《ansys使用技巧》学习资料：第十五讲 如何提取模态质量

如何提取模态质量 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 1、利用SM对 ETABLE动能数据求和获得结构总动能(ma2) 2、将结构总动能除以a2得到m,其中a是系统的角频率。 下面是《 ANSYS Verification manual》中wM89.DAT稍加修改后提取模态质量的 例子 /PREP7 /TITLE, VM89, NATURAL FREQUENCIES OF A TWO-MASS-SPRING SYSTEM Clk*k VIBRATIoN THEORY AND APPLICATIONS, THOMSON, 2ND PRINTING, PAGE 163,EX6.2-2 ET. 1. COMBIN14.,, 2 R,1. 200! SPRING CONSTANT =200 R2, 800! SPRING CONSTANT =800 R,3,,5!MASS=.5 R 4.1 MASS =1 N,1 N,4, FILL E, 1, 2! SPRING ELEMENT (TYPE, 1)AND K = 200(REAL, 1) REAL, 3 E, 2! MASS ELEMENT (TYPE, 2)AND MASS =.5(REAL, 3) TYPE. I REAL. 2 E, 2, 3! SPRING ELEMENT (TYPE, 1) AND K=800(REAL, 2) TYPE. 2 REAL. 4 E, 3! MASS ELEMENT (TYPE, 2)AND MASS = 1(REAL, 4) TYPE I REAL E, 3, 4! SPRING ELEMENT (TYPE, 1) AND K=200(REAL, 1) M,2,UX,3 OUTPR. BASIC. 1 D,1,UY,4 D,1,UX,,4,3 FINISH

如何提取模态质量 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： 1、利用 SSUM 对 ETABLE 动能数据求和获得结构总动能( ）； 2、将结构总动能除以 得到 ，其中 是系统的角频率。 下面是《ANSYS Verification Manual》中 VM89.DAT 稍加修改后提取模态质量的 例子： /PREP7 /TITLE, VM89, NATURAL FREQUENCIES OF A TWO-MASS-SPRING SYSTEM C*** VIBRATION THEORY AND APPLICATIONS, THOMSON, 2ND PRINTING, PAGE 163,EX 6.2-2 ET,1,COMBIN14,,,2 ET,2,MASS21,,,4 R,1,200 ! SPRING CONSTANT = 200 R,2,800 ! SPRING CONSTANT = 800 R,3,.5 ! MASS = .5 R,4,1 ! MASS = 1 N,1 N,4,1 FILL E,1,2 ! SPRING ELEMENT (TYPE,1) AND K = 200 (REAL,1) TYPE,2 REAL,3 E,2 ! MASS ELEMENT (TYPE,2) AND MASS = .5 (REAL,3) TYPE,1 REAL,2 E,2,3 ! SPRING ELEMENT (TYPE,1) AND K = 800 (REAL,2) TYPE,2 REAL,4 E,3 ! MASS ELEMENT (TYPE,2) AND MASS = 1 (REAL,4) TYPE,1 REAL,1 E,3,4 ! SPRING ELEMENT (TYPE,1) AND K = 200 (REAL,1) M,2,UX,3 OUTPR,BASIC,1 D,1,UY,,,4 D,1,UX,,,4,3 FINISH

/SOLU ANTYPE MODAL MODOPT, subsp, 2,,, 2, ON MXPAND. 2., YES FINISH /postl set,l,l tabl. kene kene *get, kenevall, ssum, item, kene *get, fregvall, mode, 1, freq eigen=(2*3.14159* freya11)**2 pmass1=2*kenevall/eigen set, 1.2 tabl. ke ene, kene *get, keneva12, ssum, item, kene *get, fregval2, mode, 2, freq eigen2=(2*3.14159* freya12)**2 pmass2=2*keneva12/eigen finish

/SOLU ANTYPE,MODAL MODOPT,subspa,2,,,2,ON MXPAND,2,,,YES SOLVE FINISH /post1 set,1,1 etabl,kene,kene ssum *get,keneval1,ssum,,item,kene *get,freqval1,mode,1,freq eigen1=(2*3.14159*freqval1)**2 pmass1=2*keneval1/eigen1 set,1,2 etabl,kene,kene ssum *get,keneval2,ssum,,item,kene *get,freqval2,mode,2,freq eigen2=(2*3.14159*freqval2)**2 pmass2=2*keneval2/eigen2 finish