acel#

Inertia.acel(acel_x='', acel_y='', acel_z='', **kwargs)#

Specifies the linear acceleration of the global Cartesian reference frame for the analysis.

Mechanical APDL Command: ACEL

Parameters:
acel_xstr

Linear acceleration of the reference frame along global Cartesian X, Y, and Z axes, respectively.

acel_ystr

Linear acceleration of the reference frame along global Cartesian X, Y, and Z axes, respectively.

acel_zstr

Linear acceleration of the reference frame along global Cartesian X, Y, and Z axes, respectively.

Notes

In the absence of any other loads or supports, the acceleration of the structure in each of the global Cartesian (X, Y, and Z) axes would be equal in magnitude but opposite in sign to that applied in the acel command. Thus, to simulate gravity (by using inertial effects), accelerate the reference frame with an acel command in the direction opposite to gravity.

You can define the acceleration for the following analyses types:

  • Static ( antype,STATIC)

  • Harmonic ( antype,HARMIC), full, VT [ ACEL_FN_VT_KRY ], Krylov [ ACEL_FN_VT_KRY ], or mode-superposition [ ACEL_mode-sup_LoadSupport ]

  • Transient ( antype,TRANS), full or mode-superposition [ ACEL_mode-sup_LoadSupport ]

  • Substructure ( antype,SUBSTR).

Loads for VT and Krylov methods are supported as long as they are not:

  • complex tabulated loads (constant or trapezoidal loads in tabulated form are supported)

  • used in conjunction with Rotordynamics ( coriolis,on).

In a mode-superposition harmonic or transient analysis, you must apply the load in the modal portion of the analysis. Mechanical APDL calculates a load vector and writes it to the MODE file, which you can apply via the lvscale command.

For all transient dynamic ( antype,TRANS) analyses, accelerations are combined with the element mass matrices to form a body-force load vector term. The element mass matrix may be formed from a mass input constant or from a nonzero density (DENS) property, depending upon the element type.

For analysis type antype,HARMIC, the acceleration is assumed to be the real component with a zero imaginary component.

Units of acceleration and mass must be consistent to give a product of force units.

The acel command supports tabular boundary conditions (TABNAME_X, TABNAME_Y, and TABNAME_Z) for ACEL_X, ACEL_Y, and ACEL_Z input values ( dim ) as a function of both time and frequency for full transient and harmonic analyses.

Related commands for rotational effects are cmacel, cgloc, cgomga, dcgomg, domega, omega, cmomega, and cmdomega.

See Analysis Tools

This command is also valid in prep7.