Russell Frieder

Biomechanics of Side Impact Injuries: Evaluation of Seat Belt Restraint System, Occupant Kinematics and Injury Potential

Side impact crashes are the second most severe motor vehicle accidents resulting in serious and fatal injuries. One of the occupant restraint systems in the vehicle is the three point lap/shoulder harness. However, the lap/shoulder restraint is not effective in a far-side crash (impact is opposite to the occupant location) since the occupant may slip out of the shoulder harness. The present comprehensive study was designed to delineate the biomechanics of far-side planar crashes. The first part of the study involves a car-to-car crash to study the crash dynamics and occupant kinematics; the second part involves an epidemiological analysis of NASS/CDS 1988-2003 database to study the distribution of serious injury; the third part includes the mathematical MADYMO analysis to study the occupant kinematics in detail; and the fourth part includes an in-depth analysis of a real world far-side accident to delineate the injury mechanism and occupant kinematics. Results indicate that the shoulder harness is ineffective in far-side crashes. The upper torso of the belted driver dummy slips out of the shoulder harness and interacted with the opposite vehicle interior such as the door panel. The unbelted occupants had a similar head injury severity pattern compared to belted occupants. The present study is another step to advance towards better understanding of the prevention, treatment and rehabilitation of side impact injuries

Biomechanical Analysis of Late Airbag Deployment in Motor Vehicle Crashes Using Computer Simulation

Motor vehicle collisions frequently result in serious or fatal inuries to occupants [1–4]. Frontal collisions are amongst the most severe types of accidents. The use of safety systems such as seat belts and airbags has been shown to reduce the severity of injuries sustained by occupants [5–10]. It is well known that frontal airbags act as supplemental restraints to seat belts in protecting occupants. Airbag deployment occurs through a reaction of chemicals in the inflator that rapidly produces gas and fills the canvas bag. The filled bag acts a cushion between the occupant and the vehicle’s interior components. The supplemental restraint provided by the airbag increases the amount of time and distance over which the occupant’s body decelerates, and accordingly reduces the potential for injury. The time at which the airbag deployment is initiated during the crash sequence can have an effect on the nature of the contact between occupant and airbag. Though properly timed, frontal airbags have been shown to reduce injuries sustained to occupants[11], it has been reported that airbags that deploy too late may cause injury[12]. To date, there have been a very limited number of studies that have addressed the biomechanical effects of late airbag deployment. The purpose of this study is to determine the biomechanical effects of late airbag deployment and restraint use on various sizes of occupants through computer simulation.Copyright

Biomechanical Quantification of Flexion Movement (Ducking) of the Human Head-Neck and Rollover Accidents

Rollover accidents are one of the major types of crashes contributing to the serious or fatal injuries to occupants [1]. The roof crush in rollover accidents is associated with serious injuries to head and neck system [2]. The roof crush intrudes into the occupant survival space and imparts force to the head. The excessive force on the head subjects the cervical spine to injurious level. A commonly observed cervical spine injury in rollover accidents is locked facets with no major bony fractures that are often associated with the flexion-distraction type of loading [3]. Although numerous studies addressed the mechanism of locked facet injuries and the survival space issues [4–9], limited comprehensive efforts have been advanced so far. It is noted that humans tend to duck their head while startled due to sudden fear [10,11]. It is hypothesized that the occupants inside the vehicle tend to duck their heads as a protective mechanism to avoid impact on the head. Although range of motion of the cervical spine is well reported [12], the change in downward movement of the head-neck system (ducking) is not studied well. The present study quantifies the downward movement of the head-neck system of volunteers while seated erect.Copyright

Design of rapid medical evacuation system for trauma patients resulting from biological and chemical terrorist attacks.

In the event of a large scale, biological or chemical terrorist attack it is unlikely that local emergency response organizations will have sufficient quantities of dedicated ambulances to evacuate all of the affected victims. As a potential solution to this problem, we have developed a device that can be retrofitted to a variety of government or civilian utility vehicles in order to convert them for emergency medical transport (US Pat. 7,028,351). Each installed device allows the host vehicle to safely transport either a single patient on a stretcher or multiple ambulatory patients. Additionally, each device provides a means for temporary or permanent attachment of emergency medical equipment. When not in use, the device can be collapsed to improve ease and efficiency of storage. Preliminary analyses of certain highly loaded structures on the device were carried out using known principles of solid mechanics. The analyses were carried out assuming the highest reasonable loading condition. This condition was determined to occur when the device is configured for the transport three 95th percentile males and 20 kg of medical equipment. This loading condition was assumed to be more severe than any that might occur due to an attendant performing CPR, or any other medical procedures, on a single supine patient. The base sections of the load bearing stretcher supports were then modeled using 3D CAD software and run through a finite element analysis (FEA) as a means to more accurately simulate the stresses that are likely to occur in the actual parts. As the device must be highly mobile, these analyses were used to confirm that the load bearing structures can be manufactured from low cost materials and still be light enough to be easily transported. Future work will include sizing and installation studies to ensure that the production version of the device can be rapidly implemented in a wide variety of private, commercial, and government utility vehicles