Advanced Materials Research Vols. 557-559

Abstract: In this paper, with the ANSYS, a 2D axisymmetric coupled thermo-electro-mechanical model was developed to analyze the spot welding process（RSW） of zinc coated steels with copper strips as an insert material between electrode and workpiece. A transient temperature field obtained from a prior performed thermal–electrical simulation of RSW process is applied as nodal load on the model to simulate the stress distribution. The temperature and stress distributions in such a welding process were obtained and compared with a conventional resistance spot welding process. The results show that using the same welding process parameters, the maximum transient temperature at the electrode surface is lower than the conventional RSW process due to the use of copper strips, which helps to extend electrode lifetime. In addition, the presence of inserted copper strip increased the resistance of welding system, thus generated much more heat to form larger nugget.

Abstract: Pipe reactor simulation of biological growth was investigated based on computational fluid dynamics (CFD) and reaction dynamics in single-phase laminar incompressible flow with the open-source software, OpenFOAM. OpenFOAM supplied a kind of open structure, which made it convenient to add a suitable physical model with CFD equations according to the problem. In order to compute mass transfer and biological growth as a reaction with fluid flow, the component conservation equation was listed with Navier-Stokes equations. With the equations, a pipe reactor was simulated by our solver which was developed based on OpenFOAM. By the simulation, the pressure, velocity and component mass fraction can be obtained at different time and position, which is important to analyze equipments in chemical engineering. Although some details need to be considered such as the definition of reaction term, the boundary conditions, etc., reactor simulation with OpenFOAM has showed very large potential.

Abstract: The simulation test device of filtration for high temperature dusty gas was established based on rotating foam ceramic material. The influence of performance parameter of foam ceramic on collection efficiency, concentration of dust emission, dedusting precision and pressure loss were researched under room temperature condition. The results are shown as following: the smaller the aperture of foam ceramics is, the higher filter efficiency, the overall collection efficiency and filter precision are with lower emission concentration of dust and higher gas pressure loss of dedusting system; about 95% of dust particles which is one twenty-sixth more than the aperture of the filter can be filtered by foam ceramic; increasing the thickness is effective ways to improve the filter efficiency at the expense of much increasing gas filtering resistance of dedusting system; with the increasing of foam ceramic aperture-gradient, gas filtering resistance reduces remarkably at the expense of slight reduction of filter efficiency and a little increase of the concentration of dust emission.

Abstract: Traditional boundary force method of SPH applies Lennard-Jones equation to compute the virtual repulsive force by calculation of molecular force. But this method is strongly non-linear and easily leads to not convergence in calculation. In this paper, spring-damping boundary force model is utilized to solve the problem of moving boundary. Using spring-damping boundary force model, rotary moving boundary of screw channel-driven has been simulated and the result is well consistent with the simulation of Fluent. Comparing with traditional boundary force equation, this model is long-term stable and its effectiveness has been validated by case study.

Abstract: In the oil mining process, we need to hold flow characteristic for oil- and water-sands, with low-middle volume fraction of the particles in gathered pipes, in order to design logging tool and build interpretation methods for the producing profile. We built governing equations and boundary conditions for the oil- and water-sands based on the three-D k-ε-kp model. The simulation results indicate the sand volume fraction affects the sedimentation quantity and rate obviously. Multiphase flow in the gathered pipe is compartmentalized three sections: oil-water separation section, transition section and full mixing section from entrance to exit and multiphase flow meter need to place in the full mixing section. Sediment mainly settles to the bottom of gathered pipes umbrella in the condition of low flow rate and content of sediment, which has little impact on the internal instrument, but need to clear timely. With the increase of sediment volume and reduce of flow race, the time which multiphase flow in the gathered pipe reached a steady state was nonlinear growth.

Abstract: A finite element equation has been developed to simulate the squeeze casting process of a magnesium alloy wheel, a parametric model has been established to confirm the temperature field during filling and solidification process. The model can be used to investigate the effects of die design and process parameters (die temperature, pressure etc.) on the quality of castings.

Abstract: The motion characteristic of key components is a decisional factor to the working reliability and stability of a package machine. In this paper, the motion simulation of a key component is carried out in the ADAMS software environment. By analysis of the force, variance of the center-of-mass and the moment of the component, the mutation point in the motion is found, and then the structure is optimized by selection of different structural parameters. The optimization result shows a significant improvement for the reliability and stability of the whole machine.

Abstract: cess processed and become uniform when the microlens fully formed.The curvature radius is not only affected by the value of the surface tension but also influenced by the mould size as well as the column structure.Smaller mould size results in smaller curvature radius.The curvature radius will be decreased as the result of the formation of the column sturcture. At last,The influence of the main imprint process parameters on the forming process of the microlens was analysed.The polymer microlens was perfectly produced by using the non-contact method under proper processing conditions.

Abstract: The loess cave dwellings are very common along the Yellow River in China，which are really green building. This paper focus on the influence of cave leg’s width on the safety factor. Abaqus software and Strength Reduction Method are used. Results show that existing cave leg width is safe enough.

Abstract: The plastic strain finite element mesomechanics simulation of polycrystal martensitic transformation bring up non-linear model of influence microscopic phase transition rate and stress. Further developement and application of Marc and on the base of microscopic chemical energy distribution, evenly. As the simulation showed: 1) Early into the plasticity than that of single crystal.2) Microplastic strain distribution is not uniform, microplastic strain maximum, minimum value ratio in different incremental step fluctuate greatly. 3) Meso martensitic transformation is not uniformly distributed, and uneven degree decreases with increment step. 4) The macro transformation rate simulation curves are exponential trend, and into the fully plastic state reached the point.