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The paper gives an evaluation of the performance of lap and shoulder belt restraint systems currently being used in American-built automobiles. Comparisons are made of the response characteristics of a volunteer, an anthropometric dummy, and a cadaver when subjected to identical collision environments while wearing a three or four point torso restraint system as occupants of the right front seat. Simulated frontal force barrier collisions in a modified automobile provided the realistic environment for the restraint system performance study. Human tolerances, interior vehicle geometry, and the interaction of the restrained occupant with the vehicle during the collision are reported in detail.

The search for improvements in occupant protection under vehicle impact is hampered by a real lack of reliable biomechanical data. To help fill this void, General Motors has initiated joint research with independent researchers such as the School of Medicine, U. C. L. A. – in this case to study localized head and facial trauma — and has developed such unique laboratory tools as “Tramasaf,” a human-simulating headform, and “MetNet,” a pressure-sensitive metal foam. Research applied directly to product design also has culminated in developments such as the Side-Guard Beam for side impact protection.

Traditionally, Knee Air Bag (KAB) is constructed of a woven nylon or polyester fabric. Recently, Ford developed an injection molded air bag system for the passenger side called Active Glove Box (AGB). This system integrates a plastic bladder welded between the glove box outer and inner doors. This new system is smaller and lighter, thus improving the roominess and other creature comforts inside the passenger cabin while providing equivalent restraint performance as traditional knee airbag system. This patented technology allows positioning of airbags in new locations within the vehicle, thus giving more freedom to designers. The first application of this technology was standard equipment on the 2015 Ford Mustang. Given that this technology is first in the industry, it was a challenge to design, test and evaluate the performance of the system as there is no benchmark to compare this technology. A CAE driven design methodology was chosen to overcome this challenge.

This paper reports a study of the dynamic characteristics of body mounts in body on frame vehicles and their effects on structural and occupant CAE results. The body mount stiffness and damping are computed from spring-damper models and component test results. The model parameters are converted to those used in the full vehicle structural model to simulate the vehicle crash performance. An effective body mount in a CAE crash model requires a set of coordinated damping and stiffness to transfer the frame pulse to the body. The ability of the pulse transfer, defined as transient transmissibility[1]1, is crucial in the early part of the crash pulse prediction using a structural model such as Radioss[2]. Traditionally, CAE users input into the model the force-deflection data of the body mount obtained from the component and/or full vehicle tests. In this practice, the body mount in the CAE model is essentially represented by a spring with the prescribed force-deflection data.

For more than 30 years, field research and laboratory testing have consistently demonstrated that properly wearing a seat belt dramatically reduces the risk of occupant death or serious injury in motor vehicle crashes. In severe rollover crashes, deformation to vehicle body structures can relocate body-mounted seat belt anchors altering seat belt geometry. In particular, roof pillar mounted shoulder belt anchors (“D-rings”) are subject to vertical and lateral deformation in the vehicle coordinate system. The ROllover Component test System (ROCS) test device was utilized to evaluate seat belt system performance in simulated severe rollover roof-to-ground impacts. A mechanical actuator was designed to dynamically relocate the D-ring assembly during a roof-to-ground impact event in an otherwise rigid test vehicle fixture. Anthropomorphic test device (ATD) kinematics and kinetics and seat belt tensions were compared between tests with and without D-ring relocation.

The dilemma of using a shoulder belt force limiter with a 3-point belt system is selecting a limit load that will balance the reduced risk of significant thoracic injury due to the shoulder belt loading of the chest against the increased risk of significant head injury due to the greater upper torso motion allowed by the shoulder belt load limiter. However, with the use of air bags, this dilemma is more manageable since it only occurs for non-deploy accidents where the risk of significant head injury is low even for the unbelted occupant. A study was done using a validated occupant dynamics model of the Hybrid III dummy to investigate the effects that a prescribed set of shoulder belt force limits had on head and thoracic responses for 48 and 56 km/h barrier simulations with driver air bag deployment and for threshold crash severity simulations with no air bag deployment.

In order to provide an improved countermeasure for occupant protection, a new type of active reversible preload seatbelt (ARPS) is presented in this paper. The ARPS is capable of protecting occupants by reducing injuries during frontal collisions. ARPS retracts seatbelt webbing by activating an electric motor attached to the seatbelt retractor. FCW (Forward Collision Warning) and LDW (Lane Departure Warning) provide signals as a trigger to activate the electric motor to retract the seatbelt webbing, thus making the occupant restraint system work more effectively in a crash. It also helps reduce occupant’s forward movement during impact process via braking. Four important factors such as preload force, preload velocity and the length and timing of webbing retraction play influential roles in performance of the ARPS. This paper focuses on studying preload performance of ARPS under various test conditions to investigate effects of the aforementioned factors.

At the Tenth ESV Conference, MVMA reported on the development of a component side impact test device developed for MVMA by MGA Research Corporation. Since that time, the test device has been modified by MGA to improve its biofidelity. Testing has shown that the modified device better meets the force-time corridors derived by MVMA from cadaver drop test data. The improved test device was used to test twelve 1985 Ford LTD doors at speeds of 25.7 and 37 km/h. The interior door surfaces were trimmed with either thin fiber board or foam padding identical to doors in vehicles tested by MVMA using NHTSA's full-vehicle test procedure. The tests showed that the MVMA device is simple to set up and run, is highly repeatable and easily discriminates between the unpadded and padded doors. A major issue for future research and development is how to select a priori a component test device impact speed which can account for differences in car size and side structure stiffness.

The relation cost versus performance in the design of an automobile is crucial for its success. These two characteristics, much like the project development timing, are closely related to the attributes that the new design must achieve (e.g. weight, fuel economy, torsional stiffness, NVH, safety, etc.). In this respect, the design optimization of body reinforcements (i.e. part thickness, quantity of reinforcements, and number of spot welds) contributes greatly to a sound and robust project concept. This paper describes one application of 6-Sigma methodology to evaluate the performance of different configurations of seat belt reinforcements resulting in an optimized concept that achieved the proposed performance targets with weight and sub-assembly complexity reduction. Using a Design of Experiments (DOE) and Finite Element Analysis (FEA), each proposal was evaluated for its resistance to plastic deformation.

The Hybrid III dummy is an anthropomorphic (humanlike) test device, generally used in crashworthiness testing to assess the extent of occupant protection provided by the vehicle structure and its restraint systems in the event of vehicle crash. Lumped-parameter analytical models are commonly used to simulate the dummy response. These models, by virtue of their limited number of degrees of freedom, can neither represent accurate three-dimensional dummy geometry nor detailed structural deformations. In an effort to improve the state-of-the-art in analytical dummy simulations, a set of finite element models of the Hybrid III dummy segments - head, neck, thorax, spine, pelvis, knee, upper extremities and lower extremities - were developed. The component models replicated the hardware geometry as closely as possible. Appropriate elastic material models were selected for the dummy “skeleton”, with the exterior “soft tissues” represented by viscoelastic materials.

By applying some advanced features of the CAL3D occupant simulation model, a single model incorporating the vehicle structure and a simplified occupant was developed for studying the sensitivity of occupant response to parameter changes in perpendicular, vehicle-to-vehicle side impacts, not involving vehicle rotation. The results of the model show qualitative agreement with published experimental results, which indicate that occupant responses are related to the initial clearance of the occupant from the door, the stiffnesses of the front end of the impacting vehicle, and the side structure of the impacted vehicle.

As the driving population ages, there is a need to understand the accident patterns of older drivers. Previous research has shown that side impact collisions, usually at an intersection, are a serious problem for the older driver in terms of injury outcome. This study compares the frequency of side impact, intersection collisions of different driver age groups using state and national police-reported accident data as well as an in-depth analysis of cases from a fatal accident study. All data reveal that the frequency of intersection crashes increases with driver age. The state and national data show that older drivers have an increase frequency of intersection crashes involving vehicles crossing paths prior to the collision compared to their involvement in all crash types. When taking into account traffic control devices at an intersection, older drivers have the greatest involvement of multiple vehicle crashes at a signed intersection.

Three computational gas and fluid dynamic methods, CV/UP (Control Volume/Uniform Pressure), CPM (Corpuscular Particle Method), and ALE (Arbitrary Lagrangian and Eulerian), were investigated in this research in an attempt to predict the responses of side crash pressure sensors. Acceleration-based crash sensors have been used extensively in the automotive industry to determine the restraint system firing time in the event of a vehicle crash. The prediction of acceleration-based crash pulses by using computer simulations has been very challenging due to the high frequency and noisy responses obtained from the sensors, especially those installed in crush zones. As a result, the sensor algorithm developments for acceleration-based sensors are largely based on prototype testing. With the latest advancement in the crash sensor technology, side crash pressure sensors have emerged recently and are gradually replacing acceleration-based sensor for side crash applications.

This paper describes the development of a three-dimensional lumped-mass structure and dummy model to study barrier-to-car side impacts. The test procedures utilized to develop model input data are also described. The model results are compared to crash test results from a series of six barrier-to-car crash tests. Sensitivity analysis using the validated model show the necessity to account for dynamic structural rate effects when using quasi-statically measured vehicle crush data.

Occupant protection in side impacts, in particular for near-side occupants, is a challenge due to the occupant’s close proximity to the impact. Near-side occupants have limited space to ride down the impact. Curtain and side airbags fill the gap between occupant and the side interior. This analysis was conducted to provide insight on the characteristics of side impacts and the relevancy of currently regulated test configurations. For this purpose, 2007-2015 NASS-CDS and 2017-2021 CISS side crash data were analyzed for towed light vehicles. 2008 and newer model year vehicle data was selected to ensure that most vehicles were equipped with side/curtain airbags. The results showed that side impacts accounted for approximately 26.7% of the vehicles involved and 18.9% of the vehicles with at least one seriously injured occupant. Most side impacts involved damage to the front and front-to-center of the vehicle.

Analysis and validation of current scaling relationships and existing response corridors using animal surrogate test data is valuable, and may lead to the development of new or improved scaling relationships. For this reason, lateral pendulum impact testing of appropriate size cadaveric porcine surrogates of human 3-year-old, 6-year-old, 10-year-old, and 50th percentile male age equivalence, were performed at the thorax and abdomen body regions to compare swine test data to already established human lateral impact response corridors scaled from the 50th percentile human adult male to the pediatric level to establish viability of current scaling laws. Appropriate Porcine Surrogate Equivalents PSE for the human 3-year-old, 6-year-old, 10-year-old, and 50th percentile male, based on whole body mass, were established. A series of lateral impact thorax and abdomen pendulum testing was performed based on previously established scaled lateral impact assessment test protocols.

To date, several lateral impact studies (Bolte et al., 2000, 2003, Marth, 2002 and Compigne et al., 2004) have been performed on the shoulder to determine the response characteristics and injury threshold of the shoulder complex. Our understanding of the biomechanical response and injury tolerance of the shoulder would be improved if the results of these tests were combined. From a larger data base shoulder injury tolerance criteria can be developed as well as corridors for side impact dummies. Data from the study by Marth (2002, 12 tests) was combined with data from the previous studies. Twenty-two low speed tests (4.5 ± 0.7 m/s) and 9 high speed tests (6.7 ± 0.7 m/s) were selected from the combined data for developing corridors. Shoulder force, deflection and T1y acceleration corridors were developed using a minimization of cumulative variance technique.

This paper updates the findings of prior research addressing the relationship between seatback strength and likelihood of serious injury/fatality to belted drivers and rear seat occupants in rear-impact crashes. Statistical analyses were performed using 1995-2014 CY police-reported crash data from seventeen states. Seatback strength for over 100 vehicle model groupings (model years 1996-2013) was included in the analysis. Seatback strength is measured in terms of the maximum moment that results in 10 inches of seat displacement. These measurements range from 5,989 in-lbs to 39,918 in-lbs, resulting in a wide range of seatback strengths. Additional analysis was done to see whether Seat Integrated Restraint Systems (SIRS) perform better than conventional belts in reducing driver and rear seat occupant injury in rear impacts. Field data shows the severe injury rate for belted drivers in rear-impact crashes is less than 1%.

Squeak and rattle is an important sub Noise and Vibration attribute which can be easily noticed by the costumer. A rattle was observed at seat belt retractor during subjective evaluation at a special test on a rough road It was developed an objective metric, in laboratory, with the aim to establish an acceptance criteria for the part. The objective of this paper is to show how noise, vibration and harshness engineers worked on the correlation between subjective and objective evaluation concerning this rattle.

This study examined occupant and seat responses with ABTS (all-belts-to-seat) in rear end collisions. Some have claimed improved ABTS seat performance and retention in rear impacts than conventional seats. ABTS seats tend to have higher ultimate yield strengths than conventional yielding seats. Most ABTS seats have asymmetric seatback stiffness due to the need for additional structure on one side of the seat to support shoulder belt loads. Many designs use a single-side recliner and single stanchion that anchors the D-ring. This asymmetry results in twisting of the seatback in severe rear impacts. Seatback twist can allow the occupant to move away from the shoulder belt. Rearward pull tests on ABTS seats also demonstrates seatback twisting and in some cases large drops in load during the test. The added strength and stiffness of ABTS seats lead to designs that are vulnerable to sudden force drops from separated parts.