Browsing by Author "Peterson, Andrew"

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    Pneumatically Balanced Heavy Truck Air Suspensions for Improved Roll Stability
    Chen, Yang; Ahmadian, Mehdi; Peterson, Andrew (SAE International, 2015-01-01)
    This study provides a simulation evaluation of the effect of maintaining balanced airflow, both statically and dynamically, in heavy truck air suspensions on vehicle roll stability. The model includes a multi-domain evaluation of the truck multi-body dynamics combined with detailed pneumatic dynamics of drive-axle air suspensions. The analysis is performed based on a detailed model of the suspension's pneumatics, from the main reservoir to the airsprings, of a new generation of air suspensions with two leveling valves and air hoses and fittings that are intended to increase the dynamic bandwidth of the pneumatic suspensions. The suspension pneumatics are designed such that they are able to better respond to body motion in real time. Specifically, this study aims to better understand the airflow dynamics and how they couple with the vehicle dynamics. The pneumatic model is coupled with a roll-plane model of the truck to evaluate the effect of the suspension pneumatic dynamics on the body roll, as well as the force transmission to the sprung mass. The results of the study show that maintaining a balanced airflow through the suspension improves the dynamic responsiveness of the suspension to steering, causing less body roll.
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    Simulation Evaluation on the Rollover Propensity of Multi-Trailer Trucks at Roundabouts
    Chen, Yang; Zheng, Xiaohan; Peterson, Andrew; Ahmadian, Mehdi (SAE International, 2019-01-01)
    The main intent of this study is to provide a simulation analysis of rollover dynamics of multi-trailer commercial vehicles in roundabouts. The results are compared with conventional tractor-semitrailer with a single 53-ft trailer for roundabouts that are of typical configuration to those in the U.S. cities. The multi-trailer commercial vehicles that are considered in this study are the A-double trucks commonly operated in the U.S. roads with the trailer length of 28 ft, 33 ft, and 40 ft. The multi-body dynamic models for analyzing the rollover characteristics of the trucks in roundabouts are established in TruckSim®. The models are intended to be used to assess the maximum rollover indexes of each trailer combination subjected to various circulating speeds for two types of roundabouts, 140-ft single-lane and 180-ft double-lane. The simulation results suggest that the 40-ft double has rollover speed thresholds 2-9 mph lower (more vulnerable to rolling over) as compared with the conventional 53-ft semi-trailer-truck. The lower roll stability for the 40-ft A-train configuration is attributed to its pintle-hitch coupling that allows for a certain amount of roll degree of freedom between the front and rear trailers. In addition, the worse tracking performance of the 40-ft double due to its longer wheelbase contributes to the heavier use of truck apron, greatly increasing the chance of rollover. The results also indicate that the 28-ft and 33-ft double-trailer trucks possess better maneuverability (less off-tracking) and can tolerate the rollover speed 1-3 mph higher than that of the 53-ft single-trailer truck. Furthermore, it is found that increasing the trailer from 28 ft to 33 ft results in the truck slightly less prone to rollover crashes, because of their longer wheelbase providing a slight amount of additional roll stability.