Applied Mechanics and Materials Vols. 395-396

Abstract: relevance between technological parameter and processing effects in WEDM is extremely complex. In order to solve the difficulty of set up mathematical model for technological parameter and processing effects in engineering ceramics WEDM, an prediction model based on fuzzy logic is proposed through establish fuzzy controller by input/output fuzzification, fuzzy inference and settle fuzzy, whereas, build prediction model of engineering ceramics WEDM surface roughness change according to technological parameter utilizing established fuzzy logic controller in matlab. Laboratory finding shows, utilization of this model can precisely predict surface roughness under preset condition with relatively minus error, which further validate the reliability of this model. Keywords: Engineering ceramics, fuzzy logic, WEDM, processing optimization

Abstract: The casting filling numerical simulation technology is of great significance to optimize the casting process, improve castings quality, and reduce production costs. Component wise splitting method only uses a small amount of iterations between velocity field and pressure field, so it has high computational efficiency in theory. The calculation accuracy is analyzed through Lid-driven cavity flow model, the result has a good agreement with literature results in low Reynolds number, but there is a big deviation when high Reynolds number. Finally the fraction step method is applied to the solution of the low pressure casting filling process, Calculation results coincided with the experimental results.

Abstract: For the difficulty of calculating the size of the Pre-Manufactured hole of flanging, the formula was derived by using the theory of equal line length and the theory of equal area. And the formula was verified by finite element simulation. Due to theoretical formula has certain error, the optimal design method based on interpolation was put forward and optimization design the size of the Pre-Manufactured hole of flanging. Engineering example shows that this optimization design method is accuracy and convergence speed, and it can quickly calculate the the size of the Pre-Manufactured hole of flanging.

Abstract: A three dimensional incompressible gas-liquid two-phase flow model is proposed to accurately simulate the fluid flow of casting's mould filling process. The gas entrapment during mould filling is studied under different initial velocity and pressure conditions. The simulation results show that the velocity of change has a larger effect on gas entrapment, Initial velocity affects the distribution of temperature field,meanwhile gas entrapment parts specialized sampling is proceeded for qualitative detection at the scene. The simulated result is consistent with the experimental result, which can be reference for the process parameters selection and mold design of filling process in large steel-ingot. Keywords: gas entrapment, the filling process , the numerical simulation

Abstract: A new predictive model has proposed based on compensation fuzzy neural networks for thermal error in NC machine tools . The structure of model , fuzzy rule , training algorithm and some technological problems are discussed.And the result of intelligent prediction and accuracy evaluation are given.

Abstract: Virtual manufacturing technology is used to simulate the computer numerical control (CNC) lathe, virtual prototype of the CNC lathe is established. In the simulating process, the explain module and the check module of the CNC code are analyzed, the differential radial dynamic scaling technology is used to simulate the workpiece forming process, then the motion simulation of the virtual CNC lathe system is realized, and the system is drived by the CNC code. The machining process and workpiece forming process can be observed directly in the virtual environment, so the correctness of the CNC code can be checked in advance to avoid the interference, collisions or other problems in the actual lathe processing and reduce the the scrap rate of the workpiece and tool in the actual machining process.

Abstract: The mathematical model and the simulation model of the progressive distributor are established using an analytic method and AMEsim, a kind of simulation platform, respectively in this paper. The influences of the progressive structure, the viscous friction coefficient, the flow and pressure of the system and the size of throttle orifice on the performance of the progressive distributor are analyzed by the numerical simulation method. The results show that the fluctuations of the flow and pressure of the system are produced due to the overlapping motion of the three pistons, the oil-flow of the progressive distributor can be stabilized by choosing a reasonable viscous friction coefficient, and motion stability of the pistons of the progressive distributor, and the stability of the flow and pressure for the system are influenced by the size of throttle orifice. These conclusions will provide bases for the design of the oil-air lubricating system and the improvement of the structure of the progressive distributor.

Abstract: Several air cylinders are employed in complex equipment in pebble-bed high temperature gas-cooled reactor. They were designed to actuate remote movements in radioactive environment. An electromagnetic self-locking device was designed to lock them in safe position when the compressed air source is offline by accident. But the disadvantageous temporary standstill of armature in unlocking process still needed to be eliminated. Maxwell 2D transient analysis was performed to simulate the armature motion and compared with the experimental results. A comprehensive understanding was then achieved, and the parallel capacitor solution to the standstill problem was developed. With further numerical simulation and experimental verification, the self-locking device with capacitor connection was optimized. The armature motion was accelerated and the standstill was eliminated. The maximum temperature rise did not exceed the material limit value yet. The as-improved device would help guarantee the fail-safe feature of the cylinders.

Abstract: Cage roll-forming is an advanced roll-forming technique widely used in high frequency welding (HFW) pipes production. However, to the authors' knowledge, the real cage roll-forming production is mainly on experience rather than science. Few publications can be found on cage roll-forming for its complexity. In order to improve the understanding of the technique, a large deformation elastic-plastic finite element model for the HFW660 cage roll-forming mill was established and simulated through adopting the dynamic explicit algorithm. The distribution of effective plastic strain and the deformed geometry of the strip at the pre-forming and linear section were obtained. The simulation results were validated with the measurements. The results show that the biggest effective plastic strain (EPS) occurs at the center of strip. The distribution of EPS is far from uniform on the cross-section of the strip. This may owe to the uneven distribution of down-hill amount.

Abstract: We designed a semi-real simulation platform for the cold rolling mill that was composed of Simulation Computer, Simulation System of Field Signal, AGC Control System, Console of Rolling Mill and the Main Control Computer, and built the mathematical models in the Simulation Comuter, for the hydraulic servo system, rolling force and thickness of strip material. In the platform, the Simulation System of Field Signal output the simulation data as standard sensor signal; the AGC Control System is the same as that used in real rolling mill system. We simulated the milling process of real rolling mill system at this platform using the field-recorded online data. The differences between simulation results and those in real system were small. Simulation results show that this simulation platform can be used in the research and optimization of rolling mill control system.