Papers by Keyword: Finite Element

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Authors: De Chen Zhang, Chao Wen Dong, Ming Yang, Yan Ping Sun
Abstract: The vibration of the fifth frame mill of 1450 Cold Tandem Rolling Mill in the rolling process was studied using finite element software ANSYS. The dynamic analysis of one-piece frame and two-piece frame on the fifth frame mill were carried on. The natural frequency and mode of vibration were calculated. Through analyzing, we obtained that two-piece frame performed better.
Authors: Jie Zhang, Abel Cherouat, Houman Borouchaki
Abstract: Metal orthogonal cutting and blanking are two important forming processes which include material removing. During finite element analyzing, the nonlinear problems of boundary, material and geometry must be considered to obtain the accurate calculating results. In this paper, we present an advanced adaptive remeshing procedure which has the capacities to simulate material removing processes in three dimensions. The sizes of finite elements are well adapted to local conditions which have the high distributions of physical fields using priori and posteriori error estimates. Based on constraint Delaunay Kernel, the unit mesh strategy is proposed to improve the mesh quality. By optimizing of both mesh edges and mesh elements, the mesh shape qualities are strictly controlled as the regular tetrahedrons. In this paper, Johnson-cook model is considered to simulate the elastic-visco-plastical material behaviors. The damage initiation is also judged by Johnson-cook criterion. The finite elements which reach the criterion will be killed and the material removing processes finished step by step. The proposed adaptive remeshing scheme is well present using the simulation of metal orthogonal cutting, milling and blanking processes.
Authors: Chang Liang Zhang, Ya Guo Zhang, Xiao Wei Zhang, Xiao Ning Deng, Tong Lu Li
Abstract: Ningde nuclear power plant in Fujian province is one of the national key construction projects of nuclear power, in order to insure the smooth progress of construction project, it needs to assess the rock slope stability which lies in the southeast of the living area. On the base of the rock architectural feature, the qualitative analysis, the three-dimensional limit equilibrium and the three-dimensional finite element are adopted to analyze the stability of the slope. The result of the qualitative analysis shows that most of the slope is stable, and part of it may fail after excavation. The result of the three-dimensional limit equilibrium and the three-dimensional finite element both illustrate that the slope is stable after excavation with slope ratio 1:0.25,1:0.50 and 1:0.75, and the stability factor rises with the decreasing of the slope ratio. At last, according to the above computing result, the 1:0.50 or the minor value is suggested to be adopted as the design slope ratio to excavate the slope.
Authors: Zhong Fu Wang, Han Dong Liu, Tong Jiang, Si Wei Wan
Abstract: Based on geological condition of underground factory building in Hohhot pumped storage power station, research and analysis are taken for the fundamental element which affect initial stress field, 3D finite element model of underground factory building is build for the analysis. Beigin with regrssion analysis, adopt linear elasticity caculation of finite element method to take linear regression analysis, and obtain range of optimized parameters. Adopt homogeneous design to definite various assemblies of optimized parameters at different levels. Obtain training sample by elasto plastic caculation of finite element, train for RBF model in oder to get inverse model of ground stress field. The calculation result shown that: RBF model overcome the disadvantages such as slow calculating speed and overfitting of BP model, and it could obtain distrubution rule of initial stress filed by inverse analysis in a reasonable way.
Authors: Li Bo Pan, Lin Hua, Jian Lan
Abstract: An effective method was proposed to simulate and control the motion track of guide roller during radial-axial ring rolling in FE simulation. The 3-D finite element model was constructed according to the principle and feature of rolling technology. The rolling process was simulated and analyzed by using dynamic explicit finite element technology. The different rolling processes with different technology parameter were simulated. The width spreads and rolling forces under different parameters are compared and analyzed. The results indicated that high quality ring product could be obtained when rational parameters in radial and axial were assigned.
Authors: Mohamdi Djemoui, Outtas Toufik
Abstract: Knowing the stresses and pressures in the contact between two deformable solids is fundamental in order to optimize the strength and the lifetime of mechanical components such as bearings or gears. These constraints can be determined by the calculation (finite element method or Hertz theory) or by experimental methods such as photoelasticity. The objective of this study is to model and compute the stress field and contact pressure using 3D finite element software. The validation of obtained results is done by comparison with the classical results of the non linear Hertz theory between two deformable cylinders. An application to spur gears with a circle involute profile is done and also validate with the same Hertz theory.
Authors: David Deslaef, Emmanuelle Rouhaud, Shabnam Rasouli-Yazdi
Authors: A. Alimoradi, M. Loh-Mousavi, R. Salekrostam
Abstract: The Friction Stir Welding (FSW), a relatively new welding process, was developed in 1991 at the Welding Institute near Cambridge, England. There are two tool speeds to be considered in friction-stir welding; how fast the tool rotates and how quickly it traverses the interface. These two parameters have considerable importance and must be chosen with care to ensure a successful and efficient welding cycle. The relationship between the welding speeds and the heat input during welding is complex. In this paper the friction stir welding (FSW) process of stainless steel alloys has been modeled using a three dimensional finite element method. A coupled thermal viscoplastic model was used for the simulation. Tool speeds and temperature distribution are coupled and solved together using this method. The relationship between the welding speeds and the heat input during welding is obtained by numerical analysis, and the stress contour occurred by temperature field and tool force is surveyed. In addition, the effects of FSW process conditions on heating mainly near the tool pin are investigated in this paper.
Authors: Dong Ning Wang, Ya Nan Jiao, Jia Lu Li
Abstract: Woven unit-cell geometry functions are presented for a balanced plain weave fabric. Based on the functions, a 3D geometrical model applying to a meshing preprocessor for 3D finite element is proposed. The geometry model takes into account the existence of the space between tows, the undulation of the tow, and the actual tow cross-section shape. The internal geometry of model is from micrographs of sectioned laminates, which is helpful to define the accurate and actual 3D geometrical model. The section shape of the yarn remains unchanged along the trajectory. This model can be easily identified using three parameters measured on a real fabric. An accurate hexahedral mesh developed using these geometry model is presented. This is an important point for 3D finite element simulation of fabric model, which is a powerful method to investigate the mechanical behavior and also the composites made from it.
Authors: Adrien Charmetant, Emmanuelle Vidal-Sallé, Philippe Boisse
Abstract: The preforming stage of the LCM composite manufacturing processes lead to fibrous reinforcement deformations which may be very large especially for double curvature shapes. Those deformations have significant influence on the second stage of the process, i.e. the injection of the resin. A way to predict accurately the spatial distribution of the permeability tensor consists in simulating for various configurations, the deformed shape of the reinforcement at the scale of the yarns. Mesoscopic scale analyses of textile reinforcements generally consider the yarns as a continuous material despite their fibrous nature. In order to have an accurate simulation tool, it is necessary to build up a constitutive law which accounts for the physical specificities linked to the microstructure of the yarns. Several models exist with reasonable accuracy. The present paper proposes a new approach in the hyperelasticity framework. The proposed model is based on the definition of mathematical invariants linked to the four main deformation modes of the yarn material: tension, compaction, longitudinal shear and transverse shear. The strain energy potential build up with those invariants is identified using classical fabric material tests: uni- and bi-axial tension and compression. The model has been validated on laboratory tests such as bias extension tests and gives promising results.
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