求助：有限元程序验证
浏览：89356 回答：1
我的
有限元程序是采用三维六面体单元来计算自振频率。现在我对这程序作了初步的验证，计算了悬臂梁，两端自由固定梁的前几阶自振频率，也理论值与
ansys比较，误差在1%~2%之间，结果如下：
而对于简支梁，结果如下：
对于这样的结果，我比较困惑，不知道是不是这个程序有问题。请高手指点一下，谢谢！
顺便问一下，有没有人见过用三维六面体单元来计算梁板自振频率的实例啊，有的话告诉我一下，不胜感激！！！
| 悬臂 | |||||
| 自由度181500(50000) | |||||
| 理论 | ANSYS | FEM | |||
| 1 | 101.68208327 | 101.72477012 | 0.0420% | 101.97872547 | 0.2917% |
| 2 | 101.68208327 | 101.72477012 | 0.0420% | 101.97872937 | 0.2917% |
| 3 | 637.27673189 | 636.36100791 | -0.1437% | 637.94670574 | 0.1051% |
| 4 | 637.27673189 | 636.36100791 | -0.1437% | 637.94670649 | 0.1051% |
| 5 | 1784.57280344 | 1776.75914116 | -0.4378% | 1781.17058384 | -0.1906% |
| 6 | 1784.57280344 | 1776.75914116 | -0.4378% | 1781.17058412 | -0.1906% |
| 7 | 3478.07044899 | 3467.43864362 | -0.3057% | 3475.99386845 | -0.0597% |
| 8 | 3478.07044899 | 3467.43864362 | -0.3057% | 3475.99386860 | -0.0597% |
两端固定 |
|||||
| 自由度181137(50000) | |||||
| 理论 | ANSYS | FEM | |||
| 1 | 647.08923189 | 646.22560884 | -0.1335% | 647.84876316 | 0.1174% |
| 2 | 647.08923189 | 646.22560884 | -0.1335% | 647.84876380 | 0.1174% |
| 3 | 1783.66416149 | 1775.37684040 | -0.4646% | 1779.80035858 | -0.2166% |
| 4 | 1783.66416149 | 1775.37684040 | -0.4646% | 1779.80035882 | -0.2166% |
| 5 | 3497.12659331 | 3464.86253764 | -0.9226% | 3473.42565367 | -0.6777% |
| 6 | 3497.12659331 | 3464.86253764 | -0.9226% | 3473.42565379 | -0.6777% |
| 7 | 5780.38023508 | 5695.26765799 | -1.4724% | 5709.25486086 | -1.2305% |
| 8 | 5780.38023508 | 5695.26765799 | -1.4724% | 5709.25486095 | -1.2305% |
| 两端自由 | |||||
| 自由度181863(50000) | |||||
| 理论 | ANSYS | FEM | |||
| 1 | 647.08923189 | 646.22560884 | -0.1335% | 647.78961819 | 0.1082% |
| 2 | 647.08923189 | 646.22560884 | -0.1335% | 647.78961892 | 0.1082% |
| 3 | 1783.66416149 | 1776.69630931 | -0.3906% | 1781.09003129 | -0.1443% |
| 4 | 1783.66416149 | 1776.69630931 | -0.3906% | 1781.09003156 | -0.1443% |
| 5 | 3497.12659331 | 3470.14041330 | -0.7717% | 3478.66087090 | -0.5280% |
| 6 | 3497.12659331 | 3470.14041330 | -0.7717% | 3478.66087103 | -0.5280% |
| 7 | 5780.38023508 | 5708.27385157 | -1.2474% | 5722.22862083 | -1.0060% |
| 8 | 5780.38023508 | 5708.27385157 | -1.2474% | 5722.22862100 | -1.0060% |
而对于简支梁，结果如下：
| 简支 | ||||
| 自由度181808(50000) | ||||
| 理论 | ANSYS | FEM | ||
| 1 | 285.45761752 | 284.97386961 | 285.68157338 | |
| 2 | 1141.83047007 | 389.65173682 | 393.10925234 | |
| 3 | 2569.11855765 | 1134.05211609 | 1136.85258316 | |
| 4 | 4567.32188027 | 1296.34679258 | 1304.81388714 | |
| 5 | 7136.44043793 | 2526.90863499 | 2533.33119656 | |
| 6 | 2749.39622672 | 2763.53963185 | ||
| 7 | 4399.04652912 | 4411.33246967 | ||
| 8 | 4735.95092529 | 4757.18555450 | ||
对于这样的结果，我比较困惑，不知道是不是这个程序有问题。请高手指点一下，谢谢！
顺便问一下，有没有人见过用三维六面体单元来计算梁板自振频率的实例啊，有的话告诉我一下，不胜感激！！！
weiyang5564 
