ASSESSMENT OF THE WINDING PATTERN EFFECTS ON THE BEHAVIOUR OF FILAMENT WOUND PIPES BY USING FULL FIELD MEASUREMENTS AND THE EQUILIBRIUM GAP METHOD L. Crouzeix 1 , M. Torres 1,2 , B. Douchin 1 , J.N. Périé 1 ,F. Collombet 1 , H. Hernández 2 1 : ICA (Institut clément Ader) Université de Toulouse ; INSA, UPS - 133C avenue de Rangueil, F-31077 Toulouse CEDEX Laurent.crouzeix@iut-tlse3.fr 2 : Instituto Politécnico Nacional GAID - ESIQIE, UPALM, C.P. 07300, México SUMMARY A filament-winding pipe is tested to identify the local behaviour of the structure, observed by using CCD cameras. An orthotropic variant of the Equilibrium Gap Method is then proposed and applied. The displacement field is used in order to obtain heterogeneities map for establishing a relation between local mechanical properties and the wound pattern. Keywords: Filament winding, structural tests, full field measurement, Equilibrium Gap Method. I. INTRODUCTION Composite structures are heterogeneous structures by constitution. This often leads to variations of mechanical behaviour at different scales wich may lead to complex behaviours and modelling. In some cases, e.g., because of a coarse fibrous architecture, the classical homogenisation techniques may not be applicable to get a relevant macroscopic behaviour. On another way, the material can also present singularities due to the process (holes, corner fitting, ply drop off …) that lead to structural heterogeneities. Additionally, the material may not be studied out of the structure, because of its particular process or geometry. . In the following, we focus on a structure including most of these complexities. The later consists in a filament-wound glass/epoxy composite pipe. This kind of structure is planned to be use by the French Research Institute for Exploitation of the Sea (IFREMER) for deep water research. Filament winding is one of the older processes to obtain composite structures. A horizontal CNC machine with three degrees of freedom, which are: axial displacement, mandrel rotation, and radial displacement, is used for this purpose (see Figure 1a). It has a carriage with longitudinal displacements, provided with a roving feed system. Roving is wound on the mandrel which is attached to the machine spindle. Combined axial and rotation displacements produce double helicoidal paths. This kinematics forms a rhomboid shape, which is a classical filament winding pattern (see Figure 1b). A detailed explanation of winding patterns can be found in references [1-2].