Research On The Damage Property Of Composite Laminates Under High Velocity Impact

The impact of foreign objects on civil aviation airliners has become a top priority in the safety of civil aviation operations.It has become a research hotspot in preventing accidents and casualties.The aircrafts must be conducted structural tests on the whole and theirs components,including bird strike and the crash test.Therefore,it is of great engineering significance to study the anti-penetration characteristics of the target.The superior qualities of lightweight and high-strength of composite materials make them widely used in the aviation field,especially on the surface of aircraft exterior structures.However,composite laminates are sensitive to lateral impacts and have poor anti-penetration performance owing to poor adhesion in the thickness direction.Due to the so much impact factors and any variable has a great influence on the results,therefore,the impact of nose shapes and impact angles of projectiles on damage characteristics of composite laminates under high velocity impact were investigated.The main work is as follows:One light-air gun system was used to launch projectiles with different nose shapes and ogival-nosed projectiles with different impact angles to penetrate 2 mm thick woven composite laminates based on the experimental method.The high-speed camera recorded the impact process of the projectiles and targets and the projectile velocity data and the ballistic limit velocities were obtained by fitting,and the influence of nose shapes,impact velocities and angles on anti-penetration ability and energy dissipation of the targets plate were obtained.Furthermore,the impacted composite laminates was tested by C-scan system and scanning electron microscope,and the effects of nose shapes,impact angles and velocities on the failure mechanism,damage area and fiber fracture of the targets were got.The basic mechanical performance parameters of the composite laminates were obtained by the tensile test and the normal impact of the ogival-nosed projectiles on the targets was established by ABAQUS/Explicit finite element software.Compared with the experimental data,the material parameters and the geometric model were validated.The models of normal impact with different nose shapes(CRH=0,0.5,1 and 2)and oblique impact(15°,30°,45° and 60°)of ogival-nosed projectiles based on the numerical simulation.The relationship between ballistic limits and nose shapes,impact angles and velocities were obtained,and it provides reference for engineering application.In this dissertation,the anti-penetration characteristics and damage forms of composite laminates under different impact conditions were systematically studied.The influence of nose shapes and impact angles on the results was analyzed,it can provide reference for optimization design of targets and to improve the penetration ability of projectiles,and provide guidance for the structural design of the composite aircraft.