forming process planning and technology realization of the monoblock break beam frame

In order to meet the performance demands of train lorry, a die forging drawing method based on structure features analysis was proposed to form the L A break beam frame. The finite element method was used to simulate a series of die forging processes and the drawing processes with different parameters. The optimum cross section shape of the performing die was obtained from these simulation results. It is found that local back flow of the metal is the primary cause of necking defects in drawing. Furthermore, the best drawing speed is determined to be from 87 mm/s to 96 mm/s. The results of trial manufacturing and product detection indicate that employing a die forging drawing process to form the monobloc break beam frame is feasible.     

Forging Process Development of Thrust Cone Based on Simulation Technology

以藁城、黄骅、沾化冬枣为试材,研究了不同产地冬枣采后贮藏过程中的品质变化.试验结果表明,藁城、黄骅、沾化冬枣的冰点分别为-3.5℃、-4.2℃、-3.9℃;在0℃贮藏条件下,随着贮藏时间的延长,不同产地冬枣硬度均随着贮藏期的延长而下降,VC含量逐渐减少,可滴定酸含量在贮藏过程中整体上呈下降趋势,沾化冬枣酸含量最高,藁城冬枣还原糖含量最小,在贮藏过程中变化较大.贮藏结束后各地冬枣硬度差异极显著(P＜0.01),VC含量差异显著(0.01＜P＜0.05),可滴定酸含量差异极显著(P＜0.01),还原糖含量差异极显著(P＜0.01);黄骅地区土壤中平衡的氮、磷、钾配比,适宜的气候条件,导致黄骅冬枣耐贮性优于藁城、沾化冬枣.     

Forming process of asymmetric wall forging

Asymmetric wall products are widely used in the engineering. However, there are many limitations in the traditional forming processes employed to produce them. Oil pump stator has been studied as an instance to present the forming process of asymmetric wall products. First, a theoretical analysis of the forging's forming process has been made. Second, a rigid-visco-plastic finite element model of oil pump stator has been constructed and three dimensions FEM simulation and analyzing of extruding process have been taken by employing the simulation software. At last, parameters of the forming process have been optimized, the rule of forging's metal flow in the forming process has been analyzed and some distributions of stress and strain have been offered. These data can be use to direct the production of the other asymmetric wall forgings.     

Failure analysis of upset bending equipment for a heavy crankshaft with continuous grain flow

A failure investigation is conducted on the upset bending equipment of a heavy crankshaft with continuous grain flow which is broken in the first use after the crankshaft flange is modified to deform in the die cavity. The forging process of the heavy crankshaft is simulated using the DEFORM 3D software, through which the forming load and die filling are calculated. Using the I Dears software, the structural strength calculation for the upset bending equipment is performed. The stress field and displacement in the equipment are obtained. The failure analysis of the die base is accomplished. The analysis results show that the practical crack location and orientation in the die base are consistent with those in the structural strength calculation.     

Numerical simulation of influence for the process parameters on multi-roll flexible stretch forming

Multi-roll stretch forming (MRSF) process is a new flexible process. Through extensive numerical simulations of the MRSF process, it is found that the smaller the distance between die and rollers is, the more easily the shape can be formed, and the better the quality of formed part can be. However, the distance between clamps and rollers has little effect on the formed parts. The corresponding stretch forming experiment has been done and the results show that the simulation trend is consistent with the experimental results.     

Advance in Spray Forming Technology and Its Prospect

Spray Forming technology gets involved with new materials preparation techniques in multiple domains such as powder metallurgy, fluent metal atomization, rapid cooling and non-equilibrium solidification. High performance alloy and metal matrix composite with high density, low oxygen content and microstructure featuring rapid solidification can be fabricated by spray forming. Spray forming, which is of short process flow, low cost, high deposition efficiency, flexible manufacture system, becomes a kind of near shape forming and rapid solidification technology with great prospect. Therefore the developing process history of spray forming technology is introduced and the current research and development status of spray forming technology in the fields of aluminum alloy, steel material, magnesium alloy, copper alloy and high temperature alloy and metal matrix composite is described. Multi-layer spray forming and in-situ reaction atomization spray forming are also discussed. In addition, evaluation and prospect for the technology are presented.     

Twisted Blade Virtual Design for Steam Turbine

Due to lack of estimation during initial stage of traditional physical design process for industry product, the efficiency of conduct development is low with high cost. A basic framework of twisted blade virtual design is set up based on the theory and method of product virtual design, and aiming at the thermodynamic process of middle or lower stage of steam turbine. The molding rule of twisted blade is found by thermodynamic computation program. The study of blade virtual design is carried through from 3-dimensional modeling to simulation test. The combination of thermal power theory, computer simulation technology and CAD system forms a kind of design method with the superiority such as high efficiency, low cost and good decidability is represented in the virtual design of turbine blade.     

Dynamic Simulation for Hydraulic Pressure AGC of Rolling Mill

AGC control technology is one of the key techniques used in modern rolling mill, the effect of which has influence on the accuracy of the product. On the base of analysing system composition and dynamic characteristics of the main dynamic emelent, a danamic simulation model is put forward,and then dynamic simultion for the hydraulic AGC system of 3340 rolling mill is implemented. Then, it lays a foundation for the design of rolling system and the dynamic simulation of the rolling process.     

Mathematical Model of Selective Catalytic Reaction of Nox in Reactor and Its Simulation

As the domestic technology of selective catalytic reduction(SCR) has not been mature.A assembled-parameter dynamic mathematical model is established for the primary chemistry reaction process in SCR reactor.The mass balance equation of the NH3 adsorption-desorption on the catalyzer surface and six gas components,and total energy balance equation in SCR reactor are set up respectively.A dynamic simulation model has developed by using MATLAB simulation tool.The steady calculation for model is carried on.Based on the established dynamic simulation model,two dynamic simulation experiments have been done,which include the simulation experiment of step disturbance about NOx concentration and temperature.The simulation results current is correctl.The analyzed results indicate that the established dynamic mathematical model for SCR reactor is credible,and prove that the simulation model is practical.     

Development and experiments of direct resistance heating in hot forging

A new hot-forging method by means of direct resistance heating is investigated aiming at the long produce time and large energy consumption of traditional hot forging. The hot upsetting experiments with cylindrical billet of 42CrMo4 are performed. The influences of initial contact force, surface quality of the billet and current intensity on the heating temperature are researched. The results of the experiments show that the billet can be heated quickly to forming temperature by the approach. The relatively low initial contact force is useful to increase the heating temperature. The heating temperature is proportional to the square of the current intensity, and the heating temperature is seriously affected by the surface quality. During the forming process the billet cooling rate is effectively decreased and the forming time is extended in relation to the resistance heating.     

3D Meso scale Failure Simulation of Four phase Composite Concrete

Taking into account the influence of the internal micro cracks on the strength and deformation of concrete, a four phase composite material model was proposed, in which it included mortar, aggregate, interface and random defects. Meso scale unit in concrete was subjected to elastic plastic damage constitutive of increments form in strain space. With the simulation of mesh concrete crack growth by damage elimination, the damage processes of concrete under 3 D uniaxial compression and the elasto plastic damage process of concrete under uniaxial tension with heterogeneous specimen were obtained. It was shown that the proposed four phase model added the simulation of random defects, with which it was more appropriate to the actual situation in concrete forming. The percentage of random defects in volume was the key to determine the weakening degree of macro strength of concrete. The cracks occlusion was obvious for the lower homogeneous uniaxial tension specimen and the fracture was clearer for higher homogeneous specimen. The simulation results was in good agreement with test results.     

A 3D Thin Slot Model for Shielding Analysis

The apertures or slots on shielding enclosure are the main factor to influence the shielding performance.The simulation for thin slots in the electromagnetic shielding analysis has been a bottle-neck.Subcellular models of thin slots in the finite-difference time-domain(FDTD) method are investigated.A 3D thin-slot algorithm based on contour path(CP) method is presented for the application to shielding enclosure.The accuracy and the applicability to the slot width are validated with finer mesh model or capacitive thin-slot formalism(C-TSF) for slot models with different width.     

基于OnyxFLOWER的虚拟花卉建模技术的应用研究

摘 要：随着信息技术和计算机技术的快速发展,以植物为对象的自然景物模拟现已成为计算机图形学领域的研究热点之一。本文重点介绍的是一种基于花卉多层次拓扑结构的三维建模软件OnyxFLOWER,并以麝香百合（Lilium longiflorum）为例对建模方法、建模特点进行分析说明,以期为后续研究提供思路和方法。     

Parallel and Distributing Strategy to Solve Dynamic Characteristic of Complicated Mechanical Structure

The work device of hydraulic excavator is considered as subject investigated, the parallel and distributing strategy to solve dynamic characteristic of complicated mechanical structure is put forward. When computing process isinefficient can be overcome by using high performance computing technology. The strategy can provide an effective approach to carry out system mechanical product generalized optimize.     

VR-based Urban Landscape Artistic Design

"Digital City" has gradually emerged,promoting the digitalization of urban landscape design,and meanwhile,virtual reality (VR) technology allowing us to create and experience the virtual world has come into reality.The use of VR technology in the urban landscape design,and interactive 3D dynamic view,multi-source information fusion and system simulation of the entity behavior will be beneficial to generate the simulation environment of urban landscape design on the computer,and guide the scientific development of urban landscape design.On this basis,this article analyzed the connotation of VR technology and basic characteristics of urban landscape artistic design based on the overview of previous studies on the urban landscape design in multiple aspects,and further explored the application of key technology in the VR-based simulation of urban landscape artistic design,to provide the reference and idea for urban landscape design,and improve overall effect of urban landscape artistic design.     

Implementation of Three-dimensional Terrain Based on MultiGen Creator

This paper mainly analyzes methods and technology of three-dimensional terrain with terrain module in MultiGen Creator2.6.According to character of real-time,accuracy and reality in terrain modeling,it gives the application scheme based on the terrain of space launch site.An new source data of terrain(grid map) conversion method is proposed.The authors sum up paste texture with contour strip and also put forward an method of combining Polymesh/Irregular Mesh algorithm with sampling mesh predigestion algorithm.Projection method and ellipsoid,setting LOD are chosen,an effective 3D terrain application project is given.This paper generates a three-dimensional terrain of space launch site with perfect visual effect,and the terrain has been applied to the three-dimensional simulation system.     

Numerical Simulation of Temperature Field during the Dissolution-Diffusion Bonding Process to Mending Iron Casting Defects

The common finite element method microcomputer software for simulation of the temperature field is developed by authors. It is used for calculating the temperature field duringthe mending process of iron casting defects by means of the dissolution-diffusion bonding technology. The correctness has been proved by testing results. This software has been used to analyse thecaused of hardness rising in heat effecting zone,and also find out the approach for solving the problem.     

Optimization and performance analysis of nitrogen expansion liquefaction process for CBM with different nitrogen content

A nitrogen expansion liquefaction process which is suitable for small-scale liquefaction plants is proposed for coalbed methane (CBM) with high nitrogen content. In order to investigate the effects of the nitrogen content on the liquefaction system performance, optimizations are done for CBM with nitrogen content among 0~70% via simulation and calculation with HYSYS when the liquefaction rate and the methane recovery rate are fixed respectively, and with the unit product liquefaction power consumption as the major index, the corresponding system performance is compared. The results show that, the system performance of CBM liquefaction process changes greatly along with nitrogen content. However, the changing is not monotonous.