Fatigue Life of Auxetic Re-entrant Honeycomb Structure

Auxetic materials have unique properties which still require further evaluation. One of the least researched topics in terms of auxetics is their fatigue strength. In this article, high-cycle fatigue life of auxetic re-entrant structure unit cell was calculated using Finite Element Analysis. A fully reversed cycle consisting of alternating compressive and tensile loads was applied. Also, stress-life data had to be defined as approximated Wohler’s curve. Result in form of cycles to failure contour plot was compared with corresponding contour plot obtained for regular hexagonal honeycomb lattice unit cell. It was observed that re-entrant cell has significantly higher fatigue strength than non-auxetic honeycomb cell. The test was also carried out for the models of the structure made of array of unit cells. Their results confirmed the previous observations which bring the conclusion that auxetic materials exhibit superior fatigue life properties compared with regular microstructures.