صفحه فلزی

Steel and aluminum sheet metals، and also composites have vast application in the military and aerospace industries، keeping the safety of those against balls and projectiles، and prediction of damaged zone affected by ball or projectile impact is one of the challenges of engineers and researchers. In this research، first، using the finite element method، damage mechanics، and Hooputra''s ductile damage criterion existed in the ABAQUS software، effect of direct impact of projectile to an aluminum plate applied in the military industries is simulated and the results are numerically achieved. Then، the effect of oblique angle of projectile impact to the plate، on the area and depth of the damaged zone is investigated. In order to validate the results، the projectile shooting test into the aluminum plate under the corresponding angles is practically carried out and the obtained results are compared with the simulation results. Comparison of the numerical and empirical results reveals that the simulations are in good accuracy. Hence، it is concluded that the Hooputra''s ductile damage criterion can well predict the failure and fracture zone in the high strain rate deformations.

In this study، dynamic buckling of a metallic plate with external electrorheological (ER) damper is investigated using the finite element method. The stability region and load carrying capacity of the metallic plate is improved by applying an external ER damper to the plate. The post yield behavior of the ER fluid (nonlinear behavior) is considered for modelling the ER damper. ER fluids are a class of smart fluids that their mechanical behavior is changed considerably in miliseconds by applying the electric field. In another word، applying the electric field increases the viscosity of the smart fluid. This behavior lead to an increase in the damping of the structure. Consequently، the stability of the system increases. Different parameters such as the intensity of the applied electric field and the geometric properties of the external ER damper can affect the stability regions of the structure. The effect of these parameters on the stability of the metallic plate is investigated in the present study.