Joseph D. McCleary

Assessing submarining and abdominal injury risk in the Hybrid III family of dummies

The development of an abdominal injury assessment device for belt loading due to submarining is detailed in this paper. The design concept was based on research assessing the effectiveness of safety belts with the Hybrid III dummies. The following conclusions were reached: The abdomen developed has biofidelity in its force-deflection characteristics for belt loading, and can be used to determine the probability of abdominal injury when submarining occurs; installing the abdomen in the Hybrid III dummy does not change the dummy kinematics when submarining does occur; when submarining does occur, the dummy kinematics are very similar to baseline Hybrid III kinematics, except for torso angle.

Measurement of Head Dynamics and Facial Contact Forces In the Hybrid III Dummy

Injury and disability associated with head (brain), neck (spinal cord) and facial injury account for 61.7% of the total societal harm in the most recent estimate of motor-vehicle related crash injuries. This paper discusses the need for accurate information on translational and rotational acceleration of the head as the first step in critiquing the Head Injury Criterion (HIC) and other injury predictive methods, and developing a fuller understanding of brain and spinal cord injury mechanisms. A measurement system has been developed using linear accelerometers to accurately determine the 3D translational and rotational acceleration of the Hybrid III dummy head. Our concept has been to use the conventional triaxial accelerometer in the dummys head to assess translational acceleration, and three rows of in-line linear accelerometers and a least squares analysis to compute statistical best-fits for the rotational acceleration about three orthogonal axes. For the covering abstract see IRRD 864472.

Analysis and Comparison of Head Impacts Using Baseballs of Various Hardness and a Hybrid III Dummy

The use of batting helmets in baseball has substantially reduced the incidence of head injuries, and softer baseballs have been developed to further reduce the risk of injury for an unprotected head. This study utilized a 5th-percentile Hybrid III female dummy, which is similar in size to a 10–12-year-old child, to evaluate the effectiveness of various softer baseballs. A pneumatic gun accelerated the balls to a speed of 60 mi/h (27 m/s). Head impacts were delivered frontally on the forehead or between the eyes and laterally on the temple. Peak resultant head acceleration and head injury criterion (HIC) were significantly lower with the softer baseballs. Using logist analysis of the forehead HICs, the risk of head injury was 20% with an official hardball versus 12–16% with softer baseballs, a 4–8% lower increment in injury risk. The risk of injury was higher using head acceleration and for the temple impacts; however, the range in effectiveness of the softer baseballs is smaller than predicted from the National Operating Committee on Standards for Athletic Equipment (NOCSAE) test procedure. Since the NOCSAE procedure was developed for helmeted impacts, there may be a lack of biofidelity for unprotected head impacts. The force of impact was 2.5–18.0 kN and was significantly lower with the softer baseballs. The results of this study indicate that the softer baseballs reduce the risk of head injury, but not to the degree previously claimed. Additional work is needed to determine the actual range of effectiveness in preventing sport-related injuries in children.

Assessing Submarining and Abdominal Injury Risk in the Hybrid III Family of Dummies: Part II - Development of the Small Female Frangible Abdomen

This paper describes the desin of the Frangible Abdomenn for the small female Hybrid III dummy and how to use it to assess the risk of abdominal injury from submarining. The baseline dummy and the dummy with the Frangible Abdomen have no significant kinematic differences, either qualitatively or quantitavily. Paper discusses the sled tests that were run to compare the kinematic and dynamic performance of the baseline dummy before and after the insertion of the Frangible Abdomen.

REPEATABILITY EVALUATION OF THE PRE-PROTOTYPE NHTSA ADVANCED DUMMY COMPARED TO THE HYBRID III

A comparison of the NHTSA advanced dummy and the Hybrid III is presented in this paper based on their performance in repeated sled tests under 3 different restraint systems. The restraint systems considered are: the airbag alone, the 3-point belt alone, and a combined use of the airbag and the 3-point belt. Various time-histories pertaining to accelerations, angular velocities, deflections and forces have been compared between the two dummies in order to study their repeatability. The Hybrid III appears to be more repeatable than the NHTSA advanced dummy in its response in one case, that of restraint with the 3-point belt alone. The response of the NHTSA advanced dummy in two other restraint modes, the airbag alone and the combination of 3-point belt and airbag, appears to be no less repeatable than that of Hybrid III in this series of tests. The variability in the sled pulse appears to mask the differences, if any, in the variability of response between the two dummies in two later cases. Under some restraint configurations, for some body segments, the NHTSA advanced dummy appears to show better repeatability. In addition, it appears that the read-out of the chest-deflection measurement system in the NHTSA advanced dummy is not well defined because it is influenced by the rotation of the upper spine relative to the lower spine. (A) For the covering abstract see ITRD E106439.

Investigation Into the Noise Associated With Air Bag Deployment: Part I - Measurement Technique and Parameter Study

A new system consisting of commercially available pressure transducers and microphones was assembled and a new software package was developed. This system allows the analysis of pressure-time data using two analysis methods and criteria proposed in the early 1970s. A series of experiments using this system was run over a four year period to investigate the parameters that affect the impulse noise associated with a deploying air bag. For the covering abstract of the conference see IRRD 879189.

Characterization of Belt Restraint Systems in Quasistatic Vehicle Rollover Tests

In this study, we investigate a new method of testing the occupant kinematics in a rollover crash situation. Much of this work is based on previous full scale vehicle studies by Orlowski and Bahling. Their work concentrated on FMVSS 208 dolly rollover tests of vehicles equipped with production and reinforced vehicle roofs. They found that the occupants kinematics, as opposed to roof crush, were responsible for potentially injurious neck injuries as a result of diving type accident kinematics of the head and torso. This led us to examine seat system, belt restraint system and belt restraint anchorage designs that could potentially improve the occupants head to roof clearance. A simulated vehicle environment with representative seat and belt restraint systems was chosen as the baseline system. These quasistatic tests applied a rigid roof/seat and belt restraint geometry. Kinematics of a 50th percentile Hybrid III dummy were analyzed in the quasistatic test procedure. Modifications of the seat, belt restraint system, and its anchorages changed the trajectory and kinematics of the dummy. This paper describes the laboratory test fixture, test method for simulating rollover, and results of some of over thirty rollover tests. Based on these results, a seat, belt restraint, and belt restraint anchorage design is described for this vehicle environment that reduced the excursion of the dummies from their seats in these simulations.

Impact Performance of Magnetorheological Fluids

As part of an emerging effort in what is now termed the area of mechamatronics [1], an effort was begun to assess the suitability of MR (magnetorheological) material based devices for impact energy management applications. A fundamental property of MR materials is that their yield stress alters almost instantaneously (and proportionally) to changes in the strength of an applied magnetic field. Based on this property, MR based devices, if found suitable, would be desirable for impact energy management applications because of attendant response tailorability. However, it was identified that prior to adopting MR based devices for impact energy management applications several key issues needed to be addressed. The present study focused on one of the most significant of these, the verification of the tunability of the response of such devices at stroking velocities representative of vehicular crashes. Impact tests using a free-flight drop tower facility were conducted on an MR based energy absorber (shock absorber) for a range of impact velocities and magnetic field strengths. Results demonstrated that over the range of impact velocities tested — 1.0 to 10 m/s — the stroking force/energy absorption exhibited by the device remained dependent on and thus could be modified by changes in the strength of the applied magnetic field.Copyright