我用shell单元和solid单元建钢混组合梁桥

[1546225070]

自振频率在20阶之后就变化不大，是模型出错了吗，可以帮忙看看命令流吗

[Ashish Khemka]

Hello,

Can you explain why you are going till 20th order? In most cases, high frequency modes can be neglected. And not every mode participates at the same level to the deformation of the structure under dynamic load. Please refer to the following link for more details:

Mode Participation Factor and Effective Mass — Lesson 4 - ANSYS Innovation Courses

Regards,

Ashish Khemka

[frank.wang]

查看一下前20阶的振型参与百分比，是不是达到要求了。通常桥梁结构需要达到90%参与。 如果没达到90%，检查模型20阶以后的振型是否均为局部振型， 如果为局部振型可以考虑增加模态数或者暂时去掉这些局部振型参与的杆件。模态分析包含过多结构细节意义不大，一般以把握整体振型为主。