Perforation of 12mm thick steel plates by 20mm diameter projectiles with flat, hemispherical and conical noses: Part I: Experimental study
ABSTRACT Projectiles with three different nose shapes (blunt, hemispherical and conical) have been used in gas gun experiments to penetrate 12 mm thick Weldox 460 E steel plates. Based on the experimental results, the residual velocity curves of the target material were constructed and compared. It was found that the nose shape of the projectile significantly affected both the energy absorption mechanism and the failure mode of the target during penetration. The ballistic limit velocities were about equal and close to 300 m/s for hemispherical and conical projectiles, while it was considerably lower for blunt projectiles. Blunt projectiles caused failure by plugging, which is dominated by shear banding, while hemispherical and conical projectiles penetrated the target mainly by pushing the material in front of the projectile aside. Also, the residual velocity curves were influenced by nose shape, partly due to the differences in projectile deformation at impact. The experimental study, given in this part of the paper forms the basis for explicit finite element analysis using the commercial code LS-DYNA presented in Part II of the paper.
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ABSTRACT: Experiments and numerical simulations were performed to study the failure modes and ballistic resis-tance of aluminum targets subjected to normal impact of double-nosed projectiles. Three such projectiles used in this study were designated according to their front and second nose shapes as conicoeblunt, blunteblunt and blunt conico. Each projectile was hit normally on 0.82 and 1.82 mm thick circular plate targets of 1100-H14 aluminium at different velocities. The deformation, failure mode and ballistic limit of both targets were obtained through experiments and reproduced through simulations using ABAQUS/Explicit finite element code. The ballistic limit of target was found to be highest against blunt eblunt followed by conicoeblunt and blunteconico projectile respectively. The results of target response thus obtained due to the impact of the double-nosed projectiles were compared with those of the single-nosed blunt and conical projectiles, and typical features of the plate response have been discussed for both double and single-nosed projectiles.International Journal of Impact Engineering 12/2012; 54(april):232-245. · 1.68 Impact Factor
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ABSTRACT: With the changing climate, more and more natural disasters such as cyclone, hurricane and typhoon take place around the world, which cause tremendous loss and damage. Damages of building structures by windborne debris impacts have been reported in almost all the previous major wind events. The windborne debris usually imposes localized impact loading and creates an opening on the building envelope, which might trigger serious damages to the building structures such as roof lift-up and collapse because strong wind pressures propagating into the structure. To withstand the impact of such extreme event, climate adaptation engineering solutions and technique need to be provided or improved for the building protection. The capacity requirement of panels to resist windborne debris impact is given in the Australian Wind Loading Code (AS/NZS 1170.2:2011) . Corrugated metal panel, widely used as building envelope such as roof and wall cladding, might subject to the windborne debris impact. This study evaluates the capacity of corrugated panels to resist wind borne debris impact. Laboratory tests were carried out on corrugated metal panels of dimension 0.76 m by 1.2 m subjected to 4 kg wooden projectile impacts. The effect of various impact locations, impact velocities and boundary conditions on their performance has been studied. The failure and deformation modes under various impact scenarios were observed and compared. The dynamic responses were examined based on the deformations and the strains on the panel back face. The perforation resistance capacity of panels subjected to windborne debris impact were assessed and analyzed. In addition, a numerical model was developed in LS-DYNA to simulate the response and failure of the corrugated panel under windborne debris impact. The accuracy of the numerical model was calibrated with the test data. The validated numerical model was then used to obtain the results such as impact force, boundary reaction force and energy absorption. The vulnerability curve of the corrugated panel against windborne debris impact was also derived.Engineering Failure Analysis 09/2014; 44:229–249. · 1.13 Impact Factor
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ABSTRACT: Present study deals with the numerical investigation of aluminum target plates impacted by ogive nose rigid projectile on aluminum target plates of 0.5 and 1 mm thickness at different velocities. Effect of ogive nose projectile is studied with respect to impact velocity on plate thickness and attempt is made to simulate the deformation behavior of aluminum plates. The numerical simulations of this problem have been performed using a finite element code, ABAQUS-Explicit with an adaptive mesh for the plate. To define the thermo-viscoplastic behavior of the material constituting the plate, the Johnson–Cook model has been used. This homogeneous behavior has been coupled with the Johnson–Cook fracture criterion to predict completely the perforation process. The numerical results predict correctly the behavior of projectile-plate in agreement with experimental data published by Ansari, R.U. Various parameters like choice of element and aspect ratio, which plays an important role in numerical simulation, has been studied.NATIONAL CONFERENCE ON ADVANCES IN MECHANICAL ENGINEERING, University Polytechnic, AMU, ALIGARH, INDIA; 11/2010