TCON

TEPS

DAMPT0

DEPS

IDUMP

NOCOLL

AMuSnag

18

Card:  Field

Variable

Description

Original Units

Metric Units

This card includes additional optional inputs for the SNAG Impulsive Restraint Option.

18:1

TCON

Moment constraint option. For ABS(  ) >TEPS, apply equal and opposite moments to each of the vehicles.

lb-in

N-m

18:2

TEPS

Moment constraint null band.  For values of ABS () < TEPS, apply viscous resistance.

rad/sec

18:3

DAMPT0

Linear damping option.  For velocity of the SNAG point movement greater than DEPS, apply coulomb damping  of magnitude DAMPT0.

lb-sec/in

N-sec/cm

18:4

DEPS

Linear damping null band.  For values of SNAG point velocity  <DEPS, apply viscous resistance.DAMPT0

in/sec

cm/sec

18:5

IDUMP

Option for additional DUMP of information related to the SNAG.

18:6

NOCOLL

Coll option.  If=1, turn off collision forces  (i.e. no calls  to subroutine coll)  for duration of the SNAG.  (This option is useful for situations where two vehicles lock together for a prolonged period of time after the primary collision. Use caution with this option as the collision routine is disabled from TSBEG (Card 18, field 1) until the end of the simulation run.)

18:7

Currently not used

18:8

Currently not used

18:9

AMUsnag

 μsnag_v

Inter-vehicle SNAG friction force coefficient: During the impulsive constraint this coefficient of friction can be used to model tangential forces between the two vehicle structures when the corresponding adjacent surfaces of V1 and V2 are moving with respect to each other (at a velocity greater than ζ_V). The friction force is perpendicular to the SNAG force and it opposes relative motion with a value equal to μsnag_v times the SNAG force. If used, this value should normally be set to be equal to or less than AMU (card 13, field 7), the inter-vehicle friction coefficient.