Low Cycle Fatigue in Aluminum Foam with Notch Amanda Coons

Low Cycle Fatigue in Aluminum Foam with Notch
Amanda Coons
Professors Kathleen Issen and David Morrison
MAE Department, Clarkson University
Metal foams are a new material being used in industry. These materials are used in
lightweight structures due to their high strength to weight and stiffness to weight ratios.
However, these materials have not been fully characterized yet. This research examined Alporas,
a closed cell aluminum foam, through tension-compression fatigue with crack initiation. This
research examined how crack propagation looks through digital image correlation as opposed to
how bands of dilation with intact material look. The goal is to be able to identify which
deformation mode is occurring (crack propagation or dilation band) in the material, using the
surface strain and displacement maps from digital image correlation. We tested specimens of
Alporas in a load frame under tension-compression fatigue. Images were taken both of the entire
specimen and of a zoomed-in section where a notch cut into the material encouraged crack
propagation. Images taken during the tests were then analyzed using digital image correlation
software to create surface strain and displacement maps. We were able to see crack propagation
along the surface of the specimen in the zoomed-in images. We were also able to examine the
process zone in front of the crack tip through the strain and displacement maps. This research
shows that digital image correlation is a valid method for examining failure modes of the metal
foam more in detail.
Class of 2012, Mechanical Engineering, Honors Program
Advisor: Professors Kathleen Issen and David Morrison, Dept. of Mechanical & Aeronautical