The effects of indentation loading depth and dynamic pre-compression on the creep behavior of CoCrFeNiAl_(0.3) high-entropy alloy(HEA)were studied through a series of indentation creep tests.Results show that the cree...The effects of indentation loading depth and dynamic pre-compression on the creep behavior of CoCrFeNiAl_(0.3) high-entropy alloy(HEA)were studied through a series of indentation creep tests.Results show that the creep displacement,creep stress exponent and creep strain rate are all sensitive to loading depth.A phenomenological model based on the holding time and loading depth was established by studying the characteristic relation between the loading depth and the creep displacement of CoCrFeNiAl_(0.3) HEA.The phenomenological model was used to analyze the creep behavior of the alloy under dynamic pre-compression(i.e.,dynamic compressive deformation caused by Hopkinson bar impact).展开更多
Contact stress is the important cause of wear and failure of knee joint prostheses implanted in the human body during movement.The calculation of contact stress on joint prostheses is often inaccurate due to the devia...Contact stress is the important cause of wear and failure of knee joint prostheses implanted in the human body during movement.The calculation of contact stress on joint prostheses is often inaccurate due to the deviation of joint position during activity.This paper proposes a correction method for contact stress based on finite element results.Firstly,the contact stress and contact radius between femoral and tibial prostheses of knee joint were calculated and analyzed by Hertz contact theory.Then,individualized finite element models based on the individualized geometry of the joint prosthesis and individualized loading were constructed,and the finite element contact stress was analyzed.The finite element results were calibrated utilizing the Hertz contact theory.Additionally,this study investigated the impact of three gait patterns(normal gait,medial thrust gait,and bouncing gait)on the contact stress experienced by the tibial insert.The research methods and results can provide ideas for theoretical analysis and finite element simulation of prosthetic joint contact,as well as offer theoretical support and analysis methods for evaluating the lifespan of prosthetic joints.展开更多
基金support from the China Postdoctoral Science Foundation(Grant No.2021M702605)National Natural Science Foundation of China(Grant Nos.12102287,12102289,11772217).
文摘The effects of indentation loading depth and dynamic pre-compression on the creep behavior of CoCrFeNiAl_(0.3) high-entropy alloy(HEA)were studied through a series of indentation creep tests.Results show that the creep displacement,creep stress exponent and creep strain rate are all sensitive to loading depth.A phenomenological model based on the holding time and loading depth was established by studying the characteristic relation between the loading depth and the creep displacement of CoCrFeNiAl_(0.3) HEA.The phenomenological model was used to analyze the creep behavior of the alloy under dynamic pre-compression(i.e.,dynamic compressive deformation caused by Hopkinson bar impact).
基金supported by the National Natural Science Foundation of China(Grant numbers 12102287,12302477,11972243)the Fundamental Research Program of Shanxi Province(Grant number 202203021222081).
文摘Contact stress is the important cause of wear and failure of knee joint prostheses implanted in the human body during movement.The calculation of contact stress on joint prostheses is often inaccurate due to the deviation of joint position during activity.This paper proposes a correction method for contact stress based on finite element results.Firstly,the contact stress and contact radius between femoral and tibial prostheses of knee joint were calculated and analyzed by Hertz contact theory.Then,individualized finite element models based on the individualized geometry of the joint prosthesis and individualized loading were constructed,and the finite element contact stress was analyzed.The finite element results were calibrated utilizing the Hertz contact theory.Additionally,this study investigated the impact of three gait patterns(normal gait,medial thrust gait,and bouncing gait)on the contact stress experienced by the tibial insert.The research methods and results can provide ideas for theoretical analysis and finite element simulation of prosthetic joint contact,as well as offer theoretical support and analysis methods for evaluating the lifespan of prosthetic joints.
