Browsing by Author "Frøyland, Øyvind"

Now showing items 1-18 of 18

    • Experimental and numerical study of the fragmentation of expanding warhead casings by using different numerical codes and solution techniques 

      Moxnes, John Fredrik; Prytz, Anne K.; Frøyland, Øyvind; Klokkehaug, Siri; Skriudalen, Stian; Friis, Eva; Teland, Jan Arild; Dørum, Cato; Ødegårdstuen, Gard (2014)
      There has been increasing interest in numerical simulations of fragmentation of expanding warheads in 3D. Accordingly there is a pressure on developers of leading commercial codes, such as LS-DYNA, AUTODYN and IMPETUS Afea, ...

    • Experimental study of the fragmentation of hard cores of wolfram carbide during penetration in armour steel plates 

      Moxnes, John F.; Frøyland, Øyvind (2004)
      Numerical codes,e.g. Autodyn are widely used for simulation purposes during impact and penetration of projectiles into targets. To validate the computer simulations, an experimental study of fracturing of sintered wolfram ...

    • Friction studies related to wear of gun barrels 

      Moxnes, John F.; Frøyland, Øyvind (2005)
      In this article a study of the wear of the 12.7 mm gun barrel is performed. Two new measuring methods have been developed to study the wear rates. Electron probe microscopy was also used. Theoretical and experimental ...

    • The GREAC cell used to establish constitutive models for powder type materials 

      Moxnes, John F.; Frøyland, Øyvind (2009)
      In this report a theoretical and experimental study of a glass powder (diameter of 40-80 μm) is made to establish a constitutive material model by using the GREAC (Gauged REActive Confinement) cell. The GREAC cell is simply ...

    • Gun barrel wear studies based on physical kinetics 

      Frøyland, Øyvind; Moxnes, John F. (2006)
      In this article a study of the gun barrel wear mechanisms has been carried out. We construct a mathematical model based on the theory of ordinary differential equations. The model includes heat transfer and particle ...

    • Hardness tests used to establish constitutive models 

      Moxnes, John F.; Frøyland, Øyvind (2008)
      In this report a study of the hardness of different materials are performed theoretically and experimentally. The objective was to study whether the hardness test could be used to establish constitutive material models. We ...

    • Material properties of wolfram carbide established by using a simple indentation test 

      Moxnes, John F.; Nilssen, Jan R.; Frøyland, Øyvind; Friis, Eva (2003)
      In this article a study of the fracture stress caused by indentation of wolfram carbide penetrators into steel blocks has been carried out. Experimental data was compared with simulations using the Nike-2D code and with ...

    • Mathematical relations related to the lode parameter for studies of ductility 

      Moxnes, John Fredrik; Frøyland, Øyvind (2016)
      During plastic flow, hydrostatic pressure and plastic strain control the size of the yield surface while the Lode angle is responsible for its shape. The von Mises yield condition shows no dependency of the Lode angle ...

    • Mechanical studies of wolfram carbide 

      Frøyland, Øyvind; Moxnes, John F. (2004)
      In this article a study of the mechanical properties of a sintered wolfram carbide-cobalt penetrator has been carried out. Different penetrators are studied in a compression test to establish the Young’s modulus, the bulk ...

    • Micro indentation hardness testing of commercial-grade RDX crystals 

      Moxnes, John Fredrik; Frøyland, Øyvind; Olsen, Torbjørn; Jensen, Tomas Lunde; Unneberg, Erik (2016)
      This paper describes the continuous micro indentation hardness testing of two commercial grades of RDX with differing shock sensitivities using three (3) different loads on a Berkovich indenter to obtain values of elastic ...

    • Microscopic studies of wolfram carbide after fracturing 

      Frøyland, Øyvind; Moxnes, John F. (2004)
      In this report a study of the microscopic properties of a fractured sintered wolfram carbide-cobalt penetrator has been carried out. Scanning electron microscopy (SEM) and light microscopy are used to study the fracture ...

    • A model for the burn velocity of tracers 

      Frøyland, Øyvind; Moxnes, John F. (2006)
      In this report we perform a study of the burn velocity of tracer compositions. Both the burn velocity during flight and in static conditions is studied. In addition we present results for varying densities of the tracer ...

    • On the study of ricochet and penetration in sand, water and gelatin by spheres, 7.62 mm APM2, and 25?mm projectiles 

      Moxnes, John Fredrik; Frøyland, Øyvind; Skriudalen, Stian; Prytz, Anne K.; Teland, Jan Arild; Friis, Eva; Ødegårdstuen, Gard (2016)
      We examine the ricochet and penetration behavior in sand, water and gelatin by steel spheres, 7.62 mm APM2 and 25 mm projectiles. A threshold impact angle (critical angle) exists beyond which ricochet cannot occur. The ...

    • Oxidation and carburisation steel in gun barrels 

      Frøyland, Øyvind; Moxnes, John F. (2006)
      In this report a theoretical and experimental study of some basic gun barrel erosion mechanisms have been carried out. The theoretical analysis of the reaction mechanisms leading to erosion is based on the minimalization ...

    • Projected area and drag coefficient of high velocity irregular fragments that rotate or tumble 

      Moxnes, John Fredrik; Frøyland, Øyvind; Øye, Ivar Jarle; Brate, Tom I.; Friis, Eva; Ødegårdstuen, Gard; Risdal, Tallak Harald (2017)
      3 degrees of freedom (DOF) exterior ballistic computer models are used in fragment studies to calculate individual trajectories of each fragment based on drag coefficient and the projected (presented) area in the direction ...

    • Strain rate dependency and fragmentation pattern of expanding warheads 

      Moxnes, John Fredrik; Prytz, Anne K.; Frøyland, Øyvind; Skriudalen, Stian; Børve, Steinar; Ødegårdstuen, Gard (2014-12-22)
      For the characterization of the behaviors of a metal material in events like expanding warheads, it is necessary to know its strength and ductility at high strain rates, around 104 e105 /s. The flyer plate impact testing ...

    • Studies of wear charactistics of three different gunpowder gases 

      Frøyland, Øyvind; Moxnes, John F. (2006)
      In this report a study of the gun barrel wear characteristicsof three different gunpowders are performed. The three different gunpowders are: Bofors NC 1214 NEXPLO (NEXPLO), BOFORS NC 1214 EURENCO (EURENCO) and PB Clermont ...

    • Tensile tests of Wolfram Carbide hard cores 

      Frøyland, Øyvind; Moxnes, John F. (2007)
      In this report an experimental study of the tensile strength of different hard cores of Wolfram Carbide was performed. A bending test was constructed for the study. We show that the tensile strength and strain is smaller ...