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Abstract

The damage mechanisms in sandwich plates with polymer foam cores are investigated. There has been a long-standing controversy on what is the weakest element of sandwich plates, the skin-core bonding or the foam core. Under four-point bending of a sandwich plate, we found that in all cases cracks are nucleated inside the polymer foam core as monitored by a high-speed camera. Several separated small cracks develop in the core; then the small cracks are connected and form the main crack that propagates through the core. We complemented the optical recording by the acoustic emission study which provides an additional insight in the fracture process. In addition, the influence of sub-zero temperature of the ultimate load of each material is examined at discrete values of sub-zero temperature. The results revealed that both materials become increasingly brittle with decreasing temperature.

Keywords

acoustic emission composite sandwich pmi

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References

Gibson

Ashby

. Cellular solids – structure and properties, 2nd edn. Cambridge: Cambridge University Press, 1997.

Ashby

Evans

Fleck

. Metal foams: A design guide, 1st edn. Boston, MA: Butterworth-Heinemann, 2000.

Goodall

Despois

Marmottant

. The effect of preform processing on replicated aluminium foam structure and mechanical properties. Scripta Mater 2006; 54(12): 2069–2073.

Drouillard TF and Hamstad MA. “Comprehensive guide to the literature on acoustic emission from composites. In: Proceedings society of the plastics industry (SPI) 1st international symposium on acoustic emission from reinforced plastics, 1983, New York, pp.1–60.

Hamstad

. A review: acoustic emission, a tool for composite-materials studies. Experiment Mech 1986; 26(1): 7–13.

Noble

. Acoustic emission and fatigue crack growth in rigid polyurethane foam. J Mater Sci 1983; 18(6): 1827–1835.

Kau

Huber

Hiltner

. Damage evolution in flexible polyurethane foams. J Appl Polym Sci 1992; 44(12): 2069–2079.

Charca

Shafiq

Gonzalez

. Fatigue lifetime assessment of foam core sandwich composites. J Adv Mater 2010; 42(2): 56–64.

Vaidya UK, Mahfuz H, Nellutla S, et al. Development and nondestructive characterization/evaluation of foam core composites. In: Proceedings WAM ASME conference on materials for noise and vibration control (noise control and acoustics), 1994, Vol. 18, pp.103–107.

10.

Shafiq

Quispitupa

. Fatigue characteristics of foam core sandwich composites. Int J Fatig 2006; 28(2): 96–102.

11.

Charca

Shafiq

. Damage assessment due to single slamming of foam core sandwich composites. J Sandwich Struct Mater 2010; 12(1): 97–112.

12.

Deschanel

Vanel

Vigier

. Statistical properties of microcracking in polyurethane foams under tensile test, influence of temperature and density. Int J Fract 2006; 140(1–4): 87–98.

13.

Soni

Gibson

Ayorinde

. The influence of subzero temperatures on fatigue behavior of composite sandwich structures. Compos Sci Technol 2009; 69(6): 829–838.

14.

Gibson

. A mechanics of materials/fracture mechanics analysis of core shear failure in foam core composite sandwich beams. J Sandwich Struct Mater 2011; 13(1): 83–95.

15.

ASTM (American Society for Testing and Materials). C 393-00: Standard method of flexure test of flat sandwich constructions. Annual Book of ASTM Standards, Philadelphia, PA: American Society for Testing and Materials, 2000, 15(03), pp.23–4.

16.

Kalarikkal SG. Fracture Toughness of Graphite/Epoxy Laminates at Cryogenic Conditions. Master’s Thesis, University of Florida, Gainesville, Florida, 2004.

Development of damage in some polymeric foam-core sandwich beams under bending loading

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