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The concept of increasing strength requirements for automotive seats has been proposed as a means of reducing occupant injuries, particularly in the rear-end impact environment. This paper will evaluate various safety trade-offs and practical requirements of seat design brought about by modifications that include the rigidification of seat structures. Rigidified and yielding seat design concepts are evaluated, utilizing analytical procedures as well as data from static and dynamic tests. The effect of seat rigidification is examined in terms of occupant interaction with the surrounding structure and with the restraint system. Potential effects of these modifications on occupant kinematics and resulting injury exposures are also examined. The elastic properties of conventionally rigidified seat structures are compared to rigid seat structures in terms of their effect on occupant motion during collision.

Eight full-scale collision experiments were conducted and 73 collision fire case studies were investigated to provide data relating to fuel system failure modes and susceptibility of fuel system designs to collision fires. Data regarding impact speeds, nature of injuries, and climatic conditions are included. Results of extensive laboratory experiments provide specific ignition conditions for common fuels and define ignition hazards of exhaust systems and electrical and lighting circuitry. The physics of crash fire atmospheres is described, including air quality, radiant and convective heat transfers, and the relationship between burn physiology and occupant escape time. Design concepts are suggested for limiting fuel spillages, ignition sources, and thermal stress to motorists.

The relative performances are provided for many of the forms of motorist restraining devices evaluated during 139 full scale crash tests conducted over a 20 year period at UCLA. The relative advantages of passive and active restraining devices are described. Some new concepts of passive restraints are illustrated.

Seven collision experiments were conducted, each with a motorcycle and rider striking the side of a passenger car. Speed at impact, size of motorcycle, and position impacted along the side of the passenger car represent the independent variables studied. The delivery system used for this series of motorcycle collisions is described, along with related methodology. Photographic and electronic instrumentation systems were used for obtaining essential engineering data. Findings include: 1. Body kinematics for a motorcyclist during collision. 2. Collision dynamics of the impacting vehicles, including measurements of maximum mutual collapse. 3. Deceleration values for the motorcycle and for the head, chest, and hips of the rider. 4. Peak acceleration values for the struck passenger vehicle and its occupant. 5. Calibration of damages sustained by car and motorcycle for impacts at known speeds and for specific sizes of motorcycles.

The research techniques of instrumented full-scale collision experiments were applied to evaluate relative crash performances of smaller passenger vehicles colliding with larger vehicles. The larger vehicle weighed from 1.5-4 times as much as the smaller vehicle. The structure-overriding tendencies of larger vehicles in a particular collision were found to greatly influence the severity of exposure to injury for occupants of the smaller vehicle; relative strength of structures was similarly important. The crash safety of a motorist is shown to depend more on the use of adequate restraining devices than on the smallness of his car. Mismatched sizes of vehicles were crashed head-on, as well as in rear-end and intersection-type exposures. Analytical relationships of post-impact displacements as well as transducer and photographic instrumentation data are presented. Actual accident investigations were conducted which provided background preparation for this series of crash tests.

Collision performance of automotive seat systems has been a subject of inquiry since crash research was in its infancy. However, when federal standards were initiated in 1968 regarding seat system performance, they became the baseline for automotive design, and later became the topic of numerous debates in terms of occupant crash force and energy management. This subject of energy management as it relates to seat design has been extended and expanded in the current time period. This paper will discuss current design trends in automotive seat design collision performance in terms of new data recently becoming available. Also, due to recent proposals and discussion regarding modification of FMVSS 207, a review of seatback performance data in a dynamic environment will be presented. Any proposals regarding the modification of FMVSS 207 require careful evaluation and quantification of seat system goals.