Comparison of Tensile and Compressive Creep-Fatigue Damage Behavior of Cellular Composites

Abstract

The damage behavior of cellular composites under creep and cyclic tensile loading conditions is investigated. Tensile cyclic tests at 1 Hz and 20 Hz test frequency and creep tests are performed and compared to previous investigations under compressive loading. In contrast to the compressive loading, no frequency effect is identified in tensile loading and the fatigue curves have steeper slopes. The damage behavior is analyzed by means of scanning electron microscope (SEM) and high resolution 3D X-ray tomography. It is found that microcracks are forming in the glass foam granules first; the final failure is caused by a macrocrack passing through the glass foam granules and the matrix. The damage evolution is measured in terms of stiffness loss of the specimen and is found to have different behavior than in compression.