Learning Forum

[Carlos Silva]

Hi everyone.

Currently I am trying to modeling a beam with 10 piezoeletrics coupled with an RL circuit for each one of them. Is it possible to couple a different circuit for each pzt? Can someone explain me how can I do it? I am using the elements SOLID226 and CIRCU94. The applicattion is passive damping.

[Bill Bulat]

Hi Carlos,

Are you doing this in Mechanical with command objects or are you instead using MAPDL solver directly? For the circuit elements you will need to explicitly define the nodes for use in their connectivity/definition. 

Let's say you have a command object under the solution branch in Mechanical.

*get,nmax,node,,num,max

returns the highest node number in your model. You can then define nodes, e.g.,

/prep7

n,nmax+1

n,nmax+2

 

and new element types...

*get,etmax,etyp,,num,max

et,etmax+1,94,0 ! RESISTOR

r,etmax+1,1000 ! RESISTANCE

type,etmax+1 $real,etmax+1 $e,nmax+1,nmax+2

to connect the elements to a face of a finite element mesh, use nodal coupling to force the face nodes to have a single VOLT DOF. for example, to connect CIRCU94 element node nmax+1 to face named "piezo_electrode", try:

cmsel,s,piezo_electrode

nsel,a,node,,nmax+1

cp,next,volt,all

 

I hope this helps,

 

Bill