Modal Analysis of Delaminated Flax Fibre Reinforced Epoxy Composite Plate

Abstract

This paper describes the influence of fibre orientation, delamination size and location on the natural frequencies of the single mid-plane delaminated unidirectional flax fibre reinforced epoxy (FFRE) composite plates under different boundary conditions numerically by using ANSYS MAPDL. The delaminated composite plate was modelled as two separate volumes divided at the midplane of the plate, with the nodes on the intact surfaces merged. In contrast, the nodes on the delaminated region remained separate. The results show that the CCCC delaminated composite plate has the highest fundamental natural frequency (219.996 Hz). Furthermore, for increasing fibre orientation from 0° to 45°, the fundamental natural frequencies decreased by 10.12% for the CCCC condition and increased by 6.01% for the SSSS condition. The fundamental natural frequency for the cantilever condition decreased 60.91% when fibre orientation increased to 90°. Moreover, the CCCC condition significantly reduces the fundamental natural frequency (up to 38.95%) with increasing delamination size. For CCCC and SSSS conditions, the centre delamination possesses the highest fundamental natural frequency (219.996 Hz and 116.525 Hz, respectively). The highest fundamental natural frequency for cantilever conditions is 33.081 Hz, with delamination located at the middle of the width and near the free end.