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<HTML><HEAD><TITLE>new</TITLE><META content="text/html; charset=gb2312" http-equiv=Content-Type><LINK href="text.css" rel=stylesheet type=text/css><META content="Microsoft FrontPage 4.0" name=GENERATOR></HEAD><body leftmargin="15"><center><b><br>3 固有频率的求法</b></center> <table border="0" cellpadding="0" cellspacing="0" width="560"> <tr> <td>固有频率指无阻尼线性系统的固有频率。<font color="#800000">两种方法：</font></td> </tr> <tr> <td><b><font color="#0000FF">一、通过建立振动微分方程求</font></b></td> </tr> <tr> <td>对单自由度、无阻尼、线性、自由振动系统，你已经会用各种动力学方法建立振动微分方程，写成标准形式：</td> </tr> <tr> <td> <p align="center"><img border="0" src="pic2/3083.h22.gif" width="91" height="31"></td> </tr> <tr> <td>ω<font size="1">0</font> 即系统的固有频率（圆频率）。</td> </tr> <tr> <td><b><font color="#0000FF">二、能量法</font></b></td> </tr> <tr> <td>对单自由度、无阻尼、线性、自由振动系统，其解一定为：</td> </tr> <tr> <td> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td width="9%" align="center"></td> <td width="19%" align="center"><img border="0" src="pic2/3083.h23.gif" width="136" height="28"></td> <td width="9%" align="center"><img border="0" src="pic2/3083.h24.gif" width="38" height="27"></td> <td width="19%" align="center">位移振幅：</td> <td width="17%" align="center"><img border="0" src="pic2/3083.h25.gif" width="70" height="28"></td> <td width="12%" align="center"><img border="0" src="pic2/3083.h24.gif" width="38" height="27"></td> <td width="15%" align="center"><img border="0" src="pic2/3083.h26.gif" width="39" height="28"></td> </tr> <tr> <td width="9%" align="center"><img border="0" src="pic2/3083.h24.gif" width="38" height="27"></td> <td width="19%" align="center"><img border="0" src="pic2/3083.h27.gif" width="161" height="28"></td> <td width="9%" align="center"><img border="0" src="pic2/3083.h24.gif" width="38" height="27"></td> <td width="19%" align="center">速度振幅：</td> <td width="17%" align="center"><img border="0" src="pic2/3083.h28.gif" width="91" height="28"></td> <td width="12%" align="center"><img border="0" src="pic2/3083.h24.gif" width="38" height="27"></td> <td width="15%" align="center"><img border="0" src="pic2/3083.h29.gif" width="37" height="28"></td> </tr> <tr> <td width="9%" align="center"></td> <td width="19%" align="center"><img border="0" src="pic2/3083.h32.gif" width="89" height="28"></td> <td width="9%" align="center"><img border="0" src="pic2/3083.h24.gif" width="38" height="27"></td> <td width="19%" align="center"><img border="0" src="pic2/3083.h33.gif" width="26" height="28"></td> <td width="17%" align="center"></td> <td width="12%" align="center"></td> <td width="15%" align="center"></td> </tr> </table> </td> </tr> <tr> <td></td> </tr> <tr> <td> <p align="center"> <a href="3082.htm"><font color="#FF6666">[ 上一节 ]</font></a> <a href="30831.htm">↓下一页↓</a> <a href="3084.htm"><font color="#00CC00">[ 下一节 ]</font></a> </td> </tr> </table> </BODY></HTML> ⌨️ 快捷键说明
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