Accurate 3D reconstruction of subject-specific knee finite element model to simulate the articular cartilage defects

The biomechanical relationship between the articular cartilage defect and knee osteoarthritis (OA) has not been clearly defined. This study presents a 3D knee finite element model (FEM) to determine the effect of cartilage defects on the stress distribution around the defect rim. The complete knee FEM, which includes bones, articular cartilages, menisci and ligaments, is developed from computed tomography and magnetic resonance images. This FEM then is validated and used to simulate femoral cartilage defects. Based on the obtained results, it is confirmed that the 3D knee FEM is reconstructed with high-fidelity level and can faithfully predict the knee contact behavior. Cartilage defects drastically affect the stress distribution on articular cartilages. When the defect size was smaller than 1.00 cm², the stress elevation and redistribution were found undistinguishable. However, significant stress elevation and redistribution were detected due to the large defect sizes (⩾1.00 cm²). This alteration of stress distribution has important implications relating to the progression of cartilage defect to OA in the human knee joint.     

Effect of packing parameters and gate size on shrinkage of aspheric lens parts

In order to produce the high quality optical aspheric lens,the shrinkage of lens should be strictly controlled during the injection process.Serials of experiments are done to find the factors that affect the lens shrinkage during the injection molding process.The study is focused on the effect of gate size,packing time and pressure on the shrinkage.The gate size decides the effective packing time.Only when the effective packing time is enough,the shrinkage size will be decreased along with the packing press...     

整车热管理的一维与三维耦合仿真

同时建立了三维整车热管理数值模型和发动机及其冷却系统的一维数值模型.发动机舱内流场及其换热特性三维仿真获得的对流换热系数和换热量,可用来在发动机及其冷却系统的一维仿真中算出冷却系各部件的温度;这些又可作为三维仿真的边界条件,去更新发动机舱的热流特性.如此反复迭代直至收敛.这样的一维和三维耦合仿真分析,为样机制造前整车热管理的仿真提供了一种有效的方法.