1998-02-23

3-Dimensional Simulation of Vehicle Response to Tire Blow-outs 980221

Sudden tire deflation, or blow-out, is sometimes cited as the cause of a crash. Safety researchers have previously attempted to study the loss of vehicle control resulting from a blow-out with some success using computer simulation. However, the simplified models used in these studies did little to expose the true transient nature of the handling problem created by a blown tire. New developments in vehicle simulation technology have made possible the detailed analysis of transient vehicle behavior during and after a blow-out. This paper presents the results of an experimental blow-out study with a comparison to computer simulations. In the experiments, a vehicle was driven under steady state conditions and a blow-out was induced at the right rear tire. Various driver steering and braking inputs were attempted, and the vehicle response was recorded. These events were then simulated using EDVSM. A comparison between experimental and simulated results is presented. The research was extended by simulating blow-outs at other wheel locations and observing how various driver inputs affect the vehicle's response.TIRE BLOW-OUT was cited as a factor in more than 300,000 crashes between 1992 and 1996, according to the National Center for Statistics and Analysis [1]*. These crashes resulted in over 2,000 deaths and several times that many serious injuries. Clearly, a thorough understanding of how a tire blow-out affects the potential for loss of vehicle control and subsequent crash is important to motor vehicle safety researchers.Simulation has been used to study tire blow-outs by previous researchers (e.g.,[2]). The typical approach is based on research [3] showing a blown tire has a significant loss of cornering stiffness. By simulating a maneuver with both normal and reduced cornering stiffness, the researcher is able to show the difference in behavior for a vehicle with normal tires and the same vehicle performing the same maneuver with a flat tire.The approach described above provides some insight regarding vehicle handling characteristics while driving on a flat tire. However, the authors felt this approach may be too simplistic: It essentially describes how a vehicle would handle if it left the driveway with a flat tire and was driven down the street. Greater detail and flexibility are required to perform a complete, three-dimensional analysis of the transient effects of blow-out on vehicle behavior during and after a sudden pressure loss while performing normal driving maneuvers. To meet this requirement, the EDVSM vehicle simulator [4] was extended to allow the user to simulate the transient effects of a tire blow-out at any wheel at any given time during the simulation. This capability has been named the EDVSM Tire Blow-out ModelThis paper describes the EDVSM Tire Blow-out Model. The paper includes a validation of the model by direct comparison with experiments conducted at the Transportation Research Center (TRC), in East Liberty, Ohio. The paper also provides a parameter study wherein a predefined maneuver is simulated and the wheel location for the blow-out is varied in order to assess the relative danger for loss of control from blow-out at each wheel location. Finally, EDVSM simulation results for front and rear tire blow-outs are reviewed to describe in detail the blow-out process and how that process affects vehicle handling.

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