Difference between revisions of "Setting Material Orientation"

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The <tt>Rotate</tt> command rotates material axes to define the initial orientation when using [[Material Models|anisotropic materials:
== Introduction ==
The Region command (or <tt><Body></tt> command in <tt>XML</tt>) and the BMPRegion command ley you specify a single rotation angle for material rotation about the z axis. This options has two limitations. First, the angle has to be constant or same for all material points. Second, it is only rotation about the z axis and therefore insufficient for specify arbitrary orientation ins 3D simulations. The <tt>Rotate</tt> command solves both this issues because it can set variable angles (with a [[User Defined Function|user-defined function]] and can set rotation about x an y axes too.
== Rotate Command ==
In script files, the rotate command, which must be within
<pre>Rotate #1,#2,&lt;#1,#2&gt;...
</pre>
<p>where multiple pairs of a arguments can be used to define one to three rotations. In each pair</p>
<ul>
<li>#1 is the rotation axis which must be <code>x</code>, <code>y</code>, or <code>z</code> (or 1, 2, or 3). For 2D analysis, only <code>z</code> (or 3) is allowed (and it means rotation about &theta; axis if axisymmetric). #1 can alternatively be <code>reset</code> to remove all transformations. You can then apply new transformations. This option makes it possible to have different transformations apply to different shapes within the <a href="region.html">Region</a> block.</li>
<li>#2 is a rotation angle or a <a href="function.html">user-defined function</a> of material point coordinates that evaluates to a position-dependent angle. An angle or the result of a <a href="function.html">function</a> must be in degrees.</li>
</ul>
<h3>MPM Notes</h3>
<ol>
<li>Rotate commands can only used with <a href="region.html">Region</a> blocks or within <a href="bmpregion.html">BMPRegion</a> blocks (in MPM only). The <code>reset</code>, however, can only be used in <a href="region.html">Region</a> blocks.</li>
<li>You apply rotations in order by using one to three commands. There are two physical pictures:
<ul>
<li>You can imagine sitting on the material coordinate system with the material in its final position and then and defining a series of <i>clockwise</i> rotations about the material axes that transform the <code>x-y-z</code> analysis axes into the material axes. In right-handed, 3D coordinates, if your right hand fingers wrap in the rotation direction, your thumb will point in the positive direction for the rotation axis when the rotation is counter clockwise. This rotation appears counter clockwise when viewed from positive to negative direction on the rotation axis, but appears a clockwise when viewed from negative to positive direction.</li>
<li>Alternatively (and identically) you can imagine sitting on the analysis coordinate system and defining a series of <i>counter-clockwise</i> rotations about analysis axes that transform the material axes into the analysis axes.</li>
</ul>
</li>
<li>All single and double angle rotations are allowed (<code>x</code>, <code>y</code>, <code>z</code>, <code>xy</code>, <code>xz</code>, <code>yx</code>, <code>yz</code>, <code>zx</code>, and <code>zy</code>). When doing three rotations, the only schemes currently supported are <code>zyx</code> and <code>zyz</code>. It is easy to add more if needed (or to rearrange coordinates to make one of these work).</li>
<li>2D calculations only allow <code>z</code> axis rotation (which is &theta; axis if axisymmetric), which can be done with either an <code>angle</code> option in the <a href="region.html">Region command</a> or a single <code>Rotate z,angle</code> command. You will need to use the <code>Rotate</code> command option if you want to set the angle with a <a href="function.html">user-defined function</a>.</li>
<li>Use of any <code>Rotate</code> commands within a <a href="region.html">Region</a> block will override any <code>angle</code> setting in the <a href="region.html">Region command</a> (<i>i.e.</i>, that specified <code>angle</code> will be ignored).</li>
<li>Use of any <code>Rotate</code> commands within a <a href="bmpregion.html">BMPRegion</a> block will override any <code>Angle</code> setting in an <a href="intensity.html">Intensity</a> command. Furthermore the chosen rotation angles will apply to all material points defined in the current <a href="bmpregion.html">BMPRegion</a> block. Finally, if the <a href="bmpregion.html">BMPRegion</a> block defines an angle-mask file, that file will override all <code>Rotate</code> commands.</li>
</ol>
Explain out to set angle in MPM which is either angle on the Region command or Rotate command within regions
Explain out to set angle in MPM which is either angle on the Region command or Rotate command within regions

Revision as of 09:43, 31 December 2013

The Rotate command rotates material axes to define the initial orientation when using [[Material Models|anisotropic materials:

Introduction

The Region command (or <Body> command in XML) and the BMPRegion command ley you specify a single rotation angle for material rotation about the z axis. This options has two limitations. First, the angle has to be constant or same for all material points. Second, it is only rotation about the z axis and therefore insufficient for specify arbitrary orientation ins 3D simulations. The Rotate command solves both this issues because it can set variable angles (with a user-defined function and can set rotation about x an y axes too.

Rotate Command

In script files, the rotate command, which must be within 

Rotate #1,#2,<#1,#2>...

where multiple pairs of a arguments can be used to define one to three rotations. In each pair

  • #1 is the rotation axis which must be x, y, or z (or 1, 2, or 3). For 2D analysis, only z (or 3) is allowed (and it means rotation about θ axis if axisymmetric). #1 can alternatively be reset to remove all transformations. You can then apply new transformations. This option makes it possible to have different transformations apply to different shapes within the <a href="region.html">Region</a> block.
  • #2 is a rotation angle or a <a href="function.html">user-defined function</a> of material point coordinates that evaluates to a position-dependent angle. An angle or the result of a <a href="function.html">function</a> must be in degrees.

MPM Notes

  1. Rotate commands can only used with <a href="region.html">Region</a> blocks or within <a href="bmpregion.html">BMPRegion</a> blocks (in MPM only). The reset, however, can only be used in <a href="region.html">Region</a> blocks.
  2. You apply rotations in order by using one to three commands. There are two physical pictures:
    • You can imagine sitting on the material coordinate system with the material in its final position and then and defining a series of clockwise rotations about the material axes that transform the x-y-z analysis axes into the material axes. In right-handed, 3D coordinates, if your right hand fingers wrap in the rotation direction, your thumb will point in the positive direction for the rotation axis when the rotation is counter clockwise. This rotation appears counter clockwise when viewed from positive to negative direction on the rotation axis, but appears a clockwise when viewed from negative to positive direction.
    • Alternatively (and identically) you can imagine sitting on the analysis coordinate system and defining a series of counter-clockwise rotations about analysis axes that transform the material axes into the analysis axes.
  3. All single and double angle rotations are allowed (x, y, z, xy, xz, yx, yz, zx, and zy). When doing three rotations, the only schemes currently supported are zyx and zyz. It is easy to add more if needed (or to rearrange coordinates to make one of these work).
  4. 2D calculations only allow z axis rotation (which is θ axis if axisymmetric), which can be done with either an angle option in the <a href="region.html">Region command</a> or a single Rotate z,angle command. You will need to use the Rotate command option if you want to set the angle with a <a href="function.html">user-defined function</a>.
  5. Use of any Rotate commands within a <a href="region.html">Region</a> block will override any angle setting in the <a href="region.html">Region command</a> (i.e., that specified angle will be ignored).
  6. Use of any Rotate commands within a <a href="bmpregion.html">BMPRegion</a> block will override any Angle setting in an <a href="intensity.html">Intensity</a> command. Furthermore the chosen rotation angles will apply to all material points defined in the current <a href="bmpregion.html">BMPRegion</a> block. Finally, if the <a href="bmpregion.html">BMPRegion</a> block defines an angle-mask file, that file will override all Rotate commands.


Explain out to set angle in MPM which is either angle on the Region command or Rotate command within regions

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