Model for Midwest Roadside Safety Facility Crash Test TL5CMB-2

Test TL5CMB-2 involved a 79,705-lb (36,153-kg) tractor-semitrailer vehicle impacting a concrete median barrier at 52.7 mph (84.9 km/hr) and impact angle of 15.4 degrees. The test vehicle was a 1991 White GMC tractor with a 1988 Pines 48-ft (14.6-m) semitrailer. The test article was a 42 inch (1.067 m) tall concrete median barrier with an installation length of 200 ft (60.9 m).

The tractor-semitrailer FE model used for simulating the MwRSF test TL5CMB-2 needs about 300 milliseconds (0.300 seconds) pre-impact time to stabilize and settle under gravity. The front suspension's oscillations damp out almost immediately. The rear suspension seems to take longer for the oscillations to damp out. Another approach taken by the research team was to time the rear suspension's oscillations such that the rear tires were most firmly pressed against the ground at the time of rear wheelset impact with the barrier, similar to the rear wheelset action in the video of the actual crash test. This resulted in a starting position of the tractor-semitrailer at 4.7 meters from the impact point of the barrier. This strategy also resulted in a good correlation of the simulation results with the crash test data. This initial offset distance takes less computation time than the 300 millisecond pre-impact time stabilization approach.

Input Files for the Day Cab Tractor (wheelbase 181in) with 48-foot Trailer Model

• 00Main2.k This is the input file that is submitted to LS-Dyna for analysis. It uses the *INCLUDE command to combine all the input files for the model.
• 00MainBackedUp.k This is the input file that is submitted to LS-Dyna for analysis with the tractor-semitrailer backed up 4.7 meters from the barrier. It uses the *INCLUDE command to combine all the input files for the model.
• 01a_Trac_Day_2010-0520.k The finite element model of a Freightliner FLD120 tractor geometrically modified to be a Day Cab tractor. All nodes, elements, materials, connections, etc. for the tractor are included in this file.
• 01b_Intial-stress.k File containing initial stress state for the front leaf springs of the tractor to account for equilibrium load on the leaf spring components under gravity loading. Without this file, the tractor would displace significantly under gravity load, altering the center of gravity and bumper height.
• 01c_Airide_60psi.k Part, Section and Material definition for the discrete element model of the tractor Airide suspension with properties corresponding to 60 psi internal pressure. Used in tractor-semitrailer model for trailer ballasted to 80,000 lbs (36,000 kg).
• 02a_semitrailer48_10-0521.k The finite element model of 45-ft Stoughton semitrailer. All nodes, elements, connections, etc. for the trailer are included in this file.
• 02b_AirRideTrailer72p5psi.k Part, Section and Material definition for the discrete element model of the Airide suspension with properties corresponding to 72.5 psi internal pressure. Used in tractor-semitrailer model for trailer ballasted to 80,000 lbs (36,000 kg).
• 02b_TrailerMaterials_2010-0217.k Material database for the semitrailer.
• 03Tractor2Trailer_09-0206.k Creates a spherical joint connection between the trailer kingpin and the tractor fifth-wheel. Also, defines contact between the kingpin box and fifth-wheel.
• 05NJB-Ballast-foam11b.k Ballast for the trailer model
• 05contact11.k Defines contact between the ballast parts and the trailer.
• 15TL-5_Median_Barrier_Elastic.k Impacted bridge parapet barrier
• 15contact-tractor2010-0323.k Contact between tractor and median barrier
• 15contact-trailer2.k Contact between trailer and median barrier
• 20control1.k Defines *CONTROL, *DATABASE, *CONTACT_INTERIOR for the entire model. This file is always read in last and overrides any previous definitions of these parameters from the earlier input files.

Simulation

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