Modal Analysis of Four Layered Composite Cantilever Beam with Lay-Up Sequence and Length-To-Thickness Ratio

Abstract

Abstract Composites are well known for their specific strength and specific modulus and therefore finding lots of engineering applications now a day. In this study, a first order shear deformation theory is used to describe mathematical procedure for the free vibration analysis of layered composite cantilever beam. The finite element (FE) model is prepared by using 281 Shell element having 8 nodes with six degrees of freedom at each node for the modal analysis. The detailed effect of lay-up sequence and length-to-thickness ratio with lay-up angle on natural frequencies of various modes are studied by considering four layered composite cantilever beam. Four different lay-up sequences and five different length-to-thickness ratios are considered to study their effect on bending, transverse and torsional modes of vibration. The results obtained are compared with the previously published literature to validate the efficacy and accuracy of the model. The analysis results show distinct modal characteristics due to change in lay-up sequence and length-to-thickness ratio. This study could be used for proper selection of the lay-up sequence and length-to-thickness ratio to adjust modal parameter like natural frequency of the cantilever beam in order to avoid resonance. The parametric study using analytical model would be highly complex and thus FE model is used for the purpose. Natural frequency of all the modes is observed to be highly sensitive to lay up sequence and the effect of length-to-thickness ratio also needs to be considered. Bending mode natural frequency is higher with antisymmetric lay up sequence whereas transverse mode is with symmetric layup sequence for entire range of layup angles. The torsional mode natural frequency is higher with symmetric layup sequence upto the layup angle 450