displacements of the tibia and talus of full-thread screw under all loads were reduced by approximately 50%compared with those of lag screw,showing better stability;(3)the 60scheme is more favorable for joint fusion and more stable under vertical load,while the 75has the best bending resistance;(4)the stress and strain distributions in screws indicate that the screw break is most likely to happen near its contact region with the bone inlet,the maximum stress reaches 212.2 MPa.This study is of great significance for the selection and optimization of the surgical plan.
