Study Of Hollow Integrated Sandwich Composites' Structure And Property

Hollow integrated sandwich composite is a new kind of 3D-woven sandwich composite which has a good integrated capability. It is and will be more and more widely used in aviation, aerospace, marine, automobile, architecture, chemical industry and other fields. Therefore, it is important to carry out theoretical and experimental investigations for this material.In this thesis studied the structural design,weaving process and the micro-geometry structure of hollow integrated sandwich composites.Then a mechanical model is build to predict its mechanical properties, experiments are performed to verify the predicted results. At last performed on both the new and traditional honeycomb sandwich composites through experiments.This topic first issued the structure and weaving process about the pre-forming textile, using transformed single rapier as well as double sending warp axis to off-warp. We innovative design "reverse-weaving" method to form the core, lead to the pro-forming textile as "8" shape in space and this linking warp connected top and bottom panel to an overall structure.The text followed by micro-geometry structure of hollow fabric, get the smallest unit and every geometric parameters of the fabric, which including two parts of panel and core. As well as fiber's volume content. According to the calculation of the elastic constants related to elastic properties of composites material, we can use finite element analysis to study mechanical properties and establish the finite element analysis model (Ansys model), forecasting bending stiffness, tension performance, pressure strength, side-tensile strength and side-press performance of the "8" shape overall hollow structure composites.Finally we contrast both the overall hollow structure composites and traditional honeycomb sandwich composites through experiments, which including tension, pressure, bending and shear tests. The results show that tension, bending and shear property of the overall hollow structure composites all super to traditional honeycomb sandwich composites, however the pressure strength is similar to honeycomb sandwich composites. So to note the overall hollow structure composites can replace honeycomb composites.