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Blast & Penetration Modelling in LS-DYNA

With Len Schwer PhD & Paul Du Bois

Duration: 2 Days

Blast and penetration events form a class of simulation environments well suited to the solution capabilities of LS-DYNA. LS-DYNA is unique in offering the analyst the choice of Lagrange, Eulerian (ALE) and Meshfree Methods, and combination s of these methods, for simulating high energy events such as blast loading, penetration and perforation. In addition to high energy, these events are typically associated with large deformations, damage, and failure both on the material and structural level. During the past decade successful modeling of such damage and failure has moved steadily from a 'Black Art' to a widely accepted engineering analysis.

This class focuses on the application of LS-DYNA for the simulation of high energy events. The analysis methods, and modeling, are illustrated through case studies. An emphasis is place d on modeling techniques: guidelines for which technique(s) to select, insights into which techniques work well and when, and possible pitfalls in modeling choice selections. Sufficient mathematical theory is presented for each technique, especially Eulerian and Meshfree Methods, to provide the typical user with sufficient knowledge to confidently apply the appropriate analysis technique. However, this training class is not a substitute for the in-depth treatments presented in the associated LS-DYNA training classes, i.e. ALE/Eulerian & Fluid Structure Interaction and Mesh-Free Methods (SPH-EFG), respectively.

Intended Audience

This training class is intended for the LS-DYNA analysts possessing a comfortable command of the LS-DYNA keywords and options associated with typical Lagrangian analyses. This training class will attempt to provide the analyst with the additional tools and knowledge required to model the above described class of high energy events. The typical attendee is likely to have a background in defense applications, to include protective structures and vehicles, Homeland Defense topics, and terrorist threat mitigation techniques.

Content:

  • Blast Modelling - Engineering Models
  • Blast Modelling - Blast Wave Simulation
  • Blast Wave Applications - Vehicles
  • Blast Wave Application - Structures
  • Material Modelling
  • Damage Modelling
  • Failure Modelling
  • Penetration & Perforation Modelling

Timing schedule:

Day 1:

  • Introduction
  • Equations of state and shockwaves
  • Engineering models for blast loading
  • MMALE modeling of blastwaves
  • Comparison of MMALE and engineering models

Day 2:

  • Johnson-Cook material model
  • Damage and failure models
  • Comparison Lagrangian/MMALE/SPH
  • 2D and MMALE approach for shaped charges and explosively formed projectiles

Instructor:

Paul Du Bois has worked as an independent consultant in the field of industrial application of large scale numerical simulations since September 1987. He has specialized in the application of explicit integration techniques to crashworthiness and impact problems. Amongst Pauls customers we find most of the worlds automotive assemblers such as DaimlerChrysler, GM, Ford, Opel, Fiat, Porsche, Volvo, PSA, Renault, Toyota, Nissan, Honda, Hyundai and many others including automotive suppliers and design and engineering companies. Amongst Pauls more recent projects for DaimlerChrysler are the development of a generalized plasticity law for the simulation of plastics and the formulation of a tabulated hyperelastic material law with damage for the simulation of rubber and foam. He was involved with the joint research organism of the German automotive industry, FAT, in the working groups side impact dummies from 1992 till 1997 and Foam materials from 1996 till today. In 2003 Paul was asked by LLNL to perform a training mission at the Russian national laboratory in Snezinskh. Since 2004 he is also a consultant to NASA and has worked on the space shuttles return-to-flight program. In the field of defence applications, he is a consultant to Rafael in Haifa, Israel where he was involved with the simulation of mine blast problems and helicopter crash landings.

Len Schwer has worked in the area of defense applications where failure prediction is of primary interest, for the past 25 years; he has been a DYNA3D user since 1983 and an LSDYNA user since 1998. His early work at SRI International included modeling the collapse of deeply buried tunnels under very high pressure loadings. While at Lockheed Missile and Space Company he worked on high speed earth penetrators designed to penetrate reinforced concrete structures buried in soil. From 1997 -2001 he worked with Professors Belytschko and Liu of Northwestern University on applying their meshfree methods to reinforced concrete problems of interest to the Defense Threat Reduction Agency. During 1999 -2000 he contributed to a test and simulation program focused on non-standard loading of buried pipelines. He is currently working with the US Navy to develop an analysis capability for predicting the penetration & perforation of metallic structures associated with improvised explosive devices (IEDs). He has a strong interest in verification and validation in computational solid mechanics, and is the Chair of the ASME Standards Committee on Verification and Validation in Computational Solid Mechanics. Dr. Schwer is a Fellow of the American Society of Mechanical; Engineers (ASME) and the United States Association of Computational Mechanics (USACM).

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