Applied Engineering Letters

89-99

Authors: Miloš Pešić, Nikola Jović, Vladimir Milovanović, Danilo Savić, Aleksa Aničić, Miroslav Živković, Slobodan Savić

The safety of the troop in an armored vehicle is paramount. The most serious threat to armored vehicles is a buried charge explosion or an improvised explosive device. The use of numerical approaches in the validation of armored vehicles minimizes the number of prototypes needed and speeds up the design process. This research focuses on blast simulation utilizing the ConWep (which stands for conventional weapon) method for STRENX armor steel used for blast protection in ALM (which stands for antilandmine) vehicles. The plate is modeled as a deformable solid with the Johnson-Cook plasticity model. In this paper protective plates were examined in order to determine which geometry gives the best protective conditions for the troop in an armored vehicle. Three different geometries were numerically tested, and two of them represent combined geometry. The maximal value of the plastic strain and maximal value of the vertical displacement of the central node on the protective plate was chosen as the parameters to represent the obtained results.

108-117

Authors: Yusra Jasim, Ghazwan Alwan, Tahseen Othman

Hydroforming has gained increasing attention in the manufacturing industry in recent years due to the demand for fast yet reliable production for parts, the applications of which accept a wide range of dimensional tolerances. In this study, tube hydroforming in conical dies has been analyzed. The study consists of two parts: computer simulations and experimental work. The simulation results were utilized to find the load paths which produce successful hydroforming for the selected tube specimens. Twelve load paths were identified and implemented with two friction coefficients and three pressure ranges. During the simulation process, the tubes were given an end movement that ranged from a sealing distance to twice that distance. The experimental work was implemented to verify some of the simulation results. The results showed that the best hydroforming limit was reached when the axial feeding was twice as much as the sealing distance. Also, the maximum amount of deformation rate happens shortly after the specimendie interface starts having relative motion, and it is at its slowest when the hydroforming reaches the fully-formed specimen’s shape.

125-131

Authors: Filip Klejch, Eva Schmidová, Tomáš Mejtský

Interstitial Free (IF) steels are nowadays commonly used for stamping complex parts of outer automotive bodies. Current requirements for fast production lead to the need of monitoring the real state of the material after stamping based on its real material conditions. It is desirable to describe and quantify the evolution of microstructure deformation and plastic conditions before and after the stamping process. This paper presents Electron Backscatter Diffraction analyses of deformed and non-deformed IF steel, including the quantitative measurement of the localized plastic response of the real stamped part, using an unconventional indentation method. The effect of strain rate was evaluated using the highspeed tensile tests. The increased ratio of the Low Angle Grain Boundaries was found as a good parameter to quantify the depletion of plasticity.