压电陶瓷做压电谐响应仿真问题solid226

我用solid226仿真时提示这个，There are elements with negative and positive electric charge reaction
solutions for the VOLT degree of freedom in the model. This analysis
is not valid. 用solid5就没有这个问题，但solid5貌似不能做压电谐响应仿真，求救啊。