世界最大超导线圈螺栓转配_用adina的模拟
http://www.adina.com/htechbriefs.gif http://www.adina.com/plasma-movie.gif Bolted Assembly of the World's Largest Superconducting Coil In a previous Brief, we presented some structural analysis results of the superconducting coil of the Wendelstein 7-X, the world's largest plasma fusion experimental device of the stellarator family. In this Brief, we present another aspect of this long-term R&D project. We focus on the connection of the coil to its support structure (see Ref.). Portions of the coil and the support structure are shown in Figures 1 to 3 and the movie above. Due to the symmetry of the geometry and loading, only 1/10th of the total structure is modeled. Special symmetry boundary conditions are applied to the boundaries using the constraint equations available in ADINA. The model mainly consists of 3D solid elements. Also, a number of beam elements are used to model bolts. The structure is subjected to electromagnetic forces, caused by the current in the superconducting coils, and loading due to the pre-tensioned bolts. The model consists of about 6 million DOFs, more than 120,000 contact segments and about 950 bolts. The analysis was performed in two steps. In the first step, the bolts were tightened; here the bolt forces were gradually increased to their final values. Then, in the second step, the electromagnetic forces were applied. Figures 4 and 5 show results for the bolt-tightening step, while Figures 6 and 7 show the deformations after the electromagnetic forces were applied.http://www.adina.com/plasma1.gif
Figure 1 Finite element model of the superconducting coil and its support structure
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Figure 2 Finite element model of the superconducting coil
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Figure 3Finite element model of the support structure
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Figure 4 Displacement contour plot of bolt heads and washer due to the bolt tightening
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Figure 5 Contact normal tractions at the center of the support ring after the bolt tightening
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Figure 6Displacement contour plot (coil)
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Figure 7Displacement contour plot (support structure)
Bolted assemblies are abundantly used in many industrial applications (e.g., engine blocks, axles, clutches). The above example highlights some of the powerful capabilities of ADINA in analyzing large bolted assemblies. For some other examples, see Clutch Axle Engine Block Front Chassis Reference [*]N. Jaksic, P. V. Eeten, V. Bykov, and F. Schauer, "Analysis of the magnet support structure for the plasma fusion experiment Wendelstein 7-X", Computers and Structures, in press
Keywords:
Plasma fusion experimental device, bolted assembly, bolt pre-tension, electromagnetic forces
Courtesy of N. Jaksic, P. V. Eeten, V. Bykov, and F. Schauer, Max-Planck-Institute for Plasma Physics, EURATOM Association
http://www.adina.com/htechbriefs.gif http://www.adina.com/bolts-mv.gif Modeling Bolted Structures with ADINA Bolted structures show complex mechanical behavior. Modeling such structures presents many challenges: meshing these complex structures with bolts, sequential load applications with proper pre-stressing, contact conditions between bolted parts and also between parts and bolts, to name a few. These typical requirements are easily handled using the ADINA System, which provides very efficient and practical bolt analysis capabilities supported by robust meshing algorithms. The following analysis options are available in the ADINA program for bolted structures: [*]Static analysis: bolts can be pre-stressed (or loosened) at any time during the solution process
[*]Implicit dynamic analysis using the Bathe composite or Newmark method: bolts can be pre-stressed at the beginning of the solution process and the pre-stressing can be changed at any time during the solution process
[*]Explicit dynamics in a restart run: the bolts need to be pre-stressed in a static solution and then, using the restart option, explicit time integration can be used
[*]Frequency and modal analyses: the bolts (with contact conditions) can be pre-stressed in a static run and then the restart option can be used to calculate frequencies and mode shapes, or bolt pre-stressing and frequency/modal analysis can be requested in the same run
[*]Thermo-mechanical coupling (TMC)
[*]Fluid-structure interaction (FSI) with or without thermal couplingIn this News, we show the application of ADINA in an analysis involving the standard industrial practice of sequential bolt tightening. The bolted structure shown in Figure 1 is modeled. The above animation shows the calculated stresses in the bolts as they are loaded. The animation also demonstrates how 3-D solid bolts are modeled in ADINA: for each bolt, a bolt pre-stressing is included in a single bolt element constrained between two bolt-cutting surfaces. This allows contact conditions between all connected parts to be included.
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Figure 1Bolted structure modeled, courtesy of Volvo Penta
Figure 2 shows the finite element mesh of the entire bolted model generated using ADINA. There are 23 bodies in the model, each of which is meshed with ADINA's free-form brick mesher. This meshing process comprises 3 main steps: [*]quadrangulation of all body's faces,
[*]tetrahedronization of the body and
[*]brick (hexahedron) creation from the boundary inwards.
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Figure 2 Mesh of the bolted structure
The resulting mesh is a combination of mostly bricks and some pyramids and tetrahedra. Clearly, for such a complex model, the mesh quality is remarkable. The bolt analysis options in ADINA, together with the advanced meshing capabilities, allow engineering analysts to model bolted structures easily and confidently.
Keywords:
Bolted assemblies, bolt element, contact, friction, sequential, tightening, pre-stress
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Modeling Bolts in ADINA Bolts are an integral part of engineering designs, and bolted structures can show a complex mechanical behavior. Not long ago, bolted structural parts were commonly treated as rigidly connected. With recent advances in computer-aided modeling and finite element analysis, engineers can now get insight into bolted connections that was previously difficult to obtain. Engineers can ask questions regarding, e.g., the bolt forces required to prevent leaking of fluid, the frequencies of a bolted structure when contact and friction play an important role, and the contribution of the bolted connections to noise and vibration. Also, there are often many bolts in assemblies that need to be tightened in a certain sequence. With the practical requirements of today’s design engineers in view, the bolt modeling capability in ADINA allows bolt tightening specified either by a force value or by a bolt shortening. The program allows bolts to be tightened in a specified sequence in order to model the actual assemblage process. To illustrate the ADINA bolt option, we present a typical bolt-type problem, a mount of an axle used in heavy machinery (courtesy of John Deere). A panoramic view of the assembly is shown in the movie above. 10-node tetrahedral elements are used to model the bulky parts, 8-node shell elements are used to model the frame, and 3D contact surfaces model the contact in the bolted parts. The entire model (shown in the movie above) has over 2.5 million degrees of freedom. About 40 bolts are tightened in a sequence using 25 steps with about 5 Newton-Raphson iterations per step. The band plots in the Figure below show some results.
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FigureEffective stress band plots after step 1 (left) and step 25 (right)
The ADINA solution time per step is only about 12 minutes (elapsed time) on a quad-core PC, which is remarkable for the size of the model. Such performance is possible due to the ADINA 3D iterative solver, which can handle not only 3D solid elements but also shell and other structural elements, and contact conditions. The effective modeling of bolts in linear and nonlinear solutions, including frequency analyses, is clearly an important feature in general CAE and in the use of ADINA.
相应的参考文献具体介绍其原理和建模过程**** Hidden Message ***** **** Hidden Message ***** **** Hidden Message ***** 看得不大明白，先支持一下！ 我晕，斑竹猛啊， Adina有了 新生代斑竹
版块也活跃了很多啊 9# 狼跃冲顶
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http://www.adina.com/newsgrp.shtml 学习下！！！ 能不在BEAM上加预紧力 直接在实体单元加吗 能不在BEAM上加预紧力 直接在实体单元加吗 好东西 谢谢 看看！！！！！！！！！！ 谢谢楼主，看看，学习一下！ 看下 开拓下视野 前处理也是用adina做的吗？ adina可以模拟失超吗 这个似乎没有涉及到电磁
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