Table of Contents
ISRN Mechanical Engineering
Volume 2012 (2012), Article ID 826952, 7 pages
http://dx.doi.org/10.5402/2012/826952
Research Article

Dynamic Analysis of Honeycomb Sandwich Beam with Multiple Debonds

1Department of Civil Engineering, TKM College of Engineering, Kerala, Kollam 691005, India
2Honeycomb Production and Development Division, Vikram Sarabhai Space Centre, Kerala, Thiruvananthapuram 695 022, India

Received 24 August 2011; Accepted 10 October 2011

Academic Editors: K. Ismail, N. Moes, and D. Zhou

Copyright © 2012 B. Saraswathy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Analytical formulation for the evaluation of frequency of CFRP sandwich beam with debond, following the split beam theory, generally underestimates the stiffness, as the contact between the honeycomb core and the skin during vibration is not considered in the region of debond. The validation of the present analytical solution for multiple-debond size is established through 3D finite element analysis, wherein geometry of honeycomb core is modeled as it is, with contact element introduced in the debond region. Nonlinear transient analysis is followed by fast Fourier transform analysis to obtain the frequency response functions. Frequencies are obtained for two types of model having single debond and double debond, at different spacing between them, with debond size up to 40% of beam length. The analytical solution is validated for a debond length of 15% of the beam length, and with the presence of two debonds of same size, the reduction in frequency with respect to that of an intact beam is the same as that of a single-debond case, when the debonds are well separated by three times the size of debond. It is also observed that a single long debond can result in significant reduction in the frequencies of the beam than multiple debond of comparable length.