An investigation of stress concentration, crack nucleation, and fatigue life of thin low porosity metallic auxetic structures

Francesconi, L.

First

;Taylor, M.;Baldi, A.

2019-01-01

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Abstract

This paper investigates, both experimentally and numerically, the mechanical response of low porosity thin metal samples under fatigue loads. The specimens, characterized by an overall porosity of 10%, were designed using selected patterns of voids and then fatigue tested to estimate the influence of both auxetic and non-auxetic tessellations on the mechanical performance. During the loading, detailed deformation maps were recorded by means of bi-dimensional Digital Image Correlation (DIC). The experimental data collected during this study indicate that the use of auxetic patterns could be a strategy to enhance the fatigue life of porous structures. In addition, DIC analysis is shown to be an excellent non-contact experimental method to assess the cumulative damage of the samples and to predict the crack starting points well before they are detectable by the unaided eye.