在文献里看到的特征值与系统固有频率的关系..不懂，请教！！

shimering · 发表于 2007-5-31 14:19

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系统为0.6*0.8*1的立方体（盒子），计算它的固有频率，以下是用fortran计算出来的，用边界元法。得到的是特征值和特征向量，我不明白的是怎么把特征值和系统的固有频率联系起来的？
THE NUMBER OF ELEMENT: 24
THE NUMBER OF BOUNDARY NODE: 26
THE NUMBER OF INTENAL NODE: 24
1 0.2240583252E+04  0.0000000000E+00
2 0.8404309082E+03  0.0000000000E+00
3 0.6493916626E+03  0.0000000000E+00
4 0.6109667969E+03  0.0000000000E+00
5 0.5830488892E+03  0.0000000000E+00
6 0.5539835205E+03  0.0000000000E+00
7 0.5242087402E+03  0.0000000000E+00
8 0.4787617798E+03  0.0000000000E+00
9 0.4634256592E+03  0.4488579941E+02
  10 0.4634257507E+03 -0.4488580704E+02
  11 0.4337142334E+03  0.2527867889E+02
  12 0.4337142639E+03 -0.2527868462E+02
  13 0.4145792847E+03  0.0000000000E+00
  14 0.4120252686E+03  0.0000000000E+00
  15 0.3362085876E+03  0.0000000000E+00
  16 0.3359414368E+03  0.0000000000E+00
  17 0.3325782166E+03  0.0000000000E+00
  18 0.3062510376E+03  0.0000000000E+00
  19 0.2853010864E+03  0.0000000000E+00
  20 0.2782466125E+03  0.0000000000E+00
  21 0.2446512604E+03  0.0000000000E+00
  22 0.2430144958E+03  0.0000000000E+00
  23 0.2324984741E+03  0.1720062637E+02
  24 0.2324984741E+03 -0.1720063019E+02
  25 0.2067519531E+03  0.2506055069E+02
  26 0.2067519531E+03 -0.2506055069E+02
  27 0.2007818451E+03  0.0000000000E+00
  28 0.1887295532E+03  0.1797252846E+02
  29 0.1887295837E+03 -0.1797253036E+02
  30 0.1467097015E+03  0.0000000000E+00
  31 0.1385757904E+03  0.0000000000E+00
  32 0.1254487610E+03  0.0000000000E+00
  33 0.1129418106E+03  0.0000000000E+00
  34  -0.9857665253E+02  0.0000000000E+00
  35 0.9438014221E+02  0.0000000000E+00
  36 0.8159667969E+02  0.0000000000E+00
  37 0.7372013092E+02  0.3109792328E+02
  38 0.7372012329E+02 -0.3109791946E+02
  39 0.6762364197E+02  0.0000000000E+00
  40 0.5543163300E+02  0.2190728569E+02
  41 0.5543162537E+02 -0.2190728569E+02
  42 0.5404901886E+02  0.0000000000E+00
  43 0.4721386719E+02  0.0000000000E+00
  44 0.3918638992E+02  0.0000000000E+00
  45 0.3726289749E+02  0.0000000000E+00
  46 0.3015896988E+02  0.0000000000E+00
  47 0.2736175537E+02  0.0000000000E+00
  48 0.1688852692E+02  0.0000000000E+00
  49 0.1119513035E+02  0.0000000000E+00
  50 0.1422666287E-06  0.0000000000E+00
EIGENVECOTR:
1 0.1187972650E+00  0.0000000000E+00
2  -0.1501397695E-01  0.0000000000E+00
3 0.1187981442E+00  0.0000000000E+00
4  -0.7422050089E-01  0.0000000000E+00
5 0.1187971234E+00  0.0000000000E+00
6  -0.1501230244E-01  0.0000000000E+00
7 0.1187967211E+00  0.0000000000E+00
8  -0.7421976328E-01  0.0000000000E+00
9 0.8925176226E-02  0.0000000000E+00
  10 0.3278426453E-01  0.0000000000E+00
  11 0.8924868889E-02  0.0000000000E+00
  12  -0.5435488373E-01  0.0000000000E+00
  13 0.8924612775E-02  0.0000000000E+00
  14 0.3278468177E-01  0.0000000000E+00
  15 0.8925253525E-02  0.0000000000E+00
  16  -0.5435537547E-01  0.0000000000E+00
  17 0.1187971532E+00  0.0000000000E+00
  18  -0.1501377206E-01  0.0000000000E+00
  19 0.1187976003E+00  0.0000000000E+00
  20  -0.7422064990E-01  0.0000000000E+00
  21 0.1187983453E+00  0.0000000000E+00
  22  -0.1501495671E-01  0.0000000000E+00
  23 0.1187987924E+00  0.0000000000E+00
  24  -0.7422098517E-01  0.0000000000E+00
  25  -0.1497225463E+00  0.0000000000E+00
  26  -0.1497257948E+00  0.0000000000E+00
  27 0.2711607218E+00  0.0000000000E+00
  28  -0.1636084467E+00  0.0000000000E+00
  29 0.2711596489E+00  0.0000000000E+00
  30 0.2711593211E+00  0.0000000000E+00
  31  -0.1636077762E+00  0.0000000000E+00
  32 0.2711598873E+00  0.0000000000E+00
  33  -0.9525279701E-01  0.0000000000E+00
  34  -0.1037727147E+00  0.0000000000E+00
  35  -0.9525147825E-01  0.0000000000E+00
  36  -0.9525223821E-01  0.0000000000E+00
  37  -0.1037731618E+00  0.0000000000E+00
  38  -0.9525310248E-01  0.0000000000E+00
  39  -0.9525129944E-01  0.0000000000E+00
  40  -0.1037721187E+00  0.0000000000E+00
  41  -0.9525182098E-01  0.0000000000E+00
  42  -0.9525004029E-01  0.0000000000E+00
  43  -0.1037747264E+00  0.0000000000E+00
  44  -0.9524963051E-01  0.0000000000E+00
  45 0.2711601853E+00  0.0000000000E+00
  46  -0.1636091173E+00  0.0000000000E+00
  47 0.2711593211E+00  0.0000000000E+00
  48 0.2711583972E+00  0.0000000000E+00
  49  -0.1636082530E+00  0.0000000000E+00
  50 0.2711580396E+00  0.0000000000E+00

以下是作者得到的系统的固有频率：
24 个单元，24 个内点

阶数解析解  计算解
1    86.00 183.19
2 231.56 225.00
3 258.00 286.39
4 299.29 300.67
5 335.84 334.21
6 368.51 342.73
7 385.67 376.20
8 430.00 402.51
9 438.52 407.62
10 441.55 407.62

我想知道，作者的计算解是怎么计算出来的，各位请帮忙，如果我说的不够明白，请指出！多谢！！！

pengweicai · 发表于 2007-5-31 15:37

通常我们所接触的边界元是不能算的，
建议你看看边界元用于模态分析方面的资料。

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[结构振动] 在文献里看到的特征值与系统固有频率的关系..不懂，请教！！

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