Card 98 - Secondary Collision Model

Card 98 - Secondary Collision Model - Veh1 Trailer or Veh3

The interaction of a trailer attached to vehicle#1 (or a separate Veh#3) and vehicle#2 has been added to the m-smac program. The exterior dimensions for the collision interface are taken from the trailer (specified on input Card 22, fields 7-9) or Veh#3 (as specified on cards 50-60) and using the exterior dimensions of vehicle#2 (Input card 5, fields 7-9). This card (Card 98) is analogous to input card 13, wherein the inputs for the Collision Model are specified for the interaction between the Trailer of Vehicl#1 (or Veh#3) and Vehicle #2. Users are cautioned that due to the potential differences with the crush properties of the part of the trailer (under ride of the trailer, impact on the tandem axles, etc.) and normal car-to-car type impacts, the use and/or choice of inputs for interaction between the trailer and vehicle are not well defined.

DELPS02

DELRHO2

ALAMB2

ZETAV2

AKV2(1)

AKV2(2)

AMU2

Card: Field	Variable		Description	Original Units	Metric Units
98:1	DELPS02	∆ψ₂	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
98:2	DELRHO2	∆ρ₂	The increment of change of the radius vector. (See explanation after card 13.) A value of around 0.1 is recommended.	inches	Cm
98:3	ALAMB2	λ₂	The acceptable error in inter-vehicle pressure equilibrium. Choose λ greater than Kv2₁ times ∆ρ and also greater than Kv2₂ times ∆ρ (*see explanation after card 13*). e.g. for Kv2₁ = 30.0, Kv2₂ = 50., and ∆ρ₂= 0.2, then λ could be 12.	lb./inch	N/cm
98:4	ZETAV2	ζ_v2	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 ZETAV₂ A value of around 5.-20. Is recommended.	in/sec	cm/s
98:5	AKV2(1)	K_v21	Load-deflection characteristic of *V1 Trailer* (see explanation after card 13). Values range from around 40 to around 500.	lb/inch²	N/cm²
98:6	AKV2(2)	K_v22	Same as above, but for V2 for interaction with V1 Trailer.
98:7	AMU2	μ_v2	Inter-vehicle friction coefficient: This is the coefficient of friction between the two vehicles when they are in contact and the adjacent surfaces of *V1Trailer* and V2 are moving with respect to each other (at a velocity greater than ζ_V2). 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).

Card 99 - Veh#3/Trailer Release Option