Effect of the root crack on natural frequencies of sandwich composite beams

Abstract

This study aims to examine the effect of interface crack on the free vibration response of a sandwich composite beam experimentally and numerically. Natural frequencies in a thin sandwich composite cantilever beam with root crack are determined. The crack with various lengths is opened between the face sheet and foam core, such as 50, 100, 150 and 200 mm. Free vibration tests of these samples are carried out. For the numerical analysis, ANSYS finite element software is used. Results obtained by numerical analyses and experiments are compared and it is seen that there is a good agreement between them.

Keywords

• Sandwich composites, Root crack, Natural frequency, Finite element method.

Kaynakça

1. Shipsha A and Zenkert D, “Compression-after-impact strength of sandwich panels with core crushing damage”, Applied Composite Materials, 12, 149–164, 2005.
2. Wei Z, Yam LH and Cheng L., “Detection of internal delamination in multi-layer composites using wavelet packets combined with modal parameter analysis”, Composite Structures, 64, 377–387, 2004.
3. Vinson JR. Sandwich structures. Appl Mech Rev, 54, 201–214, 2001.
4. Zenkert D, An introduction to sandwich construction. Engineering Materials Advisory Services. Published by Chameleon Press Ltd, 1995, London.
5. Karaağaç C, Özturk H and Sabuncu M, “Free vibration and lateral buckling of a cantilever slender beam with an edge crack: experimental and numerical studies”, Journal of Sound and Vibration, 326, 235–250, 2009.
6. Birman V., Simitses GJ, "Vibrations of sandwich panels and beams with matrix cracks in the facings", Composites Science and Technology, 61,1605–1613, 2001.
7. Ayorinde E., Gibson R., Kulkarni S., D. Feizhong, Mahfuz H., Islam S., Jeelani S.,"Reliable Low-cost NDE of composite marine sandwich structures", Composites Part B: Engineering, 39, 226–241, 2008.
8. Birman V and Byrd LW., “Matrix cracking in transverse layers of cross-ply beams subjected to bending and its effect on vibration frequencies”, Composites Part B: Engineering, 32, 47–55, 2001. Shu D and Della CN, “Vibrations of multiple delaminated beams”, Composite Structures, 64, 467–477, 2004.