Research On Damage Characteristics Of Composite Structures Under Explosion Impact Loads

In the protection field,there are many new materials and protective structures of new structures.The sandwich board has attracted wide attention due to its excellent characteristics such as lightweight and good energy absorption effect.With the continuous ongoing in-depth study of sandwich board structure,negative Poisson’s ratio structure has gradually come into people’s field of vision and attracted wide attention.In this paper,the three-dimensional star and arrow type are studied,and the dynamic response of the two structures under explosion load is analyzed by using ABAQUS explicit dynamic finite element analysis software,and the anti-explosion performance of the two structures is optimized by multi-objective optimization.Finally,the anti-penetration performance of the optimized structures is briefly analyzed.Firstly,the thesis introduces ABAQUS finite element numerical analysis software and introduces the relevant theories of the empirical formulas and algorithms used in the numerical simulation process.Then,the feasibility and accuracy of the Conwep explosion load application method and quarter model analysis method are verified by experiments on Dharmasena.Secondly,the relative surface density formula is used to establish the numerical calculation reference model of the three-dimensional star and arrow sandwich plate structure.Based on verifying the correctness of the simulation method,the influence of panel thickness,backplane thickness,cell size,cell bar thickness on the antiblast performance of two structures is obtained by changing a single variable method.The thickness of cell bar has the greatest influence on the anti-knock and energy absorption properties of the two structures.Then,based on the influence of these parameters on the structure,the core layer structure is set as two layers,and the Box-Behnken Design(BBD)experimental Design method in Design-Expert software is adopted.The thickness of the panel,the thickness of the backplane,the size of the cell,the thickness of the cell member were used to optimize the anti-knock properties of the two structures.The effects of the coupling effects of different structural parameters on the anti-knock properties of the structures were obtained,and two groups of sandwich plate structures with better anti-knock properties were obtained.At the same time,the structure is often faced with penetration loads such as fragments and gravel.Based on verifying the correctness of the simulation method under penetration loads,this paper briefly analyzes the penetration resistance performance of the two optimized structures.It mainly analyzes the penetration resistance performance of the two sandwich plate structures given different initial velocities of the projectile at three incident positions respectively.The results show that the ballistic limits of the two structures depend on the location of the lowest incident resistance.It is also found that the penetration resistance of the negative Poisson’s ratio structure of the arrow type is better than that of the negative Poisson’s ratio structure of the star type.In this thesis,the anti-knock and anti-penetration performance of two kinds of sandwich plate structures is analyzed.The numerical analysis model is established to restore the response process of the structure under the action of explosion impact and penetration load,and the influence law of different structural parameters on the anti-knock and anti-penetration performance of the structure is studied by numerical simulation method,so as to provide experience for future practical application.