1 Proceedings of ICTACEM 2010 International Conference on Theoretical, Applied, Computational and Experimental Mechanics December 27-29, 2010, IIT Kharagpur, India ICTACEM-2010/XXXX(144) Oblique Impact of Cylindro-conical Projectile on Thin Aluminium Plates R. Ansari a * , Sanaan H. Khan a and Arshad H. Khan a a Mech. Engg. Department, A.M.U., Aligarh-202002, India ABSTRACT In the present experimental program an attempt has been made to study the response of thin aluminium plates in oblique and normal impact of cylidro-conoical projectile in sub-ordnance velocity range. Hardened steel projectile of 12.8 mm diameter and 30 o half cone angle were impacted on to the plates at different obliquities through a pneumatic gun at varying impact velocities to study the response of the plates. Impact and residual velocities of the projectile were measured before and after perforation and profile of the perforated plate is drwn for further calculation. The mode of failure, ballistic limit and energy absorption charecteristics of the plate have been presented. The experimental results found to be in good agreement with computed results. Keywords: Oblique impact, Conical projectile, Aluminium plate 1. INTRODUCTION The study of the impact of projectiles on structural elements has long been of interest in many engineering application like crashworthiness of vehicles, defense application and several production processes. The perforation of a target plate due to the impact of a projectile may occur through various mode of deformation, like petal formation, ductile hole enlargement, plug formation, and the fragmentation of the target material. Several studies related to normal impact of projectile have appeared in literature [1-7] however the oblique impact has not been studied much. Forrestal and Rosenberg [2] developed an engineering model based partially on the dynamic, elastic-plastic expansion of a cylindrical cavity by a rigid penetrator. The cylindrical cavity approximation idealizes the target as thin, independent normal to the penetration direction. Thus, the analysis is simplified to one dimensional motion in the radial direction. The perforation model of this study was derived from kinetic energy-work balance and used this cavity expansion as one ingredient. The studies on projectile perforation of metal plates usually focus on the measurement and prediction of residual velocity and ballistic limit. Gupta et al. [6] carried out the experiments on thin aluminium plates by ogive nosed projectile at normal impact. They carried out the experiments on the aluminium plates of * Further author information: (Send correspondence to R. Ansari) R.Ansari.: E-mail: ruansari@rediffmail.com, Telephone: +91-9456404433 Sanaan H. Khan.: E-mail: er.sanan@yahoo.com, Telephone: +91-9045043698 Arshad H. Khan: Email: arshad1976@rediffmail.com, Telephone: +91-9412049206