Abstract
We examined data from two sets of penetration experiments that recorded deceleration during penetration into concrete targets with compressive strengths of 23 and 39 MPa. The 76.2-mm-diameter, 3.0 caliber-radius-head (CRH), 13 kg projectiles were machined from 4340 Rc 45 steel and contained a single-channel, 15 kHz acceleration data recorder. The data recorder was fitted into a circular hole in the solid nose of the projectile, so during penetration the accelerometer mounted in the data recorder measured structural responses as well as rigid-body projectile deceleration. Since the deceleration data were limited to 15 kHz, higher frequency responses were not measured. Furthermore, there are no available internationally accepted calibration procedures for accelerometers. Because of these complications, we present a method to correct the deceleration data so that an integration of the deceleration data agreed with the measured striking velocity. These corrections were small, and a double integration of the corrected deceleration was in good agreement with the measured depth of penetration. In addition, we developed two empirical penetration models that described deceleration versus displacement and specific kinetic energy (kinetic energy divided by projectile mass) versus displacement for the rigid-body response of the projectile. Data and model predictions showed that the deceleration-displacement response could be closely approximated by a linear rise with a depth of two projectile diameters followed by a region with constant deceleration until the projectile came to rest. Specific kinetic energy-displacement data and model predictions showed a nearly constant slope after the entry region, and this slope is the magnitude of the constant deceleration. Predictions from both methods closely agree with each other and the deceleration data.
Similar content being viewed by others
References
Forrestal MJ, Frew DJ, Hanchak SJ, Brar NS (1996) Penetration of grout and concrete targets with ogive –nose steel projectiles. Int J Impact Eng 18:465–476
Frew DJ, Hanchak SJ, Green ML, Forrestal MJ (1998) Penetration of concrete targets with ogive-nose steel rods. Int J Impact Eng 21:489–497
Forrestal MJ, Frew DJ, Hickerson JP, Rohwer TA (2003) Penetration of concrete targets with deceleration-time measurements. Int J Impact Eng 28:479–497
Frew DJ, Forrestal MJ, Cargile JD (2006) The effect of concrete target diameter on projectile deceleration and penetration depth. Int J Impact Eng 32:1584–1594
Rohwer TA (1999) Miniature single channel memory-based high-G acceleration recorder(MilliPen). Sandia National Laboratories, Albuquerque, 87185:SAND99-1392C
Forrestal MJ, Togami TC, Baker WE, Frew DJ (2003) Performance evaluation of accelerometers used for penetration experiments. Exp Mech 43:90–96
Foster JT, Frew DJ, Forrestal MJ, Nishida EE, Chen W (2012) Shock testing accelerometers with a Hopkinson pressure bar. Int J Impact Eng 46:56–61
Holmquist TJ, Johnson GR, Cook WH (1993) A computational constitutive model for concrete subjected to large strains, high strain rates and high pressures. Proceedings of the 14th International Symposium on Ballistics, Quebec, Canada: 591–600
Polanco-Loria M, Hopperstad OS, Borvik T, Berstad T (2008) Numerical predictions of ballistic limits for concrete slabs using a modified version of the HJC concrete model. Int J Impact Eng 35:290–303
Forrestal MJ, Warren TL (2008) Penetration equations for ogive-nose rods into aluminum targets. Int J Impact Eng 35:727–730
Acknowledgment
This work was supported by contract DTRA02-03-D-0002 to Applied Research Associates.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Warren, T.L., Forrestal, M.J. & Randles, P.W. Evaluation of Large Amplitude Deceleration Data from Projectile Penetration into Concrete Targets. Exp Mech 54, 241–253 (2014). https://doi.org/10.1007/s11340-013-9767-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11340-013-9767-9