运用有限元分析新型半髋假体装配过程中的应力分布  

Finite element analysis on stress distributions during novel semi-hip prosthesis assembly

作　　者：杨予[1] 储小兵[2] 童培建[2] 郝改平 石敦敦[1] 

机构地区：[1]浙江理工大学建工学院,杭州310018 [2]浙江省中医院骨伤科,杭州310006 [3]北京力达康科技有限公司,北京100044

出　　处：《医用生物力学》2013年第1期50-55,共6页Journal of Medical Biomechanics

基　　金：浙江省科技厅优先主题重点社会发展项目(2009C03014-2);浙江省自然科学基金资助项目(Y2111083)

摘　　要：目的利用计算机模拟一种新型半髋假体系统假体装配过程中与股骨相互接触作用所产生的应力,探讨分析在临床手术中的操作界限值和相适应的假体外形。方法对一名60岁正常男性志愿者进行双下肢的股骨中上段CT扫描,从扫描图像中建立实体模型后利用与有限元的数据交互功能进行实体模拟装配、网格划分、保形简化以及单元弹性模量赋值等操作步骤,最后生成三维有限元模型,并构造股骨与假体之间的面-面接触关系,模拟分析假体植入装配过程中的相对滑移和应力分布情况。结果下压装配过程中假体柄对骨皮质产生附加应力,带棱槽假体的最大接触压力产生于棱槽变截面处,而最大装配应力和相对滑移量随假体压入深度呈非线性增长,当Δz≥0.5 mm后附加应力增长速率显著提高。结论与无棱槽假体的对比分析表明采用棱槽的半髋假体更容易装配并获得机械稳定,但在临床手术装配中应参照一定的量化操作要求,避免在植入时产生过大附加应力,对骨皮质产生破坏而导致治疗失败。Objective To simulate the stress generated by contact with the femur during the assembly of novel semihip prosthesis, and discuss the operating limits and adaptive prosthesis profile in clinic. Methods CT scans were conducted on the proximal end of the femur in a male volunteer of 60 years old as a physical model. By transferring the CT data to finite element modeling software, the physical model was simplified, meshed, ma terialized and assembled with the model of prosthesis to establish the threedimensional finite element model. Surface to surface contact relationship between the femur and the prosthesis was also constructed by utilizing contact elements. Relative sliding distance and stress distribution were solved while simulating the process of as sembling the prosthesis. Results Additional stress was generated on the sudden change area of the contact surface when the prosthesis was seated. The greatest contact pressure came from the changing section of the ridge of the prothesis, and the maximum assembly stress and sliding distance range increased nonlinearly along with the pushing distance. The increase rate of additional stress was enhanced significantly while Az≥0.5 mm. Cen clusiom Compared with the prosthesis without ridge, the prosthesis with ridge can be easily seated and obtain mechanical stabilization. However, the relevant clinical operating limits should be obeyed to avoid generating ex cessive additional stress during the implantation of prosthesis, which may cause treatment failure due to the dam age in bone cortex.

关 键 词：有限元分析 半髋假体 面-面接触 应力分布 

分 类 号：R318.01[医药卫生—生物医学工程]