Ballistic Impact Response of Foam-Filled Sandwich Composites

Author(s):  
Uday K. Vaidya ◽  
Biju Mathew ◽  
Chad A. Ulven ◽  
Brent Sinn ◽  
Marian Velazquez

Abstract Sandwich composites find increasing use as flexural load bearing lightweight sub-elements rail / ground transportation and marine bodies. In recent year, alternatives to traditional foam and honeycomb cores are being sought. One such development includes filling the cells of the honeycomb core with foam. The increased surface area allows stress forces to dissipate over a larger area than that offered by the honeycomb alone. This allows for use of lowering the cost of the honeycomb cells, and thereby making the design extremely cost-effective. In the present research, phenolic impregnated honeycomb / corrugated cells with polyurethane foam filling has been considered. The intermediate and high velocity impact response of these types of sandwich constructions has been studied. The applications for such cores would be in rail and ground transportation, where impacts in the form of flying debris are common.

2000 ◽  
Vol 122 (4) ◽  
pp. 434-442 ◽  
Author(s):  
U. K. Vaidya ◽  
A. N. Palazotto ◽  
L. N. B. Gummadi

In the current work, sandwich composite structures with innovative constructions referred to as Z-pins, or truss core pins, are investigated. The Z-pin core sandwich construction offers enhanced transverse stiffness, high damage resistance, and multi-functional benefits. The present study deals with analysis of low-velocity impact (LVI) of Z-pin sandwich plate, and experimental studies of compression-after-impact characterization. Experimental studies on LVI of Z-pin sandwich plate considered in the analysis have been reported in Vaidya, et al., 1999, “Low Velocity Impact Response of Laminated Sandwich Composites with Hollow and Foam-Filled Z-Pin Reinforced Core,” Journal of Composites Technology and Research, JCTRER, 21, No. 2, Apr., pp. 84–97, where the samples were subjected to 11, 20, 28, 33, and 40 J of impact energy. The LVI analysis is developed with regards to Z-pin buckling as a primary failure mode (and based on experimental observations). A finite element model accounting for buckling of the pins has been developed and analyzed using ABAQUS. This paper also presents experimental results on compression-after-impact (CAI) studies which were performed on the sandwich composites with Z-pin reinforced core “with” and “without” foam. The experimental LVI tests were performed in Vaidya, et al., 1999, “Low Velocity Impact Response of Laminated Sandwich Composites with Hollow and Foam-Filled Z-Pin Reinforced Core,” Journal of Composites Technology and Research, JCTRER, 21, No. 2, Apr., pp. 84–97. The results indicate that selective use of Z-pin core is a viable idea in utilizing space within the core for sandwich composites in structural applications. [S0094-4289(00)02904-2]


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