Applied Mechanics and Materials Vol. 394

Abstract: The proportional modification parameters are useful for compensating the tooth form errors of spiral bevel gears. Based on the mathematical model for calculating the machine setting parameters and according to the relative position relationship between cutter and workpiece, the formulae for calculating the second-order proportional modification parameters for gears manufactured by spread blade method was deduced by the curvature and normal vector at calculation point. The proportional modification parameters can make the lengthwise curvature or profile curvature or lengthwise twist curvature of the concave and convex flank produce uniform change or difference change. The formulae is verified by experiment on CNC spiral bevel gear grinding machine and M&M sigma 7 gear measuring center.

Abstract: HSS cutting tools are used for aluminum mold milling experiments, different sets of milling parameters are taken to do comparative experiments, the impact of law of the respective milling parameters on the processing quality is Learned about, process improvements and best milling parameters are proposed, suggestions for improvement methods in effectively reduce the vibration of the mold processing, deformation, and improve processing efficiency and workpiece surface quality and other aspects are put forward.

Abstract: Precise measurement of tooth profile errors is the key technology for realizing close-loop manufacturing of spiral bevel gears. The measuring principle of tooth profile errors and the processing method of measuring datum is the key technology for realizing precise measuring. Based on the generating principle of spiral bevel gears and the model of CNC machine tool, the on-machine measuring principle and the measuring datum processing method were established. In order to verify the correctness of on-machine measuring principle, the on-machine measuring simulation system was established based on AutoCAD development platform. According to the spatial coordinates and normal vector of the discrete points of theoretical tooth profile, the on-machine measurement of tooth profile errors was simulated by intersection Boolean operation and the values of errors were calculated. The correctness of simulation algorithm is validated by comparing simulation result with the practical measuring result.

Abstract: This paper presents the improvement in chatter vibration damping using different types and arrangements of magnets, as well as comparison with normal cutting conditions in turning of stainless steel AISI 304. Chatter is defined as the self-excited violent relative motion between the cutting tool and work-piece. It is the common vibration problem that limits the productivity of machining processes, since it leads to shortened tool life, poor surface finish, breakage and premature damage of cutting tool, as well as mechanical deterioration. The occurrence of chatter during metal cutting process also causes instability of the machine tool system. Though there has been a large number of works on identifying the causes of chatter and its behavior, there is still no consensus among researchers on this very vital issue of machining. Previously, the incidence of chatter was thought to be due to forced vibration, BUE formation, cutting speed, and cracking during chip formation. Different ways to overcome this problem have been investigated, such as using piezoelectric inertia actuators, feed-forward neural network controllers, and work-piece preheating methods. In this research, permanent magnets with different size, strength, and composition are mounted around the cutting tool. A vibration sensor (accelerometer) is placed at the bottom of the tool to record the suppression of chatter amplitude in turning operation. It is shown that magnetic force can modify the frequency response function of the cutting tool resulting in improved cutting stability in turning operations. Chatter can then be effectively suppressed due to increased cutting stability.

Abstract: ntelligent power consumption system is an important mean to improve the energy efficiency. An embedded terminal was designed in the system, which can achieve intelligent control and management for devices, and reduce power and energy consumption. The terminal in the system was designed and implemented based on ARM platform, using B/S structure to communicate with the remote server through Internet. It has several wired and wireless communication interfaces, which can be connected with various electric equipments. For extensibility, the software of the terminal uses a hierarchical and modular approach which includes communication layer, device layer, interface layer and intelligent power consumption layer. Meanwhile, the communication protocol and the unified interface design in the terminal make sure that the terminal can interact with the remote server reliably and timely. Through experiments in the demonstration operation region, it concludes that the terminals work stable and reliable, and equipment intelligent control and management are fulfilled. The system has many advantages such as modularity and scalability, which can be widely used in many fields like smart grid and smart home, etc.

Abstract: Because of lacking of effective management and various energy-saving measures, a family smart power management system is introduced. The system includes the servers, LAN and smart power management terminal; the system can control the equipment to achieve the scientific management, and provide users a platform to interact with electrical equipment; the user can use the phone , PAD, PC and other mobile devices log the specified smart power management service website anytime, anywhere to control the electrical household electrical household appliances and query the power consumption, also can control the electrical household electrical household appliances at home through the smart power management terminal. According to the test of the system, the performances verify the system can effectively improve the power consumption rate, and achieve a good energy saving effect.

Abstract: The CO₂ reforming of coke oven gas (COG) for hydrogen production was investigated over mesoporous NiO/La₂O₃-ZrO₂ catalysts. At optimized reaction conditions, the conversions of CH₄ and CO₂ more than 93%, while a H₂ selectivity of 94.7% and a CO selectivity of 98.6% have been achieved at 800 °C. The effect of reaction temperature on the catalytic performance was investigated in detail. The catalysts with appropriate La₂O₃ content showed better catalytic activity and resistance to coking, which will be promising catalysts in the catalytic dry reforming of COG.

Abstract: This article introduces, in low voltage circuit breaker on the switch instantaneous performance detecting station, in order to adapt to the requirement of modern high-speed automated production test, the main factors affecting the detection speed - switch measurement point method is studied, the improvement, the existing method of "contact switch" to replace "non-contact switch method, through theoretical derivation and experimental proof, proved that the new method is feasible and economical.

Abstract: The overall mathematical model of doubly-fed induction generator (DFIG) is established in this paper, a controller is designed in detail for DFIG under the strategy of stator flux orientation (SFO). Simulation studies are carried out in this paper with Matlab/Simulink under three operation states of DFIG, the simulation results verified that the controller designed can realize the decoupling of active and reactive power effectively.

Abstract: The dual power supply system is widely used in our daily life. When power instantaneously switched between the main power and the stand-by power supply, the voltage fluctuations had the varying degree influence on machines. Based on the principle of correlation coefficient of two waveforms and instantaneous reactive power theory, the dual-power supply automatic and instantaneous switching device without disturbance is provided in this paper. The equipment could identify and isolate the broken-down power source in 5ms. At the same time, power supply keeps continuous meeting the requirements of power quality without voltage drop.