Search Results

Analytical computer simulations were used to optimize and fabricate an Advanced Integrated Safety Seat (AISS) for frontal, rear, side, and rollover crash protection. The AISS restraint features included: dual linear recliners, pyrotechnic lap belt pretensioner, 4 kN load-limiter, extended head restraint system, rear impact energy absorber, seat-integrated belt system, and side impact air bag system. The evaluation and optimization of the AISS design was achieved through analytical simulations using MADYMO multi-body analysis software, LS-DYNA3D finite element software, and through LS-DYNA3D/MADYMO coupling. Frontal and rear impact sled tests were also conducted with physical AISS prototypes and baseline integrated seats to verify performance. Both the analytical modeling and the experimental sled testing demonstrated safety improvements over the baseline integrated seat.

Static out-of-position tests were performed to identify the potential for injury as a function of position, airbag type and vehicle seat characteristics. Seat and door mounted airbags, head curtains and head tubes were evaluated. Out-of-position testing was carried out with the Hybrid III 3 year old, 6 year old and the TNO Q3 3 year old child dummies. In-position tests and a dynamic test were conducted to monitor child seat and airbag interactions and to confirm that properly restrained children would not be exposed to undue risk from a deploying side airbag. Results of the out-of-position testing suggest that current side airbag designs may cause serious and/or fatal neck and chest injuries. In-position static testing with child seats suggested a potential for intrusion into the child occupant space leading to structural damage of the car seat.

Vehicle manufacturers are developing dynamically deploying upper interior head protection systems to provide added occupant protection in lateral crashes. These devices are used to protect the head and neck areas and to prevent ejection from the vehicle. The National Highway Traffic Safety Administration (NHTSA) has established requirements in Federal Motor Vehicle Safety Standard (FMVSS) 201 [1] for these systems. This paper will discuss testing methodologies in the areas of component testing of curtain-type side airbag systems and full scale side impact testing of a vehicle into a rigid pole. These testing methodologies have been created as a direct result of the development phase of several airbag systems. Prior to pole impact testing, tests have been developed which evaluate these types of systems for characteristics such as inflation time, fill capacity, and how long the system stays inflated during side impact and rollover simulations.

The risk of sustaining injury in rear impact collisions is correlated to collision severity as well as other factors such as restraint usage. The most recent National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) data available (1997 to 2011) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) between 5:00 and 7:00, indicating a rear impact collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on resultant delta-V and restraint system use. Each body region (head, spine, thorax, abdomen, upper extremity, and lower extremity) was considered separately.

Child dummies were seated in size appropriate child restraints and exposed to in-vehicle, static, side mounted airbag deployments as well as full scale side impact crash tests. The child seat sample included rear and forward facing child restraints and booster seats. Anthropomorphic test dummies (ATD) included an 18 month infant and fully instrumented Hybrid III 3 year old and Hybrid III 6 year old child dummies. Preliminary results suggest that properly restrained infants and children occupying age appropriate child seats may receive some protective benefits from side airbags provided the child seat and the child occupant are correctly positioned.

The purpose of this paper is to review injuries found in real-world lateral collisions and determine the mechanisms responsible for certain kinds of biomechanical failure. During the last years the distribution of deaths among the different types of accidents has changed. Lateral collisions now are the most frequent cause of fatal and other serious injuries. Every third accident is an impact from the side, while every second fatality is the result of a lateral accident. Just a few years ago this value was no higher than 30%. This is probably the result of increasing safety standards for frontal collisions (airbags, seatbelt usage, structural improvements of cars, etc.). Although the number of registered vehicles increased, the total amount of fatalities decreased during the same period. Thus it is now necessary to pay greater attention to the lateral accident situation in order to improve road safety and decrease the number of traffic injuries.

This paper reports on the status of work of the International Harmonized Research Activities (IHRA) Side Impact Working Group (SIWG) as at its 11th meeting prior to the 17th ESV conference in Amsterdam in June 2001. This includes decisions made and the reasons for them as well as identifying outstanding issues that require resolution.

The Inflatable Tubular Structure (ITS) is a safety system intended to provide head protection during side-impact car accidents. The ITS is an inflatable device fixed at two points; at the front end, to the A-pillar, and at the aft end, to the roof rail behind the B-pillar. It is stowed over the side window under the trim of the A-pillar and the headliner. At one end, a gas generator is electrically connected to the side-impact crash-sensing system which inflates the ITS when needed. The ITS is fabricated in a unique way so that, upon inflation, its diameter greatly increases and its length correspondingly decreases. This causes the ITS to pull itself out of its stored location over the side window into a straight line between its anchor points. The ITS thereby forms a taut semi-rigid structural member across the window opening.

Injuries in side impact collisions constitute one fourth of the serious or fatal injuries sustained by occupants in ordinary passenger cars. The Volvo Side Impact Protection System (SIPS) provides a substantially enhanced protection for car occupants in side collisions. The protection level of the SIPS system has been further increased by the addition of the Sipsbag, a quick-deploying side impact airbag system integrated in the seat backrest. The design of the non-electrical Sipsbag system is explained, as well as the advantages with a completely seat-integrated system. The process to industrialise the side airbag concept is summarised. Laboratory test results are discussed. Using methodology to correlate laboratory test data with accident data, an estimate of the injury-reducing effectiveness of the SIPS and Sipsbag system is made.

Frontal crashes and near-side crashes were compared and found to be significantly different events. In a frontal crash, the energy to be dissipated from the occupant is constant for a given speed. In a side crash, the energy transferred to a struck-side occupant depends highly on his interaction with the door. That difference has important implications on the choice of countermeasures, injury criteria, and subsystem tests. In a frontal crash, chest and abdominal injuries occur in the “second” impact when the occupant, acting like a free-flight mass, strikes the interior. Padding can absorb some of the free-flight energy, reduce the impact force, and provide earlier and longer contact of the occupant with the interior. The earlier contact decreases the differential velocity of the occupant to the interior, and the longer contact allows more time and greater distance to dissipate the kinetic energy.

The NHTSA notices of proposed rulemaking on side impact protection have focused worldwide attention on one of the most difficult and frustrating efforts in automobile crash safety. Traditional vehicle design has evolved obvious structural contrasts between the side of the struck vehicle and the front of the striking vehicle. Protection of near-side occupants from intruding door structure is a most perplexing engineering challenge. Much useful and insightful engineering work has been done in conjunction with NHTSA's proposed rulemaking. However, there are many major engineering issues which demand further definition before reasonable side impact rulemaking test criteria can be finalized. This paper reviews recent findings which characterize the human factors, biomechanics, and occupant position envelope of the typical side impact crash victim.

Fatalities in various modes of transportation are reviewed, with the point being made that distance death rates must decrease as mankind's average trip distances increase. The multiple origins of airbag restraint concepts are traced. The possibility is presented of having no restraint other than the seats prior to a crash situation, then automatically inflating transparent chest airbags to “grab the wife and kids” if a crash is developing. The driver would wear a lap belt and shoulder Straps. The bags would automatically deflate after the crash. Analytical models of automobile crash loads, and of passenger motions in the airstop restraint, consisting of a chest airbag and an inflated “airseat,” are reviewed, with emphasis on rear and side collisions. For higher speed crashes, additional protection is suggested by using a 10,000 pound loop strength lap belt on the airseat, and within 0.03 seconds after impact preloading the chest airbag to a higher pressure proportional to speed.

Every year in the U.S., about 8,000 fatalities occur in side impacts, and about 9,500 fatalities occur in vehicle rollovers. Severe head trauma and spinal cord injuries are the prevalent traumatic injuries that are directly related to the extent of inward crushing or intrusion into the occupant's “survival space” and to the rigidity and shape of interior edges and surfaces. Based on accident evaluations and assessment of available technologies, there are feasible and practical advanced design features for vehicle bodies and interiors that can concurrently enhance both side-impact protection and rollover roof-integrity protection: Strengthened vehicle body by the use of rigid-foam-filled tubular members that strengthen and stiffen the vehicle body, by tripling resistance to bending and compression. Strengthened doors with full-perimeter overlap and multiple latches. Multi-layer laminated floorpans, cross-panels, and roofs of composite materials.

Car accident investigations have shown that the head, the chest and the abdomen are the three most vulnerable body regions in side impacts, when serious-to-fatal (MAIS 3-6) injuries are considered. Injuries are much more common to occupants seated on the struck side than to those on the non-struck side. The development of new side impact protection systems has therefore been focused on struck side occupants. The first airbag system for side impact protection, jointly developed by Volvo and Autoliv, was introduced on the market in 1994. The SIPS bag is seat-mounted and protects mainly the chest and the abdomen, and also to some extent the head, since the head's lateral relative displacement is reduced by the side airbag, thereby keeping the head inside the car's outer profile. However, if an external object is exposed in the head area, for example in a truck-to-car side impact or in a single car collision into a pole or a tree, there is a need for an additional head protection device.

A new additional airbag system will provide enhanced protection in side impact collisions. The so - called Window Bag will be installed in some Mercedes cars beginning with the E-Class Sedan for the MY99 and in the new S - Class.

Diffuse brain injuries are very common in side impacts, accounting for more than half of the injuries to the head. These injuries are often sustained in less severe side impacts. An English investigation has shown that diffuse brain injuries often originate from interior contacts, most frequently with the side window. They are believed to be mainly caused by quick head rotational motions. This paper describes a test method using a Hybrid III dummy head in a wire pendulum. The head impacts a simulated side window or an inflatable device, called the Inflatable Curtain (IC), in front of the window, at different speeds, and at different impact angles. The inflated IC has a thickness of around 70 mm and an internal (over) pressure of 1.5 bar. The head was instrumented with a three axis accelerometer as well as an angular velocity sensor measuring about the vertical (z) axis. The angular acceleration was calculated.

A sled-to-sled subsystem side impact test methodology has been developed by using two sleds at the WSU Bioengineering Center in order to simulate a car-to-car side impact, particularly in regards to the door velocity profile. Initially this study concentrated on tailoring door pulse to match the inner door velocity profile from FMVSS 214 full-scale dynamic side impact tests. This test device simulates a pulse quite similar to a typical door velocity of a full size car in a dynamic side impact test. Using the newly developed side impact test device three runs with a SID dummy were performed to study the effects of door padding and spacing in a real side impact situation. This paper describes the test methodology to simulate door intrusion velocity profiles in side impact and discusses SID dummy test results for different padding conditions.

Side impact crashworthiness development presents a unique challenge to auto safety engineers. One fundamental issue is how to evaluate side impact air bags with a component test that realistically simulates the kinematics of a full scale side impact crash test. This paper presents a test methodology that can be used to evaluate side impact air bags utilizing an accelerator-type sled typically used for frontal impact simulation. The approach uses a “two carriage” system, whereas the struck door and vehicle acceleration profiles are simulated. These acceleration responses are matched through a series of sled variables including thrust column setting, metering pin shape and an on-board pneumatic cylinder which controls the relative response between the two carriages.

This paper has been withdrawn by the publisher because of non-attendance and not presenting at WCX 2024.