• A Multi-Scale Approach for Modelling of Fracture in Aluminium Alloys under Impact Loading 

      Valle, Heidi; Frodal, Bjørn Håkon (Master thesis, 2015)
      The main objective of this thesis was to investigate the ballistic properties of an isotropic AlMgSi aluminium alloy both experimentally and numerically. Uncoupled and coupled fracture models were calibrated using ...
    • A nano-scale material model applied in finite element analysis of aluminium plates under impact loading 

      Johnsen, Joakim; Holmen, Jens Kristian; Myhr, Ole Runar; Hopperstad, Odd Sture; Børvik, Tore (Journal article, 2013)
      Finite element simulations of AA6070 aluminium plates struck by ogival-nose projectiles are performed. The aluminium plates are 20 mm thick and heat treated to temper O, T4, T6 and T7. A nano-scale material model, consisting ...
    • Ballistic impact of layered and case-hardened steel plates 

      Holmen, Jens Kristian; Solberg, Jan Ketil; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2017)
      We investigated the ballistic resistance of hot-rolled structural steel plates with a nominal yield stress of 355 MPa in this study. Ballistic tests were conducted with 7.62mm armor piercing bullets on monolithic and ...
    • Ballistic Perforation of Surface Hardened Mild Steel Plates 

      Thorsen, Henrik; Orthe, Erlend (Master thesis, 2014)
      The main objective with this thesis was to investigate experimentally and numerically the effect surface hardening has on the ballistic properties of monolithic and laminated mild steel plates. 300x300 mm^2 plates of ...
    • Cylindrical cavity expansion approximations using different constitutive models for the target material 

      Johnsen, Joakim; Holmen, Jens Kristian; Warren, Thomas L.; Børvik, Tore (Journal article; Peer reviewed, 2017)
      In this article, we investigate the results obtained using different constitutive models for the solution of the cylindrical cavity expansion problem under plane strain conditions. The cylindrical cavity expansion solutions ...
    • Discrete modeling of low-velocity penetration in sand 

      Holmen, Jens Kristian; Olovsson, Lars; Børvik, Tore (Journal article; Peer reviewed, 2017)
      In this paper, a discrete particle method was evaluated and used in numerical simulations of low-velocity penetration in sand. Hemispherical, blunt, and ogival-nosed impactors were tested at striking velocities below 5 ...
    • Dynamic Behaviour of a High-Strength Structural Steel at Low Temperatures 

      Perez-Martin, Maria Jesus; Holmen, Jens Kristian; Thomesen, Susanne; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2019)
      The main objective of this experimental study is to determine the effect of low temperatures on the mechanical behaviour of Strenx 960 Plus high-strength structural steel at different strain rates and stress triaxialities. ...
    • Effects of heat treatment on the ballistic properties of AA6070 aluminium alloy 

      Holmen, Jens Kristian; Johnsen, Joakim; Jupp, S; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2013)
      The ballistic properties of the aluminium alloy AA6070 in different tempers are studied, using target plates of 20 mm thickness in tempers O (annealed), T4 (naturally aged), T6 (peak strength) and T7 (overaged). The ...
    • Effects of Heat Treatment on the Ballistic Properties of AA6070 Aluminium Plates 

      Holmen, Jens Kristian; Johnsen, Joakim (Master thesis, 2012)
      The thesis includes a summary of important theory in the fields of impact engineering and plasticity theory, and a literature study is carried out on aluminium designations, alloying and heat treatment. The true stress-strain ...
    • Experimental and Numerical Study on the Perforation of Empty and Sand-filled Aluminium Panels 

      Bjerke, Fredrik Risåsen; Hansen, Lars Magnus (Master thesis, 2015)
      The discrete particle approach has previously proven to give excellent agreement between experiments and numerical analysis for blast and penetration in granular medias. The main objective in this thesis is to further ...
    • Experiments and simulations of empty and sand-filled aluminum alloy panels subjected to ballistic impact 

      Holmen, Jens Kristian; Børvik, Tore; Hopperstad, Odd Sture (Journal article; Peer reviewed, 2017)
      In this study, we use a discrete particle method in combination with finite element analysis to describe the interaction between structures and granular media during ballistic impact. By applying a discrete particle method ...
    • Fracture and fragmentation of blast-loaded laminated glass: An experimental and numerical study 

      Osnes, Karoline; Holmen, Jens Kristian; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2019)
      In this study, we use the explicit finite element method in combination with higher order elements and 3D node splitting to simulate fracture and fragmentation of blast-loaded laminated glass. Node splitting is a modelling ...
    • Impact behavior of high-strength steel at low temperatures 

      Holmen, Jens Kristian; Børvik, Tore (Chapter, 2018)
      A wide range of material and ballistic tests were conducted to explore the behavior of a high-strength steel at low temperatures. Our test program included quasi-static and dynamic uniaxial and notched tension tests, Charpy ...
    • Impact Behaviour of Steel at Low Temperatures 

      Gunathasan, Piraveena (Master thesis, 2017)
      This thesis represents a continuation of the work carried out by Susanne Thomesen during her master's thesis in 2016. The primary objectives in this thesis were to determine the ballistic properties of the high strength ...
    • Impact Behaviour of Steel at Low Temperatures 

      Thomesen, Susanne (Master thesis, 2016)
      The main objective of this thesis was to determine the impact behaviour of the high strength steel Strenx-960-Plus at room and low temperatures, and to investigate if the deformation and failure mode changed from ductile ...
    • Influence of fragmentation on the capacity of aluminum alloy plates subjected to ballistic impact 

      Holmen, Jens Kristian; Johnsen, Joakim; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2016)
      In this paper, the perforation resistance of 20 mm thick aluminum plates subjected to moderate velocity impacts is examined experimentally and numerically. Plates made of four different tempers of aluminum alloy AA6070 ...
    • Influence of yield-surface shape in simulation of ballistic impact 

      Holmen, Jens Kristian; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2017)
      A high-exponent yield criterion is applied in 3D nonlinear finite element simulations of ballistic impact. The computational models are based on a comprehensive experimental study including material tests of 12 mm thick ...
    • Low-velocity impact on multi-layered dual-phase steel plates 

      Holmen, Jens Kristian; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2015)
      In this paper an experimental program investigating the behavior of monolithic and multi-layered configurations of 0.8 mm and 1.8 mm medium-strength steel plates is presented. We have considered impacts by blunt-ended and ...
    • Modeling and Simulation of Ballistic Impact 

      Holmen, Jens Kristian (Doctoral theses at NTNU;2016:240, Doctoral thesis, 2016)
      Numerical simulations are increasingly becoming an important tool to obtain efficient designs of protective structures, and the existing literature shows that many phenomena can be accurately described by standard methods ...
    • Modeling and Simulation of Hypervelocity Impact Against Debris Shields for Spacecraft Protection 

      Tjønn, Else (Master thesis, 2017)
      In this project, IMPETUS Afea Solver was used to simulate hypervelocity impact on Whipple shields. The micrometeoroid and orbital debris environment around the International Space Station was studied in order to understand ...