TO 
TF 
DTTRAJ 
DTCOLL 
DTCOLT 
DTPRNO 
UVMIN 
PSIDMN 
IVEHO 

1 
Card: Field 
Variable 

Description 
Original Units 
Metric Units 
1:1 
TO 

The time at which the program starts. TO is arbitrary, and is generally chosen to be 0.0 for convenience. 
seconds 

1:2 
TF 

The time at which the program ends. TFTO = total duration of the run. 
seconds 

1:3 
DTTRAJ 

The program approximates a continuous, nonlinear path in time and space by breaking it into small increments, taken as linear, rather than by a true line integral. DTTRAJ is the time interval before, and again after, vehicle contact. This will generally be the largest time interval used (on the order of .01 seconds; smaller where forces or speeds are high), since changes are gradual and continuous during a trajectory. (With this, and with all intervals, a smaller value will yield greater accuracy, but may increase computer time. In general, the accuracy desired will be greater when the user wishes to match a set of empirical data than when seeking to simulate a situation for heuristic purposes.) 
seconds 

1:4 
DTCOLL 

This is the interval of integration during the collision, where large crush forces require a small time interval (on the order of .001) to obtain a good approximation. 
seconds 

1:5 
DTCOLT 

This is the interval of integration for the first 0.25 seconds immediately after a vehicle separation. DTCOLT will generally be smaller than DTTRAJ (e.g., .005) since higher speeds and spin are often involved at this stage. For instances where secondary contact (“sideslap”) may be simulated, .001 seconds is recommended. 
seconds 

1:6 
DTPRNO


The printout time interval. Generally you should use .01 to .05 seconds. The use of small print time intervals (.001) increases dramatically the amount of disk activity and can degrade the speed and performance of the simulation run. You can also optionally use the Print Interval Change options discussed below on Input Card1, seq 1. 
seconds 

1:7 
UVMIN


If the absolute value of the total vector velocity is less than UVMIN for both vehicles, and the absolute value for the angular velocity is less than PSIDMN for both vehicles, the run terminates. If no minimum value cutoff is desired, these can be set to 0.0 (1 mph = 17.6 inches/second). 
MPH

m/sec

1:8 
PSIDMN


See description for field 1:7 above. 
deg/sec 
deg/sec 
1:9 
IVEHO 

Number of simulated vehicles (1. or 2.). If IVEHO = 1, program ignores inputs on records 3, 5, 7, 9, &11; however, these must be included in keeping with format. 


1:10 


The numerals 01, 02,    , 14 go in columns 79 and 80. This item is omitted in subsequent record explanation. 


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