A1

B1

TR1

FIZ1

FMASS1

TR1R

XF1

XR1

YS1

4

Card:  Field

Variable

Description

Original

Units

Default

Units

Metric Units

4:1

A1

a₁

The distance from the center of gravity of V1 to the midpoint between the front wheels, taken as positive..

inches

mm

4:2

B1

b₁

The distance from the center of gravity of V1 to the midpoint between rear wheels, taken as positive.

inches

mm

4:3

TR1

T₁

Average tread width;  i.e., distance between the center of the  left and right tires, averaged over front and rear pairs.

(optional) Front tread width; i.e., distance between the center of the  left and right front tires if the Rear tread width is input in card 4 field 6 below.

inches

mm

4:4

FIZ1

I_Z1

Yaw moment of inertia of V1. This is a measure of the torque needed to induce a rotation about a vertical axis through the center of gravity of V1 and it depends both on the total mass of the vehicle and on how far this mass is, on  average, from the center of gravity. For typical values of mass and of l (lz1=k xM), see the back page of this manual (from the CRASH3 Manual)

lb-sec²-in

kg-m²

4:5

FMASS1

M₁

The total mass of V1.  If vehicle weight in lbs is known, its mass  can be found by dividing by 386.4. (For DEFAULT option input is for weight)

lb-sec²/in

lbs.

kg

4:6

TR1-R

T_1R

(optional) Rear tread width; i.e., distance between the center of the  left and right rear tires. 

Note: This field in original SMAC was used for an optional rear axle steer angle; The inputs for vehicle 1 rear steer angle time history can optionally be input on m-smac input card(s) 10.

inches

mm

4:7

XF1

X_F1

Distance from center of gravity of V1 to the front end of the car body, taken as positive .

inches

mm

4:8

XR1

X_R1

Distance from center of gravity V1 to the rear end of the car body, taken as negative, may be entered as positive or negative.

inches

mm

4:9

YS1

Y_S1

Distance from the center of gravity of V1 to the side of the car body; 1/2 total width (this conforms with original SMAC).

YS1 may also be entered as the total vehicle width. The magnitude of YS1 is compared to the Track Width (TR1) and if YS1 > TR1, the input is assumed to be for the total width.

inches

mm