DELPS0

DELRHO

ALAMB

ZETAV

AKV(1)

AKV(2)

AMU

FMOVIE

13

Card:  Field

Variable

Description

Original Units

Metric Units

13:1

DELPS0

∆ψ

The interval between radial vectors. The SMAC program calculates all collision forces in a clockwise sweep about the center of gravity of V1. The sweep  is broken into increments  (360/ DELPSO must be an integer).  Too large a value of  DELPSO will cause inaccuracies;  too small a value will exceed the  program's capacity. The collision interface is  handled in a  table of up to 200 points. If more than 200 points are required to handle the damage area, the message "ISTOP=9" appears on the  printout.  The suggested value is 1 degree, which can be increased (e.g. to 2 or 3)  if the error message "ISTOP=9" appears.

degrees

13:2

DELRHO

∆ρ

The increment of change of the radius vector. (See explanation after card 13.)  A value of around  0.1 is recommended.

inches

cm

13:3

ALAMB

λ

The acceptable error in inter-vehicle pressure equilibrium. Choose λ greater than Kv1 times ∆ρ and also greater than Kv2 times  ∆ρ   (see explanation after card 13). e.g. for Kv1 = 30.0,  Kv2 = 50., and  ∆ρ= 0.2, then λ could be 12.

lb./inch

N/cm

13:4

ZETAV

ζ_v

The minimum relative velocity for full inter-vehicle  friction. If, while in contact, the adjacent surfaces of the two vehicles move with respect to each other  at a speed less than this, the effective inter-vehicle friction increases, starting from zero, as a linear function of the relative velocity and it reaches the full value at ZETAV

A value of around 5.-20. Is recommended. Note for higher values of AMU (field 7) use of lower zetaV values may produce rapid fluctuations in the direction of the resultant accelerations (“chatter”).

in/sec

cm/s

13:5

AKV(1)

K_v1

Load-deflection characteristic of V1 (see explanation after card 13). Values range from around 40 to around 90.

lb/inch²

N/cm²

13:6

AKV(2)

K_v2

Same as above, but for V2.

13:7

AMU

μ_v

Inter-vehicle friction coefficient: This is the coefficient of friction between the  two vehicles when they are in contact and the adjacent surfaces of V1 and V2 are moving with respect to each other (at a velocity greater than ζ_V). The force  tangent to the interface opposing the relative motion = μ_v times the force with which the surfaces are pressed together.   A value of about 0.55 is recommended (The maximum range of this input should be from 0.0 to 1.0).

13:8

FMOVIE

If >=0, write time history of damage display (for graphics program). To omit , set < 0.