The discoid medial meniscus is an extremely rare anomaly. Bilateral discoid medial menisci are much more rare but intermittently reported. We report the first case of bilateral discoid medial menisci with positive double PCL sign, which typically indicates a bucket-handle tear of medial meniscus. A literature review was also conducted on bilateral discoid medial menisci.

This paper presents a methodology to design optimal forming process parameters of the sleeper fixed reinforcing plate based on the use of computer aided engineering (CAE) technology. The methodology uses Unigraphics software to establish the numerical model and DYNAFORM software to simulate its sheet forming process to determine the feasible process parameters affecting its manufacturability, including whether the mould requires the binder, binder force, friction coefficient, and die fillet radius. The forming limit diagram and the thickness distribution diagram are selected to appraise and analyze the forming results. The orthogonal experiment method is adopted to simulate the design parameters to find out the optimum values for mould design.

During casting process design, CAD/CAE technology can play important role to avoid macroscopic irregularity, internal defect and assure casting performance. Based on the casting process analysis and gating system design, the numerical simulation of gray iron butterfly valve was done by hydrodynamic software Flow-3D to obtain its optimal process scheme. According to the simulation results including flow field, temperature field and defect distribution, the merits and faults of designed schemes were investigated and then the feasible gating system was proposed. The results showed that, compared with top or intermediate casting, when adopting bottom casting, steady flow of molten metal and reasonable temperature distribution could be achieved. And workpiece defects mainly distributed in riser. The predicted results are in good agreement with practical ones.

Polytetrafluoroethylene (PTFE) is known as a solid material with high lubricating property and low friction coefficient. The application of PTFE is significant to improve the tribological properties of coating. In this paper, Scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffractometry (XRD), Microhardness test and friction and wear experiment are adopted to study the effects of PTFE content on the structure, morphology and properties of coating. The results show that the addition of PTFE particles can reduce spherical particle size and increase the hardness and friction properties of coating when typical cauliflower shaped druse and excellent interface binding characteristics are maintained. If the content of PTFE is too much, some area of coating is prone to powder hoarding which may lead to the decrease of coating density, hardness, and friction coefficient stability.

Flanging and bending forming processes of the crossmember in car intermediate floor are investigated respectively by using numerical simulation technology. The numerical model of the crossmember was established and its press forming effect was simulated to determine the feasible process parameters affecting its manufacturability. Forming limit diagram and thickness distribution diagram are used to evaluate simulation results of different process schemes. And then optimum values of process parameters for flanging and bending are found, which can reduce the tendencies of wrinkling, springback and crackling during the stamping of the product.