Analysis Of Riveting Damage,Deformation And Mechanical Properties Of Carbon Fiber Composites

Carbon fiber reinforced polymer(CFRP)are widely used in aerospace,automobile manufacturing and wind power generation due to their light weight and high strength.According to statistics,the consumption of composite materials in the first passenger aircraft C919 independently developed by my country accounts for 12%,while the consumption of composite materials in the CR929 passenger aircraft jointly developed by China and Russia is expected to reach 50%.The amount of advanced composite materials represented by CFRP has become one of the indicators to measure the level of high-end equipment manufacturing.However,there is still a lack of relevant technical and theoretical guidance in the connection and assembly of composite materials.As one of the commonly used assembly methods for composite materials,rivet connection is widely used in the connection of aircraft skins and automobile bodies.However,during the riveting process of composite materials,damage and local small deformations are usually generated near the rivet hole,resulting in local failure and warping deformation of the entire connection,resulting in assembly gaps,which affects the assembly accuracy and the service life of the equipment..Therefore,studying the influence of damage and deformation in the process of composite material riveting,and predicting damage and deformation,and then proposing suppression strategies,is of great significance for improving the high-quality riveting assembly of composite material components.(1)Incorporate the improved composite material damage judgment criteria into the UMAT subroutine and connect it to the tensile model of the CFRP laminate with openings.Compare the finite element analysis results with the tensile test results to verify the The validity of the damage model.(2)Carry out the single nail riveting experiment of CFRP laminates to analyze the force of the laminates at each stage of the riveting process.The relationship between the pressure riveting force and the amount of riveting interference is established,the damage and deformation of the laminates with different interference amounts are observed and analyzed,and the single-nail riveting finite element simulation is carried out for verification.(3)A strategy to suppress the deformation and damage generated during the riveting process of composite materials is proposed.The method of embedding stepped metal embedded parts inside the laminate is used to suppress,and the finite element software is used to obtain the embedded laminates.Stress,deformation and damage,and compare the suppression effect.(4)Analyze the tensile properties of riveted components under different interference levels,compare their load-displacement curves and the damage of the laminate,and consider the verticality error generated during the processing of the laminate,and use finite element software to analyze the riveting The effect of hole perpendicularity error on tensile properties.