/IMPACC

Block Format Keyword Defines imposed accelerations on a group of nodes.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/IMPACC/impacc_ID/unit_ID
impacc_title
fct_IDT Dir Skew_ID sens_ID grnd_ID
Ascalex FscaleY Tstart Tstop

Definition

Field Contents SI Unit Example
impacc_ID Imposed acceleration block identifier.

(Integer, maximum 10 digits)
unit_ID Unit identifier.

(Integer, maximum 10 digits)
impacc_title Imposed acceleration block title.

(Character, maximum 100 characters)
fct_IDT Time function identifier.

(Integer)
Dir Direction: X, Y, and Z in translation; XX, YY, and ZZ in rotation.

(Text)
Skew_ID Skew identifier.

(Integer)
sens_ID Sensor identifier.
≠ 0 (sensor activated)
The imposed acceleration is applied at the time of sensor activation and the time versus acceleration function are shifted in time.

(Integer)
grnd_ID Node group on which the imposed acceleration is applied.

(Integer)
Ascalex Abscissa (time) scale factor for fct_IDT.

Default = 1.0 (Real)

 [ s ]
FscaleY Ordinate (acceleration) scale factor for fct_IDT.

Default = 1.0 (Real)

 [ m s 2 ] or [ r a d s 2 ] MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaWaamWaaeaada WcaaqaaiaadkhacaWGHbGaamizaaqaaiaadohadaahaaWcbeqaaiaa ikdaaaaaaaGccaGLBbGaayzxaaaaaa@3CA7@
Tstart Start time.

(Real)

 [ s ]
Tstop Stop time.

Default = 1030 (Real)

 [ s ]

Comments

  1. The acceleration direction must be right justified in the ten characters of field number 2.
  2. If Tstart and Tstop are specified, the acceleration is imposed between these times, but the time versus acceleration function is not shifted to begin at Tstart.
  3. When a sensor is defined sens_ID, the imposed acceleration is applied at the time of sensor activation and the function is shifted by the sensor activation time.
  4. When a sensor sens_ID is used with Tstart and Tstop, the imposed acceleration will only occur if the sensor activation time occurs between Tstart and Tstop.
  5. The AscaleX and FscaleY are used to scale the abscissa (time) and ordinate (translational or angular acceleration).

    The actual load function value is calculated as:

    a ( t ) = F s c a l e y ⋅ f T ( t A s c a l e x ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8akY=xipgYlh9vqqj=hEeei0xXdbb a9frFf0=yqFf0dbba91qpepeI8k8fiI+fsY=rqaqpepae9pg0Firpe pesP0xe9Fve9Fve9qapdbaGaaiGadiWaamaaceGaaqaacaqbaaGcba GaciyyaiGacIcacaWG0bGaaiykaiabg2da9iaadAeacaWGZbGaam4y aiaadggacaWGSbGaamyzamaaBaaaleaacaWG5baabeaakiabgwSixl GacAgadaWgaaWcbaGaamivaaqabaGcdaqadaqaamaalaaabaGaamiD aaqaaiaadgeacaWGZbGaam4yaiaadggacaWGSbGaamyzamaaBaaale aacaWG4baabeaaaaaakiaawIcacaGLPaaaaaa@5228@

    Where, f T MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8akY=xipgYlh9vqqj=hEeei0xXdbb a9frFf0=yqFf0dbba91qpepeI8k8fiI+fsY=rqaqpepae9pg0Firpe pesP0xe9Fve9Fve9qapdbaGaaiGadiWaamaaceGaaqaacaqbaaGcba GaciOzamaaBaaaleaacaWGubaabeaaaaa@3BC7@ is the function of fct_IDT.

    Unlike /GRAV, this keyword is a kinematic condition which is applied to a set of nodes. The node will always be moving with the specified acceleration.