The mechanics of debonding of foam core sandwich structure under cyclic loading Anette M. Karlsson, University of Delaware, Newark, DE Leif A. Carlsson, Florida Atlantic University, Boca Raton, FL
This work aims to increase the understanding of fatigue in foam core sandwich structures. Foam core sandwich structures are composite structures consisting of two face sheets (typically aluminum or fiber reinforced polymer) and a cellular foamed polymer. Since sandwich structures are composed of widely dissimilar materials, they display peculiar and sometimes unexpected failure modes. Traditionally, the rate in which the cracks grow during cyclic (fatigue) loading is established by extensive (and therefore expensive) material testing. Theories describing damage (e.g., plastically dissipated energy) at the crack tip and the ensuing crack growth rate are developed in this research. These theories are quantified in numerical computer simulations. Only limited experimental investigations for determining important materials parameters will be needed as input to the computer code. The fatigue life predicted from the numerical simulations will be verified by full scale fatigue testing.
Composite sandwich structures are light-weight structures with high strength, high impact resistance, and high resistance to corrosion along with low radar and acoustics signals. Current applications range from aircraft structures, to wind turbine blades, to ship hulls. Successful outcome of the research will result in a life prediction methodology relying on limited experimental input. This in turn will lead to reliable light-weight, and therefore more energy efficient, engineering structures. The research includes a significant educational component, including involving undergraduate students ? in particular from underrepresented groups ? in the research. The results will also be disseminated to K-12 students and science teachers through the University of Delaware, College of Engineering Outreach Programs.
