Applied Mechanics and Materials Vols. 271-272

Abstract: The ball surface and sub-surface defects can be test by the eddy current nondestructive method. The core part of the eddy current system is the sensor’s design, including the coil and the process of induction signals. At the end, through experiment of detecting a set of defect ball, with a better result. It’s shows that the amplitude of the detection signal is proportional to the depth of the steel balls crack.

Abstract: The computer-aided design is applied more and more widely in the engineering field. In order to enhance the design efficiency of the V-belt transmission, combined the computer-aided design with the optimization design. With the analysis on the characteristics of chart data in the traditional design, put forward a programmed method for the data, lists, charts in the ordinary V-belt transmission design, by using the linear weighted sum method with VB as a programming language, to establish the optimal mathematical model. A sample has been carried out and results have shown that the programmed method may simplify the design process and reach the purpose of improving the design efficiency and accuracy.

Abstract: To effectively form three-dimensional sheet metal parts with various curvatures produced in small quantities, flexible rolling forming, a new flexible forming method is being developed. Firstly, concept of the flexible rolling forming is introduced and its characteristics and working principle are analyzed by the combination of conventional rolling and multi-point forming. Secondly, the equipment design scheme of flexible rolling forming is put forward and the relevant device is developed. Thirdly, the feasibility and practicality of flexible rolling forming are verified by rolling several typical three-dimensional surface parts such as spherical and saddle surface parts by self-developed device. Finally, verifies the reasonableness of the device and at the same time possesses the important guiding significance to the research and development of practical flexible rolling forming equipment.

Abstract: Aimed at the contradiction between high frequency response and large flow of servo valve, the paper puts forward a 2D servo valve with differential drive based on magnetic controlled shape memory alloy(MSMA). To realize large flow control, the valve-spool is set of flow increasing orifice to match the flow increasing window on the valve-sleeve. The paper briefly introduces the structural features of the 2D servo valve and the working principle of the differential drive. It also has a simulation analysis on the magnetic field of the drive and the low field of the valve. Simulation results show that, the flow of the valve is linear with the input current.

Abstract: The energy gradually become the mainstream of the development of the new century automobile. Worsen environmental problems and increases nervous energy issues forcing people to continue to seek a clean alternative fuels, in order to improve the traffic situation. Energy to become the focus of attention of Governments and car manufacturers. People have spared no effort to carry out energy vehicles.

Abstract: The speed increasing gearbox is the key part of the wind turbine, and it requires higher reliability and service life than general mechanical system. The single-stage planetary gears train(PGT) are commonly used in the semi-direct drive wind turbines, which sustain low speed, heavy load, varying speed and varying load. The dynamic characteristics are very complex, due to the frequent disturbance under the random wind and have a greater impact on reliability and stability of wind turbines. In this paper, the torsional dynamic model for PGT of semi-direct drive wind turbine was developed by lumped parameter method. According to the configuration and design parameters of the planetary gears, the natural frequencies are calculated, and the vibration modes are also analyzed. The actual wind speed is simulated by the weight sparse least squares support vector machines (WSLS- SVM), and the input torque load is also obtained. Considering the varying wind load and parameter excitations of system, the dynamic response of the PGT is calculated by numerical method.

Abstract: In order to accurately obtain the influence of rotational effect on fluctuating component of turbulent wind acted on wind turbine, considering source spectrum and rotational sample points were changed since wind shear changed mean wind speed in the rotor plane along the vertical direction, rotational Fourier spectrum with wind shear was deduced. Based on the investigation on a 3MW three-bladed pitch regulated wind turbine, rotational Fourier spectrums with and without wind shear were compared, the effect of radius on rotational Fourier spectrum was analyzed, cross power spectral densities of rotational Fourier spectrum with different blades and variable radius were compared. The results show that the effect of wind shear on amplitude of rotational Fourier spectrum is unconspicuous while the phase frequency characteristic is alternative for the sample points are changed. Rotational Fourier spectrum energy removes to the high frequency bands, the amplitudes of peak at the integer multiple rotational frequencies increase with radius increases. The initial phase has little influence to the amplitude of spectrum, and cross power spectral densities of different radius are obviously less than auto power spectral densities of the same radius.

Abstract: To predict energy density response of random structures using EFEM, a perturbation method was introduced into governing equations of energy density for one- and two-dimensional structures. Two equation sets governing the energy density response of random structures were obtained. Simulations were carried for a plate with random damping ratio and the energy density response was obtained. It can be seen that EFEM provides space- and frequency-averaged response. Comparing with probabilistic method, the governing equation sets provide the same mean response and a smaller response range. The perturbation method using in EFEM turns out an effective method with less uncertainty and a promising method for response prediction for random structures.

Abstract: According to the usage of vehicle radar antenna pedestal connection plate, this article analyzes and compares the structure characteristic of welding and casting. We decide to adopt the casting structure and use cast aluminium ZL101A. Based on the connection plate of using conditions, we analyze the deformation and stress of connection plate by the finite element analysis software. The design is in line with the material allowable requirements and to meet the requirements of the system stiffness.

Abstract: To handle change propagations during complex product development, an analysis framework based on linkage model was proposed. Firstly linkage was defined to encapsulate the relations among product characteristics, and methods of linkage identification from multi-dimensions and linkage model construction were given. Then how to identify change propagation paths step by step in open scene and how to identify change propagation paths with improved mouse maze algorithm in closed scene were discussed. In the following a quantitative evaluation method of change impact risk was advanced. Finally an example of carrier robot moving structure design change was provided to validate this method.