Research On Stability Of The Integrally Stiffened 2D Textile Composites Panel

Advanced composite structures range and the proportion of applications in modern vehicle body, has become an important indicator of the progressiveness of new aircraft. Research on the stability of integral stiffened panel of 2D textile composites, not only is the important research content of the mechanical behavior of the new material, but also is one of the key problems to be solved urgently to evaluate the bearing capacity of 2D textile composites and to ensure the safety of the structure. Well, the complexity of the micro structure significantly increased the difficulty of the design and analysis of the integral structure of this kind of material. The existing researches mainly focus on the prediction of the elastic properties of 2D textile composites, and few studies have reported on the stability of stiffened panel structures. Therefore, closely linked to the 2D textile composites integrally stiffened panel macro-meso structure characteristics, the establishment of efficient multi-scale mechanics analysis model, explore the structure stability and the influence law, has important academic value and engineering significance.In this paper, based on the idea of two scale modeling, the stability of 2D textile composite panels and stiffened panels under typical loads are studied systematically. First, on the meso-scale, based on the 2D textile composite weaving process, a geometrical model of meso- scale structure of 2D biaxial and 2D triaxial braided composites was established, and the prediction model of unit cell elastic properties was presented. Model prediction results agree with the experimental results, the validity of the macroscopic mechanical properties of the composites was proved, and the influence of the braided angle and fiber volume content on the elastic properties of the 2D textile composites were analyzed. Secondly, on the macroscopic-scale, by use of analytical method and finite element method, the buckling behavior of 2D biaxial and 2D triaxial braided composite panels are analyzed, the influence of dimension volume fraction and braid angle on the buckling behavior of the panels was discussed. Finally, the paper focuses on two kinds of typical stiffened panel structures. The finite element method is used to study the buckling and post buckling behavior of the. It is verified that the finite element model predictions are in good agreement with the experimental results, which indicates the validity of the proposed model. Then, the influence rules of braided angle, fiber volume content, the height of ribs, etc on the buckling and post buckling of stiffened panels are studied, the nonlinear equilibrium path and deformation of the structure under axial compression are obtained. The results show that the fiber volume content and ratio of width to thickness of plate have a great influence of buckling load influence. Braided angle, fiber volume content, the height of ribs, etc affect stiffened panels buckling load and post buckling load significantly.