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 <title>iMechanica - Derivatives of a volume integral with singular kernel - Comments</title>
 <link>http://imechanica.org/node/2012</link>
 <description>Comments for &quot;Derivatives of a volume integral with singular kernel&quot;</description>
 <language>en</language>
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 <title>Derivatives of a volume integral with singular kernel</title>
 <link>http://imechanica.org/node/2012</link>
 <description>&lt;p&gt;
Hi everybody,&amp;nbsp;
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In fact, I encounter this problem in my research and I would be grateful if someone can help. In micro mechanics, there are many problems concerning Green functions, e.g: the displacement is calculated from the distributed force in the domain, etc. Consider the following integral to determine the displacement field.
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&lt;strong&gt;u&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;)=&amp;int;&lt;strong&gt;A&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;,&lt;strong&gt;y&lt;/strong&gt;)dVy where&amp;nbsp;&lt;strong&gt;A&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;,&lt;strong&gt;y&lt;/strong&gt;) is singular of order r-2 (i.e r2=(&lt;strong&gt;x&lt;/strong&gt;-&lt;strong&gt;y&lt;/strong&gt;)(&lt;strong&gt;x&lt;/strong&gt;-&lt;strong&gt;y&lt;/strong&gt;)).
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Now I want to take the derivative of &lt;strong&gt;u&lt;/strong&gt; to derive the strain &lt;strong&gt;&amp;epsilon;&lt;/strong&gt;, how can I introduce the derivative after the integral sign?
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&lt;strong&gt;&amp;epsilon;&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;)=d/d&lt;strong&gt;x&lt;/strong&gt;&amp;int;&lt;strong&gt;A&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;,&lt;strong&gt;y&lt;/strong&gt;)dVy =&amp;int;d/d&lt;strong&gt;x &lt;/strong&gt;&lt;strong&gt;A&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;,&lt;strong&gt;y&lt;/strong&gt;)dVy + ???.
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I have tried to calculate the above derivative considering the derivative of the principal value of &lt;strong&gt;A&lt;/strong&gt;(&lt;strong&gt;x&lt;/strong&gt;,&lt;strong&gt;y&lt;/strong&gt;), but I&amp;#39;m not sure it is correct because I have no references on this.
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Thank you&amp;nbsp;
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&lt;br class=&quot;clear&quot; /&gt;</description>
 <comments>http://imechanica.org/node/2012#comments</comments>
 <category domain="http://imechanica.org/taxonomy/term/76">research</category>
 <category domain="http://imechanica.org/taxonomy/term/1372">green functions</category>
 <category domain="http://imechanica.org/taxonomy/term/18">micromechanics</category>
 <pubDate>Sun, 30 Sep 2007 04:49:43 -0400</pubDate>
 <dc:creator>TO Quy Dong</dc:creator>
 <guid isPermaLink="false">2012 at http://imechanica.org</guid>
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