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[求助] 求助接触分析的疑问.

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发表于 2009-6-2 10:40 | 显示全部楼层 |阅读模式
接触分析是组件的分析,首先我们得组装起来,组装元件是按着什么格式装配呢?
比如说,销和孔的连接,是用运动分析装配中所用到的 "销钉" 连接方式,还是用"用户定义"方式装配呢?或者说并不影响后续的有元分析呢(在分析模块中还要定义每个元件的约束和接触件的接触面)?

[ 本帖最后由 good0311 于 2009-6-2 10:47 编辑 ]

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发表于 2009-6-2 11:41 | 显示全部楼层
只能在mechanica中定义接触!
之前的装配只是确定它们之间的位置关系而已,因此,就不必要使用机构装配的那些,如果用了这些连接方式,在mechanica中也没影响,毕竟接触分析只认在mechanica中定义的接触类型。

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 楼主| 发表于 2009-6-2 12:51 | 显示全部楼层
如果是两个很简单的长方体元件,小的长方体放在大的上面,在mechanica中定义接触面是什么形式呢?刚性连接吗?还是不用定义直接分析呢?
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发表于 2009-6-2 13:12 | 显示全部楼层
如果你将组件导入mechanica中,什么都不定义的话,默认是刚性连接,即————将导入的组件作为一个整体。
定义接触的对话框:
3.jpg
界面的三种形式:绑定、自由、接触。
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 楼主| 发表于 2009-6-2 15:23 | 显示全部楼层
在mechanica中,什么也不定义,组件若表示一个整体的话,应该和形状相同的一个元件的分析结果应该相同吧(我试了下,结果略有不同).比如两个长方体构成的组件的分析结果,和一个元件(形状和两个元件构成的组件形状相同)的分析结果.
而且,两个元件构成组件,在mechanica中,什么也不定义和定义刚性连接的分析结果也有略微不同.
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发表于 2009-6-2 16:55 | 显示全部楼层
其实在进入mechanica的native时,就会出现mechanica modal setup对话框
1.jpg
这个就是默认的状态,
也就是以bonded interface方式。
如果你将组件导入mechanica中,什么都不定义的话,默认是刚性连接,即————将导入的组件作为一个整体。

说的不确切(以bonded的方式作为一整体)对给楼主朋友造成的误解表示歉意,

[ 本帖最后由 iampopdeng 于 2009-6-2 17:35 编辑 ]
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发表于 2009-6-2 16:57 | 显示全部楼层
更详细的情况见help。参考一下吧。
connections:
A connection is the mating area between two assembly components. Use the Insert>Connection command to create connections in Mechanica. When analyzing an assembly for which you have created connections, Mechanica uses the connection type and definition to determine the nature of the association between the connected areas.
You can create the following kinds of connections:
Native Mode:welds、interfaces、fasteners、rigid links、weighted links;
FEM Mode:welds、interfaces、rigid links、weighted links、gaps

For assemblies in the native mode that include compressed midsurface shells, you must consider how you want Mechanica to treat mating and overlapping surfaces. When the surfaces of a component modeled with midsurfaces mate or overlap with the surfaces of another component, Mechanica creates automatic midsurface connections between all surfaces of the two components that are in contact with each other. Mechanica makes an exception for any surface where you explicitly create a weld, fastener, rigid link, or an interface.

After you create connections in the model, you can preview the different types of connection in your model using the Info>Model Connectivity command.

Links defined in the component, are propagated to the assembly. The coordinate system that the part refers to is transformed at the assembly level. That is, if a link refers to certain directions in the WCS of a part, then at the assembly level it refers to a UCS at the part WCS location.

Bonded Interfaces:
Use the Bonded interface to connect the components or surfaces that are touching each other. The components connected with bonded always touch each other during analysis. During meshing, the coincident nodes on these components merge.  

You can create a Bonded interface in Structure and Thermal module of Mechanica.

In Native mode, you can create Bonded interface only between mating surfaces. If you select Surface-Surface reference type and select two surfaces that are not touching, Mechanica displays an error message after you click OK on the Interface Definition dialog box.

In FEM mode, you can connect non-matting surfaces also using Bonded interface. You can create rigid links instead of merging the nodes. When you select Bonded as a Type of interface on the Interface Definition dialog box, Mechanica selects the Merge Coincident Nodes check box in the Properties section. If you clear this check box, Mechanica creates links between coincident nodes on two bonded surfaces.

When you create a Bonded interface between any two surfaces in an assembly, Mechanica automatically creates a force measure to calculate the magnitude of resultant force over the bonded interface. When you create a Bonded interface between any two surfaces in the Thermal module, Mechanica automatically creates a heat transfer rate measure to calculate the rate of total heat transfer over the bonded interface.

[ 本帖最后由 iampopdeng 于 2009-6-2 17:34 编辑 ]
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tsek 该用户已被删除
发表于 2010-4-22 11:37 | 显示全部楼层
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发表于 2010-4-25 03:07 | 显示全部楼层
深      我刚入行     请问你是不是做仿真和运动分析很厉害
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发表于 2010-4-25 03:07 | 显示全部楼层
You can create a Bonded interface in Structure and Thermal module of Mechanica.

In Native mode, you can create Bonded interface only between mating surfaces. If you select Surface-Surface reference type and select two surfaces that are not touching, Mechanica displays an error message after you click OK on the Interface Definition dialog box.

In FEM mode, you can connect non-matting surfaces also using Bonded interface. You can create rigid links instead of merging the nodes. When you select Bonded as a Type of interface on the Interface Definition dialog box, Mechanica selects the Merge Coincident Nodes check box in the Properties section. If you clear this check box, Mechanica creates links between coincident nodes on two bonded surfaces.

When you create a Bonded interface between any two surfaces in an assembly, Mechanica automatically creates a force measure to calculate the magnitude of resultant force over the bonded interface. When you create a Bonded interface between any two surfaces in the Thermal module, Mechanica automatically creates a heat transfer rate measure to calculate the rate of total heat transfer over the bonded interface.

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