Research On Impact Damage Of Composite Material Curved Plates Based On Peridynamics

Composite materials have the characteristics of high specific strength,high specific stiffness,small specific gravity,high temperature resistance and corrosion resistance.They have a wide range of applications in the aerospace industry.However,under the impact load such as the falling of the tool,the composite material may crack and stratify the matrix,causing serious safety hazards.Therefore,research on impact damage of composite materials has been increasing in recent years.Peridynamics(PD)theory is a multi-scale non-local theory.The theory establishes the equation of motion based on the intra-domain space integral,which is different from the motion equation based on the spatial displacement derivative which requires displacement continuity in the classical continuum theory.Therefore,it has great advantages in solving the discontinuity problems such as fracture.According to the orthotropic composite constitutive model based on the bond-based PD theory,this article studys some specific problems of composite plate impact damage.The main work of this article is as follows:(1)Three kinds of typical carbon fiber reinforced epoxy resin composite flat plate specimens were prepared by hot press forming method.Low-speed impact tests of three different velocities and energies of 2 m/s,3 m/s and 4 m/s were carried out by using a drop hammer test device.Ultrasonic C-scan was performed on the specimen after the impact,and the impact damage area of the specimen was obtained.(2)According to the bond-based PD theory,the simulation analysis program of composite impact damage was written in Fortran language.The impact damage analysis of composites under various ply types and impact velocities was carried out.The results show that the multi-directional laminated composite structure has better impact resistance.And the correctness of the prepared analysis program is verified by comparing the simulation results with the experimental results.(3)A composite curved plate model with sinusoidal structure was established,and the impact resistance of different height curved plates was analyzed.The results show that increasing the height of the curved plate can enhance the impact resistance of the plate.When the distance of the bottom edge is about 1/2 times,the impact resistance of the curved plate is optimal.After increasing the height,the impact resistance of the curved plate is reduced.(4)The effects of different impact angles on the damage of composite curved plates are analyzed.Some energy of oblique impact is transformed into intra-layer impact,and the impactenergy perpendicular to the in-plane becomes smaller,which makes the impact damage area smaller.At the same impact speed,the 45-degree fiber direction curved plate has better impact resistance.