title: The relationship between mechanical properties and ballistic penetration depth in a viscoelastic gel.
abstract: The fundamental material response of a viscoelastic material when impacted by a ballistic projectile has important implication for the defense, law enforcement, and medical communities particularly for the evaluation of protective systems. In this paper, we systematically vary the modulus and toughness of a synthetic polymer gel to determine their respective influence on the velocity-dependent penetration of a spherical projectile. The polymer gels were characterized using tensile, compression, and rheological testing taking special care to address the unique challenges associated with obtaining high fidelity mechanical data on highly conformal materials. The depth of penetration data was accurately described using the elastic Froude number for viscoelastic gels ranging in Young's modulus from ~60 to 630 kPa. The minimum velocity of penetration was determined to scale with the gel toughness divided by the gel modulus, a qualitative estimate for the zone of deformation size scale upon impact. We anticipate that this work will provide insight into the critical material factors that control ballistic penetration behavior in soft materials and aid in the design and development of new ballistic testing media.
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States. Electronic address: randy.a.mrozek.civ@mail.mil.
authors: Randy A
authors: RA
authors: Mrozek
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Brad
authors: B
authors: Leighliter
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Christopher S
authors: CS
authors: Gold
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Ian R
authors: IR
authors: Beringer
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Jian H
authors: JH
authors: Yu
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Mark R
authors: MR
authors: VanLandingham
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Paul
authors: P
authors: Moy
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States.
authors: Mark H
authors: MH
authors: Foster
authors: US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005, United States. Electronic address: jospeh.l.lenhart.civ@mail.mil.
authors: Joseph L
authors: JL
authors: Lenhart
mesh_terms: D055119:Elastic Modulus; D005782:Gels; D008422:Materials Testing; D009038:Motion; D011095:Polyethylenes; D011137:Polystyrenes; D012212:Rheology; D013232:Steel; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D014783:Viscosity
chemical_list: D005782:Gels; D011095:Polyethylenes; D011137:Polystyrenes; C050192:styrene-ethylene-butylene-styrene-block copolymer; D013232:Steel