Search

The occurrence of size effects in the microforming leads to the uncertainties in process determination and quality control. In this research, a series of experiments were conducted in UTM4104 testing machine to investigate the grain size effect and feature size effect in micro-bending. Different grain size (d), thickness to grain size ratio () and micro-mold feature size (W) were prepared to explore size effects on formability of copper foil. The formability characterized by forming depth, deformation uniformity and surface integrity was discussed. It was found that the normalized forming depth presented a gradually rise and then declined markedly when N value further decreased to 0.79. The ductile fracture mode was observed for all grain-sized workpiece and the corresponding limit forming depth decreased with increasing grain size. Besides, the thickness thinning distribution and microhardness distribution showed the similar variation tendency like M. Both the standard deviation of thickness reduction and the roughed degree of surface topography indicated the worsening deformation uniformity of the foils with a larger grain size. The inhomogeneous plastic flow of material may be the reason to explain the depression near fracture location which is only observed in coarse-grained workpiece. Overall, it is concluded that the fine-grained copper exhibited better formability as the coarse-grained workpiece experienced severe strain incompatibility.

A variety of micro forming processes has been invented, and the size effects have become a research hotspot at home and abroad. Micro bending molds with different feature sizes were designed. Quasi-static tester loading and dynamic laser shock loading with soft punch for micro bending forming was studied by numerical simulation respectively based on ANSYS implicit analysis and LS-DYNA explicit analysis. The constitutive models of workpiece are bilinear kinematic hardening model and Johnson-cook model respectively. The effects of different loading conditions and feature sizes of the die on the forming depth, equivalent plastic strain and equivalent plastic strain rate were studied. The results of numerical simulation show that, with the increasing of feature size of the mold, the forming depth under two kinds of loading conditions shows a tendency to increase. In dynamic laser shock loading, the equivalent plastic strain and equivalent plastic strain rate of the key position of the bent part would decrease with the increasing of the feature size of the die. While in quasi-static loading, the opposite law is shown. The research shows that, the flexible micro-bending processes with different loading models showed similar size effect. However, compared with quasi-static loading, in dynamic loading, the strain of forming parts is more centralized, and there is a high strain rate and better formability of the workpiece.

The 3D Finite Element Method (FEM) model of engine connecting rod was established in this paper. And, nonlinear analysis of engine connecting rod was made, Stress distribution of the connecting rod under condition of maximum stretching and maximum compressing was simulated. The result shows that the results coincide with the actual results and connecting rod can satisfy the strength requirement, the method turns out to be very effective in practice.

An optimization algorithm of phase angle calculation based on FPGA implementation is mainly described in this paper .From two arctangent function calculation algorithms analysis, we combine the strengths of them, and propose a optimized algorithm of phase angle calculation. The theoretical analysis and hardware validation shows that the algorithm has good performances such as high accuracy, good real-time performance, less resource consumption. At the same time, this algorithm can be comprehensive, and can be considered as an IP core to realize the high-speed, parallel calculation of transcendental function.

In this paper, the finite method is applied and ABAQUS software is used, the vortex flow field is loaded as boundary condition of wraps. The stress and deformation in scroll under the action of gas pressure, temperature load and both of them is analyzed, the stress distribution and deformation of wraps in different shaft rotation angles is discussed, the stress distribution and deformation discipline of wraps are also respectively obtained. The results show that the overall stress and deformation in scroll are the largest when compression chamber is moving near the vent position and the thermal deformation is the main factor of affecting the overall deformation of scroll.

In this paper, a three stories villa was build and furniture was arranged according to the actual usage condition. The scene that building caught fire and flames escaped from the window and spread upward along the facade cladding system was simulated to verify the actual effect of fire barrier. The results showed that the first fire barrier obviously prevented flame dispersing and can raise ETICS fire safe ability.

Keywords: strain, stress, material constants, constitutive equation, anisotropy. Abstract. If the material is anisotropic, there are differences in stress distribution under the same boundary conditions when it was simplified as an orthotropic material. We established a simple finite element model for rectangular perforated planar material, in which one side was fixed, the opposite side was loaded with uniform force, and the other sides were set free. Based on this model we studied the difference of distribution of stress between anisotropic material and its simplified form, orthotropic material. The results showed differences in some cases quite large, the maximum relative error of extreme stress can reach 341%. In conclusions, this study does not support that the complex anisotropic materials are simplified to orthotropic materials. If researchers only concern the location of extreme stress, this study does not deny that the complex anisotropic materials can be simplified to orthotropic one.

With increasing evidence that vascular risk factors play a role in the development of glaucoma, it is critical to be familiar with factors related to intraocular blood flow. It is important to obtain that the modal of the optical never head including the retinal blood vessel. The images optical never head of a cat using the optical coherence tomography images were obtained. Then, the three modal of the optical never head and the retinal blood vessel were reconstructed using the technology of image process, respectively. The three-dimensional modal of optical nerve head including retinal blood vessel could get using Boolean Operation.

High speed torque is very important in tennis batting process , this paper discusses the shoulder and torso rotation torque generated by the weight of tennis sports influence. Taking 48 tennis players as research objects, the rotation torque of professional tennis players are relatively outstanding with performance value,so we concluded that in the case of keeping the torso erect and through the process optimization of the rotation, we could combined shoulder movement and body bottom-up movement. These results suggested that some given hitting model can not only increase the performance of the tennis player on the pitch, but also reduce the risk of causing excessive damage.

The RapidIO architecture is an interconnect technology based on a high-performance and packet-switched interconnect technology. The paper uses the RapidIO Interconnect technology to design a fiber optic bus. The fiber optic bus provides a tightly coupled interconnect with Gigabit speed, which can improve the processing capability of the space distributed system, such as the weapons platform with high-speed and high-capacity multi-system.

The finite element simulation of T-tube hydroforming process is conducted with the FEM software Pam-Stamp 2G 2005. The results of numerical simulation and experiment are compared and analyzed. The tube hydroforming simulations under various internal pressures of constant pressure load path are also conducted. The simulation and experimental results of T-tube hydroforming are compared. The results show that the tube wall thickness distribution is more uniform and the hydroforming effect is more ideal in T-tube hydroforming process with constant pressure load path. The constant pressure load path of T-tube hydroforming is relatively easy to implement in the practical production process. Of the four constant pressure load paths of T-tube hydroforming, the simulation result under constant pressure 150MPa is most ideal.

The researches on competitive mode choice behavior between electric bike and bike are useful for the analysis and forecasting of traffic mode, non-motorized traffic planning and related policy. With the sampling survey data in Kunming, individuals’ attitude and preference are analyzed based on SP data. The competitive choice model between electric bike and bike based on discrete choice model is established. The impact of latent variables on mode choice behavior between bike and electric bike is measured based on the estimation results. The result shows that the latent variables have significant impact on the choice behavior. The latent variables can be used to improve the performance of the model and to better capture taste heterogeneity.

The limit drawing ratios of the steel sheets are studied by the numerical simulation using the finite element software PAM-STAMP 2G. The limit drawing ratios of the steel sheets are also measured by the practical Swift cup test. The results of the experiments and the simulations are compared and analyzed. The results show that the overall shapes of the deep drawing parts of the experiment and the simulation are roughly the same. The maximum deviation of limit drawing ratio values between the experimental results and the simulations for two steel sheets with various thicknesses is only 2.2%. The deviation of limit drawing ratio of steel sheet obtained through PAM-STAMP FEM software is small. The PAM-STAMP software is highly reliable for the steel sheet deep drawing simulation.

A 3D thermo-mechanical coupled model of hot leveling and cooling process of steel plate with nine rolls has been conducted with the aid of commercial non-linear FEM software. The effects of four hot leveling deformation rates on the transversal and longitudinal residual stresses of steel plate in the condition of same initial temperature distribution pattern has been analyzed. Different plastic deformation rates are obtained through the reduction change of No.2 leveler. The transversal and longitudinal residual stress distributions at different parts of steel plate are also studied. The results show that the transversal and longitudinal residual stresses increase with plastic deformation rates through hot leveling and cooling. The residual stress distribution patterns at various positions of the steel plate in the conditions of different plastic deformation rates can be confirmed quantitatively, which can provide guidance to practical determination of hot leveling plastic deformation rates.

The application of vanadium-nitrogen alloy to develop a certain low carbon high strength H-beam steel was determined through the combination of theoretical study, product requirements and existing practical conditions. The specific rolling process was further defined through laboratory experiments. The developed low carbon high strength H-beam steel was trial produced and its properties were also analyzed. The results showed that the newly developed low carbon high strength H-beam steel had excellent mechanical properties and good weldability.

The fire-resistant hot-rolled H-beam steel is the newly developed structure material. The development situation of the fire-resistant H-beam steel is briefly introduced. The chemical composition, microstructure, room temperature and high temperature mechanical properties and weldability of several batches of the developed domestic fire-resistant hot-rolled H-beam steels are comprehensively analyzed. The results show that the newly developed hot-rolled fire-resistant H-beam steel has very high room temperature strength, certain high temperature strength, good welding performance, but the toughness needs to be further improved. The performance of web and flange of H-beam steel has large gap.

A three-dimensional thermo-mechanical coupled model of hot leveling and cooling processes of the steel plate has been conducted with MSC.Superform software. Four kinds of initial temperature distribution patterns have been determined according to literature. The effects of hot leveling and cooling processes on the transversal and longitudinal residual stresses of the steel plate have been analyzed. The results show that the initial temperature distribution patterns have significant influence on the residual stress of the plate. The more uniform temperature distribution patterns along the width of the plate, the smaller residual stress and also the smaller stress fluctuations. The cooling process has greater effect on the residual stress compared with the hot leveling process. The bigger the temperature gradient along the width of steel plate, the larger the residual stress and its fluctuation is. Through the FEM study, the value and direction of transversal and longitudinal residual stresses can be confirmed quantitatively at various positions along the width and length of plate, which can provide guidance to actual measurement of residual stress.