In this work, the mechanical and failure behavior of injection molded aviation standard optical grade polycarbonate (PC) was investigated through uniaxial tensile testing. The effect of different injection molding process parameters including injection velocity, packing pressure, cooling time, mold temperature, and melt temperature were determined to observe their effect on yield and postyield behavior of PC. Out of these examined parameters, the mold and melt temperature show significant effect on mechanical behavior of studied polymer. The yield and flow stresses in polymer increase with the increase in mold and melt temperature during injection molding. However, other process parameters i.e., packing pressure, injection velocity, and cooling time showed little effect on mechanical performance of the polymer. The molded specimens were annealed at different temperatures and residence time to evaluate its effect on mechanical behavior and fracture morphology. The yield stress increases gradually with the increase in annealing temperature and time. The annealing treatment also changed the failure mode of PC specimens from ductile to brittle. In addition to process parameters, the effect of increased loading rate was also undertaken which shows substantial effect on mechanical and failure behavior of PC.

Explosively Formed Projectiles (EFPs) are used to attack armored vehicles, on the other hands the armored vehicles use Explosive Reactive Armor (ERA) to enhance their protection. Using LS-DYNA software, this paper studies the problem of interaction of EFP with single sandwich ERA. The effect of various ERA configurations like the thickness of metal flyer plates/explosive and the inclination angle of ERA is analyzed against an EFP. The study concludes that the effect of light ERA i.e. with flyers upto 5mm is limited and the residual EFP still has enough energy to penetrate significant thickness of steel target, however when the ERA configuration is changed to heavier steel plates, most of the EFP is consumed during interaction with the ERA and only a small portion reaches the steel target, which does not have sufficient energy to penetrate the target. The simulation results were validated by testing the EFP against ERA.

Soft body impact tests were conducted using an artificial bird of 0.2 kg with a striking velocity of 150 m·s −1 on three different configurations of metallic wing leading edge (LE) structures. The objective of these experiments is to address the preliminary design of LE wing structures to soft body impact loads. The explicit finite element software PAM-CRASH was selected to simulate these experiments using smoothed particle hydrodynamics (SPH) techniques for modelling the bird. The impact tests were also performed for a velocity of 70-180 m·s −1 on instrumented aluminium and steel flat plates to attain the bird material parameters. The artificial bird material parameters for a hydrodynamic material model (Murnaghan equation of state) and elastic-plastic solids with damage and failure were optimised using iSIGHT and PAM-CRASH coupling technique in conjunction with tests on flat plates. The experimental and numerical correlations of the flat plates suggested that at high velocity the hydrodynamic material model gives good results. Bird-strike simulations on wing LE structures were performed using optimised artificial bird parameters. The load transferred to the support structure and post-test deflection-simulated results showed good conformity with the experiment. The SPH method proved to be very effective for modelling a bird strike on flat plates and LE structures. The deformation behaviour of the SPH bird appears to be in excellent agreement with the video stills, with the flow around the structure and break-up into particles.

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