Search Results

The rear seat occupant has been the subject of an increasing number of research efforts in recent years. However, the majority of the research has focused on frontal impact, while there are also a number of studies concerned with low to moderate delta-V rear impact. Very limited work exists regarding the fate of the rear seat occupant involved in high-severity rear impact, especially when utilizing the BioRID anthropomorphic test device (ATD). Furthermore, it is evident that the out of position rear occupant, as defined by leaning forward prior to rear impact, is also of relevance to this line of research. The objective of this study is to explore and compare the response of BioRID and 50 th percentile Hybrid III in conjunction with the effects of head restraint geometry and the occupant seating configuration (normal seating versus forward leaning) in high-severity rear impact tests.

Truck-trailers are required to have rear impact protection guards per Federal Motor Vehicle Safety Standards 223 and 224. The standards define the minimum strength and energy absorption requirements at the guard component level, while allowing the guard manufacturer to use a rigid test fixture when certifying the guard. Due to the limitations inherent in “rigidizing” the under-structure of a trailer, often some amount of deformation in the supporting structures is tolerated when certifying a guard. Hence there is a tendency to certify the impact guard as a “guard system” composed of guard members and the support (mounting) structures. In this paper, a previously validated 1990 Ford Taurus FE model was used to analyze the effect of compliance in the guard support members on its dynamic performance. Two guard systems, one with rigid supports and another with some compliance in the supports were modeled.

FMVSS 223 and 224 set standards for “Rear Impact Protection” for trailers and semi-trailers with a gross weight rating greater than 10000 pounds. A limited amount of experimental data is available for evaluating the different performance attributes of rear impact guards. The crash tests are usually limited to fixed parameters such as impact speed, guard height, strength and energy absorption, etc. There also seems to be some misunderstanding of the interdependence of guard strength and energy absorption, and their combined effect on the guard's ability to limit underride while keeping occupant acceleration forces in a safe range. In this paper, we validated the Finite Element (FE) model of an existing rear impact guard against actual FMVSS 223 tests. We also modified a previously evaluated FE model of a 1990 Ford Taurus by updating its hood geometry and material properties.

This study provides a preliminary investigation of occupant kinematics for rear seat occupants involved in high-severity rear impacts. The effect of a seatbelts equipped with or without a pyrotechnic pretensioner on restraining the rear seat adult occupant was evaluated. Further, the study examined the result of the occupant's seating alignment by comparing a Nominal Seating Position (NSP) to an occupant whose torso would be rotated forward to be placed in a Moderately Displaced Position (MDP) prior to impact. A series of eight sled tests were performed using a deceleration sled subjected to a delta-V of 30 mph. Instrumented HIII 50th and 5th ATDs were positioned in the outboard, rear seating positions. The study found that pretensioners had little effect on the occupant kinematics of rear seat occupants in either the NSP or the MDP. But, there were marked differences in kinematic evaluations between the occupant seating alignment configurations.

The first objective of this paper was to evaluate a public domain finite element (FE) model of a 1990 Ford Taurus from the perspective of crush energy absorption. The validity of the FE model was examined by first comparing simulation results to several published full-frontal crash tests. Secondly, the suitability of the model for underride simulation was evaluated against two series of full-scale crash tests into vertically offset rigid barriers. Next, the evaluated FE model was used to pursue the main objective of this work, namely to develop an approach for estimating underride crush energy. The linear-spring methodology was adopted whereby the underride crush stiffness was determined by relating the residual upper radiator support deformation to crush energy. An underride crush stiffness estimation method was proposed based on modifying the full-frontal stiffness coefficients.

Many signature analysis techniques have been developed for detecting bearing damage. In this paper, a number of these techniques are evaluated and their abilities to detect and trend damage are compared quantitatively. Needle bearings are used for this evaluation because they are noisier than ball bearings, and there has been little published regarding their vibration behavior. The signature analysis techniques are evaluated using three increasing levels of outer race damage. The evaluation criteria are based on the ability of a technique to repeatedly detect a damaged bearing and to correctly trend the damage progression. Results show that a number of time and frequency domain techniques correctly identify and trend the bearing damage. Of these techniques, the matched-filter root-mean-square (Mfrms) technique applied to an enveloped (smoothened) signal consisently showed high sensitivity to bearing damage and its progression.