Numerical simulation of dynamic response and radiation noise of gearbox

Considering the internal dynamic excitation produced by stiffness excitation, error excitation and mesh impact excitation, a dynamic finite element model of transmission system and structure system of gearbox is established. The normal mode and the dynamic responses of gearbox under the internal dynamic excitation are calculated by using the numerical simulation software ANSYS. Based on the result of dynamic responses, the boundary excitation condition is determined, and then the acoustic boundary element model is built. With the software of SYSNOISE, the surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The test of airborne noise is carried out. The computational results obtained are in a good agreement with the data of experimental test.     

Object-oriented Design of Three-Dimensional Numerical Manifold Method

The Object-Oriented technology is introduced into the 3-d Numerical Manifold method(NMM). The design method and management of the Classes about the three dimensional Numerical Manifold Method are studied. The Classes are designed and the prototypes of some key classes are shown. As an example,the 3-d numerical calculation results are given. The calculation results are in good agreement with the theoretical solutions. It shows that the Object-Oriented programming of 3-d NMM is correct.     

Effects of Thorax Muscle Fiber on Body Surface Potentials

A numerical method calculating the forward problem of electrocardiogram (ECG) has been presented. By using this method, the torso part including anisotropic muscle layers has been discretized by means of the finite element method (FEM). The rest of torso have been divided into the surface elements by the boundary element method (BEM). The effects of the skelltel muscle layers over thorax wall, have been discussed in terms of a three-dimensional torso models.     

Die design of a compacting spring bracket

Based on an analysis of the current die design situation, the numerical simulation software Dynaform was applied to die development. In a compacting spring bracket project, the finite element method and shape forming technology were used to simulate and validate the pressing and forming processes. Top to bottom technology of Pro/Engineering next was adopted to design the die. The result shows such die design methods and technologies can help designers develop dies quickly and accurately and improve productivity.     

Design and simulation of electromagnetic parking brake embedded in wheel motor

Based on the electromagnetic theory and the work principle of electromagnetic parking brake,a new structure power breaker electromagnetic brake is designed,which is low energy consumption and embedded in in wheel motor,and a kind of analysis computation method is proposed. Through the analysis of magnetic circuit of electromagnetic brake,the mathematical model is established. A three dimensional finite element model is established via Ansoft software with the purpose of analyzing the electromagnetic property and work performance of electromagnetic brake,as well as simulating the dynamic work process of electromagnetic brake. By profoundly investigating the intricate internal magnetic field strength and power density distribution of the electromagnetic brake,the current research has obtained the exciting coil with time curve,electromagnetic force with work air gap curve and the armature displacement with time curve,etc. The conformity of the final simulation results with the experimental data indicates that the electromagnetic finite element method is accurate and reliable to analyze the electromagnetic property of electromagnetic brake,which can meet the requirements of sensitivity,reliability and specialization in electric scooter parking brake system.     

Numerical analysis of material surface thaw depth under pulsed electron beam irradiation

We developed a finite element method model. An equality heat source was used to thaw metal with an electron beam in numerical analysis. The temperature field was obtained after the metal thawed with electron beam by numerical analysis. The influence of the material thaw depth was analyzed at differing voltages, energy densities, and energy evenness. A thaw depth diagram was obtained where energy evenness is from 0.9 to 1.0, energy density is from 2 J/cm2 to 17 J/cm2, and voltage is from 25 kV to 50 kV. The change rule of material thaw depth was derived which provides a theoretical reference for fine mould machining with electron beams.     

Numerical simulation of remodeling in mandible under orthopedic loads

The research on the remodeling in mandible under the action of orthopedic loads is important for the determination of orthopedic scheme. a three-dimensional finite element model of mandible and temporomandibular joint is established. Using Cowin Remodeling Law, the finite element simulation of the remodeling in mandible during the orthopedics under the action of orthopedic loads is carried out. Comparing the numerical results after remodeling with those before remodeling, it is demonstrated that the normal remodeling greatly affects the distribution of strain and strain gradient on the surface, therefore the effect cannot be ignored in the determination of the orthopedic scheme.     

Numerical simulation of lahar in Changbai Mountain region

Lahar is one of most serious volcanic disaster, threats people’s lives and property security of volcanic region. The numerical simulation result can predict the characteristics of lahar, provide reference materials for making disaster prevention plan, and make the measure of lahar disaster relief transition from passive to active. Selected the area near the Tianchi as the research region, and divided the research region into forming region, circulation region and accumulation region. In order to establish the calculation model, divided the circulation region and accumulation region into many meshes, which are small enough to meet the calculation accuracy. The calculation time step length is also identified very small as 0.001 min. Calculated the average and peak velocity of lahar, triggered by the assuming medium and small eruption of Tianchi volcano, through the Delft 3D software. The longitudinal variation of lahar frontal average and peak velocity is acquired by the numerical simulation result. The time to area inundation by lahar, triggered by medium eruption, is obtained by calculation. The lateral variation of lahar depth at each cross-section is simulated. Although there is some different between the assumption of this research and the actual condition, flow velocity and accumulation situation of lahar are calculated in quantity and extension by numerical simulation, these result has reference value for preventing and reducing lahar disaster.     

Analysis of Numerical Simulation of Seepage Failure and Seepage Feature of Seawall

In order to analyze seepage feature and seepage failure mechanisms of seawall under flood infiltration, a numerical model for saturated-unsaturated and unsteady seepage flow analysis considering soil permeability variation with seepage failure process was established. And the corresponding finite element computation program was made. Numerical simulation of flood seepage for typical section of real seawall was carried out by use of the program. The computed results were compared with the measured results of field test, which shows good agreement. Based on the numerical simulation results, it can be seen that flood seepage of seawall is a saturated-unsaturated and unsteady seepage flow process and seepage failure of seawall is caused by long time flood infiltration under large seepage gradient. Therefore, upon the flood infiltration, seepage failure of the seawall is a very complicated process, which involves soil permeability variation with seepage failure process and saturated-unsaturated/unsteady seepage flow. It is questionable to use the steady seepage analysis method to simulate seepage failure process of seawall.     

Numerical simulation and optimization of high strength steel bumper forming process and springback control

Production of high strength steel bumper can greatly enhance the occupant safety.However,it is very hard to form high strength steel plate.There is rare domestic successful reference.The hot stamping technology aboard increases costs significantly,and the efficiency is low.Therefore,the only solution is combining advanced numerical simulation technology with current adjusting stamping process.The cold forming process of a sedan’s high strength steel bumper is simulated by FEM software Dynaform and the results show that springback and crack are the main defects.A law is summed up by researching the influence of different shapes of addendums on part forming and springback.Finally,the optimized shape of addendum is obtained by adjusting the addendum and adding convex roofs.It provides references for manufacturing similar high strength steel parts.     

Numerical simulation of desulfurization characteristics in CFB flue gas with bypass

This paper uses the standard k-ε model, DPM, Species Transport and Finite-Rate Chemistry model to simulate momentum, energy and composition equations of a new CFB desulfurization tower with gas bypass. The numerical simulation results agree well with the experimental results. The characteristics of desulfurization and flow resistance of two desulfurization towers are analyzed by numerical simulation, and the influence of SO2 concentration to desulfurization efficiency of bypassing desulfurization tower is also analyzed. The results show that both desulfurization and flow resistance characteristics of bypassing desulfurization tower are better than those of non-bypassing desulfurization tower. The desulfurization efficiency of bypassing desulfurization tower decreases with the increase of SO2 concentration, the desulfurization efficiency increases with the increase of the relative humidity of bypassing desulfurization tower.     

Numerical simulation of the mechanism of atypical dynamic phenomena in mines

An atypical dynamic phenomenon of mines, including its action forms and definition, were put forward, based on the mining accident at the Furong Mining Group Company in Sichuan, P. R. China. The mechanism of the atypical dynamic phenomenon was revealed by analyzing rock stress distribution, calculating the first and cycle broken distance of each thick and hard roof, and analyzing the balance structure of broken rock based on the three dimensional finite element software. The first stratum of the bent, sunken, aged strip was influenced by the geological conformation and the coal mining activity. This created the first break of the key stratum and led to the atypical dynamic phenomenon. We show that the key factors affecting the phenomena are the roof and floor structures, surrounding rock, and initial stress and rock burst tendency of the key stratum.     

Numerical Simulation of Groundwater Flow and Quality

With societal development, wastes exist in industry, agriculture and human life. In particular, a large volume of urban industrial sewage is discharged and pesticides and fertilizers are widely used, leading to groundwater pollution in many areas. Based on a water quality model of hydrodynamic dispersion and the multi element balance (MEB) method, a general program for simulating groundwater flow and quality is carried out using the program VC++ for visual presentation. Using this program in a case study, the transportation mechanism of groundwater flow and quality is simulated numerically. The result indicates that the program is visual and can be manipulated well. It offers a point of reference for the reasonable exploitation, protection and utilization of the groundwater.     

Application of Object-oriented FEM in Developing Simulation Software System

Based on object-oriented method, the classes of object-oriented finite element are defined. The finite element program of static, dynamic characteristics and stability analyses for spatial frame structures is developed with c++ object_oriented language which is successfully incorporated into a computer simulation system of derricks. The results of static, dynamic characteristics and stability analysis for the derricks of F320-A and JJ250/42-K types, obtained with the developed system, are consistent with those obtained by a commercial software, which illustrates the correctness of object-oriented FEM and the reliability of the simulation software.     

Numerical simulation of carbon dioxide storage in unmineable coalbed

The injection of carbon dioxide (CO2) in deep unmineable coalbeds（CO2-ECBM） is a very attractive option for geologic CO2storage. The CO2 is stored and at the same time the recovery of coalbed methane is enhanced. The revenue of methane (CH4) production can offset the expenditures of the storage operation. The processes involving in the CO2-ECBM include multi-components gas adsorption,diffusion,and gas-water two phase flow in coalbed. On the basis of above processes,a model considering adsorption induced coal matrix swelling is developed, which can be used to describe multi-components gas adsorption/desorption-diffusion-flow in coalbed. The finite difference method is used to solve this model,and the comparison of the results with the existed model suggests the model is valid. Then the model is applied to evaluated the influence of permeability of coal seam,different gas adsorption induced swelling,CO2/CH4 adsorption capacity ratio,pore model considering matrix swelling,and gas composition of injection gas on CO2 sequestration and methane production, and these results are very important for site selection and technological parameters optimum of CO2-ECBM project.     

Numerical Analysis on Stability of Rock in Sijiaotian Tunnel

The Sijiaotian Tunnel in Yunnan Dabao Highway lies in the narrow defile landscape,and the engineering geology condition is complex,with plenty of cienega.According to the actual situation of the Sijiaotian Tunnel Project in Yunnan Dabao Highway,the stability of the surrounding rock mass is studied by using a 3-D non-linear FEM.The Drucker-Prager criterion is chosen as the failure criterion of the rock.The relatively dangerous zone and the monitoring points in the tunnel are determined.The numerical results show that the Sijiaotian Tunnel is relatively stable.The conclusion has some significance for guiding the construction of similar projects.     

simulation and improvement of an all terrain vehicle muffler

Aiming at a muffler of a 400 all terrain vehicle(ATV), a vibration model and an acoustics model of the muffler were built by finite element method(FEM). The vibration and acoustics characteristic analysis of the muffler are carried out according these models, it shows the 3D model is exact and it is possible to generate regeneration noise. Acoustics model can help to know further about the characteristic of each chamber and intention of the designer. According the demand of factory, some projects of improvement are offered. The final result of road test proves that he improved muffler is feasible.     

板坯连铸结晶器内凝固坯壳的三维数值模拟

基于流场和温度场的计算,对断面为1 780 mm×225 mm的板坯结晶器进行数值模拟,考虑3种不同水口条件下,钢液流动对凝固壳的冲刷,计算出凝固壳厚度的三维分布特征,并与二维切片法的计算结果进行了对比。结果表明：有水口时结晶器角部位置凝固壳最大值为约45 mm,宽面和窄面中心凝固厚度壳最大值为24 mm,分别比无水口条件下凝固壳薄1~2 mm;钢液的扩散会使凝固壳在距离结晶器角部300 mm和顶部400 mm的位置形成约深度2.5 mm的凹陷;同时钢液会冲刷整个结晶器窄面的凝固壳,在窄面中心最严重;对比不同的水口,凸底水口冲刷最大,凹底最小。     

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.     

Numerical Analysis of Flow and Acoustic Field Inside the Automobile Exhaust Muffler

The acoustic field,flow field and temperature field inside a muffler are studied by the numerical analyze method.And an improved design is made aiming at the existent problem.The comparison of the computationally predicted and the experimentally measured transmission loss shows a good agreement.It is indicated that the numerical analysis method can simulate the exhaust muffler's characteristic accurately.So it is an effective method to predict exhaust muffler's performance and have an improved design.