Fatigue of metal hollow spheres structures
Résumé
A study was conducted to examine and formulate the effect of the microstructure of metal hollow spheres structures (MHSS) on their fatigue properties. Standard compression/compression fatigue tests were conducted to measure the macroscopic properties of microstructures with different structural parameters. The stress concentration inside the complex microstructure was measured to develop a model that shows properties of the materials. X-ray tomographic images were obtained to study their three-dimensional (3D) architecture. The tomography was also used to determine the morphological parameters. The 3D images were processed and analyzed using a granulometry procedure based on sequential opening operations. A hydraulic fatigue machine (MTS) at a frequency of 10 Hz was used to perform all the fatigue tests. Results show that the ratio of the fatigue limit to the yield stress is about 0.5 in each condition, providing a useful design rule for microstructure.