Acoustic Emission Characterization Analysis of Quasi-Static and Fatigue Compression Properties of Aluminum Foam

Abstract

In order to explore the evolution of physical and mechanical properties and acoustic emission (AE) characteristics of aluminum foam under fatigue and quasi-static compression from a microscopic point of view, the AE monitoring technology was used to analyze the deformation, hardening, and energy absorption characteristics of open-cell aluminum foam under quasi-static compression at different rates (2, 10 and 50 mm/min) and fatigue loading tests with different peak stress ratios k (k = maximum stress/yield stress) by means of MTS fatigue testing machine and CCD camera. The results indicated that under different compression rates, the AE ring down count had the same trend as the engineering stress–strain response of the specimens, the AE ring down count rate at the plastic deformation stage showed the same performance as the work hardening rate, and the AE energy absorption efficiency corresponded well to the experimental results. The specimen entered the densification stage with the stability of AE count and the decrease in energy absorption efficiency. During the fatigue tests of different k values, the change trend of strain was consistent with the response of acoustic emission characteristic parameters, and the fatigue compression damage caused by the deformation process of the specimen can be monitored by the change in AE characteristics. The AE characteristics can dynamically monitor the compression process and provide a new research method and idea for the study of mechanical properties of aluminum foam.