Research On Dynamic Buckling And Penetration Behavior Of Composite Cylindrical Shell

Composite materials are widely used in many fields, such as aviation, spaceflight, cars, architecture, chemical industry, shipbuilding etc, because of their superior strength, stiffness, anti-fatigue, anti-knock, designability and good process over most metallic materials. The buckling of composites structure is always one of hot topics of solid mechanics and concerned by more researchers. Because the methods of solving the problems are different, the results are also different. In present paper, several aspects are investigated in the following:1. The present researches on dynamic response and buckling of composite structure are simply generalized, and the main methods and conclusions are summarized.2. Considering the stress wave, Basing on the principle of Love, the dynamic buckling of composite cylinder shell subject to step load, Analysing the characteristic of dominating equation, the dynamic buckling results are obtained. According to the condition nontrivial solution, the buckling critical condition is obtained, i.e. determinant equals zero. Solving the characteristic determinant by numerical method, the relation of critical load and critical length is obtained. The critical load of one end clamped and the other fixed wasand dynamic critical buckling load is obtained. The critical load of one end clamped and the other fixed was in there n1=n, n2=n+2(n=1、2、3……).When n1=1, n2=3, the minimum critical load and one end simply supported and the other fixed was n1=n, n2=n+1(n=1、2、3……),When n1=1, n2=2, the minimum critical load is3. Using ABAQUS6.10, the dynamic buckling of composite cylinder shell subject to rigid body and step load are simulated. The time-history curves of displacement for key points of impact section of composite shell are obtained, and based on B-R criterion, the critical buckling load also can be acquired by the displacement-time curve. Effects of fiber angle and impact velocity on dynamic buckling of composite shell are also investigated. The results indicate that when the shell is impacted by step load, the critical buckling load gradually decreases with increase of ply-angle; in the same condition, dynamic buckling time decrease with increase of the step load.4. Computer simulation of cylindrical shell subject to lateral impact by rigid projectile is carried out using LS-DYNA、ABAQUS6.10. The effects of different kinds of typical rigid projectiles, geometric parameters of metal materials cylindrical and fiber reinforced shell constraint conditions on critical speed are analyzed. The results indicate that the shape of projectile and size of cylindrical shell have a great influence on penetration, and the tapered projectile has a minimum critical speed. The influence of constraint conditions on penetration has a great relationship with thickness of cylindrical shells; energy distribution varies with different thickness of cylindrical shells. Computer simulation of cylindrical shell oblique penetrated by rigid projectile has been also carried out. The critical speed, the deformation and damage modes of cylindrical shell are obtained when the cylindrical shell is subjected to different projectile impact at different incident angles. For flat-nosed projectiles, the critical speed is the minimum when the incident angle is45°. For tapered projectiles, the critical speed is the minimum when the incident angle is15°, and the critical speed increases with the angle of incidence increasing when the angle is greater than15°. The influence of penetration can be obtained by impacting on fiber reinforced composite cylindrical shell from different angles.