Applied Mechanics and Materials Vols. 651-653

Abstract: It is affected by multi-dimensional vibration during car’s driving. In this paper, the forms of multi-dimensional vibration from car instruments and equipment are determined, and the type selection principals for main body mechanism of car multi-dimension vibration-absorption device are introduced. Besides, using software ADAMS, virtual design and kinematical characteristics test for car multi-dimension vibration-absorption device are fulfilled.

Abstract: Ultrasonic vibratory cavitation erosion tests were carried out on studying the cavitation erosion protection performance of different type of heavy-duty engine coolants for cast iron material of wet sleeve cylinder liners. The influence of coolant type, freezing point, corrosion inhibitor content and test duration on anti-cavitation performance were analysed. The experimental results showed that the anti-cavitation erosion performance of organic acid type heavy-duty engine coolants were better than the inorganic salt type heavy-duty engine coolants. For the same formulation coolant, increasing the content of ethylene glycol or corrosion inhibitor can improve the anti-cavitation erosion performance. With the extension of ultrasonic vibration test time, the anti-cavitation erosion protection performance for cast iron was reduced.

Abstract: Ground target position estimation of near space vehicle is the key technology in military and civilian field. In this paper, we propose an effective method using the cubature Kalman filter (CKF) based on direction of arrival (DOA) and its rate of change. Comparisons with the location method only using DOA and the classic EKF algorithm are conducted respectively. Simulation results indicate that the proposed method has faster convergence speed and better location precision.

Abstract: The paper presents a circuit topology favorable to drive piezoelectric actuators for high frequency servo valve. It begins with a short overview of different energy-saving PZA drive types and their tradeoff between efficiency and circuit complexity. Then the mechanical structure and equivalent model of the piezoelectric servo valve are described. And the circuit topology including an energy-saving oscillator, an efficient DC bias power and a repetitive controller especially for tracking reciprocating motion, is proposed. The efficiency-improved PZA drive is then derived from the above design. Finally, the drive together with the servo valve is tested in the simulation experiments.

Abstract: It is always difficult to obtain a reliable result of helicopter mission effectiveness evaluation (HMEE) by traditional methods. In order to solve the problem, this paper compared and analysed advantages and disadvantages of traditional effectiveness evaluation methods, and presented a simulation-based helicopter mission effectiveness evaluation method. The method is based on the simulation data. The method combines with advantages of multi parameter evaluation method, computer simulation evaluation method and logarithmic evaluation method. By using the reliable helicopter flight simulation data and an objective weight coefficient calculation methods, we can get accurate and reliable helicopter mission effectiveness value. Research proves that this method can be applied in the field of effectiveness evaluation.

Abstract: Network latency was usually uncertain or random, and the packet loss and temporal disorders could also be attributed to a certain degree of time delay. This paper briefly described the basic principle of predictive control and deduced the predictive control algorithm based on Toeplitz equation, finally combined with the simulation example to verify the validity and superiority of the new algorithm, from the operation speed of the algorithm, the signal tracking capabilities when time delay existed, and performance for overcoming the influence of model mismatch.

Abstract: Transmission loss is an important noise reduction parameter of exhaust muffler. Based on the finite element method, transmission loss is calculated, and the influential effect of the fluid is considered in this paper. Through calculation of transmission loss of the single expendable muffler and composite muffler, the results show that expansion ratio affects amplitude of transmission loss, and expansion chamber length affects the attenuation frequency bandwidth. The analysis method and conclusions are instructive to the design parameters of exhaust muffler.

Abstract: The flow rate in high pressure hydraulic system is greatly affected when flow meter is inserted in the system. A method was proposed that was by measuring the lateral pipe flow instead of directly measuring system of main flow. According to this method, simulation model was set up based on software. And the influence of the flow distribution relationship between main and side oil-way by the change of relief valve. Theoretical studies show that the measurement method is feasible.

Abstract: This paper was concerned with stability analysis and controlers design with packet dropouts for discrete-time NCSs. Stability controllers via state feedback is constructed for the switched system by using an LMI-based method.

Abstract: . Since the theory of one-dimensional plane wave is difficult to predict the internal sound field of the complex structure muffler accurately. Mathematical model of the composite muffler is analyzed, and the three-dimensional finite element method is adopted to establish the acoustic model in this paper. Transmission loss and characteristics of internal sound field of the composite muffler are calculated through sound and vibration simulation. Influential effect of the fluid on transmission loss is analyzed. The analysis method and conclusions provide a basis for the design of composite muffler.