BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//6.6.4.4//EN TZID:Asia/Jerusalem X-WR-TIMEZONE:Asia/Jerusalem BEGIN:VEVENT UID:0-508@aerospace.technion.ac.il DTSTART;TZID=Asia/Jerusalem:20150617T163000 DTEND;TZID=Asia/Jerusalem:20150617T173000 DTSTAMP:20230603T192527Z URL:https://aerospace.technion.ac.il/events/experimental-investigation-of- projectile-resisting-force-in-polycarbonate-targets/ SUMMARY:Experimental Investigation of Projectile Resisting Force in Polycar bonate Targets DESCRIPTION:Lecturer:Alon Weiss\n Faculty:Department of Aerospace Engineeri ng\n Institute:Technion – Israel Institute of Technology\n Location:Clas sroom 165\, ground floor\, Library\, Aerospace Eng.\n Zoom: \n Abstract: \ n Details: \n The earliest recorded studies on terminal ballistics date ba ck to eighteenth century ideas by Euler and Robins who argued that project ile resisting force remains constant during the penetration process. Later work by Poncelet (1829)\, Resal (1895) and Petry (1910) has paved the way to modern penetration science and engineering in deriving velocity depend ent formulae for resisting force.\nThis work presents a comprehensive expe rimental and analytical observation on polycarbonate ballistic response. D eep penetration and plate perforation tests were conducted with several th icknesses of polycarbonate targets at normal impact and within a striking velocity range of 500-900 m/sec. Projectile penetration location\, velocit y and acceleration\, were monitored using high-speed cameras for tracking the depth of penetration path and orientation.\nOne of the primary objecti ves of this work was to examine the possibility of a simple constitutive e quation to predict the depth of penetration for rigid projectiles into pol ycarbonate targets. Experimental results have confirmed the original hypot hesis of Euler that the resisting force during penetration is nearly const ant. This observation is based on a wide range of test data with ogive hea d armor piercing projectiles.\nFollowing the standard approach of steady s tate cavity expansion\, cavitation fields in spherical and cylindrical con figurations are derived and applied to predict the specific cavitation ene rgy for polycarbonate targets. The specific cavitation energy\, identified with the cavitation pressure\, can be used for estimating the penetration depth and the ballistic limit of protective plates in which ductile hole- formation is the dominant mode of failure.\nIt is suggested that not all o f the projectile kinetic energy converts to plastic deformation energy\, p art of the projectile energy is diverted to the cracking process within th e layer adjacent to the projectile. We obtain formulae for the cavitation pressure that apply for assessment of resisting stress during projectile b allistic penetration. We found that the spherical cavitation pressure in p resence of damaged zones is in satisfactory agreement with test data. Mate rial response is modeled as elastic/perfectly-plastic of Mises type with n eglect of elastic compressibility. Sensitivity to failure strain is examin ed and useful closed form formulae are derived. CATEGORIES:Seminars LOCATION:Classroom 165\, ground floor\, Library\, Aerospace Eng. END:VEVENT BEGIN:VTIMEZONE TZID:Asia/Jerusalem X-LIC-LOCATION:Asia/Jerusalem BEGIN:DAYLIGHT DTSTART:20150327T030000 TZOFFSETFROM:+0200 TZOFFSETTO:+0300 TZNAME:IDT END:DAYLIGHT END:VTIMEZONE END:VCALENDAR