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3.4  Using the Electrode stack entry

SDT 6.6 underwent significant revisions to get rid of solver strategies that were specific to piezo applications. The info,Electrodes of earlier releases is thus no longer necessary. To avoid disruption of user procedures, you can still use the old format with a .ver=0 field.
p_piezo ElectrodeInit is used to build/verify a data structure describing master electric DOFs associated with electrodes defined in your model. The info,Electrode stack entry is a structure with fields

• .data rows NodeId IsOpen gives the electrode nodes and for each one 1 if the circuit is open (voltage free), and 0 if it is closed (voltage enforced or fixed, actuator).
• .ver=1 is used to specify that the more general piezoelectric strategies of SDT >= 6.6 are used. This is the combined with the p_piezo Electrode2Case command which builds piezo loads and sensors. For SDT 6.5 strategies, use .ver=0.
• .def .DOF, .lab_in only needed when combining multiple electrodes into a single input. The .lab_in is a cell array of strings, you should end the string with V so that it shows Q for associated charge sensors.

  Each column gives the weighting coefficients associated with each electrode. Thus def=[1;0;1] corresponds to a single equal input on electrodes 1 and 3. Note that it does not make sense to combine electrical DOFs that are of mixed nature (actuator/sensor).

  The .DOF field should contain NodeId+.21 since the potential corresponds to DOF .21.

  The .lab_in field can be used to provide labels associated with each actuator/sensor defined as a column of def. You should end the label with V so that the collocated sensor ends with a Q label.

• .cta .lab (optional) can be used to combine electrodes into sensors / actuators. Each row of .cta defines a sensor (with matching .lab). Each column corresponds to an electrode declared in the .data field. You cannot combine open and closed circuit electrodes. It is possible to use both a .cta and a .def field.

[model,data]=p_piezo('ElectrodeInit',model); generates a default value for the electrode stack entry. Combination of actuators and sensors (both charge and voltage) is illustrated in section section ??.