Applied Mechanics and Materials Vols. 556-562

Abstract: Parametric resonance can lead to roll motions and endanger the ship, cargo and crew. The QR-factorization method for calculating lyapunov characteristic exponents (LCEs) was introduced. And then, parametric resonance stability of ships in longitudinal waves was analyzed by taking the fishing-entertainment rotational molding boat as an example. Simulation results show that, this method can be used to analyze ship stability and to accurately identify safe and unsafe operating conditions for a ship in longitudinal waves.

Abstract: The design method of ideal steering ratio based on constant yaw rate gain is studied in this paper.The linear 2-DOF vehicle model is established.The open loop total variance is selected as the objective function and the yaw rate gain is optimized by genetic algorithm. Then the ideal steering ratio is calculated and improved. The results of the simulation test show that the ideal steering ratios control can improve the handling stability of the steering-by-wire vehicle better compared with the traditional vehicle .

Abstract: In order to monitor the operation state and implement fault diagnosis of rolling bearing in rotating machinery, this paper presents a method of fault diagnosis of rolling bearing, which is based on EMD and resonance demodulation. Using EMD to decompose the signal, which comes from QPZZ-II experimental station, the components of intrinsic mode function (IMF) will be obtained. Then, calculating the correlation coefficient of each IMF component, the highest correlation coefficient of IMF component will be analyzed by resonance demodulation. Finally, the experimental results show that the method can accurately identify and diagnose the running state and bearing fault type.

Abstract: Film coating machine by way of spraying the coating solution onto the drug is in a continuous rolling surface. The tablet tends to produce tape smaller even if the spray flow blockage. Then the tablet will crack due to high temperature. Therefore, pharmaceutical tablet coating spray flow rate is a key factor affecting the quality. This article first proposes preventive clearing blocked in the pipeline but not blocking the upcoming clogged. Air purge starts immediately. PLC real-time acquisition is carried out by the pressure at both ends of the pipeline, the pipeline flow liquid contents, when the pressure is detected. The flow reaches a critical point obtained by BP network training, immediately starting the high-pressure air purge. The value of real-time detection uses PLC gun pipeline pressure, flow, etc. It combined weights of the neural element BP neural network model that was trained by the PLC programming. Gun pipe blockage and promptly started high pressure alarm air purge, preventive clearing blocked. Experiments show that preventive clearing blocked pipe blockage can promptly remove the gun.

Abstract: In order to improve the step accuracy of two-phase hybrid stepping motors, this paper presents a high-performance stepping motor driver based on controllable dead-time compensation. After CPLD(Complex Programmable Logic Device) logical processing, the subdivision drive signal created by microcontroller STM32 becomes a complementary dead-time compensation drive signal which can realize precise control of stepper motor. The experiment shows that this program not only has effectively reduced the power consumption of the stepping motor, but also made whole system cost less.

Abstract: The paper analyzes the rotor imbalance of cooling fan for the engine, and come to influence coefficient per unit quality. We can easy count the practice balancer cooling fan rotor. This method is very simple.

Abstract: In order to improve reliability of automobile transmission system and its running stability, this paper raises a reliability assessment calculation method. This method considers dependent failure of the parts, material strength degradation with increasing load times and uncertainty of load times in micro and macro scopes to explore main factors affecting the system reliability. The feasibility of this method has been validated by the example analysis. As a result , material properties of each gear parts, torques and load times play key parts in reliability of the system.

Abstract: After a torpedo anchor is released into water during its installation, the directional stability of this anchor is an important factor for its penetration performance. In this paper, a CFD method is used to simulate the falling behavior of the anchor, and detailed parametric studies are conducted to analyze the effects of various parameters to the directional stability. The results show that some parameters like weight, gravity center, and aspect ratio of fin have significant influence on the directional stability.

Abstract: The excellent braking characteristics is a key security measure for automobile operation. The study focuses on modeling and parameter settings of brake system, tire system and body system. During automobile design stage, a full model of automobile is established in ADAMS software circumstance in according to structural feature and main parameters. Virtual model technology can simulate the working condition, analyze whole performance of related products, solve some drawbacks in the traditional design and manufacturing process. Based on the requirement of country standard and national standard, the braking performance analysis and appraise is carried out in this study, at the same time, the braking performance is optimized.

Abstract: The purpose of this paper is to develop clinching technology using AC servo direct-drive device. The control systems of AC servo direct-drive device are designed to control the clinching. It could accurately control the connection of aluminum alloy 6061 sheets with the round joint. The joint quality is evaluated by the tensile tests. The results of the tensile tests shown that fracture load satisfied the required joint strength. Meanwhile, AC servo direct-drive device also could ensure the efficiency and quality of clinching process.