Geometric imperfection sensitivity of curved panels under combined compression and in-plane bending - a study using adaptive meshing and DIC

The existence of geometric imperfections, either resulting from the use of manufacturing tolerances or because of damage in situ is known to have a detrimental effect on the buckling and post-buckling behaviour of thin-walled structures, which depending upon factors such as geometry and loading, can be significant. This paper presents an automated technique, based on the use of topography data obtained from optical measurement, for creating finite meshes representative of the geometry of real structures, which can be analysed to obtain accurate predictions of unstable behaviour. The technique incorporates an algorithm to allow mesh density to be varied across the specimen according to level of curvature thus ensuring the meshes generated are not only accurate but also computationally efficient by reducing the number of degrees of freedom where appropriate. The results of applying this technique to a series of curved panels subject to combined shear and in-plane bending (an example of a component of an aero engine blade) are reported