New Accreditation To Supervise Research : Francois BOUSSU
Comprhension des paramtres de produit et de procd de fabrication des tissus 3D interlocks chaines. Applications en tant que renfort fibreux de solutions de protection l'impact.
The results and analyses, presented in these five main themes of this report, are all built around a common denominator, namely: 3D warp interlock fabrics.
The first theme focuses on the observation and parameterization of 3D warp interlock fabrics to define more precisely the observed woven structures. A definition of 3D warp interlock fabrics and a classification of different types of architectures are exposed. Different observations, through cross-sectional views of warp and weft yarns, can reveal the complexity of geometries representation of 3D warp interlock fabrics and the influence of process parameters on weaving positioning changes in the structure of multi-layered woven fabrics. A classification of the main cross-section shapes of warp and weft yarns, located inside a 3D warp interlock fabric, is presented in order to optimize the overall performance of multi-layer woven structure. Finally, the influence of the bonding type of 3D warp interlock fabric on the mechanical properties during quasi-static loading is proved both on dry and impregnated reinforcements.
The second theme tends to reveal the residual properties of 3D warp interlock fabrics as multi-fibre reinforcement for complex composite structures. Through a literature review completed with our search results, we highlighted the advantages and disadvantages of the manufacturing process, architecture woven and mechanical properties of 3D warp interlock fabrics. The delamination and the impact resistances appear to be the two main mechanical characteristics of the 3D warp interlock fabrics. Based on these properties, we have shown their ability to be deformed by bending process and dry forming at quasi-static speed.
The third theme focuses on the analysis of the manufacturing process of fabrics, allowing to reveal its complex nature and requiring some adjustments. Visual observation of images, obtained by high speed videos, of the kinematic of the weaving process and the measurement of stresses applied to the material by the use of innovative sensor yarns, helps to better understand the manufacture of fabrics. The kinematics of the weaving process have been reproduced by simulation, to analyse different dynamical movements of the loom parts which act on the actual geometry of the woven fabric. Observation of cross sections of warp and weft yarns and their positioning into the fabric, show high similarity between the simulated and actual fabrics. The optimization of the manufacturing process tends to minimize the yarn degradation during the weaving process. The design of weaving machines suitable for prototyping of 3D warp interlock fabric for all types of yarns (carbon and other types) is based on this experience and understanding of the manufacturing process and helped to optimize the multi-woven structures layers.
The fourth theme aims at identifying flexible impact protection solutions, defining the dynamic deformation modes of textile structures. A multi-scale, macroscopic and mesoscopic numerical model, 2D fabric was used to simulate the influence of different yarns parameters on the ballistic performance of woven structures. Various studies of experimental research of impacts on 3D warp interlock fabrics have revealed the influence on the ballistic performance of certain parameters of the fabric; especially the homogeneity of the warp and weft density values, the number of layers of the 3D warp interlock fabric and the warp and weft yarns yields. Based on this understanding of the behaviour model of the impact of flexible textile structures, three different solutions have been proposed to meet the protection needs of body armour under impact of various munitions at varying speeds.
The fifth subject identifies hard impact protection solutions, including integrating composites alone or coupled with other materials like metal or ceramics. Through a literature review completed with our research observations, we have identified endogenous fabric parameters of 3D warp interlock fabrics which can influence the impact behaviour. Based on these characteristics, we have found various hard protection solutions, integrating composite materials, fibre reinforcement type as 3D warp interlock fabrics with different architecture, yarns and resin impregnations, in response to the impacts of various different munitions speeds.
All of this research aims to better define and understand the product parameters and manufacturing process of 3D warp interlock fabrics.