Experimental investigation of the fatigue of closed-cell aluminum alloy foam

Tension-tension fatigue tests are carried out to investigate the fatigue of closed-cell aluminum alloy foam. The stress-life (S-N) curve of the foam is obtained, in which large scatter is observed and discussed in detail. To understand the scatter of fatigue life of the foam, fracture surface is examined. The fatigue life decreases as the number and the size of large cells increase. The irregularity of inner cell structure of the foam attributes to the scatter of fatigue life. Then, a statistical stress-life model is developed, and a series of statistical probability-stress-life (P-S-N) curves are obtained. The P-S-N curve is efficient in describing the fatigue of foam materials.