Papers by Keyword: Finite Element Analysis (FEA)

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Authors: Da Wei Sun, Kang Ping Wang, Hui Qin Yao
Abstract: As a very popular dam style, more concrete- faced rockfill dams have been built in the world, but there is presently only a few high CFRDs with dam height more than 100m built on thick alluvium deposits. ChaHaWuSu CFRD with dam height 107.60m and the maximum thickness of alluvium deposits 46.70m, has been built in Xinjiang province, China recently. The excessive of displacement of foundation and dam body may lead to big deformation of peripheral joint and cause the failure of seal materials and produce water leakage. Therefore, 3D finite element analysis was carried out to estimate the deformation of dam. Firstly, 3D mesh including surrounding mountain and alluvium deposits was established by use of advanced grid discreteness technique. Secondly, Desai thin layer elements were adopted to model the interface between the face slab and cushion layer. Moreover, joint elements were adopted to model the joints between the face slab and plinth, plinth and connecting slab, connecting slab and connecting slab, connecting slab and diaphragm wall. Finally, large scales of equations solving method were adopted in the procedure thus the computer calculation time was greatly reduced. The calculation result was compared with the monitored deformation date of ChaHaWuSu CFRD. All in all, the above research will do much benefit to the CFRD design on thick alluvium deposits.
Authors: Da Wei Sun, Kang Ping Wang, Hui Qin Yao
Abstract: As a competitive dam style and full of life-force, the concrete- faced rockfill dam (CFRD) is widely used in China in recent years. Experts in China pointed out that “Extra high CFRD generally means those CFRDs with their heights higher than 150 m ” However, the history of construction and design of extra high CFRD is short and some problems during the construction of Extra high CFRD is still need to be explored. Therefore, stress and deformation characteristic of DongQing extra high CFRD was analyzed by 3D finite element method and some beneficial reference was obtained. Firstly, the advanced 3D mesh generation procedure written by Fortran language was used to form the finite element mesh which contained not only the dam with large amount of vertical joins and perimeric joints, but also the rock foundation and surrounding mountains. Moreover, the layer by layer construction procedure of dam was detail considered during 3D mesh generation. Since the node number of 3D mesh is still larger, large scales equations solving method-element by element method and others efficient measures were adopted. As the results, the computer calculation time decreased from former 48 hours to 20 minutes. According to the calculation results, the design scheme of DongQing CFRD was finally optimized.
Authors: Dong Wei Qiao, Xiu He Wang, Chang Qing Zhu
Abstract: In consideration of low power density of electric excitation claw-pole alternator (EECA) and some difficulties in magnetic field regulation of permanent magnet claw-pole alternator (PMCA), a novel hybrid excitation brushless claw-pole alternator (HEBCA) is proposed in this paper. Its structure and field control principle are described. Three dimensional finite element analysis is used to obtain the no-load magnetic field distributions and field control capability under different field currents. The result shows that the flux of the prototype machine can be adjusted over a wide range with a relatively low field current
Authors: Jian Ping Wang, He Jia Liu, Shao Kai Sun, Shi He Jian
Abstract: To provide the doctors a basis for treating sacral fractures and offer optimal surgical program, three-dimensional (3D) finite element method was used to simulate normal pelvis and the unstable pelvis sufferedIsection, IIsection and III section sacral fracture respectively.The unstable pelvises were respectively fixed with five different internal fixation implants types, which are respectively rectangular plate with cannulated screw, rectangular plate with solid screw, expansile bolt, convex plate with cannulated screw, convex plate with solid screw. The stress distribution and the X, Y, Z direction displacement of the sacrum were calculated for each sacral fracture treatment of five internal fixation implants after giving 500N axial load on lumbar vertebra and were compared with the normal pelvis, then the optimal surgery program were determined. After the analysis, by comparing the five combinations for each sacral fracture treatment of five internal fixation implants, the preferred combinations for the reset treatment of theIsection sacral fractures were rectangular plate with cannulated screw and convex plate with cannulated screw; The preferred combination for the reset treatment of the II section sacral fractures was expansile bolt; The preferred combination for the reset treatment of the III section sacral fractures was convex plate with cannulated screw.
Authors: Chuan Sheng Wang, Shan Hu Li, Ping Fu, Chun Lei Lü
Abstract: The physical, mathematical and finite element model of the extruding part of mixing-extruding machine was established to carry on the finite element simulation of the extrusion part flow field. Results showed that the double cone screw have better mixing and feeding properties than single screw.
Authors: Hui Guang Bian, Chuan Sheng Wang, Lei Wang
Abstract: This text introduced general flow field analyzed method about mixer flow in chamber, though analysis meshing rotor 3D flow field with the FEM.. While this process used six meshing-angles along the rotor circle for analysis the mixed mechanism of meshing rotors, which can improve mixer chamber’s structure and the quality of rubber etc.
Authors: Jean Guillaume Orliac, Adrien Charmetant, Fabrice Morestin, Philippe Boisse, Stephane Otin
Abstract: In order to simulate 3D interlock composite reinforcement behavior in forming processes like Resin Transfer Molding (RTM), it is necessary to predict yarns positions in the fabric during the preforming stage of the process. The present paper deals about thick 3D interlock fabric forming simulation using a specific hexahedral semi-discrete finite elements simulation tool : Plast4. Using the virtual work principle, we distinguish the virtual internal work due to tensions in yarns from other internal virtual works. The part of material stiffness relative to yarns tension is described as "first order stiffness" by a 3D discrete beam model. The rest of the rigidities - like transverse compression, shear strains or friction between yarns - are depicted by a continuous quad-based discretization designated in our work as "second order stiffness". A combination of this "first order" discrete model and a continuous orthotropic hyperelastic "second order" material formulation will enables us to simulate interlock preforming process. Jointly to the simulation work, we also had to specify and perform experimental testing identification of material's parameters. Thoses parameters concern both parts of the model. A bilinear tension approach for the yarns discrete modelization and an orthotropic continuous material for the "second order" part.
Authors: Ali Sobhanmanesh, Ramli Bin Nazir, Nurly Gofar
Abstract: The behavior of reinforced and unreinforced embankment on soft and stiff grounds has been investigated using the centrifuge tests and verified using numerical simulations. Four different cases have been investigated in this study based on various types of foundation materials and reinforcement condition. Two-dimensional (2D) and three-dimensional (3D) finite element programs, Plaxis 2D and Plaxis 3D Foundation respectively used to simulate and analyze the prototypes behavior provided by centrifuge tests. Deformation behavior, settlements and effect of reinforcement have been studied in this study. Comparison of the results of the numerical analysis with the measurements obtained from the centrifuge tests shows good agreement in terms of settlement and the reduction of settlement due to geosynthetics reinforcement.
Authors: Marialuisa Mongelli, Gerardo de Canio, Ivan Roselli, Marialaura Malena, Andrea Nacuzi, Gianmarco de Felice
Abstract: Technological advances in the digital camera industry and computing resources make the use of photogrammetry a very fast, low-cost, contactless and non-destructive technique. It can represent a good alternative to obtain 3D information for monitoring and conservation of cultural heritage assets, especially where it is not possible to use 3D laser scanners and also in situations where areas to be inspected are not easily accessible [1]. Resolution generally depends on the number of images, their quality and the level of overlap between them, as well as hardware and software capabilities. Starting from 2D aerial or terrestrial photographic images, photogrammetry allows to reconstruct a 3D model in the form of a "point cloud" and also to derive accurate 3D measurements of large architectural elements.This paper is about stereo-photogrammetric scanning by drone performed by MENCI software s.r.l. aimed at the definition of the state of conservation of the “Bridge of the Towers” in Spoleto and its long term preservation without building scaffoldings. It was performed within the RoMA (Resilience enhancement of a Metropolitan Area) project, through an agreement between the “Italian National Agency for New Technologies, Energy and Sustainable Economic Development” (ENEA) and the “Italian Ministry of Cultural Heritage and Activities” (MIBACT).Photogrammetric scanning and FE modelling were applied within the project together with many other monitoring techniques in order to assess the bridge cracks pattern and its structural health by a multidisciplinary approach that allows their mutual validation [2].As one of the most important problems in the use of photogrammetric 3D reconstruction is the considerable demand in terms of hardware and software resources for images processing and data storage, thanks to the HPC (High Performance Computing) resources provided by the CRESCO infrastructure (Research Computational Centre on Complex Systems), it was possible to analyse and process a large amount of high-resolution photos in order to detect the crack pattern and to assess the actual damage state to be monitored over time [3].
Authors: Dan Jiang, Ping Yang, Ren Tian Ma
Abstract: As a necessary component in pneumatic muscle, minimum switch and minimum mechanical hand, pen cylinder used as prime actuator possesses the characteristics of high speed actuation possible, easy installation, improved wear resistance and so on. The construction and working principle of the pen cylinder are introduced. Using 3-D stress field finite element analysis (FEA) method, the stress field distribution of pen cylinder with preload in mounting nut is analyzed. Simulation results are presented. The stress characteristics are compared between different preload in mounting nut and thickness of mounting bracket.
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