dcvswp

Mapdl.dcvswp(option='', elem='', cnum='', vmax='', vinc1='', vinc2='', gap='', **kwargs)

Performs a DC voltage sweep on a ROM element.

APDL Command: DCVSWP

Parameters
  • option

    Sweep option:

    GV - Perform voltage sweep up to given voltage Vmax.

  • elem – Element number of the ROM element for the ROM use pass analysis.

  • cnum – Number of sweep conductor.

  • vmax – Maximum voltage. For the PI option, this voltage should be below the pull-in voltage value.

  • vinc1 – Voltage increment for Vmax (default = Vmax/20).

  • vinc2 – Voltage increment for pull-in voltage (default = 1).

  • gap

    Gap elements option:

    0 - Create gap elements (COMBIN40) (default).

Notes

Vinc1 is used to ramp the sweep conductor voltage from 0 to Vmax. Vinc2 is used to increase the sweep conductor voltage from Vmax to the pull- in value if the PI sweep option is used.

Because ramping the voltage may lead to the unstable region of an electromechanical system, DCVSWP might not converge when the sweep conductor voltage approaches the pull-in value. To avoid non-converged solutions, you should use the gap option to create a set of spring-gap elements (COMBIN40). By default, DCVSWP creates two spring-gap elements with opposite orientations for each active modal displacement DOF of the ROM element. The gap size is set to the maximum absolute values of the deflection range for the corresponding mode, as calculated by RMMSELECT or modified using the RMMRANGE command. The spring constants are set to 1.E5 for all the COMBIN40 elements. Along with the spring- gap elements, DCVSWP creates a set of constraint equations relating the ROM element modal displacements DOF (EMF) and the displacement DOF (UX) of the gap elements. Constraining the modal displacements using the spring-gap elements allows DCVSWP to converge in the pull-in range. The DCVSWP macro has a limit of 900 equilibrium iterations. If this limit is not sufficient to reach convergence, try the advanced techniques given in Overcoming Convergence Problems in the Structural Analysis Guide. For more information on gap elements, see Using Gap Elements with ROM144 in the Coupled-Field Analysis Guide.

Distributed ANSYS Restriction: This command is not supported in Distributed ANSYS.