Advanced Materials Research Vols. 482-484

Abstract: Through large-scale model tests on composite foundation of cement-soil piles under cyclic loading, a program was compiled based on the platform of MATLAB 7.0, considering the effects of cement mixing ratio, replacement ratio, cyclic stress ratio and number of cyclic on the permanent settlement of composite ground. A back-propagation neural network model to predict the settlement was established, and its prediction accuracy was inspected. Meanwhile, an predicting model of multivariable linear regression analysis was established .To compare the prediction accuracy of the two methods, and the result shows that the trained neural network have the better predictive and generalization.

Abstract: In this paper, regarding a spur gear as the object, the natural characteristics under thermal effect are calculated by using ANSYS. Firstly, taking the friction heat and convection heat as the thermal loads, the gear is analyzed under a steady state temperature. Secondly, taking the thermal stress into account, the natural frequencies are calculated. Comparing the natural frequencies between change and without change of temperature. The result of this study shows that the thermal stress produced by the variation of temperature is the main reason of natural frequency change.

Abstract: Aimed to satisfy damping force change requirement of vehicle MRF suspension vibration control system, a controller of MRF suspension system based on On-Off control algorithm is designed, and a control system is carried out. The system takes single chip AT90CAN128 which obey the CAN bus protocols as micro-controller, and it accomplish AD conversion of sensor signal, design of On-Off algorithm and output of PWM voltage power control signal. The system also is used in vibration control experiment of tracklayer vehicle suspension system. The experiment shows that the controller can improve control accuracy, and the control effect is obviously.

Abstract: Make continuous extrusion test on cast AZ31 magnesium alloy by TLJ250 continuous extruding machine, and observe and compare the changes of product under different processes. Result shows that: when the extrusion speed is 3 to 4r/min, higher deformation and friction heat can provide heat for recrystallization due to higher deformation speed. The grains are even and fine, and under identical cavity structure and raw material, the grain refinement level relates to the extrusion ratio; when the extrusion ratio increases, the deformation of metal in cavity increases, and shear deformation goes to the heart of product; the deformation starts becoming evener, and the grains become move even.

Abstract: A synthetic approach to synthesize 4,8-Dibromobenzo-[1,2-c;4,5-c’] bis[1,2,5]thiadiazole from a common precursor 2,1,3-Benzothiadiazole is reported. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions.

Abstract: Wireless sensor network node positioning technology is one of the key technologies. Due to self-localization of sensor nodes in the process of positioning accuracy is not high, In this paper， the genetic algorithm approach to take, through the evolution of control, making the location of the nodes for continuous progress toward the optimal solution, in order to achieve continuous process of node positioning optimization. Simulation results show that the evolution of the genetic algorithm control, can reduce errors, improve positioning accuracy.

Abstract: In the Non-stability radial ring rolling process, the ring may collide with the guide roll, making the ring become a polygon. In extreme cases the rolling process could be terminated and the ring be scrapped. The stability evaluation of radial ring rolling has great theory and practice significance. In this article, based on the kinematics theory, a classified research on the dynamic phenomenon of radial ring rolling was done, and a stability evaluation method during the radial ring rolling was put forward. The evaluation provided a good base for the future ring rolling dynamic research.

Abstract: The overlap of the voltage and current of power MOSFET will leads large power loss when power MOSFET in a ballast turns on. To solve this problem, a self-adaptive ZVS protection circuit is proposed, which consists of a dead time control circuit and a ZVS control circuit. Compared with traditional circuit with fixed dead time, it can regulate the dead-time automatically to realize ZVS with a negative feedback loop and result reduction advantages come from, such as the induction of power loss and EMI, meanwhile the efficiency is improved. Hspice simulation shows that the ZVS protection circuit in the ballast with an input voltage of 14V and an operation frequency of 50 kHz can realize the self-adaptive dead time.

Abstract: In medium plate rolling, the calculation and setting of roll gap value considered not only insufficient austenite recrystallization effect on rolling force, but also coupling of bend elastically and rolling force; and based on combining pre-pressure force and local measurement could get the modal of roll gap value setting and prediction. The result indicated that the prediction of roll gap value is accord with measurement value, it can increase the production quality and hit rate of close-tolerance in medium plate rolling by means of the modal as the method to controlling dimensional accuracy.

Abstract: For industrial robot manipulator system, PD control theory is extensively used in the dynamic characteristics controlling. A new modified feed-forward compensation PD controller is introduced to optimize the stability and convergence of traditional PD controller for industrial manipulator system. By the co-simulation on ADAMS and Matlab/ Simulink, the paper designs a modified feed-forward compensation PD controller based on two-link manipulator model and completes track control trial. Through result comparison and analysis, the superiority of the new modified PD controller for two-link manipulator is verified.