ACCLR

Bulk Data Entry Defines accelerometer for geometric nonlinear analysis.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ACCLR AID GID F            

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ACCLR 100 34 100.0            

Definitions

Field Contents SI Unit Example
AID Unique accelerometer identification number.

(Integer > 0)

  
GID Grid point identification number.

(Integer > 0)

  
F Cutoff frequency.

(Real > 0)

  

Comments

  1. The accelerometer option computes a filtered acceleration in the output system.
  2. These filtered accelerations provided by an accelerometer are used in either a SENSOR or in post-processing acceleration time history without aliasing problems.
  3. A 4-pole Butterworth filter is used.
  4. The recommended value for F is 1650 Hz (1.65 ms-1) to obtain a class 1000 SAE filtering.
  5. In addition to these filtered accelerations, the accelerometer also allows the output of the integrals of X, Y, and Z of the raw accelerations projected to the output coordinate system to time history. These quantities are not used by SENSOR.
  6. If the coordinates are moving, the integrals of X, Y, and Z raw accelerations projected to the output coordinate system are not the same as the velocities projected to the output coordinate system, as described in XHIST. Computation of these integrals in a post-processor allows retrieving the accelerations projected to the output coordinate system without aliasing problems. Integration and differentiation are acting like another filter on top of the 4-pole Butterworth.
  7. This card is unsupported in HyperMesh.