Search Results

Safety restraint technology relies on woven fabrics as the principle material of construction. On impact, gases are generated instantaneously to inflate the bag. As the pressure within the bag increases during deployment and later from passenger contact, the airbag fabric stretches in a biaxial-manner. Passenger contact with the slowly deflating airbag accelerates the gaseous outflow through the fabric, airbag seams, and through specially constructed vents. A fraction of the impact energy can also be adsorbed by mechanical biaxial stretching of the fabric's fibers. However, the fabric's permeability and/ or vent system appear to be of primary importance to energy dissipation. A unique blister-inflation technique was developed and used to evaluate the fabric properties necessary for energy dissipation by these four mechanisms. The performance of fabrics woven from two traditional commercial polymeric fibers offered for airbag construction were considered.

The response of the head to blunt impact was investigated using anesthetized live and repressurized- and unrepressurized-postmortem Rhesus. The stationary test subject was struck on the occipital by a 10 kg guided moving impactor. The impactor striking surface was fitted with padding to vary the contact force-time characteristics. A nine-accelerometer system, rigidly affixed to the skull, measured head motion. Transducers placed at specific points below the skull recorded epidural pressure. The repressurization of postmortem subjects included repressurization of both the vascular and cerebrospinal systems.

Heart-aortic trauma was investigated using live, anesthetized and postmortem canines subjected to frontal impact with a blunt impactor. The major focuses of this research program were: trauma to the heart aortic system, the kinematic response of the thoracic cage, and pressure in the ascending and descending aorta.

This paper discusses techniques developed and used by the Biosciences Group at the University of Michigan Transportation Research Institute (UMTRI) for measuring three-dimensional head motion, skull bone strain, epidural pressure, and internal brain motion of repressurized cadavers and Rhesus monkeys during head impact. In the experimental design, a stationary test subject is struck by a guided moving impactor of 10 kg (monkeys) and 25 or 65 kg (cadavers). The impactor striking surface is fitted with padding to vary the contact force-time characteristics. The experimental technique uses a nine-accelerometer system rigidly affixed to the skull to measure head motion, transducers placed at specific points below the skull to record epidural pressure, repressurization of both the vascular and cerebrospinal systems, and high-speed cineradiography (at 1000 frames per second) of radiopaque targets.