Abstract The present study is based on experimental investigation and numerical simulation of impact of different nose shape projectiles on thin polycarbonate plates. Rigid hardened projectiles of two different geometries (Blunt and Truncated cone) keeping the same shank diameter and total mass were prepared. These projectiles were impacted through pneumatic gun setup on circular polycarbonate plates at varying impact velocities upto 106 m/s. Impact and residual velocities were measured before and after perforation, respectively. Numerical simulations were performed in ABAQUS/EXPLICIT finite element code. The problem has been modelled based on Mie-Gruneisen equation of state. The experimental results obtained in terms of ballistic limit, residual velocity, energy absorbed and deformation mechanism have been compared with the numerical results and are found to be in excellent agreement. It is observed that the ballistic limit for normal impact is greater for blunt projectile compared to truncated conical projectile. Velocity drop and the energy absorbed is higher for blunt projectile compared to truncated conical projectiles for the impact velocities under study.

Active Vibration Control (AVC) using smart structure is used to reduce the vibration of a system by automatic modification of the system structural response. AVC is widely used, because of its wide and broad frequency response range, low additional mass, high adaptability and good efficiency. A lot of research has been done on Finite Element (FE) models for AVC based on Euler Bernoulli Beam Theory (EBT). In the present work Timoshenko Beam Theory (TBT) is used to model a smart cantilever beam with surface mounted sensors / actuators. A Periodic Output Feedback (POF) Controller has been designed and applied to control the first three modes of vibration of a flexible smart cantilever beam. The difficulties encountered in the usage of surface mounted piezoelectric patches in practical situations can be overcome by the use of embedded shear sensors / actuators. A mathematical model of a smart cantilever beam with embedded shear sensors and actuators is developed. A POF Controller has been designed and applied to control of vibration of a flexible smart cantilever beam and effect of actuator location on the performance of the controller is investigated. The mathematical modeling and control of a Multiple Input multiple Output (MIMO) systems with two sensors and two actuators have also been considered.