| With the continuous development of automotive lightweight technology in recent years,automotive composite materials have received extensive attention from the industry.The excellent comprehensive mechanical properties of fiber-reinforced composite products have been recognized by automobile companies,but their wide application in car bodies is still limited by many factors,such as the high cost of carbon fiber composite materials,low production efficiency of composite materials,and difficulty in recycling and processing.Therefore,the application of fiber composite products in the automotive field still needs to be continuously explored.In the context of the tight supply and demand of global carbon fiber resources,my country takes continuous basalt fiber composite materials as a new direction of exploration.Basalt fiber composite materials have outstanding characteristics in terms of mechanical properties,corrosion resistance,sound insulation,heat preservation,noise reduction,and cost,and can replace glass fiber,carbon fiber and asbestos products to a large extent.Three-dimensional woven composite materials have been widely used in the manufacture of engineering structures that require high delamination resistance.As a typical structural form of three-dimensional woven fabrics,the layer-by-layer angle interlocking structure composite material has high rigidity and strength in the warp,weft and thickness directions.In addition,due to the presence of warp yarns woven in the thickness direction,the delamination resistance and damage tolerance of the corner interlocking structure composite material have been greatly improved.This paper takes the three-dimensional angle interlocking woven composite material as the research object,adopts two methods to enhance the mechanical properties of the composite material by optimizing structural parameters and mixing carbon fibers in the layer.Finally,the black carbon hybrid composite material is applied to the car roof beam for basic research.The specific research content is as follows:(1)Prepare three-dimensional corner interlocking basalt fiber composite and basalt hybrid fiber composite samples,and conduct related mechanical performance tests,including tensile,in-plane shear,interlaminar shear and three-point bending tests,to obtain basic mechanical performance parameters.(2)The method of fiber hybrid and structural parameter optimization is used to enhance the mechanical properties of basalt fiber composites.The way of fiber mixing is to change the weft basalt fiber yarn to carbon fiber yarn.Establish a representative volume element model of basalt fiber composite material,predict its elastic performance parameters and compare the test results to prove the validity of the established representative volume element model,optimize the structural parameters through orthogonal experiments,and finally optimize the combination of structural parameters The yarn width is 0.7mm,the yarn spacing is 0.2mm,the yarn thickness is 0.1mm,and the eccentricity of the oval yarn section is 0.6.(3)A three-dimensional progressive damage constitutive model based on the three-dimensional Hashin criterion and the stiffness index degradation scheme of fracture toughness is established,and the VUMAT subroutine is written in Fortran language,and the subroutine is debugged and verified.Based on the homogenization theory,a finite element simulation model of bending and low-velocity impact was established,and the accuracy of the model was verified by comparison with experiments.Various damage modes of composite materials under bending load and delamination damage under impact load were analyzed.Research has found that mixing carbon fiber in basalt fiber composites can give full play to the excellent ductility of basalt fiber and the advantages of carbon fiber high modulus strength,and increase the maximum peak force under bending and low-speed impact conditions.(4)Combining the two mechanical performance enhancement methods of fiber hybrid and structural parameter optimization in the layer,the three-dimensional corner interlocking black carbon hybrid fiber composite material is applied to the car roof beam.The body-in-white using composite roof beams and steel roof beams is compared under bending,torsion and modal conditions.The research results show that the roof beam made of three-dimensional angle interlocking black carbon hybrid composite material can reach the performance indexes of steel roof beam,such as modal frequency,bending stiffness,and torsional stiffness,and the mass is reduced by 40%.Preliminary exploration of the three-dimensional angle The effect of interlocking woven composite material applied to automobile roof beam. |
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