magnet的运动网格和空气建模的问题

lilulilu

1.根据它关于电机转动的例子，好像是把气隙分两半，一半转动，一半固定。
  那要模拟直动运动的话，是不是在运动方向上不能有固定部件，要不然不能移动。
  如果建一个最简单的电磁铁模型，周围空气好像没法建模，因为collision mesh.如图。

2.是不是不需要用空气包围衔铁部件？
  我没有建空气，也可以得到力。那么它计算力是基于什么原理啊？

3.在电磁场计算中，材料都要求density，那么计算时计入重力了吗？

因为刚刚接触，资料很少，问题很多，有没有同学指点一二，谢谢～
ps：能否推荐几个这个软件的网站?

lilulilu

关于第一个问题，回去想了想，可以让空气运动

但是如果同样结构旁边有另一个固定结构，就很难建模了

lilulilu

我继续一个人说，一个人问
做了一个分析，为什么电流小的时候磁力线会挤在一起啊，没道理啊，电流越大磁力线慢慢展开，如图。
这是什么原因啊？期望大家来说说

[ 本帖最后由 lilulilu 于 2007-6-28 13:39 编辑 ]

perch88

看不懂，好像最后这个跟前面得很不一样

lilulilu

我说的不清楚。
一楼和二楼是一个问题。说的是电磁铁建模的问题。


3楼是我做的一个例子。磁力线挤在一起了，不知道是什么原因。

bonbon

1，magnet中运动体交接面两侧材料需赋成空气（air）。
2，这个软件会自动计算体积，根据密度求出重量。

lilulilu

喔。就是上下两界面附空气？左右不用？针对我的图
都计算重量的话，对运动有影响吗？两个都自由落体？

还有那个瞬态磁力线挤在一起是怎么回事啊？你有没有遇到过啊？谢谢～～

北极熊甲

原帖由 lilulilu 于 2007-6-28 10:34 发表
我继续一个人说，一个人问
做了一个分析，为什么电流小的时候磁力线会挤在一起啊，没道理啊，电流越大磁力线慢慢展开，如图。
这是什么原因啊？期望大家来说说

你的问题还没有解决:L

挤在一起？ 是不是主要受到运动衔铁的变化（主要是位置导致的间隙的变化吧）而引起的？电流大的话，电流产生的磁场掩盖了运动衔铁运动达带来的磁场变化。

你衔铁速度大概为多大？如果速度不大，不至于产生很快的磁场变化的话，多个静态，ANSYS可能要算得好。你可以在magnet试试速度小时和大时的区别先。

magnet的帮助写得有点简单:L

[ 本帖最后由 北极熊甲 于 2007-6-29 10:38 编辑 ]

北极熊甲

至于你的第二个问题用户文档的那个文件里面有，用的是虚功法。

北极熊甲

右边有固定物（我用了铁)，我大概地试了试，没发现什么问题，可以计算。

北极熊甲

算了5分钟，由于c盘的空间太小（不到70MB ），magnet的临时文件放不下了，停了。一看c盘300多KB:L 。

力刚开始由于重力的影响是－的，计算到了3.9ms。应该可以往下计算的。

bonbon

原帖由 lilulilu 于 2007-6-28 18:40 发表
喔。就是上下两界面附空气？左右不用？针对我的图
都计算重量的话，对运动有影响吗？两个都自由落体？

还有那个瞬态磁力线挤在一起是怎么回事啊？你有没有遇到过啊？谢谢～～

我只做过旋转电机的例子，气隙需要被分成两部分或者四部分，在分界面两侧是空气。我觉得可以使所有的交界面两侧都用空气试一试，包括左右。

我在做旋转电机例子的时候附材料密度是为了MagNet计算物体的转动惯量，不知道重力是否能被考虑进去。

bonbon

可以看看一个名字叫“Axisymmetric Actuator”的例子。

lilulilu

又有新的问题。谢谢~
如图：
1.为什么这个例子的边界都是虚线，我的是实线呢？
那个虚线怎么出来的？
2.那个整体的airbox是怎么做的？
我做的都是一个个的air拼的。

lilulilu

现在先建了airbox画网，airbox连成一体了，但与后面建的其他网格不一致
还是那个错误collision detected in motion mesh.

wty123456

• The Motion Component is completely embedded in a single re-mesh component. No part of the moving body may touch or intersect the AIR re-mesh component's boundary.

  

  Typical configuration for Type A.

• The Motion Component is completely embedded in a single re-mesh component, but some of its faces are coincident with faces of the AIR re-mesh component located on the exterior boundary of the model (which are usually planes of symmetry). No part of the moving body may touch or intersect the re-mesh component's boundary, apart from those faces coinciding with an exterior boundary. The Motion Component must remain in contact with the same (exterior) faces at all time instants.

  

  Typical configuration for Type B.

• The outer shell of the Motion Component is on the exterior boundary of the model except for a motion interface face which connects it to the stationary part of the model. In this case there are two AIR re-mesh regions adjacent to the motion interface face: one connected to the stationary part of the mesh, and one that is part of the Motion Component. The motion is strictly rotary or linear for this case since the moving object "slides" against the stationary part of the model. Most models of this type have periodic boundary conditions (this is necessarily the case in 3D). Typical linear and rotary sliding interface configurations are shown below.
    
  Typical linear single (left) and double (right) sliding interface configurations for Type C.
    
  Two views showing a typical rotary sliding interface configuration for Type C. The Motion Component (consisting of the blue solid part, the yellow re-mesh and their encompassing air box) is shown rotated, while the stationary re-mesh region is shown in green.
  Note that
  
  • Each AIR component that is in contact with the sliding interface must cover the entire area of the sliding interface. This includes any partially overlapping component having a lower precedence;
  • The re-mesh region can either be adjacent to, partially intersect, or be embedded into the larger stationary or moving air component. The re-mesh region could even correspond to the larger air component itself, but this usually entails longer re-meshing time at each time step than having the smallest re-mesh region possible;
  • No object can be completely embedded in a re-mesh region, i.e. no object can be "floating" inside a re-mesh region without being in contact with one or more of its boundaries excluding the sliding interface. Objects can thus partially intersect a re-mesh region, as long as they are not in contact with a sliding interface;
  • Selecting the Motion object in the Object page while the Initial Mesh is displayed highlights all the Motion Component's regions, after the precedence rules have been applied. This allows to confirm that all the proper components, including the re-mesh component, are actually part of the Motion Component.
  • Mesh nodes are fixed in time on all re-mesh region surfaces apart from the sliding surfaces, on which the nodes are displaced freely from one time step to the other.

Guidelines for 2D motion

• Re-mesh regions cannot share a common boundary. This means that if there are several Motion Components, either
  • each of them must be embedded in a separate re-mesh region that is not in contact with the other re-mesh regions, OR
  • all of them must be embedded into a common, single re-mesh region.
• For Type A, although it is recommended that no part of the moving body be in contact with the re-mesh regions' boundaries, the motion model will be valid as long as an air region separates a Motion Component from the rest of the model.
• For Type C, the re-mesh regions must be defined as distinct stationary-moving pairs.

北极熊甲

图片看不到

lilulilu

图片是看不到，能不能重新发一次？这个图片要输入密码什么的。谢谢

wty123456

请看附件，word格式。

wty123456

注意，有三种情况,A, B, C, 对应不同的remesh区域规则。