HuiLiu
Ansys Employee

I see, so you are using acoustic module. Unfortunately piezo ACT doesn't work with acoustic, it only works with structural. You have to use command object to define the piezo body. Alternatively, you can use an earlier version, in "structural harmonic", use both Acoustic and Piezo & MEMS ACTs. Note Acoustic ACT is not working with newer versions since now we have the native modules, that ACT is no longer maintained for newer version.