Accession Number : ADA258755


Title :   Three-Dimensional Finite Element Modeling of Confinement Stress for Projectiles Embedded in Rock - A Preliminary Study


Descriptive Note : Final rept. Jan-Oct 1990


Corporate Author : NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA


Personal Author(s) : Hoge, Larry R ; Shugar, T A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258755.pdf


Report Date : Nov 1992


Pagination or Media Count : 110


Abstract : The explicit three-dimensional finite element computer program DYNA3D was applied to the problem of modeling penetration of anchor projectiles into seafloor rock media. It was used to computer the dynamic response and the residual stresses and strains for an axisymmetric penetration model where the penetrator axis and velocity vector are normal to the seafloor. Homogeneous nonlinear material behavior is considered for both the anchor projectile and the seafloor rock material, and a frictional interface is prescribed between the anchor projectile and rock media. An introductory discussion of cavity expansion theory is also included and used to guide physical interpretation of the data obtained from the numerical model. Validation of the three-dimensional model was limited to comparison with previous DYNA2D results for penetration depths. Qualitative agreement with very approximate analytical methods was also observed. A parameter study revealed that the rock target hardness, as represented by the strain hardening modulus in an elastic-plastic model of rock behavior, strongly influenced the confinement stress acting on the embedded projectile. Conversely, it was found that the coefficient of friction of the contact surface between the projectile and rock had only minor affect on the confinement stress, although it did affect the depth of penetration. DYNA3D is potentially a convenient and forthcoming framework for determining the relationship between confinement stress and various parameters of seafloor rock and anchor projectiles.


Descriptors :   *PROJECTILES , *ROCK , *PROPELLING CHARGES , *OCEAN BOTTOM , COMPUTER PROGRAMS , FINITE ELEMENT ANALYSIS , THREE DIMENSIONAL , RESIDUAL STRESS , ANCHORS(MARINE) , FRICTION , HARDNESS , EMBEDDING , SOILS , DEPTH , STRAIN(MECHANICS) , STRESS ANALYSIS


Subject Categories : Marine Engineering
      Ammunition and Explosives
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE