| As a novel type of directionally oriented textile structural material, Multi-layered Biaxial Weft Knitted (abbreviated as MBWK) fabric (Patented by Composite Research Institute, Tianjin Polytechnic University) was firstly applied to the laminate. This new kind of composite is attracting more and more interests and attention due to its outstanding mechanical properties and competitive production cost. It possesses a great application potential in the field of aerospace quality components, automotive frames, marine parts, military industry, construction industry, etc. According to the previous investigations, the research on the geometric configuration and mechanical properties of MBWK fabric reinforced composite is blank, so it goes without doubting that the study in this field is of most importance.In order to quicken and broaden the applications, this paper systematically studied the loop structure, in-plane mechanical and ballistic properties of MBWK reinforced composite. The loop structure was firstly studied in this paper. Generally speaking, MBWK fabric reinforced composite structure is much more different from those of traditional textiles: the reinforced fabric is composed of three yarn systems, warp inserting yarns, weft inserting yarns and stitching loops, of which the stitching loop goes in 3-dimensional space. Although this structure is comparatively complex, it still can be divided into sub-strctures to study. This paper puts forward for the first time the loop geometric model of MBWK fabric reinforced composite. And based on this research, the total structural model for the MBWK fabric reinforced composite was also derived subsequently. In addition, the Non-Uniform Rational B-Spline Curve (NURBS for abbriv.), an engineering standard method in modern scientific research, was applied to simulate in detail the loop structure in order to study the 3-dimensional structure of MBWK fabric reinforced composite, predict mechanical response when stressed or deformed and instruct the forming process. The 3D effect of loop structure can be expressed even more clearly by means of NURBS method. However, the actual calculation is relatively time-consuming. On the other hand, this ideamay be adopted in constructing geometric models for other kinds of composites. Secondly, the Classic Laminate Theory (CLT for abbreviation.) was applied to study the in-plane mechanical properties of composite. Based on the research results about the unit cell structure of MBWK fabric reinforced composite, it is reasonable that the CLT should be taken into consideration in modeling the mechanical relationship. The model of the in-plane stress-strain relationship for MBWK fabric reinforced laminated composite was established for the first time under some assumptions and simplifications. Furthermore, the shear properties of MBWK fabric reinforced composite were also studied in this paper theoretically. According to the experimental results, the theoretical models mentioned above meet the experimerntal data vey well.Finally, as an application example, the MBWK fabric reinforced composite ballistic laminate was studied for the first time. The fiber material used in this study was Ultra High Molecular Weight Polyethylene (UHMWPE), the most popular in the protection field. The experimental phenomena and testing results were analyzed and discussed in detail. It was shown that this product has excellent mechanical properties and good bullet-impact resistance, which lends it a great potential in the field of ballistic materials and industrial application.
|
PDF Full Text Request