Removing fiber orientation uncertainty from the finite element model of a composite lamina with direct updating algorithm

Abstract

In this paper, a direct updating algorithm is proposed to remove the uncertainties present in the simulated/analytical finite element (FE) model of a composite material lamina. There are number of possible uncertainties present in the composite materials such as its constituent properties and its orientations, boundary conditions and its assumed dimensions etc It is observed from this analytical study that the uncertainty present in the fiber orientation in the matrix put its direct effect on the modal-model (natural frequencies and corresponding mode shapes) of the composite material lamina. The direct updating algorithm has been already used for many isotropic structures. However, for anisotropic structures like composite materials, the application to accurate the simulated-finite element model by using finite element model updating techniques is a new area of research. In this regard, to remove these uncertainties from the simulated-finite element model of a composite lamina, the application of direct updating algorithm is proposed. It is observed from the present study that by updating the mass and the stiffness matrices through direct updating algorithm, the vibration pattern of the mode shapes are updated. It is found that the maximum percentage error in the constituent properties and in the fiber orientation is 22.58% and 100% respectively that are reduced to 0% in the modal-model of the lamina by the application of direct updating algorithm. This represents the novelty of the application of direct updating method for composite lamina structures. The overlay of frequency response function (FRF) curves are plotted to authenticate the results. Also, it is found that the application of the direct updating algorithm increases the tracking performance of the simulated FE model response when excited at different resonant frequencies.