Study of energy absorption characteristics of a thin walled tube filled with carbon nano polyurethane foam

Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.In last few decades much research work has been conducted on the development of most efficient crashworthy structures which can protect vehicle drivers, passengers or at least reduce the severity of the accident by absorbing kinetic impact energy in the event of an accident. Thin-walled tubes are most commonly used members as crashworthy structures. It has been shown that thin walled tubes, filled with foam materials, possess efficient energy-absorbing capability than the empty crashworthy structure. This characteristic of foam materials has led to the development of different new foam materials, which can absorb more impact energy. Nanotechnology is one of the emerging techniques used in development of advanced materials for engineering and other applications. One such application is in developing energy absorbing materials, which can be used in automotive and aerospace industry. The purpose of this thesis is to analyze properties of the thin walled tubes with respect to energy absorption capacity, when filled with carbon nano-foam. The application of such carbon nano foam in the bumper area of a particular vehicle model namely Dodge Caravan is analyzed at different speeds. To accomplish this study, the Ls-Dyna code, a non-linear dynamic finite element solver is utilized. First, experiment using compression tests are carried out to obtain the behavior of the foam material by adding different weight percentages of carbon nano fibers. Next, the axial crushing behavior of thin walled steel tube was observed. The energy absorption capabilities of this crashworthy tube are tabulated and results are compared with rigid polyurethane foam under similar conditions. Finally carbon nano foam is applied in the bumper area of a vehicle model to study its crashworthy behavior in frontal impact at different speeds of the vehicle