Study On The Blast And Impact Resistance Of S-shaped Composite Foldcore Sandwich Structure

The sandwich structure has lightweight,high specific strength,high specific stiffness,excellent blast and impact resistance,so it is widely used in the design of civil and military protective structures.As the performance requirements of modern warfare on protective structures are increasing,the traditional sandwich structure can no longer meet the engineering design requirements,and there is an urgent need to develop a new sandwich structure with excellent energy absorption capability.S-shaped sandwich structure,as a novel sandwich structure,is very promising to replace honeycomb sandwich structure in the design of protective structures.Blast and ballistic impact are the forms of impact loads that protective structures often face.Therefore,it is important to conduct blast and ballistic impact studies on S-shaped foldcore sandwich structure to lay the foundation for further engineering applications of sandwich structures.The main research work is as follows.(1)The S-shaped foldcore was designed based on the V-shaped foldcore,and the S-shaped hot press molding mold was designed and prepared.The S-shaped composite foldcore sandwich structure was prepared with glass fibre prepreg.(2)The blast resistance of S-shaped foldcore sandwich structures was investigated with aluminium foam projectile loading means,and the dynamic deformation process of the rear face sheet of the target was recorded by three-dimensional digital image correlation(3D-DIC)method.The effects of impact location,shock wave intensity,face sheet thickness and core thickness on the blast resistance performance of the structure were studied.The results show that the structural configuration parameters have a significant influence on its blast resistance performance,which provides some basic data support for the lightweight design and blast resistance design of the S-shaped foldcore sandwich structure.(3)The response characteristics of the S-shaped foldcore structure under the high-speed impact of flat-headed projectile were investigated using a one-stage air gun,and the influence of impact location and impact velocity on the impact damage pattern of the foldcore structure was obtained.Based on the Hashin and Yeh failure criterion using the FORTRAN language to write the user material subroutine(VUMAT),the finite element model of the projectile impacting the target was established in the ABAQUS/Explicit,and the validity of the simulation results was verified by experiments.The results show that the S-shaped foldcore sandwich structure node position has better impact resistance.The impact position has no effect on the damage pattern of the face sheet,but there is an effect on the damage pattern of the core.