EDLCS命令讨论，怎么用？？？

fmg410155503

EDLCS, Option, CID, X1, Y1, Z1, X2, Y2, Z2, X3, Y3, Z3
Defines a local coordinate system for use in explicit dynamics analysis.
[url=mkMSITStore:d:\Program%20Files\Ansys%20Inc\v90\commonfiles\help\en-us\ansyshelp.chm::/Hlp_C_CH2_5.html]PREP7[/url]: Explicit Dynamics
<> <> <> DY <> <> <> <> <> <> ED
Option
Label identifying the option to be performed:

ADD	—	Define a coordinate system (default).
DELE	—	Delete a coordinate system. If CID is blank, all coordinate systems are deleted.
LIST	—	List defined coordinate systems. If CID is blank, all coordinate systems are listed.

CID
Coordinate system ID.
X1, Y1, Z1
X, Y, and Z coordinates坐标 of a point on the local x-axis.
X2, Y2, Z2
X, Y, and Z coordinates of a point on the local x-y plane.
X3, Y3, Z3
X, Y, and Z coordinates of the origin. X3, Y3, and Z3 all default to zero.
晕死了，通过这九个参数来进行定义啊，好复杂，想一想：
1、指定一个点，作为局部坐标系的原点。
确定一个方向，即局部坐标系的方向，
最后，
NotesLocal coordinate systems defined by this command are used in an explicit dynamic analysis.

For example, a local coordinate system may be used when defining orthotropic material properties (see EDMP).

The coordinate system is defined by 2 vectors, one from the origin (X3, Y3, Z3) to a point on the x-axis (X1, Y1, Z1), and one from the origin to a point on the x-y plane (X2, Y2, Z2).


The cross product 向量的叉积of these two vectors determines the z-axis, and the cross product of the z-axis vector and x-axis vector determines the y-axis.
If X3, Y3, and Z3 are not specified, the global origin (0,0,0) is used by default (as shown in the figure below).

The x-axis vector and the xy vector should be separated by a reasonable angle to avoid numerical inaccuracies.
When you use the local coordinate system (defined by the EDLCS command) to define a load (EDLOAD command), the direction of the load will depend on the load type.
For force and moment loads (Lab = FX, MX, etc. on EDLOAD), the load will be applied in the direction of the local coordinate system defined by EDLCS.
For prescribed motion degrees of freedom (Lab = UX, ROTX, VX, AX, etc. on EDLOAD), the motion will act in the direction of a vector from point (X1, Y1, Z1) to point (X2, Y2, Z2) as input on EDLCS. See the EDLOAD command for more information.
This command is also valid in SOLUTION.
Distributed ANSYS Restriction. This command is not supported in Distributed ANSYS.
Menu Paths

Main Menu>reprocessor>Loads>Load Step Opts>Other>Change Mat Props>Local CS>Create Local CS

Main Menu>Preprocessor>Loads>Load Step Opts>Other>Change Mat Props>Local CS>Delete

Main Menu>Preprocessor>Loads>Load Step Opts>Other>Change Mat Props>Local CS>List

Main Menu>Preprocessor>LS-DYNA Options>Constraints>Apply>Local CS>Create Local CS

Main Menu>Preprocessor>LS-DYNA Options>Constraints>Apply>Local CS>Delete

Main Menu>Preprocessor>LS-DYNA Options>Constraints>Apply>Local CS>List

Main Menu>Preprocessor>Material Props>Local CS>Create Local CS

Main Menu>Preprocessor>Material Props>Local CS>Delete

Main Menu>Preprocessor>Material Props>Local CS>List

Main Menu>Solution>Constraints>Apply>Local CS>Create Local CS

Main Menu>Solution>Constraints>Apply>Local CS>Delete

Main Menu>Solution>Constraints>Apply>Local CS>List

Main Menu>Solution>Load Step Opts>Other>Change Mat Props>Local CS>Create Local CS

Main Menu>Solution>Load Step Opts>Other>Change Mat Props>Local CS>Delete

Main Menu>Solution>Load Step Opts>Other>Change Mat Props>Local CS>List

fmg410155503

大家好，就这个命令，帮看看怎么定义的局部坐标系？？？？？？？？？

x1 y1 z1 x2 y2 z2 x3 y3 z3？怎么用？？？

evan_jin

请高手帮忙说明下，感谢

challengeall

帮助说明的很清楚了。首先是对命令的一个说明，通过三个点来定义一个局部坐标系。第一个点对应的是你的坐标系x轴上的，第二个点对应的是xy平面上的，第三个点对应你的坐标原点，缺省原点。坐标系的三个轴对应是，第三个点到第一个点形成x轴的一个向量，第三个点到第二个点形成一个向量，他们二者之间的叉积也就是垂直他们二者的向量形成z轴，那么z轴和x轴的叉积形成y轴。这样就建立了一个坐标系。
而对应这个命令的使用分两种情况：第一是在施加fx和mx这样的载荷时，施加的载荷方向就是对应的坐标轴方向。
第二种情况是在施加位移像ux，rotx，vx，ax等时，施加的载荷方向是由命令中第一个点和第二个点的方向决定的。第三个点缺省成（0，0，0）就行了。

sbysbw

challengeall 发表于 2010-8-26 15:32
帮助说明的很清楚了。首先是对命令的一个说明，通过三个点来定义一个局部坐标系。第一个点对应的是你的坐标 ...

我想请问一下，比如我研究两个齿轮大齿轮的中心点点坐标是（0,0,0),小齿轮中心点的坐标是（-1.75205,-0.762,0）.则如何在小齿轮新建一个坐标系？EDLCS,ADD,11，-,-,-,-,-,-,-,-,-这个九个横线处应该如何填写坐标值啊？谢谢了

dongfengye

就是定义一个可以满足旋转要求的坐标系，4#回答非常清楚哈