Buckling Analysis Of Warp-knitted Glass Fiber And The Mechanical Properties Analysis Of Composite

Composite material with warp-knitted fiber has the advantages of thin wall,light weight,strong impact resistance,good shape stability,flexible design and so on.It has been widely used in the fields of aeronautics,wind power generation,transportation instruments.The physical and mechanical properties of fiber fabric in addition to the characteristics of fiber,it is also closely related to fiber knitting technology.To a great extent,knitting technology determines the physical and mechanical properties of composites and products.In this paper,warp-knitted glass fiber is selected as the research object.The manufacturing process,tensile properties and buckling behavior of glass fiber fabric are mainly studied.The tensile properties of glass fiber reinforced resin matrix composites were tested and analyzed.Its impact resistance is simulated by finite element method using ANSYS Workbench software.The main contents and results are as follows:(1)Based on the multiscale theory,theoretical derivation on elastic constants of the warpknitted glass fiber,and the expression of the elastic constants was obtained.(2)The tensile tests of two kinds of glass fiber bundles and warp-knitted glass fiber were carried out.The constitutive relationship of fiber bundles and the elastic constants of the fabric were measured.Finally,the experimental results are compared with the theoretical results.The results of the two are in good agreement.(3)Warp-knitted glass fiber and glass fiber square fabric are respectively made into composite materials according to the fabrication technology of composite materials.And the tensile properties of the two composites were tested and compared.The results show that the tensile properties of warp-knitted glass fiber reinforced composites are about 10% higher than those of square reinforced composites.(4)The buckling analysis of warp-knitted glass fiber is carried out by finite element analysis,the causes of frills in glass fiber production are analyzed,and the results are used for technical guidance of fabric production.The deformation of the fiber fabric is that the fiber fabric has a pulling force on the fiber bundle in the needle bed during the production process,and the tension exceeds the critical buckling load in each direction,which makes the fabric flexed.(5)The impact resistance of warp-knitted glass fiber reinforced resin matrix composite plate was simulated by finite element method using ANSYS Workbench software.The change of displacement with time and the variation of stress with time when composite plate under different impact velocity are studied,and the damage area is analyzed.The impact resistance of laminates with different layers number and layers order is also compared,providing a safety basis for the application of composite materials.