Papers by Keyword: Effective Strain

Abstract: This study uses the dies of the dray fasteners processing graphics provided by the fastener’s industry to establish 3D dies and components solid models based on the embedded drawing function tools provided by the component model (Standard.ipt) of Autodesk Inventor CAD software. After finishing the dies and components drawing, the integrated assembly drawing of dies can be obtained through the assembly model (Standard.iam) firstly. Three stages forming processes can be conducted and carried out the FEM simulation to check the forming acceptance. The effective stress, the effective strain, the velocity field, and the forging force can be obtained by the FEM simulation. Moreover, the realistic experiment can be performed to verify the acceptance of FEM simulation. The dimensions of final product can be measured to get the errors between FEM and experiment. It is noted that the errors show a good agreement with the experiment.

Abstract: The paper presents the simulated 3D Finite Element Model (FEM) while grinding the Ti6Al4V alloy using a single abrasive wheel. Grinding simulation was carried out using a Lagrangian finite element based machining model to predict the tangential cutting force, temperature distribution at grinding zone and the effective stress and strain. All simulations were performed according to the cutting conditions designed, using the plane up-grinding. The work piece was considered as typical materials to machine difficulty. As the cutting speed is increased from 15 m/min to 33 m/min at higher feed rate, a maximum value of 750 MPa stress and higher temperature localization to an extent of 900°C at grinding zone were observed.

Abstract: Severe plastic deformation is defined as metal forming methods in which a very large strain is imposed to a bulk in order to make an ultra-fine grained metal. ECAP is one of the most effective methods in SPD. The influences of main parameters on deformation include extrusion route, extrusion pass, die corner, friction, extrusion speed and so on. In this investigation, a model of ECAP process has been developed based on FEM and effects of extrusion speed on effective strain, load and effective stress imposed in the copper road are researched. The results of simulation have shown that lower extrusion speed can lead to higher load of top die and effective stress while the effect of extrusion speed on effective strain of copper road is slight.

Abstract: Severe plastic deformation is now recognized the most efficient way of producing ultrafine grained metals and alloys. At the present time a lot of severe plastic deformation methods have been proposed and developed. They differ in the deformation schemes. Unlike such severe plastic deformation methods as high pressure torsion and equal-channel angular pressing, rolling with the velocity asymmetry is a continuous process. It helps to solve the problem of the limited length of manufactured bars with semi ultrafine structure. Rolling process with roll velocity asymmetry generates high shear strain necessary for obtaining ultrafine structures of the processed material. A new process of asymmetric rolling of profiles in multi-roll passes has been developed. This process can be used for production of high-strength profiles such as circles, hexagons, wire rods, etc. Compression of the bar in multi-roll passes can be done not only from two, as usual, but from three or four sides. In case of a multi-crimped bar, a uniform compression scheme with large hydrostatic pressure is created in the deformation zone. It enhances the ductility of the material and allows increasing the strain intensity. Simulation in DEFORM 3D^TM proved that the process of asymmetric rolling in multi-roll calibers allows to obtain higher values of shear strain and strain effective.

Abstract: Traditionally, NdFeB magnets with high remanent flux density or high energy product could only be manufactured through altering the material compounds. In recent years, studies indicated that the magnet properties of NdFeB magnets could be improved through plastic deformation. These studies pointed out that the degree of plastic deformation is a key factor to improve magnetic properties. However, there are still many other process parameters that could affect the magnetic properties either positively or negatively. In this paper, process parameters such as strain, strain rate, and temperature are studied to illustrate their influences on the magnetic properties of NdFeB magnets. The magnetic property could be greatly improved when the preferred orientation appears on the microstructure of deformed NdFeB magnets. One of the experimental results showed that the energy product value had been increased by 76.7% when the effective strain value had reached 0.65. Experimental results also showed that strain rate is a dominating factor with regard to the flow stress of material. Through a proper combination of these parameters, one can obtain NdFeB magnets with their magnetic properties greatly improved.

Abstract: In order to refine the microstructure and improve the mechanical properties of the thicker steel plate, the large rolling reduction should be conducted. Confined to the biting angle of rolling mill, the maximum press quantity is constant. The research indicates that shear stress produced in the deformation region during snake rolling process is helpful and the snake rolling method can be used in the thick steel plate production. The effective strain of steel plate with various roller speed ratio, plate thickness, fraction and roller speed was determined by numerical calculation method. By comparison, the effective strain changing law was obtained. The calculation results indicate that compared to traditional rolling process, the effective strain produced in the plate can be improved with the increase of roller speed ratio, and the deformation permeability can also be improved.

Abstract: A lot of test data from many domestic and foreign articles about concrete bending and shearing beam reinforced with FRP was collected and analyzed. Through the statistical analysis of test data and comparative analysis of the theoretical calculation based on the current standard and the existing calculation model, the size of ultimate strain of bending beam and shearing beam reinforced with FRP was shown.It was found that the effective strain of most test members was less than the lower limit value of current design code.It was suggested that in practical projects, for bending and shear reinforcement with FRP ,effective strain were not less than 0.006, 0.004 respectively.

Abstract: In order to investigate the effect of continued equal channel angular pressing (ECAP) with different routes and passes on the homogeneity of structure, the process of continued ECAP for pure aluminum bar was simulated by DEFORM-3D software. It obtains the load-stroke curves for different passes, distribution of effective stress and effective strain in different routes after the sample is extruded eight passes by ECAP in routes A, BC and C. The results show that the uniformity of the sample is improved with the increase of passes. The microstructure of specimen which is extruded in route BC is the most uniform, but it is the worst in route A.

Abstract: Three different numerical tests, i.e. no rolling test, free rolling test and rolling resistance test, in the framework of discrete element method (DEM) are carried out to simulate the micro-structure development in shear bands. The rotational angles and effective strain in the specimen under different conditions are given out. By contrast, it can be concluded that the development of shear bands in granular material can be simulated well when the rolling resistance is taken into account in DEM.

Abstract: The bicycle is not only a pollution-free method of transportation, but also has sport and recreation functions. Therefore, the bicycle attracted attention in now society gradually. This study uses the rigid-plastic finite element (FE) DEFORM^TM software to investigate the plastic deformation behavior of a 7075 aluminum alloy workpiece as it is formed through a ring rolling die. This study systematically investigates the relative influences of ring rolling velocity, entering velocity, and workpiece temperature under various ring rolling forming conditions. The effective strain, effective stress, and workpiece damage distribution in the ring rolling process are also investigated. Results confirm the suitability of the proposed design process, which allows a ring rolling manufacturer to achieve a perfect design during finite element analysis.