Applied Mechanics and Materials Vol. 487

Abstract: The numerical simulation method was adopted to study the single-pass controlled rolling deformation process of the 400mm thick slab .Two forms of the rolling deformation which are uniform temperature rolling and rolling of temperature waiting under air cooling have been used to simulate the center strain changes of the thick slab. It was shown that: increasing the deformation of single-pass can significantly increase center strain of the thick slab; temperature waiting under air cooling can lead to a large temperature range between surface and center, which can increase center strain of thick slab during subsequent rolling.

Abstract: Based on the governing equations of the unsteady flow of the power law fluid in the eccentric annuli with the inner cylinder reciprocating axially in bipolar coordinate system, the calculation formulae of normal force distribution on the wall of the inner cylinder of the power law fluid flowing in the eccentric annuli with the inner cylinder reciprocating axially in the bipolar coordinate system were established,and the relevant numerical calculation method was given.Taking the aqueous solution of partially hydrolyzed polyacrylamides (HPAM) for examples,the normal force distribution were calculated by using the calculation formulae and numerical calculation method mentioned above, the curves of the normal force distribution on the wall of the inner cylinder of HPAM aqueous solution were plotted and the effects on the normal force distribution of the flow behavior index of the power law fluid, the stroke and the stroke frequency of the inner cylinder were analyzed.

Abstract: Granular materials are ubiquitous in industrial, mining and pharmaceutical processes. In this paper, we study the flow pattern and optimization of granular chute flow with two bottlenecks. The dependence of flux on channel width show dilute to dense flow transition. A remarkable bistable phenomenon appears near the transition point. Base on this discovery, one can optimize the flow rate along such channels.

Abstract: This paper presents the characterization of a single chip high power LED package through simulation. Ansys version 11 was used for the simulation. The characterization of the LED package with aluminum cylindrical heat slug was carried out under natural convection condition at ambient temperature of 25°C. The junction temperature and the stress of the LED chip was assesed. The LED chip was powered with input power of 0.1 W and 1 W and the heat dissipation was assesed. Results showed that that the junction temperature and the Von Mises Stress of the single chip LED package increases with the increased input power.

Abstract: As one of the important parameters of dynamic soft reduction technology, reduction position seriously affects the using effect of this technology to decrease center segregation and porosity of continuous casting slabs. According to the actual production conditions, a two-dimensional solidification and heat transfer model was established. In order to obtain more accurate model, the heat transfer coefficient was amending by the pin shooting technique in measuring shell thickness. The laws of the effect of casting speed, superheat degree and specific water flow on reduction position were analyzed respectively and reduction positions were predicted in different working conditions based on the model. The experimental results show that the center segregation and porosity decreased obviously when it produces at the reduction position predicted by the model.

Abstract: The nonlinear Sequential Quadratic Programming algorithm is adopted to optimize the large reflector antenna with 110-meter aperture. Firstly, an initial finite element model of the antenna is built with the parametric programming language APDL in ANSYS. Then, taking into account of two levels in size and shape and two working conditions in zenith and horizon, the structural optimal model is given with surface precision as the goal. Finally, a better structure satisfying the design requirements is obtained through the structural optimization in multi-levels and multi-working conditions.

Abstract: The electromagnetic field and the heat generation rate distribution in the semi-infinite body which is heated by the induction coil, are obtained by solving the Maxwell equations through the analytical method. The impacts of the air gap width, induction coil width, current density and current frequency on the heat generation rate distribution in the workpiece are studied. The results show that the heat generation rate in the workpiece is in direct proportion to the square of the eddy current density and the square of the induction coil width. The heat generation rate follows the exponential attenuation law with the increase of the air gap width. The current density has effects on both the maximum heat generation and the heat generation distribution. When the effect of the air gap is neglected, the higher the current frequency, the larger the maximum heat generation rate. However, when the effect of the air gap is considered, the maximum heat generation rate will increase with the augment of the frequency when the frequency is less than the critical frequency and decrease with the augment of the frequency when the frequency is larger than the critical frequency, which is firstly reported in the paper. Moreover, the higher the current frequency, the heavier the heat generation rate attenuation in the workpiece.

Abstract: The velocity distribution coupled thermal and fluid flow a rib-tube was studied in this article. Based on theory analysis and numerical simulation, we choose modal and wall function to simulate the flow in rib-tube, velocity to definite the dispersed phase. The governing equations were built and solved by numerical way. The progress of flow and heat exchange in rib-tube, the rules and contours of temperature, velocity were obtained, they shows that, along the rib-tube, velocity was changed with the temperature rising , which could give us a reference for engineering application .

Abstract: The purpose of this paper is to study the contact-impact between ellipse and ground. The contact-impact position is non-fixed when the ellipse is rotated. Ellipse equations are built by generalized coordinates. The contact point is estimated by the elliptical geometric characteristics and equations. Do dynamics analysis by the method of continuous processing which uses spring damper mode in this point. This spring damper mode is based on the nonlinear spring damper model of Hunt-Crossley. Friction is ignored in this paper. Finally the numerical solution is given by Matlab.

Abstract: In this paper, a comparative thermal analysis is carried out according to the bottom of HR-FD51 electric cooker liner about a large or small fillet. And then the thermal analysis results are applied to stress analysis as the body loads. The results show that it can reduce thermal stress and total deformation with a large fillet, thereby, improves the lifespan of electric cooker liner and thermal effects as well.