[转帖]如何提取模态质量

VibInfo

模态分析过程中打开振型型则化开关(MODOPT命令的Nrmkey设置为ON)，ANSYS程序将自动将每阶模态的最大位移单位化，就可以提取模态质量。计算方法如下：<BR>1、利用SSUM对ETABLE 动能数据求和获得结构总动能( ）；<BR>2、将结构总动能除以 得到 ，其中 是系统的角频率。<BR>下面是《ANSYS Verification Manual》中VM89.DAT稍加修改后提取模态质量的例子： <BR><BR>/PREP7<BR>/TITLE, VM89, NATURAL FREQUENCIES OF A TWO-MASS-SPRING SYSTEM<BR>C*** VIBRATION THEORY AND APPLICATIONS, THOMSON, 2ND PRINTING, PAGE 163,EX 6.2-2<BR>ET,1,COMBIN14,,,2<BR>ET,2,MASS21,,,4<BR>R,1,200 ! SPRING CONSTANT = 200<BR>R,2,800 ! SPRING CONSTANT = 800<BR>R,3,.5 ! MASS = .5<BR>R,4,1 ! MASS = 1<BR>N,1<BR>N,4,1<BR>FILL<BR>E,1,2 ! SPRING ELEMENT (TYPE,1) AND K = 200 (REAL,1)<BR>TYPE,2<BR>REAL,3<BR>E,2 ! MASS ELEMENT (TYPE,2) AND MASS = .5 (REAL,3)<BR>TYPE,1<BR>REAL,2<BR>E,2,3 ! SPRING ELEMENT (TYPE,1) AND K = 800 (REAL,2)<BR>TYPE,2<BR>REAL,4<BR>E,3 ! MASS ELEMENT (TYPE,2) AND MASS = 1 (REAL,4)<BR>TYPE,1<BR>REAL,1<BR>E,3,4 ! SPRING ELEMENT (TYPE,1) AND K = 200 (REAL,1)<BR>M,2,UX,3<BR>OUTPR,BASIC,1<BR>D,1,UY,,,4<BR>D,1,UX,,,4,3<BR>FINISH<BR><BR>/SOLU<BR>ANTYPE,MODAL <BR>MODOPT,subspa,2,,,2,ON<BR>MXPAND,2,,,YES<BR>SOLVE<BR>FINISH<BR><BR>/post1<BR><BR>set,1,1<BR>etabl,kene,kene<BR>ssum <BR>*get,keneval1,ssum,,item,kene<BR>*get,freqval1,mode,1,freq<BR>eigen1=(2*3.14159*freqval1)**2<BR>pmass1=2*keneval1/eigen1<BR><BR>set,1,2<BR>etabl,kene,kene<BR>ssum<BR>*get,keneval2,ssum,,item,kene<BR>*get,freqval2,mode,2,freq<BR>eigen2=(2*3.14159*freqval2)**2<BR>pmass2=2*keneval2/eigen2<BR><BR>finish<BR>

linda

将总能量除以什么？怎么没写出来？

happy

<DIV class=quote><B>以下是引用<I>alina</I>在2005-9-30 10:50:02的发言：</B><BR>将总能量除以什么？怎么没写出来？</DIV>
<br>结构总动能除以1/2*ω*ω就可以得到m

skysea

这个看不懂喔