股骨头坏死是股骨头血供受损或中断,导致骨髓成分及骨细胞死亡,随后发生修复,继而导致股骨头结构改变甚至塌陷的系列病理改变与临床表现。国际骨循环研究协会(Association Research Circulation Osseous,ARCO)制订的股骨头坏死分期在指...股骨头坏死是股骨头血供受损或中断,导致骨髓成分及骨细胞死亡,随后发生修复,继而导致股骨头结构改变甚至塌陷的系列病理改变与临床表现。国际骨循环研究协会(Association Research Circulation Osseous,ARCO)制订的股骨头坏死分期在指导治疗、判断预后、评估疗效方面得到广泛应用。2019年11月,关节外科杂志(Journal of Arthroplasty)在线发表了韩国学者Kyung-Hoi Koo牵头的专家组制订的股骨头坏死分期标准修订版。这是自1994年以来国际骨循环研究协会分期的重大改变。修订后的ARCO分期为四分期体系,特点包括:取消了0期分期,确定Ⅰ和Ⅱ期为塌陷前病变,Ⅲ期细化为早、晚期,X线片出现关节间隙变窄、髋臼改变和关节破坏的骨关节炎表现归入Ⅳ期。这次ARCO分期的改良,可谓化繁为简,却没能做到执简驭繁,对疾病治疗指导和预后判断的效果和意义有待进一步验证。展开更多
In this work, the prediction of wear for revolute joint with clearance in multibody systems is investigated using a computational methodology. The contact model in clearance joint is established using a new hybrid non...In this work, the prediction of wear for revolute joint with clearance in multibody systems is investigated using a computational methodology. The contact model in clearance joint is established using a new hybrid nonlinear contact force model and the friction effect is considered by using a modified Coulomb friction model. The dynamics model of multibody system with clearance is established using dynamic segmentation modeling method and the computational process for wear analysis of clearance joint in multibody systems is presented. The main computational process for wear analysis of clearance joint includes two steps, which are dynamics analysis and wear analysis. The dynamics simulation of multibody system with revolute clearance joint is carried out and the contact forces are drawn and used to calculate the wear amount of revolute clearance joint based on the Archard's wear model. Finally, a four-bar multibody mechanical system with revolute clearance joint is used as numerical example application to perform the simulation and show the dynamics responses and wear characteristics of multibody systems with revolute clearance joint. The main results of this work indicate that the contact between the joint elements is wider and more frequent in some specific regions and the wear phenomenon is not regular around the joint surface, which causes the clearance size increase non-regularly after clearance joint wear. This work presents an effective method to predict wear of revolute joint with clearance in multibody systems.展开更多
文摘股骨头坏死是股骨头血供受损或中断,导致骨髓成分及骨细胞死亡,随后发生修复,继而导致股骨头结构改变甚至塌陷的系列病理改变与临床表现。国际骨循环研究协会(Association Research Circulation Osseous,ARCO)制订的股骨头坏死分期在指导治疗、判断预后、评估疗效方面得到广泛应用。2019年11月,关节外科杂志(Journal of Arthroplasty)在线发表了韩国学者Kyung-Hoi Koo牵头的专家组制订的股骨头坏死分期标准修订版。这是自1994年以来国际骨循环研究协会分期的重大改变。修订后的ARCO分期为四分期体系,特点包括:取消了0期分期,确定Ⅰ和Ⅱ期为塌陷前病变,Ⅲ期细化为早、晚期,X线片出现关节间隙变窄、髋臼改变和关节破坏的骨关节炎表现归入Ⅳ期。这次ARCO分期的改良,可谓化繁为简,却没能做到执简驭繁,对疾病治疗指导和预后判断的效果和意义有待进一步验证。
基金the National Natural Science Foundation of China (Grant Nos. 50975056 and 11072066)the Scientific Research Foundation of Harbin Institute of Technology at Weihai (Grant No. HIT(WH)XB201120)the Fundamental Research Funds for the Central Universities (Grant No. HIT.NSRIF.2013122)
文摘In this work, the prediction of wear for revolute joint with clearance in multibody systems is investigated using a computational methodology. The contact model in clearance joint is established using a new hybrid nonlinear contact force model and the friction effect is considered by using a modified Coulomb friction model. The dynamics model of multibody system with clearance is established using dynamic segmentation modeling method and the computational process for wear analysis of clearance joint in multibody systems is presented. The main computational process for wear analysis of clearance joint includes two steps, which are dynamics analysis and wear analysis. The dynamics simulation of multibody system with revolute clearance joint is carried out and the contact forces are drawn and used to calculate the wear amount of revolute clearance joint based on the Archard's wear model. Finally, a four-bar multibody mechanical system with revolute clearance joint is used as numerical example application to perform the simulation and show the dynamics responses and wear characteristics of multibody systems with revolute clearance joint. The main results of this work indicate that the contact between the joint elements is wider and more frequent in some specific regions and the wear phenomenon is not regular around the joint surface, which causes the clearance size increase non-regularly after clearance joint wear. This work presents an effective method to predict wear of revolute joint with clearance in multibody systems.
