Applied Mechanics and Materials Vols. 716-717

Abstract: Residual stress generated in the body parts during stamping process influences on its structural strength and stiffness partly. In this paper, the formality, stiffness and strength of hood-outer panel had been analysis based on Autoform and Altair-hypermesh, and the diagrams of major strain and plastic strain are shown. Compared the results by Geomagic Qualify; there are the same areas of stress concentration from the results. According to this, the body parts can be optimized to get excellent preference of stiffness and strength.

Abstract: The drilling speed to shorten the drilling cycle plays a decisive role in drilling process.Using the fire-suction hydraulic impactor can achieve percussive-rotary drilling.The fire-suction hydraulic impactor can transform drilling fluid’s pressure energy into mechanical energy.Withing bit static pressure,rotational cutting and vertical impact loading,the way of rock breaking will be faster and more efficient.Using Newton's second law to establish the corresponding kinetic equations,motion equations and displacement equations.The comparison between parameters and measured data validated the correctness of the formulas,which provides a theoretical basis for the products to improve and seriation.

Abstract: View of the current ice-making machine for cooling system of the state of loosely designed in this paper under operating principle and structure and the cooling characteristics of a household ice-making machine,precise exposition of various refrigeration equipment`s design and calculation method, analysis of its selection ideas for the ice-making machine for cooling system designed to provide a important value of reference.

Abstract: As a new numerical simulation method, the extended finite element method can deal with the discontinuous problems more effectively than the finite element method. In this paper, the basic theory about the extended finite element method is introduced briefly. The stress intensity factor of the crack of mode I is numerically calculated based on the extended finite element method. The numerical calculations show that the extended finite element method is an approach with high-efficiency for the problems with crack.

Abstract: CFD is the abbreviation of the computational fluid dynamics, which is widely used in engineering fluid simulation. Based on two-dimensional N-S equation and k-e turbulence model, this paper uses FLUENT software, finite volume method and SIMPLEC algorithm to do numerical simulation and analysis on flow field in centrifugal fan. In order to improve the efficiency and accuracy of calculation, this paper uses AutoCAD to establish the two-dimensional model of fan, and uses the structured triangular mesh to divide grid. Encrypting the blade can improve the precision and also save the computer memory. Through the calculation we get the internal flow field velocity and pressure distribution in the wind turbine, and get the power level cloud of internal noise in fan. It provides the technical reference for the optimization design of wind turbine.

Abstract: The new broken-explosive warhead for back deep underground target and airport runway hard target has a unique advantage. Through analyzing hard target characteristics of the concrete , process using ANSYS/LS-DYNA software to break-explosive warhead of a warhead forming process and penetration into concrete target is studied by numerical simulation. Experiments show: the simulation results are accurate. A warhead on concrete penetration and expanding role better, open a channel for level two warhead implement efficient damage. To counter this deep underground and airport target road of hard target penetration has a certain application prospect. .

Abstract: On the basis of javelin wind tunnel experiment, we established mathematical model of javelin flight to conduct a computer optimization and got the conclusions. When the initial velocity is in the range of 25m/s-30m/s, the best throwing condition is: the throwing angle is 40°, the angle of attack is 11°. The javelin throwing condition is not zero angle of attack was necessary and sufficient for obtained aerodynamic efficiency.

Abstract: In order to analysis the response of aerated flow depth to the VOF model, in this paper, we used VOF combining turbulent model to simulate aerated flow depth in a hydropower station spillway tunnel with high head and large discharge in China. The results show that aerated flow depth is slightly larger than the experiment water depth, but the maximum deviation are not greater than 5% (except the pile number 0+605.236 m). So, using empirical formula to converse the calculate value of water depth into aerated flow depth can make up for the defects of the VOF model which cannot directly get aerated flow depth of the cross section inside the spillway tunnel. But the section water depth can’t be obtained by empirical formula calculation value conversion when cavity exists in the spillway tunnel.

Abstract: According to the main characteristics of boiler operation process, part parameters of boiler and monitoring data, we not only can tease the relationship between various each physical quantity and the influence on the thermal efficiency of the boiler, but also be reasonable parameters and omit the complex on the minimal influence factors of heat loss, finally we use the counter balance calculation method to calculate heat loss, which is mainly aimed at the greatest effect of excess air coefficient, and we consider other major factors that affect the thermal efficiency of the boiler. According to the definition established physical model, the thermal efficiency of the boiler is optimized.

Abstract: The shape of hybrid monohull at the bow is quite complex and the viscosity force is the main component of the damping force in the drainage area of the bow when the ship moves in waves so that the result of the motion predicition by the traditional potential flow method is very different from the result of experiments. This paper tries to use new numerical compute method considering the effect of the viscosity to improve the precision of the sea keeping predicition. Based on the Reynolds Averaged N-S Equations (RANS) method, the paper takes a hrbrid monohull to compute the hydrodynamic coefficients. According to the result of model test, the prediction of the hybrid monohull’s the longitudinal motion in regular waves at speed of 18kn also indicates that RANS method can reflect viscid influence reducing the motion of hybrid monohull in waves.