Title page for ETD etd-07212004-215953


Type of Document Master's Thesis
Author Ballew, Wesley D.
Author's Email Address wesballew@alumni.ncsu.edu
URN etd-07212004-215953
Title Taylor Impact Test and Penetration of Reinforced Concrete Targets by Cylindrical Composite Rods
Degree Master of Science
Department Engineering Science and Mechanics
Advisory Committee
Advisor Name Title
Batra, Romesh C. Committee Chair
Hyer, Michael W. Committee Member
Kriz, Ronald D. Committee Member
Keywords
  • Element erosion
  • Oblique impact
  • Damage
  • Composite penetrator
  • Thermomechanical deformations
  • Taylor impact test
Date of Defense 2004-07-19
Availability unrestricted
Abstract
We use the three-dimensional finite element code DYNA3D to analyze two problems: (a) the normal impact of a cylindrical monolithic or composite rod against a smooth flat rigid target, (commonly known as the Taylor impact test), and (b) the penetration of composite and monolithic steel cylindrical rods into reinforced concrete targets. The composite rod is made of either a steel or copper shell enclosing a ceramic. The ceramic and the steel are assumed to fail at a critical value of the effective plastic strain, whereas no failure is considered in the copper. The thermoviscoplastic response of steel and copper is modeled by the Johnson-Cook relation and the ceramic and concrete are assumed to be elastic-plastic. Values of material parameters in the constitutive relation for the reinforced concrete (RC) are derived by the rule of mixtures. Failure of a material is simulated by the element erosion technique for ceramic and steel, and element erosion along with stiffness reduction for the RC. The effect of the angle of obliquity of impact on the damage induced in the target is ascertained.

For the solid cylindrical copper rod impacting a smooth flat rigid target, the time history of the deformed length and the axial variation of the final diameter are found to match well with the experimental findings. For the composite rod, the diameter of the deformed impacted surface, the shape and size of the mushroomed region and the volume fraction of the failed ceramic material strongly depend upon the impact speed, the shell wall thickness and the thickness of the solid copper rod at the front end.

Some composite cylindrical rods impacting at normal incidence RC targets were found to buckle during the penetration process in the sense that their outer diameter at a cross-section close to the impacted end increased by at least 20%. For steel penetrators, the damage experienced increased as the nose shape got blunter and the angle of obliquity became larger whereas the damage induced to the target only increased with penetrator bluntness.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  ComRiRCT_03.avi 1.48 Mb 00:06:50 00:03:31 00:03:04 00:01:32 00:00:07
  ComRiRT1_05.avi 2.81 Mb 00:12:59 00:06:41 00:05:50 00:02:55 00:00:14
  ComRiRT2_05.avi 1.77 Mb 00:08:12 00:04:13 00:03:41 00:01:50 00:00:09
  CopRiRT1.avi 2.96 Mb 00:13:43 00:07:03 00:06:10 00:03:05 00:00:15
  CopRiRT2.avi 4.24 Mb 00:19:38 00:10:05 00:08:50 00:04:25 00:00:22
  Input.pdf 48.73 Kb 00:00:13 00:00:06 00:00:06 00:00:03 < 00:00:01
  Pen.pdf 37.67 Kb 00:00:10 00:00:05 00:00:04 00:00:02 < 00:00:01
  Plot.pdf 14.96 Kb 00:00:04 00:00:02 00:00:01 < 00:00:01 < 00:00:01
  SPiRCT_05.avi 2.72 Mb 00:12:34 00:06:27 00:05:39 00:02:49 00:00:14
  SPiRCT_08.avi 2.85 Mb 00:13:11 00:06:47 00:05:56 00:02:58 00:00:15
  Target.pdf 29.73 Kb 00:00:08 00:00:04 00:00:03 00:00:01 < 00:00:01
  TaylorInput.pdf 39.10 Kb 00:00:10 00:00:05 00:00:04 00:00:02 < 00:00:01
  TaylorPen.pdf 32.77 Kb 00:00:09 00:00:04 00:00:04 00:00:02 < 00:00:01
  Thesis.pdf 2.23 Mb 00:10:20 00:05:19 00:04:39 00:02:19 00:00:11

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