beam188/189的模态分析

新做的一个桥梁模型，其中有beam188/189,shell63和link10单元，做模态分析时发现前两阶频率都是0，其他的几阶都没有很大的变化，总是出现elem type 2 is beam189. keyopt(1)=1 is suggested for non-circular cross sections.
elem type 3 is beam188. keyopt(1)=1is suggested for non-circular cross sections and keyopt(3)=2 is always suggested.
并且出现好多的
Term 1 (node 1987 ROTZ) on CE number 264 is not active on any element
This CE is ignored.
The first term of CE number=226 has no active DOF associated with it.
This CE is ignored
请问是什么意思？该怎么解决呀？