LS-DYNA
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LS-DYNA is a most advanced general-purpose multiphysics simulation software package, actively developed by the Livermore Software Technology Corporation (LSTC).
While the package continues to contain more and more possibilities for the calculation of many complex real world problems, its origins and core-competency lie in highly nonlinear transient dynamic finite element analysis using explicit time integration.
LS-DYNA is being used by Automobile, Aerospace, Military, Manufacturing and Bioengineering Companies.
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[edit] Typical uses
Nonlinear means at least one (and sometimes all) of the following three complications:
- changing boundary conditions, as a contact between parts which changes over time
- large deformations as in the crumpling of sheet metal parts
- nonlinear materials, which do not behave ideally elastic, e.g. thermoplastic polymers
Transient dynamic means analyzing short events with high speeds, where inertial forces are important.
Therefore typical uses include:
- Car crash (deformation of chassis, airbag inflation, seatbelt tensioning, ...)
- Explosions (underwater mines, shaped charges, ...)
- Manufacturing (sheet metal stamping, ...)
[edit] History
(written off the top of my head, please improve and correct! -- BjKa)
- John Hallquist writes the FEA program DYNA-3D for Lawrence Livermore National Laboratory, which uses explicit time integration to study nonlinear dynamic problems.
- As a former US-Military project, the code of DYNA-3D is released into the public domain
- Several Software developers take up the DYNA-3D code and develop their own version of an explicit dynamics FEM package. (e.g. Pam-Crash)
- LSTC was founded in 1987 by John Hallquist
- LSTC continually develops and expands the capabilities of LS-DYNA with the goal of creating a sort of universal tool for most simulation needs.
- As of 2007 the near future will see LS-DYNA with capabilities for electromagnetism.
[edit] Characteristics
LS-DYNA consists mainly of a single executable file. Theoretically nothing more than a command shell, the LS-DYNA executable and enough free disk space is needed to run a calculation. Additionally any plain-ASCII text editor can be used as a powerful tool for the construction or quick and simple modification of input files.
More easily the preparation of input data (i.e. preprocessing) and the analyzation of LS-DYNA results (postprocessing) can be made with LSTC's LS-PREPOST. LS-PREPOST runs without a license, which means that the results of a calculation can always be examined in full depth even where there is no access to an LS-DYNA License. Many users however choose from a number of third party software products like ANSA, HyperMesh or Oasys.
Licensees of LS-DYNA automatically have access to all of the program's capabilities, from the simple linear static mechanical analysis, up to advanced thermal or flow solving methods. Futhermore they can use LSTC's LS-OPT software, a standalone Design Optimization and Probabilistic Analysis package with an interface to LS-DYNA.
[edit] Capabilities
LS-DYNA's potential applications are numerous and can be tailored to many fields. LS-DYNA is not limited to any particular type of simulation. In a given simulation any of LS-DYNA's many features can be combined to model a wide range of physical events. An example of a simulation, which involves a unique combination of features, is the NASA JPL Mars Pathfinder landing simulation which simulated the space probe's use of airbags to aid in its landing.
LS-DYNA analysis capabilities:
- Nonlinear dynamics
- Rigid body dynamics
- Quasi-static simulations
- Normal modes
- Linear statics
- Thermal analysis
- Fluid analysis
- Eulerian capabilities
- ALE (Arbitrary Lagrangian-Eulerian)
- Fluid-structure interactions
- FEM-rigid multi-body dynamics coupling (MADYMO, CAL3D)
- Underwater shock
- Failure analysis
- Crack propagation
- Real-time acoustics
- Implicit springback
- Multi-physics coupling
- Structural-thermal coupling
- Adaptive remeshing
- Smooth particle hydrodynamics
- Element-free meshless method
[edit] Materials and elements database
LS-DYNA's comprehensive library of material models:
- Metals
- Plastics
- Glass
- Foams
- Fabrics
- Elastomers
- Honeycombs
- Concrete & soils
- Viscous fluids
- User-defined materials
LS-DYNA's large element library:
- Solids
- 8-node thick shells
- 4-node shells
- Beams
- Welds
- Discrete zero length beams
- Trusses and cables
- Nodal masses
- Lumped inertias
[edit] Algorithms
LS-DYNA's contact algorithms:
- Flexible body contact
- Flexible body to rigid body contact
- Rigid body to rigid body contact
- Edge-to-edge contact
- Eroding contact
- Tied surfaces
- CAD surfaces
- Rigid walls
- Draw beads
[edit] Applications
[edit] Automotive Crashworthiness & Occupant Safety
LS-DYNA is widely used by the automotive industry to analyze vehicle designs. LS-DYNA accurately predicts a car's behavior in a collision and the effects of the collision upon the car's occupants. With LS-DYNA, automotive companies and their suppliers can test car designs without having having to tool or experimentally test a prototype, thus saving time and expense.
LS-DYNA's specialized automotive features:
- Seatbelts
- Sliprings
- Pretensioners
- Retractors
- Sensors
- Accelerometers
- Airbags
- Hybrid III dummy models
- Inflator models
[edit] Sheet Metal Forming With LS-DYNA
One of LS-DYNA's most widely used applications is sheet metal forming. LS-DYNA accurately predicts the stresses and deformations experienced by the metal, and determines if the metal will fail. LS-DYNA supports adaptive remeshing and will refine the mesh during the analysis, as necessary, to increase accuracy and save time.
Metal forming applications for LS-DYNA include:
- Metal stamping
- Hydroforming
- Forging
- Deep drawing
- Multi-stage processes
[edit] Aerospace Industry Applications
LS-DYNA is widely used by the aerospace industry to simulate bird strike, jet engine blade containment, and structural failure.
Aerospace applications for LS-DYNA include:
- Blade containment
- Bird strike (windshield, and engine blade)
- Failure analysis
[edit] Other applications
Other LS-DYNA applications include:
- Drop testing
- Can and shipping container design
- Electronic component design
- Glass forming
- Plastics, mold, and blow forming
- Biomedical
- Metal cutting
- Earthquake engineering
- Failure analysis
- Sports equipment (golf clubs, golf balls, baseball bats, helmets)
- Civil engineering (offshore platforms, pavement design)
[edit] References
Crashworthiness Engineering: Course Notes. Paul Du Bois
