塔式起重机静动力分析【转】
本帖最后由 Chelsea 于 2011-3-15 17:27 编辑单位取mm，kg
!===========================================================================
FINISH
/CLEAR,START
/FILNAME,QTZ25
/TITLE,QTZ25 tower crane
/PREP7
ET,1,beam4 !单元为空间梁单元BEAM4
MP,EX,1,3E5 !弹性模量EX
MP,PRXY,1,0.3 !泊松比
MP,DENS,1,7.8e-9 !密度DENS
Acel,0,0,9800 !重力加速度
R,1,7775,5e6,5e6,100,100 !定义单元的第一类实常数:Area,Mement Inerta,Height
/VIEW,1,1,1,0
/VUP,1,Z !Z轴向上
/REPLOT
!======================定义塔身标准节上的节点
N,141,650,-650,21500
N,142,650,650,21500
N,143,-650,650,21500
N,144,-650,-650,21500
N,145,650,-650,21600
N,146,650,650,21600
N,147,-650,650,21600
N,148,-650,-650,21600
N,149,650,-650,21700
N,150,650,650,21700
N,151,-650,650,21700
N,152,-650,-650,21700
N,153,650,-650,22800
N,154,650,650,22800
N,155,-650,650,22800
N,156,-650,-650,22800
N,157,650,-650,23900
N,158,650,650,23900
N,159,-650,650,23900
N,160,-650,-650,23900
N,161,650,-650,24000
N,162,650,650,24000
N,163,-650,650,24000
N,164,-650,-650,24000
!==============================定义塔顶节点
N,165,500,-500,24380
N,166,500,500,24380
N,167,-500,500,24380
N,168,-500,-500,24380
N,169,500,-500,25625
N,170,500,500,25625
N,171,-500,500,25625
N,172,-500,-500,25625
N,173,500,-500,26870
N,174,500,500,26870
N,175,-500,500,26870
N,176,-500,-500,26870
N,177,500,0,24380
N,178,0,500,24380
N,179,-500,0,24380
N,180,0,-500,24380
N,181,500,0,26870
N,182,0,500,26870
N,183,-500,0,26870
N,184,0,-500,26870
N,185,0,-500,27000
N,186,0,500,27000
N,187,500,-500,27000
N,188,500,500,27000
N,189,-500,500,27000
N,190,-500,-500,27000
N,191,458.3333,-403.3333,27853.33
N,192,458.3333,500,27911.67
N,193,-458.3333,500,27911.67
N,194,-458.3333,-403.3333,27853.33
N,195,416.6667,-306.6667,28706.67
N,196,416.6667,500,28823.33
N,197,-416.6667,500,28823.33
N,198,-416.6667,-306.6667,28706.67
N,199,375,-210,29560
N,200,375,500,29735
N,201,-375,500,29735
N,202,-375,-210,29560
N,203,333.3333,-113.3333,30413.33
N,204,333.3333,500,30646.67
N,205,-333.3333,500,30646.67
N,206,-333.3333,-113.3333,30413.33
N,207,291.6667,-16.66666,31266.67
N,208,291.6667,500,31558.33
N,209,-291.6667,500,31558.33
N,210,-291.6667,-16.66666,31266.67
N,211,250,80,32120
N,212,250,500,32470
N,213,-250,500,32470
N,214,-250,80,32120
!======================定义塔臂的节点
N,215,-500,750,27000
N,216,500,750,27000
N,217,-390,1565,27000
N,218,390,1565,27000
N,219,0,2043,27850
N,220,-390,2520,27000
N,221,390,2520,27000
N,222,0,2998,27850
N,223,-390,3182,27000
N,224,390,3182,27000
N,225,0,3398,27850
N,226,-390,3728,27000
N,227,390,3728,27000
N,228,0,4205,27850
N,229,-390,4682,27000
N,230,390,4682,27000
N,231,0,5160,27850
N,232,-390,5638,27000
N,233,390,5638,27000
N,234,0,5750,27850
N,235,-390,5750,27000
N,236,390,5750,27000
N,237,0,5862,27850
N,238,-390,5862,27000
N,239,390,5862,27000
N,240,0,6340,27850
N,241,-390,6817.2,27000
N,242,390,6817.2,27000
N,243,0,7295,27850
N,244,-390,7772.4,27000
N,245,390,7772.4,27000
N,246,0,8250,27850
N,247,-390,8727.6,27000
N,248,390,8727.6,27000
N,249,0,9205,27850
N,250,-390,9682.8,27000
N,251,390,9682.8,27000
N,252,0,10160,27850
N,253,-390,10638,27000
N,254,390,10638,27000
N,255,0,10750,27850
N,256,-390,10750,27000
N,257,390,10750,27000
N,258,0,10862,27850
N,259,-390,10862,27000
N,260,390,10862,27000
N,261,0,11340,27850
N,262,-390,11817.2,27000
N,263,390,11817.2,27000
N,264,0,12295,27850
N,265,-390,12772.4,27000
N,266,390,12772.4,27000
N,267,0,13250,27850
N,268,-390,13727.6,27000
N,269,390,13727.6,27000
N,270,0,14205,27850
N,271,-390,14682.8,27000
N,272,390,14682.8,27000
N,273,0,15160,27850
N,274,-390,15638,27000
N,275,390,15638,27000
N,276,0,15750,27850
N,277,-390,15750,27000
N,278,390,15750,27000
N,279,0,15862,27850
N,280,-390,15862,27000
N,281,390,15862,27000
N,282,0,16340,27850
N,283,-390,16817.2,27000
N,284,390,16817.2,27000
N,285,0,17295,27850
N,286,-390,17772.4,27000
N,287,390,17772.4,27000
N,288,0,18250,27850
N,289,-390,18727.6,27000
N,290,390,18727.6,27000
N,291,0,19205,27850
N,292,-390,19682.8,27000
N,293,390,19682.8,27000
N,294,0,20160,27850
N,295,-390,20638,27000
N,296,390,20638,27000
N,297,0,20750,27850
N,298,-390,20750,27000
N,299,390,20750,27000
N,300,0,20862,27850
N,301,-390,20862,27000
N,302,390,20862,27000
N,303,0,21340,27850
N,304,-390,21817.2,27000
N,305,390,21817.2,27000
N,306,0,22295,27850
N,307,-390,22772.4,27000
N,308,390,22772.4,27000
N,309,0,23250,27850
N,310,-390,23727.6,27000
N,311,390,23727.6,27000
N,312,0,24205,27850
N,313,-390,24682.8,27000
N,314,390,24682.8,27000
N,315,0,25160,27850
N,316,-390,25638,27000
N,317,390,25638,27000
N,318,0,25750,27850
N,319,-390,25750,27000
N,320,390,25750,27000
N,321,0,25862,27850
N,322,-390,25862,27000
N,323,390,25862,27000
N,324,0,26340,27850
N,325,-390,26817.2,27000
N,326,390,26817.2,27000
N,327,0,27295,27850
N,328,-390,27772.4,27000
N,329,390,27772.4,27000
!========================平衡臂重的节点
N,350,408,-10000,25000
N,351,-408,-8500,27000
N,352,408,-8500,27000
N,353,-408,-10000,27000
N,354,408,-10000,27000
N,355,-408,-8500,25000
N,356,408,-8500,25000
N,357,-408,-10000,25000
!=======================通过节点生成各单元
E,141,145
E,142,146
E,143,147
E,144,148
E,141,142
E,142,143
E,143,144
E,141,144
E,141,143
E,145,149
E,146,150
E,147,151
E,148,152
E,149,153
E,150,154
E,151,155
E,152,156
E,153,157
E,154,158
E,155,159
E,156,160
E,157,161
E,158,162
E,159,163
E,160,164
E,149,150
E,153,154
E,157,158
E,150,151
E,154,155
E,158,159
E,151,152
E,155,156
E,159,160
E,149,152
E,153,156
E,157,160
E,149,154
E,154,157
E,150,155
E,155,158
E,151,156
E,156,159
E,152,153
E,153,160
E,153,155
E,157,159
E,161,165
E,162,166
E,163,167
E,164,168
E,165,169
E,166,170
E,167,171
E,168,172
E,169,173
E,170,174
E,171,175
E,172,176
E,165,177
E,166,177
E,166,178
E,167,178
E,167,179
E,168,179
E,168,180
E,165,180
E,169,170
E,170,171
E,171,172
E,169,172
E,173,181
E,174,181
E,174,182
E,175,182
E,175,183
E,176,183
E,176,184
E,173,184
E,169,177
E,170,177
E,170,178
E,171,178
E,171,179
E,172,179
E,172,180
E,169,180
E,169,181
E,170,181
E,170,182
E,171,182
E,171,183
E,172,183
E,172,184
E,169,184
E,185,190
E,185,187
E,186,189
E,186,188
E,185,194
E,185,191
E,186,193
E,186,192
E,187,188
E,191,192
E,195,196
E,199,200
E,203,204
E,207,208
E,189,190
E,193,194
E,197,198
E,201,202
E,205,206
E,209,210
E,213,214
E,191,194
E,195,198
E,199,202
E,203,206
E,207,210
E,211,214
E,192,193
E,196,197
E,200,201
E,204,205
E,208,209
E,212,213
E,188,191
E,191,196
E,196,199
E,199,204
E,204,207
E,207,212
E,189,194
E,194,197
E,197,202
E,202,205
E,205,210
E,210,213
E,194,195
E,195,202
E,202,203
E,203,210
E,210,211
E,193,196
E,196,201
E,201,204
E,204,209
E,209,212
E,187,191
E,191,195
E,195,199
E,199,203
E,203,207
E,207,211
E,188,192
E,192,196
E,196,200
E,200,204
E,204,208
E,208,212
E,189,193
E,193,197
E,197,201
E,201,205
E,205,209
E,209,213
E,190,194
E,194,198
E,198,202
E,202,206
E,206,210
E,210,214
E,211,212
E,173,187
E,174,188
E,175,189
E,176,190
E,215,216
E,217,218
E,220,221
E,223,224
E,226,227
E,229,230
E,232,233
E,218,220
E,221,223
E,227,229
E,230,232
E,219,222
E,222,225
E,225,228
E,228,231
E,231,234
E,215,219
E,217,219
E,219,220
E,220,222
E,222,223
E,223,225
E,225,226
E,226,228
E,228,229
E,229,231
E,231,232
E,216,219
E,218,219
E,219,221
E,221,222
E,222,224
E,224,225
E,225,227
E,227,228
E,228,230
E,230,231
E,231,233
E,216,218
E,218,221
E,221,224
E,224,227
E,227,230
E,230,233
E,215,217
E,217,220
E,220,223
E,223,226
E,226,229
E,229,232
E,232,235
E,233,236
E,189,215
E,188,216
E,234,237
E,235,238
E,236,239
E,237,240
E,240,243
E,243,246
E,246,249
E,249,252
E,252,255
E,238,241
E,241,244
E,244,247
E,247,250
E,250,253
E,253,256
E,239,242
E,242,245
E,245,248
E,248,251
E,251,254
E,254,257
E,237,238
E,238,240
E,240,241
E,241,243
E,243,244
E,244,246
E,246,247
E,247,249
E,249,250
E,250,252
E,252,253
E,238,239
E,239,241
E,241,242
E,242,244
E,244,245
E,245,247
E,247,248
E,248,250
E,250,251
E,251,253
E,253,254
E,237,239
E,239,240
E,240,242
E,242,243
E,243,245
E,245,246
E,246,248
E,248,249
E,249,251
E,251,252
E,252,254
E,255,258
E,256,259
E,257,260
E,258,261
E,261,264
E,264,267
E,267,270
E,270,273
E,273,276
E,259,262
E,262,265
E,265,268
E,268,271
E,271,274
E,274,277
E,260,263
E,263,266
E,266,269
E,269,272
E,272,275
E,275,278
E,258,259
E,259,261
E,261,262
E,262,264
E,264,265
E,265,267
E,267,268
E,268,270
E,270,271
E,271,273
E,273,274
E,259,260
E,260,262
E,262,263
E,263,265
E,265,266
E,266,268
E,268,269
E,269,271
E,271,272
E,272,274
E,274,275
E,258,260
E,260,261
E,261,263
E,263,264
E,264,266
E,266,267
E,267,269
E,269,270
E,270,272
E,272,273
E,273,275
E,276,279
E,277,280
E,278,281
E,279,282
E,282,285
E,285,288
E,288,291
E,291,294
E,294,297
E,280,283
E,283,286
E,286,289
E,289,292
E,292,295
E,295,298
E,281,284
E,284,287
E,287,290
E,290,293
E,293,296
E,296,299
E,279,280
E,280,282
E,282,283
E,283,285
E,285,286
E,286,288
E,288,289
E,289,291
E,291,292
E,292,294
E,294,295
E,280,281
E,281,283
E,283,284
E,284,286
E,286,287
E,287,289
E,289,290
E,290,292
E,292,293
E,293,295
E,295,296
E,279,281
E,281,282
E,282,284
E,284,285
E,285,287
E,287,288
E,288,290
E,290,291
E,291,293
E,293,294
E,294,296
E,297,300
E,298,301
E,299,302
E,300,303
E,303,306
E,306,309
E,309,312
E,312,315
E,315,318
E,301,304
E,304,307
E,307,310
E,310,313
E,313,316
E,316,319
E,302,305
E,305,308
E,308,311
E,311,314
E,314,317
E,317,320
E,300,301
E,301,303
E,303,304
E,304,306
E,306,307
E,307,309
E,309,310
E,310,312
E,312,313
E,313,315
E,315,316
E,301,302
E,302,304
E,304,305
E,305,307
E,307,308
E,308,310
E,310,311
E,311,313
E,313,314
E,314,316
E,316,317
E,300,302
E,302,303
E,303,305
E,305,306
E,306,308
E,308,309
E,309,311
E,311,312
E,312,314
E,314,315
E,315,317
E,318,321
E,319,322
E,320,323
E,321,324
E,324,327
E,322,325
E,325,328
E,323,326
E,326,329
E,321,322
E,322,324
E,324,325
E,325,327
E,327,328
E,322,323
E,323,325
E,325,326
E,326,328
E,328,329
E,321,323
E,323,324
E,324,326
E,326,327
E,327,329
E,190,351
E,187,352
E,351,353
E,352,354
E,355,357
E,350,356
E,351,355
E,352,356
E,353,357
E,350,354
E,351,352
E,355,356
E,353,354
E,350,357
!=================4根斜拉杆
E,213,282
E,212,282
E,214,353
E,211,354
/PNUM,NODE,OFF
EPLOT
SAVE
!=================固定塔身底部的4个结点
d,141,all
d,142,all
d,143,all
d,144,all
!======================(1)空载时的情况
/SOLU
SOLVE
FINISH
/POST1 !进入后处理模块POST1
SET,1 !读入第一个荷载步的计算结果
PLDISP,2 ! 在图形窗口显示结构变形
FINISH
!==========================(2)塔臂端部满载情况，并求解
/SOLU
ANTYPE,0 !申明求解类型是静力分析
F,328,FZ,-15000 !在塔臂最前端施加沿-Z方向的吊重15000
F,329,FZ,-15000
SOLVE !开始求解
/POST1 !进入后处理模块POST1
PLDISP,2 !在图形窗口显示结构变形
/VIEW,1,1,1,0
/VUP,1,Z !Z轴向上
/REPLOT
Etable,LS1,ls,1 !
Etable,LS2,ls,2
Etable,LS3,ls,3
Etable,LS4,ls,4
Etable,LS5,ls,5
Etable,V,Volu !用单元体积定义单元表V
Etable,smax,NMISC,1 !起始端的最大拉应力
Etable,smin,NMISC,2 !起始端的最大压应力
pretab,LS1,LS2,LS3,LS4,LS5,smax,smin !列表指定单元表的内容
FINISH
!===================(3)进行模态分析
/SOLU
ANTYPE,2 !模态分析
MXPAND,5,,,,0 !最大模态展开数为5阶
MODOPT,LANB,5,0,0,,OFF !用分块Lanczos方法求解矩阵特征值问题
SOLVE
FINISH
/POST1
SET,LIST !列表显示频率计算结果
SET,First !读入第1阶模态
PLDISP,2 !图形显示模态
ANMODE,8,0.2 !用8帧每帧间隔0.2秒生成动画
SET,1,2 !读入第2阶模态
PLDISP,2
AnMODE,12,0.1 !用12帧每帧0.1秒生成动画
SET,1,3 !读入第3阶模态
PLDISP,2
ANMODE,12,0.1 !用12帧每帧0.1秒生成动画
SET,1,4 !读入第4阶模态
PLDISP,2
ANMODE,12,0.1 !用12帧每帧0.1秒生成动画
SET,LAST !读入最后一阶模态
PLDISP,2
ANMODE,12,0.1 !用12帧每帧0.1秒生成动画
FINISH
回复 1 # Chelsea 的帖子
chelsea老师，请教个问题，某一振动系统的某阶模态质量（或模态刚度）是否必小于系统的真实总质量（总刚度）？望能简单解释一下，谢谢了！ 补充一点，问题的前提条件是：模态振型标准化原则为以振型向量为单位向量时 另有一问题请教，何种结构会出现大型、稀疏、带状矩阵？因兰索斯法求模态参数说适合此种矩阵？ 本帖最后由 Chelsea 于 2011-3-18 09:46 编辑
tomjohn 发表于 2011-3-16 11:08 static/image/common/back.gif
回复 1 # Chelsea 的帖子
chelsea老师，请教个问题，某一振动系统的某阶模态质量（或模态刚度）是否必小于 ...
='
展开你就知道了 本帖最后由 Chelsea 于 2011-3-18 09:51 编辑
tomjohn 发表于 2011-3-16 12:05 static/image/common/back.gif
另有一问题请教，何种结构会出现大型、稀疏、带状矩阵？因兰索斯法求模态参数说适合此种矩阵？
在 ANSYS 中有以下几种提取模态的方法：
– (1) Block Lanczos 法
– (2) 子空间法
– (3) PowerDynamics 法
– (4) 减缩法
– (5) 不对称法
– (6) 阻尼法
使用何种模态提取方法主要取决于模型大小（相对于计算机的计算能力而言）和具体的应用场合。
(1) Block Lanczos 法
Block Lanczos 法可以在大多数场合中使用：
- 是一种功能强大的方法，当提取中型到大型模型（50,000 ~ 100,000 个自由度）的大量振型时（40+），这种方法很有效；
- 经常应用在具有实体单元或壳单元的模型中；
- 在具有或没有初始截断点时同样有效。（允许提取高于某个给定频率的振型）；
- 可以很好地处理刚体振型；
- 需要较高的内存。
(2) 子空间法
子空间法比较适合于提取类似中型到大型模型的较少的振型 （<40）
- 需要相对较少的内存；
- 实体单元和壳单元应当具有较好的单元形状，要对任何关于单元形状的警告信息予以注意；
- 在具有刚体振型时可能会出现收敛问题；
- 建议在具有约束方程时不要用此方法。
(3) PowerDynamics 法
PowerDynamics 法适用于提取很大的模型（100.000个自由度以上）的较少振型（< 20）。这种方法明显比
Block Lanczos 法或子空间法快，但是：
- 需要很大的内存；
- 当单元形状不好或出现病态矩阵时，用这种方法可能不收敛；
- 建议只将这种方法作为对大模型的一种备用方法。
注: PowerDynamics 方法
- 子空间技术使用 Power 求解器 (PCG) 和 一致质量矩阵；
- 不执行 Sturm 序列检查 (对于遗漏模态); 它可能影响多个重复频率的模型；
- 一个包含刚体模态的模型, 如果你使用 PowerDynamics 方法，必须执行 RIGID 命令 (或者在分析设置对话框中指定
RIGID 设置)。
(4) 减缩法
如果模型中的集中质量不会引起局部振动，例如象梁和杆那样，可以使用缩减法：
- 它是所有方法中最快的；
- 需要较少的内存和硬盘空间；
- 使用矩阵缩减法，即选择一组主自由度来减小 和 的大小；
- 缩减[的刚度矩阵 是精确的，但缩减的质量矩阵 是近似的，近似程度取决于主自由度的数目和位置；
- 在结构抵抗弯曲能力较弱时不推荐使用此方法，如细长的梁和薄壳。
注意：选择主自由度的原则请参阅<<ANSYS结构分析指南>>。
(5) 不对称法
不对称法适用于声学问题（具有结构藕合作用）和其它类似的具有不对称质量矩阵和刚度矩阵 的问题：
- 计算以复数表示的特征值和特征向量
* 实数部分就是自然频率
* 虚数部分表示稳定性，负值表示稳定，正值表示不确定
注意： 不对称方法采用 Lanczos 算法，不执行 Sturm 序列检查，所以遗漏高端频率。
(6) 阻尼法
在模态分析中一般忽略阻尼，但如果阻尼的效果比较明显，就要使用阻尼法：
- 主要用于回转体动力学中，这时陀螺阻尼应是主要的；
- 在 ANSYS 的 BEAM4 和 PIPE16单元中，可以通过定义实常数中的 SPIN（旋转速度，弧度/秒）选项来说明
陀螺效应；
- 计算以复数表示的特征值和特征向量。
* 虚数部分就是自然频率；
* 实数部分表示稳定性，负值表示稳定，正值表示不确定。
注意：
- 该方法采用 Lanczos 算法
- 不执行 Sturm 序列检查，所以遗漏高端频率
- 不同节点间存在相位差
- 响应幅值 = 实部与虚部的矢量和
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