Paper number 869

LOW ENERGY IMPACT BEHAVIORS OF NONSTITCHED AND STITCHED FOAM CORED SANDWICH STRUCTURES

Sung-Ho Yoon1, Ki-Jong Jang1, Sae-Hyun Cho2, Byung-Jun Park2, and Jung-Mi Cho2

1School of Mechanical Engineering, Kumoh National University of Technology
188 Shinpyung-Dong, Kumi, Kyungbuk, 730-701, Korea
2Advanced Composite Materials Institute, Hankuk Fiber Glass Company
181-1 Youngji-Ri, Bubuk-Myun, Milyang, Kyungnam, 627-850, Korea

Summary The objective of this study is to investigate the impact behaviors and the failure mechanisms of nonstitched and stitched sandwich structures. These sandwich structures are made of glass fabric faces with a urethane foam core. The polyester fibers as the through-the-thickness reinforcements are used to combine the upper face and the lower face through the core in stitched sandwich structures. Several impact conditions are considered, such as the drop height of the impact tup, the impactor shape, and the weight of the impact tup. Low energy impact tests are conducted on these sandwich structures using the drop weight impact tester. Various sandwich specimens, each having a different core thickness, are tested to determine the effect of the core thickness on the impact behaviors. The results show that stitched sandwich structures can sustain higher impact force than nonstitched sandwich structures and have the ability for averting delamination. Also, it is important to improve the wetting ability of the through-the-thickness reinforcements in order to utilize stitched sandwich structures effectively.
Keywords nonstitched and stitched sandwich structures, glass fabric faces, polymeric foam core, drop weight impact tester, low velocity impact behaviors, through-the-thickness reinforcements.

Theme : Mechanical and Physical Properties ; Dynamic, Impact and crashworthiness

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