Effects of the cell number and anisotropy in the open cell metal foams on the energy absorption efficiency

Abstract

By means of cellular structure, open cell metal foams can be used as a light-weight material, and they can absorb impact energy effectively. In this study, effects of cell number and anisotropy in 30 and 45 ppi (pores per inch) foams on the energy absorption efficiency are investigated by quasi-static compression tests. According to current study, strength of foams decreases with lowering the number of cells for the same foam dimensions. However, energy absorption efficiency increases with decreasing number of cells. The reason for this is the enlarging of cell voids with increasing cell size; therefore, cells deform with less hardening. Effects of loading direction of metal foams on the energy absorption efficiency could not be found. It was observed that the cuboid foam samples exhibited larger strength as compared to the cubic foam samples, and this could be expressed by deformation concentrations.

Keywords

• Metal foams,Compression testing,Efficiency,Hardening

Açık hücreli metal köpüklerde hücre sayısının ve anizotropinin enerji absorbe etme verimliliği üzerine etkisi

Öz

Açık hücreli metal köpükler hücresel yapısı sayesinde hem hafif malzeme olarak kullanılabilir hem de darbe enerjisini etkin bir şekilde sönümleyebilir. Bu çalışmada 30 ve 45 ppi (inç başına gözenek sayısı) metal köpük içerisinde bulunan hücre sayısının ve anizotropinin enerji sönümleme verimi üzerine etkisi kuazi-statik basma deneyleriyle araştırılmıştır. Bu çalışmaya göre aynı boyuttaki köpüklerde hücre sayısının azalmasıyla mukavemet düşmektedir. Fakat enerji sönümleme verimliliği hücre sayısının azalmasıyla yükselmektedir. Bunun sebebi hücre boşlukları hücre büyüklüğünün artmasıyla artar böylece hücreler daha az sertleşmeyle deforme olmaktadır. Metal köpüğün yüklenme doğrultusunun enerji sönümleme verimliliği üzerine etkisi bulunamamıştır. Küboid köpük parçaların küp şeklindeki parçalara nazaran daha yüksek mukavemet gösterdiği bulunmuştur bu da deformasyon konsantrasyonu ile açıklanabilir.

Anahtar Kelimeler

• Metal köpükler,Basma deneyi,Verimlilik,Sertleştirme

Kaynakça

1. Gibson LJ, Ashby M. Cellular Solids: Structure and Properties. 2nd ed. Cambridge, United Kingdom, Cambridge University Press, 1997.
2. Jung A, Wocker M, Chen Z. Seibert H. “Microtensile testing of open-cell metal foams-experimental setup, micromechanical properties”. Materials & Design 88, 1021-1030, 2015.
3. Jung A, Lach E, Diebels S. “New hybrid foam materials for impact protection”. International Journal of Impact Engineering, 64, 30-38, 2014.
4. Mangipudi KR, Epler E, Volkert CA. “Topology-dependent scaling laws for the stiffness and strength of nanoporous gold”. Acta Materialia, 119, 115-122, 2016.
5. Andrews EW, Gioux G, Onck P, Gibson LJ. “Size effects in ductile cellular solids. Part II: experimental results”. International Journal of Mechanical Science, 43(3), 701-713, 2001.
6. Onck PR, Andrews EW, Gibson LJ. “Size effects in ductile cellular solids. Part I: modeling”. International Journal of Mechanical Science, 43(3), 681-699, 2001.
7. Marvi-Mashhadia M, Lopesa CS, Lorca JL. “Effect of anisotropy on the mechanical properties of polyurethane foams: An experimental and numerical study”. Mechanical Materials, 124, 143-154, 2018.
8. Kaya AC, Zaslansky P, Ipekoglu M, Fleck C. “Strain hardening reduces energy absorption efficiency of austenitic stainless steel foams while porosity does not”. Materials & Design, 143, 297-308, 2018.

9. Fischer SF. “Energy absorption efficiency of open-cell pure aluminum foams”. Materials Letters, 184, 208-210, 2016.
10. Kaya AC, Zaslansky P, Nikolaus A, Fleck C. “Tensile failure observations in sintered steel foam struts revealed by sub-micron contrast-enhanced microtomography”. Materials & Design, 105, 190-200, 2016.
11. Kaya AC, Fleck C. “Deformation behavior of open-cell stainless steel foams”. Materials Science and Engineering A, 615, 447-456, 2014.
12. Matz AM, Matz BS, Jost N, Eggeler G. “On the accumulation of irreversible plastic strain during compression loading of open-pores metallic foams”. Materials Science and Engineering A, 728, 40-44, 2018.
13. Jang WY, Kyriakides S, Kraynik AM. “On the compressive strength of open-cell metal foams with Kelvin and random cell structures”. International Journal of Solids Structures, 47 2872-2883, 2010.
14. Jang WY, Kyriakides S. “On the crushing of open-cell foams: Part I. Experiments”. International Journal of Solids Structures, 46, 617-634, 2009.
15. Fleck N. A., Muller GM, Ashby MF, Hutchinson JW. “Strain gradient plasticity: Theory and experiment”. Acta Metallurgica et Materialia, 42, 475-487, 1994.
16. Olurin OB, Fleck NA, Ashby MF. “Deformation and fracture of aluminium foams”. Materials Science and Engineering A, 291, 136-146, 2000.
17. Andrews E, Sanders W, Gibson LJ. “Compressive and tensile behaviour of aluminum foams”. Materials Science and Engineering A, 270, 113-124, 1999.
18. Mondal DP, Jain H, Das S, Jha AK. “Stainless steel foams made through powder metallurgy route using NH4HCO3 as space holder”. Materials & Design, 88, 430-437, 2015.
19. Jain H, Gupta G, Kumar R, Mondal DP. “Microstructure and compressive deformation behavior of ss foam made through evaporation of urea as space holder”. Materials Chemistry and Physics, 223, 737-744, 2019.
20. Frömert J, Lott TG, Matz AM, Jost N. “Investment casting and mechanical properties of open-cell steel foams”. Advanced Engineering Materials, 21, 1900396, 2019.
21. Kaya AC, Zaslansky P, Rack A, Fischer SF, Fleck C. “Foams of gray cast iron as efficient energy absorption structures: a feasibility study”. Advanced Engineering Materials, 21, 1900080, 2019.
22. Brezny R, Green DJ. “The effect of cell size on the mechanical behavior of cellular materials”. Acta Metallurgica et Materialia, 38, 2517-2526, 1990.
23. Seeber BSM, Gonzenbach UT, Gauckler LJ. “Mechanical properties of highly porous alumina foams”. Journal of Materials Research, 28, 2281-2287, 2013.
24. Thornton PH, Magee CL. “Deformation of aluminum foams”. Metallurgical Transactions, 6, 1253-1263, 1975.
25. Mondal DP, Jain H, Das S, Jha AK. “Stainless steel foams made through powder metallurgy route using NH4HCO3 as space holder”. Materials & Design, 88, 430-437, 2015.
26. Bekoz N, Oktay E. “The role of pore wall microstructure and micropores on the mechanical properties of Cu-Ni-Mo based steel foams”. Materials Science and Engineering A, 612, 387-397, 2014.
27. Taherishargh M, Sulong MA, Belove IV, Murch GE, Fiedler T. ”On the particle size effect in expanded perlite aluminum syntactic foam”. Materials and Design, 66, 294-303, 2015.