1976-02-01

AUTOMOTIVE SEAT DESIGN AND COLLISION PERFORMANCE 760810

Eighty-five laboratory full-scale force-deflection tests were conducted on passenger vehicle seats, foreign and domestic, for purposes of evaluating specific resistance to a collision environment and mechanisms of collision induced seat distortion. These tests evaluated seats that span the past thirty years; additionally, seat design studies were conducted evaluating basic features of automotive seating during the past eighty years.
Data from full-scale collision experiments and from a large number of actual accidents facilitated the establishment of seat design criteria for greatly improved collision performance. Evolution of seat and head support standards in the United States and Europe are presented with evaluation of their relative significance to the requirements of automotive seat collision performance.
The foregoing research provided foundation for modification of a production automobile seat into an integral safety seat, based on a design concept that minimizes bending moments during collision. The modified seat was subjected to the same laboratory test procedure applied to the 85 non-modified production seats and results of its performance is given.
Design concepts are presented that would serve to mitigate undesirable seat distortions during collision and thus improve seat restraint capabilities without compromising the important factors of comfort and cost.
ALTHOUGH SAFETY IS A BASIC CONSIDERATION in all aspects of automotive engineering, it is a fact of life that safety advances are not uniformly accomplished. Some essential aspects of motorist protection have in the past, and probably will in the future, continue to be greatly outstripped by advances made in other areas. In some instances, the design challenge simply exceeds current technology; on other occasions an adequate safety standard and concerted industry interest can correct obvious safety deficiencies. For example, although improved tires resulted only after new materials evolved, a greatly improved motorist restraining system resulted from industry initiated research that culminated in a standard requiring installation of combination cross chest lap belts for all outboard front seat locations.
During the past 20 years, new materials and techniques have improved the comfort and wear resistance of automotive seats while simultaneously reducing their weight and cost; however, significant safety related improvement in seat design during this period has not been accomplished. A summary of findings from prior research (1)* published in 1966 classified a structurally redesigned Integral Seat with built-in 3-point belt restraint as critically important for reduction of motorist injuries; this summary also pointed out the lack of safety-seat research up to that time. Although some research has been conducted since that time, the development of a safety seat still has not been accomplished. In the same study special devices, including the air bag, were rated as only of moderate relative importance.
After 10 years of government regulated safety standards and nearly that many years of intensive air bag development sponsored by both government and industry, the consensus of many automotive safety researchers in Europe (2), (3) and elsewhere is to change the emphasis back to development of active restraint systems and to increase effectiveness by means of mandatory use laws. Air bags, if used, would serve a supplementary function in conjunction with active systems. Progress in safer seat design has been impeded throughout a decade of automotive safety standard making, and many lives have been lost that could have been fully protected with a fraction of the inventive genius and funding lost to air bag development. A basic common sense approach to motorist protection from collision trauma calls for special attention to design of the critically important structure nearest the motorist, his seat.
A vital consideration of seat design is its capacity to protect motorists, to the extent practical, from all types of collision injury exposures. This paper provides basic design data for crashworthy automotive seat systems with integral active restraints, as determined from the authors' collision research and laboratory studies as well as experience gained from investigation of relevant accidents.

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