Paper number 133

GENERAL THEORY FOR THE MODELLING OF LAMINATED MULTI-LAYER PLATES AND ITS APPLICATION FOR THE ANALYSIS OF SANDWICH PANELS WITH PLY DROPS

Ole Thybo Thomsen

Institute of Mechanical Engineering, Aalborg University
Pontoppidanstraede 101, DK-9220 Aalborg East, Denmark

Summary

Multi-layer sandwich type structures can be identified in many structural assemblies involving composite materials. These multi-layer composite assemblies are characterised by having interchanging layers of high density and high stiffness separated by low density and compliant interface layers. A characteristic feature of such multi-layer assemblies is that severe and highly localised stress concentrations appear under certain conditions. The quantitative understanding of these phenomena involves a detailed description of the complicated mechanical interaction of the stiff layers through the compliant interface layers. The paper presents a high-order plate theory formulation, which inherently includes a description of the global response as well as the local responses of the individual layers of an arbitrary multiple layer structural plate assembly. The features of the high-order multi-layer plate theory are demonstrated through analysis of the elastic response of a CFRP/honeycomb cored sandwich panel with symmetric exterior ply drops.

Keywords

multi-layer plates, sandwich type structures, stiff solid laminates, compliant interface layers, high-order plate theory, discontinuities, terminating plies, ply drops.