Learning Forum

[Abdulsalam]

Dear All, nI am Simulation square Dielectric Elastomer Actuator (DEA) under various voltages and frequencies using the element SOILD226. And I want to assume/assign electrodes at the top and bottom of the Dielectric elastomer film. my question here is: nHow I can assign perfect electrodes with zero resistance and negligible thickness that can expand freely without affecting the elastomer actuation? (The Electrodes are placed at the center of the elastomer film) nOr, can I neglect the electrodes and just apply the voltage directly to the Dielectric elastomer film (on nodes) in 20 cm diameter at the center? nMy geometry dimensions are as follows, Length =60cm, Width =60cm, electrodes =20cm in diameter (in the center) and thickness of the Dielectric elastomer is = 0.05cm. Forgot to mention that I need to preform my simulation in ANSYS APDLnany help/recommendation is much appreciated. nKind Regards, n

[Erik Kostson]

See APDL help manual example (couple field analysis chapter).n2.4.3. Example: Electrostatic-Structural Analysis of a Dielectric Elastomernn

[Abdulsalam]

Dear,nThank you for your quick response!nI have already read the couple field analysis Guide and also all the examples related to Electrostatic-Structural Analysis but I still could not figure it out. I have attached the command I used for my simulation for you valuable feedback. because whenever I run the simulation I got this error:n*** ERROR ***              CP =   49.594  TIME= 23:46:26n Specified constraint not allowed on slave degree of freedom in coupled  n set.                                   n Coupled set number 10 First node= 58802 Slave node = 66002 Degree of  n freedom = VOLT.                             n Move Move constraint to first node or remove coupling and constrain  nnThank you in advancen

[Erik Kostson]

From the error message it says that we are applying VOLT BC on a slave node (66002), something that we can not do. So the workaround could be toskip the CP command and apply the Voltage BC on the electrodes directlynapply the Voltage only to the Master node in the constraint point set (CP), so only to node nr: 58802 (as per the error message). As the nodes are coupled to the master node, they will also get this voltage. So use D,58802,volt,voltage on the master node only.n

[Abdulsalam]

Dear,nI just want to clarify in one thing first, is it possible to apply the voltage directly in to my solid226 model with out specifying a contact element? nIn the simulation of DEAs they usually neglect the electrodes due to their thickness is very small usually in micrometer size. So, I want to apply the voltage directly to specific nodes and try to run the simulation. nin regards to the errors actually there are tones of them, I think that all the nodes I selected to apply the voltage are the ones that produce these errors, is there another commands I can use instead of CP ? or am I doing something wrong with the boundary conditions? nMy knowledge with MAPDL is quite limited and I am learning everything from scratch. any recommendation or help is much appetited. I have also attached the errors files for your reference. nThank you in advance,n

[Erik Kostson]

So see my response above,nso in the first option we do not have CP command, and we apply the voltage straight on the nodes of the electrode using just the D command , say e.g., D,58802,volt,100 ! 100 Voltnsecond one if we use CP command to connect all of the electrode nodes to have the same voltage we need to apply it only to the master node so from your message in the previous post node 58802Finally see 2.4.3. Example: Electrostatic-Structural Analysis of a Dielectric Elastomernand understand the flow and commands (so understand all commands by finding them in the command reference)n(Also be aware that we can not and will not open attachments.)nnThank you

[Abdulsalam]

HinOkay I will try both options you provided. Thank you for your feedback and response nnBest Regards,

[Erik Kostson]

No worries - glad I could be of some help.nnAll the bestnnErikn