Piezoelectric Circuit
CIRCU94 Element Description
CIRCU94 is a circuit element for use in piezoelectric-circuit analyses. The element has two or three nodes to define the circuit component and one or two degrees of freedom to model the circuit response. The element may interface with the following piezoelectric elements:
| PLANE13, KEYOPT(1) = 7 coupled-field quadrilateral solid |
| SOLID5, KEYOPT(1) = 0 or 3 coupled-field brick |
| SOLID98, KEYOPT(1) = 0 or 3 coupled-field tetrahedron |
| PLANE223, KEYOPT(1) = 1001, coupled-field 8-node quadrilateral |
| SOLID226, KEYOPT(1) = 1001, coupled-field 20-node brick |
| SOLID227, KEYOPT(1) = 1001, coupled-field 10-node tetrahedron |
CIRCU94 is applicable to full harmonic and transient analyses. For these types of analyses, you can also use CIRCU94 as a general circuit element. See CIRCU94 in the Mechanical APDL Theory Reference for more details about this element.
CIRCU94 Input Data
The geometry, node definition, and degree of freedom options are shown in Figure 94.1: CIRCU94 Circuit Options. Active nodes I and J define the resistor, inductor, capacitor and independent current source. They are connected to the electric circuit. Active nodes I and J and a passive node K define the independent voltage source. The passive node is not connected to the electric circuit. It is associated with the CURR degree of freedom (which represents electric charge for this element).
KEYOPT(1) settings and the corresponding real constants define the circuit components. Real constant input is dependent on the element circuit option used. A summary of the element input options is given in "CIRCU94 Input Summary". Real constants 15 (Graphical offset, GOFFST) and 16 (Element identification number, ID) are created for all components.
The independent current and voltage sources (KEYOPT(1) = 3 or 4) may be excited by constant load (transient) or constant amplitude load (harmonic), sinusoidal, pulse, exponential, or piecewise linear load functions as defined by KEYOPT(2); see Figure 94.2: Load Functions and Corresponding Real Constants for Independent Current and Voltage Sources.
The time-step size for a transient analysis is controlled by the DELTIM or NSUBST commands. The CIRCU94 element does not respond to automatic time stepping (AUTOTS command), but AUTOTS can be used as a mechanism for ramping the time step to its final value.
CIRCU94 is only compatible with elements having a VOLT DOF and an electric charge reaction solution. Electric charge reactions must all be positive or negative. KEYOPT(6) sets the electric charge reaction sign. See Element Compatibility in the Low-Frequency Electromagnetic Analysis Guide for more information.
CIRCU94 Input Summary
- Nodes
I, J, K
- Degrees of Freedom
VOLT, CURR (charge) (see Figure 94.1: CIRCU94 Circuit Options)
- Real Constants
Dependent on KEYOPT(1) and KEYOPT(2) settings. See Table 94.1: CIRCU94 Real Constants for details.
- Material Properties
None
- Surface Loads
None
- Body Loads
See KEYOPT(2)
- Special Features
This element works with the large deflection and stress stiffening capabilities of PLANE13, SOLID5, SOLID98, PLANE223, SOLID226, and SOLID227.
- KEYOPT(1)
Circuit component type:
- 0 --
Resistor
- 1 --
Inductor
- 2 --
Capacitor
- 3 --
Independent Current Source
- 4 --
Independent Voltage Source
- KEYOPT(2)
Body loads (only used for KEYOPT(1) = 3 and 4):
- 0 --
Constant load (transient) or constant amplitude load (harmonic)
- 1 --
Sinusoidal load
- 2 --
Pulse load
- 3 --
Exponential load
- 4 --
Piecewise Linear load
- KEYOPT(6)
Electric charge reaction sign:
- 0 --
Negative
- 1 --
Positive
Table 94.1: CIRCU94 Real Constants
| Circuit Component and Graphics Label | KEYOPT(1) | Real Constants | ||
|---|---|---|---|---|
| Resistor (R) | 0 | R1 = Resistance (RES) | ||
| Inductor (L) | 1 |
| ||
| Capacitor (C) | 2 |
| ||
| Independent Current Source (I) | 3 | For KEYOPT(2) = 0:
| ||
| Independent Voltage Source (V) | 4 | For KEYOPT(2) = 0:
|
Note: For all above Circuit options, the GOFFST and ID real constants (numbers 15 and 16) are created by the Circuit Builder automatically:
Figure 94.2: Load Functions and Corresponding Real Constants for Independent Current and Voltage Sources
CIRCU94 Output Data
The element output for this element is dependent on the circuit option selected. Table 94.2: CIRCU94 Element Output Definitions summarizes the element output data.
The Element Output Definitions table uses the following notation:
A colon (:) in the Name column indicates that the item can be accessed by the Component Name method (ETABLE, ESOL). The O column indicates the availability of the items in the file Jobname.OUT. The R column indicates the availability of the items in the results file.
In either the O or R columns, “Y” indicates that the item is always available, a number refers to a table footnote that describes when the item is conditionally available, and “-” indicates that the item is not available.
Table 94.2: CIRCU94 Element Output Definitions
| Name | Definition | O | R |
|---|---|---|---|
| For KEYOPT(1) = 0: Resistor | |||
| EL | Element Number | Y | Y |
| NODES | Nodes-I,J | Y | Y |
| RES | Resistance | Y | Y |
| VOLTAGE | Voltage drop between node I and node J | Y | Y |
| CURRENT | Current | Y | Y |
| POWER | Power loss | Y | Y |
| For KEYOPT(1) = 1: Inductor | |||
| EL | Element Number | Y | Y |
| NODES | Nodes-I,J | Y | Y |
| IND | Inductance | Y | Y |
| IL0 | Initial current | Y | Y |
| VOLTAGE | Voltage drop between node I and node J | Y | Y |
| CURRENT | Current | Y | Y |
| POWER | Power absorption | Y | Y |
| For KEYOPT(1) = 2: Capacitor | |||
| EL | Element Number | Y | Y |
| NODES | Nodes-I,J | Y | Y |
| CAP | Capacitance | Y | Y |
| VC0 | Initial voltage | Y | Y |
| VOLTAGE | Voltage drop between node I and node J | Y | Y |
| CURRENT | Current | Y | Y |
| POWER | Power absorption | Y | Y |
| For KEYOPT(1) = 3: Independent Current Source | |||
| EL | Element Number | Y | Y |
| NODES | Nodes-I,J | Y | Y |
| CURRENT SOURCE | Real or imaginary component of applied current | Y | Y |
| VOLTAGE | Voltage drop between node I and node J | Y | Y |
| CURRENT | Current | Y | Y |
| POWER | Power (loss if positive, output if negative) | Y | Y |
| For KEYOPT(1) = 4: Independent Voltage Source | |||
| EL | Element Number | Y | Y |
| NODES | Nodes-I,J,K | Y | Y |
| VOLTAGE SOURCE | Real or imaginary component of applied voltage | Y | Y |
| VOLTAGE | Voltage drop between node I and node J | Y | Y |
| CURRENT | Current at node K | Y | Y |
| POWER | Power (loss if positive, output if negative) | Y | Y |
Table 94.3: CIRCU94 Item and Sequence Numbers lists output available through the ETABLE command using the Sequence Number method. See The General Postprocessor (POST1) in the Basic Analysis Guide and The Item and Sequence Number Table in this reference for more information. The following notation is used in Table 94.3: CIRCU94 Item and Sequence Numbers:
- Name
output quantity as defined in Table 94.2: CIRCU94 Element Output Definitions
- Item
predetermined Item label for ETABLE command
- E
sequence number for single-valued or constant element data
CIRCU94 Assumptions and Restrictions
CIRCU94 is applicable only to full harmonic and transient analyses. You cannot use CIRCU94 in a static analysis or in a transient analysis with time integration effects turned off (TIMINT,OFF).
Only MKS units are allowed (EMUNIT command).
Only the sparse solver is available for problems using the independent voltage source circuit option.
This element may not be compatible with other elements with the VOLT degree of freedom. For example, it is not compatible with CIRCU124 or CIRCU125. To be compatible, the elements must have the same reaction solution for the VOLT DOF. Elements that have an electric charge reaction solution must all have the same electric charge reaction sign. For more information, see Element Compatibility in the Low-Frequency Electromagnetic Analysis Guide.