Experimental Impact Protection with Advanced Automotive Restraint Systems: Preliminary Primate Tests with Air Bag and Inertia Reel/Inverted-Y Yoke Torso Harness

Both the inverted-Y yoke torso harness with inertia reel and the air bag restraint system have had extensive independent development for some time by several engineering and research organizations for both aviation and ground vehicle occupant protection. The research reported in this paper consists of the first biomechanical primate evaluation of these concepts as experimentally adapted for possible automotive use. These tests are a continuation of a study involving the relative impact protection and effectiveness of major restraint systems utilized in general aviation aircraft and in limited automotive use. The objective of this test series was to determine how much protection those advanced restraint concepts provided; to obtain preliminary biomechanical and physiological data; to identify problems of technique and applications in occupant protection; and to provide an initial basis for direction of future test requirements.

Of 13 tests run in this series, nine tests of Savannah baboons (Papio cynocephalus) were made using a scaled-down air bag restraint system. All were oriented in the forward-facing position (-G_X or 0-0-0) and at a 13° seat-back angle. Entrance velocities ranged from 71 ft/sec (33 peak G) at 3000 g/sec onset rate, to 94.2 ft/sec (57 peak G) at 6000 g/sec onset rate. In addition, four tests were conducted with the yoke harness, utilizing inertia reels activated at. 3G. Three of these were in the for ward-facing (-G_X body orientation in impacts of 73 to 94.4 ft/sec (30-49 peak G) and 2700 to 6100 g/sec onset rate. In a fourth test, the subject was oriented for a 90° sideward impact at 75.2 ft/sec (32G). Since over 60 tests of baboon subjects now have been conducted with various restraint systems under identical controlled impact conditions, valid relative assessments of the impact injury protection offered by these systems may be made. Documentation included physiological data, restraint loadings, high-speed photography for body kinematics, biological assessments including gross and microscopic autopsy procedures, whole-body X-rays, and pre- and post-run blood analyses for stress and tissue damage determinations. Two air bag tests were run on each profile, and three animals were allowed to survive to monitor any neurological or other post-impact trauma. Conclusions of the relative value of these restraint systems for automotive use to protect occupants during impact are discussed from a biomechanical viewpoint.