Experimental determination of the macroscopic fatigue properties of metal hollow sphere structures

Fatigue and cyclic creep of replicated microcellular aluminium

“…Most have been conducted with commercially available metallic foams: Fraunhofer TM [1], Alporas TM [2][3][4][5], and Alulight TM [6] closed-cell foams, or Duocel TM [2,7,8] open-cell foam; however, some give data for foams produced in the laboratory [9][10][11][12]. By and large, characteristics of metal foam fatigue are that (i) cyclic creep is often observed (i.e., a steady net permanent deformation of the material in the direction of the mean stress after each cycle, also called "ratchetting") [1][2][3]5,6,9,10,12,13], and (ii) towards the end of the fatigue life an accelerating strain accumulation is observed, ending in rupture of the foam. Samples typically fail by the formation and propagation of cracks along discrete deformation bands under compression-compression fatigue [1,3,6,8], or by the formation of a single dominant crack that broadens with additional fatigue cycles under tension-tension or tension-compression fatigue [2,5,6,[14][15][16].…”

“…The lifetime of fatigued foams has been measured as a function of the applied stress or strain amplitude with Alporas TM [2,3,9,13], Fraunhofer TM [1], Alulight TM [6,14,15,17], Duocel TM [2,7,8] or Foamtech TM [18] foams and Plansee TM bonded metal hollow-sphere structures [12]. The fatigue strength of all of these foam types increases with the relative density, decreases with increasing stress amplitude, and is highly sensitive to both.…”

Fatigue properties of expanded perlite/aluminum syntactic foams

“…However, the research on the mechanical properties of the metallic foams has been focused prominently on uni-axial compressive loading. There are few studies investigating the cyclic loading of metallic foams in compression-compression [2][3][4][5][6][7][8][9], tension-tension [10][11][12][13], or tension-compression [1,[14][15][16] conditions. Some research compared the response of the foams in different loading conditions [17][18][19].…”

“…Some limited studies have been performed on foams with uniform structure i.e. metallic hollow sphere structures with [9] or without a metallic matrix [13]. Establishing a metallic matrix around a space holder material results in a uniform structure.…”

Influence of Interphase Imperfections on the Macroscopic Stiffness of Hollow-Sphere Reinforced Composites

“…The experimental investigation of damage and failure mechanisms in metallic hollow-sphere structures based on scanning electron microscope and X-ray tomography is addressed in [7][8][9].…”