三维光弹性法对不同长度和直径桩核的应力分析

目的：对比不同长度和直径的桩核受力后应力分布情况。方法：根据桩的长短、粗细将实验分成4组，通过垂直和斜向加载，采用三维光弹性应力冻结法，经模型切片观察计算出模型各测点的最大剪应力。结果：桩的直径增加根尖区最大剪应力相应增高，桩核交界处和核与根面交界面最大剪应力明显增高。桩的长度增加，应力分布更为均匀。结论：从抗力固位角度出发有一定长度的粗细合适的柱形桩核较为理想。     

三维光弹性法对不同长度和直径桩核的应力分析

目的对比不同长度和直径的桩核受力后应力分布情况.方法根据桩的长短、粗细将实验分成4组,通过垂直和斜向加载,采用三维光弹性应力冻结法,经模型切片观察计算出模型各测点的最大剪应力.结果桩的直径增加根尖区最大剪应力相应增高,桩核交界处和核与根面交界面最大剪应力明显增高.桩的长度增加,应力分布更为均匀.结论从抗力固位角度出发有一定长度的粗细合适的柱形桩核较为理想.     

不同长度和直径桩核的三维光弹性应力分析

目的 对比不同长度和直径的桩核受力后应国分布情况。方法 根据桩的长短、粗细胞将实验分成四组,通过垂直和斜向加载,采用三维光弹性应力冻结法,经模型切片观察计算出模型各测点的最大剪应力。结果 桩的直径增加根尖区最大剪应力相应增高,桩核交界处和核与根面交界面最大剪应力的明显增高。桩的长度增加,应力分布更为均匀。结论 从抗力固位角度出发有一定和蔗的粗细合适的柱形桩核较为理想。     

瓷层厚度影响金瓷界面抗断裂能力的初步研究

目的：采用云纹干涉法结合界面断裂力学研究瓷厚度对金瓷界面抗断裂能力的影响。方法：比较瓷厚度分别为0．5mm,1.5mm,2.5mm的试件（金属均为0．5mm)界面断裂韧性Jc并观测裂纹扩展。结果：0．5mm组试件的Jc值及承受最大载荷均值（2．813N/m,9.979N)低于1．5mm及2．5mm组（5．395N／m,19.134N与5．429N/m,19.256N).1.5mm与0．5mm组试件，裂纹易沿界面扩展。结论：（1）瓷厚度为1．5mm与2．5mm组的金瓷界面抗断裂能力相当，厚度为0．5mm时减弱，（2）瓷厚度为1．5mm与0．5mm组的界面裂纹易沿界面扩展，厚度为2．5mm组易向瓷层内扩展。     

Three-dimensional photoelasticity analysis of Nitinol Patellar Concentrator for treating patellar fractures

ood results are got when the patellar fractures aretreated by Nitinol Patellar Concentrator (NT-PC )L','],and the NT-PC is appraised to .be the idealest one amongall the methods on treating patellar fractu.,L3]. The objective of our experiment is to study the distribution of stressin patellar when it is fi-cated by NT-PC, which is made ofNi-Ti shape memory alloy. The biomechanical elements ofit in treating codrinuted patellax fractUres and distal polecoconuted patellar fractIJres is il…     

用投影散斑立体摄影法测量人体关节的三维运动

本文采用白光散斑法，由两个摄像机同时记录人体关节运动过程中的数字图像，通过数字相关测出各标志点的平面位移．然后用立体摄影法求解各测点在运动过程中的三维坐标，得到各标志点的三维运动．针对刚体大位移的特点，提出了被测区域的侧转和自转指标，实现对人体关节一般空间运动的定量分析，为医学手术的评价提供实验测量基础。     

颈椎椎间盘髓核内压力测试分析研究

颈椎椎间盘是维持颈段脊柱的重要组成部分,它在维持颈椎稳定性方面起着非常重要的作用,但各种原因导致颈椎椎间盘退变或突发引起一系列的临床病症。本文通过人体全段颈椎标本模拟人体中立位生理载荷运动,建立力学模型,并用直接和间接的方法测定颈椎椎间盘髓核内压力的数据子以验证,为颈椎椎间盘研究提供相应的生物力学评价和理论依据。     

云纹干涉法应用于金瓷界面抗断裂能力研究的初步探讨

目的探讨云纹干涉法在金瓷界面抗断裂能力研究中的应用。方法在5组金瓷厚度不同的试件表面制作光栅,加载后采集u场及。场云纹干涉条纹,推算各组金瓷界面断裂韧性Jc值并观测裂纹扩展方向。结果加载条件下,裂纹周围显示应力集中区,条纹随载荷增加逐渐变密。由云纹干涉图位移场算得各组试件金瓷界面断裂韧性各不相同,其裂纹扩展方向也有差异。结论云纹干涉法适用于金瓷界面断裂韧性的研究,也可用于观测并预测裂纹的扩展方向及趋势。     

Comparative study of various internal fixation methods for treating patellar fractures by three-dimensional photoelasticity

Objective: To compare the biomechanical basis of 3 different internal fixation methods: nitinol patellar concentrator (NT-PC),tension band and wire circle in treating patellar fractures. Methods:The epoxy resin three dimensional photoelasticity patellar models were made by precise moulding, and were fixated by nitinol patellar concentrator (NT-PC) , tension band and wire circle respectively. The patellar models with frozen stress stripes were put into the polarized light field and the stress distributions were compared. As for the model fixated by NT-PC, by dividing layer, photographing and tracing, we used the iterative method to calculate the stress value of every internal node of the epoxy resin patellar model, and the character of stress was analyzed. Results:An overall stress field was yielded when the patellar model was fixated by NT-PC, and the stripes were more than that of tension band model and wire circle model, which have only few stress stripes in the fixated layers. Further analysis indicated that there were continuous fixated stresses in the facies articularis and distal pole of patella, and the character of stresses produced by NT-PC were mainly in longitudinal direction, then in transverse direction. The shearing stresses were small. Conclusion: The initiative and continuous memorial stress of NT-PC and its overall stress distribution character are the essence of NT-PC distinguished with tension band and wire circle in treating patellar fractures. The stress character produced by NT-PC is good for the stability of fracture site and prompts fracture healing.