The Effects of Passenger and Cargo Load on Light Truck/Van and Sport Utility Mass Properties. Society of Automotive Engineers, Inc., Paper no. 952676, SAE 1995 Truck and Bus Meeting and Exposition, Winston-Salem, North Carolina, November 13-15, 1995. Arndt, Mark W., Charles P. Dickerson, Stephen M. Arndt, and Gregory A. Mowry, Arndt & Associates, Ltd.

Vehicles may be loaded with passengers and cargo in varying configurations that affect its mass properties during normal use. Mass properties include Cg location, weight, and mass moments of inertia. The objective of this paper is to develop an approach identifying possible passenger and cargo load configurations and accurately calculate and display their effect on a motor vehicle's mass properties. An approach is presented and discussed. The calculation method accounts for suspension compliance due to passenger and cargo loading. Overall, the approach provides more accurate and useful estimates of a motor vehicle's Cg location and other mass properties. The approach may be of use to vehicle designers, operators, and regulators, providing enhanced access to vehicle parameters which are relevant to motor vehicle safety.

Evaluation of Experimental Restraints in Rollover Conditions. Society of Automotive Engineers, Inc., Paper no. 952712, Stapp Car Crash Conference, San Diego, California, November 8-10, 1995. Arndt, Mark W., Charles P. Dickerson, Gregory A. Mowry, and Stephen M. Arndt, Arndt & Associates, Ltd.

A controlled experimental program was conducted to determine the response of humans and a human surrogate with experimental lap belt restraints in -Gz acceleration environments. In the program, lap belt anchorage position (belt angle) and belt tension/slack were varied. Human volunteers were subjected to a static -1.0 Gz acceleration for each restraint configuration. A 95th percentile male Hybrid III dummy was subjected to a nominal 4.25 m/s (9.5 mph), -5 Gz impact while restrained by each restraint configuration. For the -Gz acceleration, significant changes in occupant head excursion were observed with varied lap belt configurations. In general, less pre-crash belt slack and higher lap belt angles produced significant reductions in occupant vertical excursions. This research provides data for use in evaluating or developing occupant survivability systems for rollover crash environments.

Motor Vehicle Mass Property Envelopes. Society of Automotive Engineers, Inc., Paper no. 951065, Warrendale, Pennsylvania, February 1995. Arndt, Mark W., Charles P. Dickerson, Gregory A. Mowry, Stephen M. Arndt, and Steven C. Shapiro, Arndt & Associates, Ltd.

A vehicle may be loaded in varying configurations that affect its mass properties during normal use. These properties include total mass, center-of-gravity (Cg) location, and moments of inertia. The ranges of these parameters, which are determined by the varied load configurations, define the vehicle's mass property envelopes. These envelopes are useful for evaluating the effect of any load configuration relative to vehicle performance/design specifications. Mass property envelopes provide a clear visual representation of a range of key parameters that significantly affect motor vehicle control. Examples are provided in this paper that illustrate the usefulness of the vehicle mass property envelopes.

Evaluation of Vehicle Velocity Predictions Using the Critical Speed Formula. Society of Automotive Engineers, Inc., Paper no. 950137, Warrendale, Pennsylvania, February 1995. Dickerson, Charles P., Mark W. Arndt, Stephen M. Arndt, and Gregory A. Mowry, Arndt & Associates, Ltd.

Tire marks left by the vehicle prior to impact, rollover, or other event, are important forensic evidence reconstruction of motor vehicle accidents. Often these tire marks have some curvature that is measured and used to calculate the speed of vehicle prior to the event. This calculation is based on the coefficient of friction of the tire/road interface and the radius of curvature of the vehicle center of gravity (c.g.) path. There is controversy about the validity of this approach. To explore this theory, a test vehicle was driven through a series of maneuvers that produced yaw marks for direct comparison of actual vehicle velocity to the velocity calculated by the critical speed formula. Test results show the critical speed formula is inaccurate for most circumstances and does not correctly describe vehicle limit performance behavior.

Error Analysis of Center-of-Gravity Measurement Techniques. Society of Automotive Engineers, Inc., Paper no. 950027, Warrendale, Pennsylvania, February 1995. Shapiro, Steven C., Charles P. Dickerson, Stephen M. Arndt, Mark W. Arndt, and Gregory A. Mowry, Arndt & Associates, Ltd.

The height of a vehicle's center-of-gravity (CG) is one factor that influences its handling characteristics. A number of height methods are used to measure CG within the automotive industry. This research determined which method has the greatest potential to produce accurate CG height measurements, given anticipated measurement tolerances.

Several techniques for measuring vehicle CG height were analyzed mathematically. The contributions of various parameters to total error were determined and the total error inherent in each method was then compared.