| At present,body armor and its materials should meet the requirements of“high hardness,high strength,high toughness,low density,and low cost”as much as possible.However,no homogeneous single-phase material can meet the above requirements at the same time.The honeycomb sandwich composite bulletproof system has significant advantages in bulletproof energy consumption and penetration resistance,and has been widely used in military and civilian fields.This research aims to reduce the indirect harm to human body and protect human life safety.It will be comprehensively compared and analyzed to provide a research basis and theoretical basis for seeking a new type of bulletproof suit that simultaneously meets the requirements of light weight,high strength,good penetration resistance,good energy absorption effect,and high flexibility.The subject aims at bulletproof structure design,using 3D printing rapid prototyping technology,composite material selection,structural innovation design,and numerical simulation of the projectile penetration process using ANSYS/LS-DYNA software to explore the angle and size of different structures.The impact of bullet penetration resistance,and through the quasi-static and different strain rate(800s-1,1100 s-1,1400 s-1)dynamic compression experiments,explore the mechanical properties and energy absorption characteristics of different angles to verify Simulation results.The main research contents and results are as follows:1.Based on the ceramic-metal sandwich composite material,this project uses the fragments of boron carbide ceramics to frustrate and destroy the projectile,and then uses the titanium alloy honeycomb structure with a negative Poisson's ratio effect to fully absorb the residual energy of the projectile and ceramic fragments.The bullet penetration process achieves the impact and collapse ability of the honeycomb sandwich composite energy-absorbing bullet.2.Drawing on the traditional honeycomb structure in nature,Solidworks software is used to design a concave honeycomb structure with negative Poisson's ratio effect,and the macro size and unit structure size of different honeycomb structures are determined.Under the condition that the overall size of the protective substrate is kept constant,the concave honeycomb structure is optimized by changing the angle and size of the cell structure in the protective substrate to obtain the optimized parameters of the concave honeycomb structure.3.By establishing a finite element model in Hypermesh,using ANSYS/LS-DYNA to numerically analyze and calculate the projectile penetration process.Import the calculated data into the post-processing software LS-PrePost for processing.By comparing the damage of the projectile,the deformation of the target plate,the residual kinetic energy of the projectile and the energy absorption,the difference in the ballistic performance of the composite sandwich ballistic system with different angles and different sizes of the concave honeycomb was studied.Through simulation,the optimized parameters are 36°,unit height is 3.9 mm,width is2.58 mm,and aspect ratio is 1.51.4.Through the quasi-static compression mechanics test,explore the mechanical response characteristics and energy absorption characteristics of the concave honeycomb structure with different angles to obtain the quasi-static compression stress-strain curve.Through the analysis of experimental data and graphs,the compression modulus of the honeycomb structure with angles of 36°,48°,60°,and72°is:36.59 MPa,30.10 MPa,31.51 MPa,32.02 MPa;yield strength is 56.73 MPa,45.65MPa,52.41MPa,54.44MPa.Comparing the differences in mechanical properties and energy absorption effects of honeycomb structures at different angles,36°is the optimal angle,which is consistent with the simulated structure.5.Through dynamic compression mechanics experiments,explore the mechanical response characteristics and energy absorption characteristics of concave honeycomb structures with different angles to obtain quasi-dynamic compression stress-strain curves.By analyzing the experimental data and graphs,the dynamic yield strength of the concave honeycomb structure with an angle of 36°is higher than that of the concave honeycomb structure with angles of 48°,60°,and 72°,indicating that its resistance under dynamic compressive load The deformation performance is the strongest.At the same time,compared with the other four sets of angled concave honeycomb structures,within the range of strain value of 0-10%,the concave honeycomb structure with an angle of 36°absorbs the most energy and has the best energy absorption effect.The accuracy of the simulation. |
PDF Full Text Request