Structural Design Of Tubular Three-dimensional Woven Composite Reinforcement Of Its Model

Tubular composites are widely used in aerospace,civil engineering,and pipeline transportation as aircraft engine sealing shells,fire hoses,and ultra-high temperature pipes.The processing of traditional tubular composites is carried out by winding the fiber or fabric with the matrix,and the interlayer only relies on bonding with the matrix,which is prone to interlayer damage.If a tubular three-dimensional woven fabric is used as the reinforcement structure and compounded with the matrix,the resistance to interlaminar damage can be effectively improved due to the yarn connection between the layers.Therefore,the structural design of tubular three-dimensional woven fabric has good application value for the design and production of tubular three-dimensional composite materials.This topic takes the structural design of tubular 3D woven fabric as the research object,combines the design principles of 3D woven fabric and tubular woven fabric,and proposes the design method of tubular 3D woven fabric organization.Firstly,a common three-dimensional woven fabric(through the orthogonal,through the corner interlock,jointed multi-layer,etc.)is selected as the wall of the tube,that is,the table organization of the tubular three-dimensional woven fabric is determined.Then,according to the "negative flip method",the lining organization of the tubular three-dimensional woven fabric is obtained.Finally,according to the 1:1 embedding of warp and weft yarns of surface and lining tissues,and according to the layered weaving method of "flattening-weaving-restoration",the organization chart of tubular three-dimensional woven fabric is obtained.According to the above interweaving law,the relationship between the number of layers and the number of fully organized warp and weft yarns of different tubular wall tissues and corresponding tubular three-dimensional woven fabrics was established.Secondly,in order to improve the design efficiency of tubular 3D woven fabric organization,the corresponding matrix model is constructed.The rows and columns of the matrix represent the weft and warp yarns,and the elements "1" and "2" are selected to represent the warp tissue points of tubular three-dimensional woven fabric table and lining tissue,and "0" represents the weft tissue points of tubular three-dimensional woven fabric table and lining tissue.The weft tissue points of the surface and lining tissues of the tubular 3D woven fabric are selected.According to the parametric design,the table organization matrix is obtained,and the lining organization matrix is obtained by relying on the find and fliplr functions in Matlab software to realize the "negative flip".The table and lattice organization matrices and the fork product element matrix are subjected to Kronecker product operation to realize the establishment of the tubular 3D woven fabric organization matrix model.In order to better understand the relationship between warp,weft and knotted yarns of tubular 3D woven fabric,we use Texgen and 3ds MAX software to realize the 3D modeling of tubular 3D woven fabric structure and tubular3 D woven fabric structure respectively.Finally,in order to verify the feasibility of the proposed design method of tubular 3D woven fabric and to explore the geometric relationship between the wall thickness,tube diameter and the apparent diameter of fiber bundles,the number of layers of the wall and the total number of warp roots,small prototype weaving experiments were conducted.The tubular 3D woven fabric preforms with different number of layers and different wall structures were woven separately.The tube diameter,thickness,warp and weft density of different tubular 3D woven fabrics were measured.The results show that the matrix model established for tubular 3D woven fabrics and the matrix generation algorithm based on Matlab functions can improve the design efficiency of the organization chart.The test results of small sample weaving show that the thickness of tubular 3D woven fabric depends on the number of layers and the wall structure,and the relationship between the number of layers(N)and the thickness(D)and yarn diameter(d)of tubular 3D woven fabric under the same wall structure is about: D=5d N.Under the condition of the same layer thickness,as the total number of warp roots of tubular 3D woven fabric increases,the inner and outer diameter of tubular 3D woven fabric tube Therefore,the mathematical relationship between the tube diameter and the total number of warp roots is established.