LS-DYNA
Encyclopedia
LS-DYNA is an advanced general-purpose multiphysics simulation software package 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 (FEA) using explicit time integration. LS-DYNA is being used by the automobile
, aerospace
, construction
, military
, manufacturing
, and bioengineering industries.
program DYNA3D, developed by Dr. John O. Hallquist at Lawrence Livermore National Laboratory
(LLNL) in 1976. DYNA3D was created in order to simulate the impact of the Full Fusing Option (FUFO) or "Dial-a-yield" nuclear bomb for low altitude release (impact velocity of ~ 40 m/s). At the time, no 3D software was available for simulating impact and 2D software was inadequate. While the FUFO bomb was canceled, development of DYNA3D continued. DYNA3D used explicit time integration to study nonlinear dynamic problems, with the original applications being mostly stress analysis of structures undergoing various types of impacts. The program was initially very simple largely due to the lack of adequate computational resources at the time. A two-dimensional version of the same software was developed concurrently. In 1978 the DYNA3D source code was released into the public domain without restrictions after a request from France.
In 1979 a new version of DYNA3D was released which was programmed for optimal performance on the CRAY-1
supercomputers. This new release contained improved sliding interface treatment which was an order of magnitude faster than the previous contact treatment. This version also eliminated structural and higher order solid elements of the first version, while including element-wise integration of the integral difference method developed in 1974.
The 1982 release included nine additional material models which allowed for new simulations, such as explosive-structure and soil-structure interactions. The release also permitted the analysis of structural response due to penetrating projectiles
. Improvements in 1982 further boosted the execution speed by about 10 percent. Hallquist was the sole developer of DYNA3D until 1984, when he was joined by Dr. David J. Benson. In 1986, many capabilities were added. The added features included beams, shells, rigid bodies, single surface contact, interface friction, discrete springs and dampers, optional hourglass treatments, optional exact volume integration, and VAX
/VMS
, IBM
, UNIX
, COS
operating system compatibility. At this point, DYNA3D became the first code to have a general single surface contact algorithm.
Metal forming
simulation and composite analysis capabilities were added to DYNA3D in 1987. This version included changes to the shell elements, and dynamic relaxation
. The final release of DYNA3D in 1988 included several more elements and capabilities.
By 1988 LLNL had sent approximately 600 tapes
containing simulation software. Hallquist had consulted for nearly 60 companies and organizations on the use of DYNA3D. As a result, at the end of 1988 Livermore Software Technology Corporation (LSTC) was founded to continue the development of DYNA3D in a much more focused manner, resulting in LS-DYNA3D (later shortened to LS-DYNA). Releases and support for DYNA3D were thus halted. Since then, LSTC has greatly expanded the capabilities of LS-DYNA in an attempt to create a universal tool for most simulation needs.
Transient dynamic means analyzing high speed, short duration events where inertia
l force
s are important. Typical uses include:
format and thus can be prepared using any text editor
. Input files can also be prepared with the aid of a graphical preprocessor
. There are many third party software products available for preprocessing LS-DYNA input files (e.g.TrueGrid). LSTC also develops its own preprocessor, LS-PrePost, which is freely distributed and runs without a license. Licensees of LS-DYNA automatically have access to all of the program's capabilities, from simple linear static mechanical analysis up to advanced thermal and flow solving methods. Furthermore they have full use of LSTC's LS-OPT software, a standalone design optimization and probabilistic analysis package with an interface to LS-DYNA.
JPL Mars Pathfinder
landing which simulated the space probe's use of airbags to aid in its landing.
LS-DYNA's analysis capabilities:
LS-DYNA's specialized automotive features:
Metal forming applications for LS-DYNA include:
, jet engine blade containment, and structural failure.
Aerospace applications for LS-DYNA include:
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
, aerospace
Aerospace
Aerospace comprises the atmosphere of Earth and surrounding space. Typically the term is used to refer to the industry that researches, designs, manufactures, operates, and maintains vehicles moving through air and space...
, construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
, military
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
, manufacturing
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
, and bioengineering industries.
History
LS-DYNA originated from the 3D FEAFinite element method
The finite element method is a numerical technique for finding approximate solutions of partial differential equations as well as integral equations...
program DYNA3D, developed by Dr. John O. Hallquist at Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
(LLNL) in 1976. DYNA3D was created in order to simulate the impact of the Full Fusing Option (FUFO) or "Dial-a-yield" nuclear bomb for low altitude release (impact velocity of ~ 40 m/s). At the time, no 3D software was available for simulating impact and 2D software was inadequate. While the FUFO bomb was canceled, development of DYNA3D continued. DYNA3D used explicit time integration to study nonlinear dynamic problems, with the original applications being mostly stress analysis of structures undergoing various types of impacts. The program was initially very simple largely due to the lack of adequate computational resources at the time. A two-dimensional version of the same software was developed concurrently. In 1978 the DYNA3D source code was released into the public domain without restrictions after a request from France.
In 1979 a new version of DYNA3D was released which was programmed for optimal performance on the CRAY-1
Cray
Cray Inc. is an American supercomputer manufacturer based in Seattle, Washington. The company's predecessor, Cray Research, Inc. , was founded in 1972 by computer designer Seymour Cray. Seymour Cray went on to form the spin-off Cray Computer Corporation , in 1989, which went bankrupt in 1995,...
supercomputers. This new release contained improved sliding interface treatment which was an order of magnitude faster than the previous contact treatment. This version also eliminated structural and higher order solid elements of the first version, while including element-wise integration of the integral difference method developed in 1974.
The 1982 release included nine additional material models which allowed for new simulations, such as explosive-structure and soil-structure interactions. The release also permitted the analysis of structural response due to penetrating projectiles
Penetration (weapons)
Strictly speaking penetration occurs when a projectile enters a target without passing through it and perforation occurs when the projectile completely passes through the target, but the word penetration is commonly used to refer to either....
. Improvements in 1982 further boosted the execution speed by about 10 percent. Hallquist was the sole developer of DYNA3D until 1984, when he was joined by Dr. David J. Benson. In 1986, many capabilities were added. The added features included beams, shells, rigid bodies, single surface contact, interface friction, discrete springs and dampers, optional hourglass treatments, optional exact volume integration, and VAX
VAX
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...
/VMS
OpenVMS
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
, IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
, UNIX
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
, COS
Cray Operating System
The Cray Operating System was Cray Research's proprietary operating system for its Cray-1 and Cray X-MP supercomputers, and those platforms' main OS until replaced by UNICOS in the late 1980s...
operating system compatibility. At this point, DYNA3D became the first code to have a general single surface contact algorithm.
Metal forming
Metalworking
Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...
simulation and composite analysis capabilities were added to DYNA3D in 1987. This version included changes to the shell elements, and dynamic relaxation
Dynamic relaxation
Dynamic relaxation is a numerical method, which, among other things, can be used do "form-finding" for cable and fabric structures. The aim is to find a geometry where all forces are in equilibrium...
. The final release of DYNA3D in 1988 included several more elements and capabilities.
By 1988 LLNL had sent approximately 600 tapes
Magnetic tape data storage
Magnetic tape data storage uses digital recording on to magnetic tape to store digital information. Modern magnetic tape is most commonly packaged in cartridges and cassettes. The device that performs actual writing or reading of data is a tape drive...
containing simulation software. Hallquist had consulted for nearly 60 companies and organizations on the use of DYNA3D. As a result, at the end of 1988 Livermore Software Technology Corporation (LSTC) was founded to continue the development of DYNA3D in a much more focused manner, resulting in LS-DYNA3D (later shortened to LS-DYNA). Releases and support for DYNA3D were thus halted. Since then, LSTC has greatly expanded the capabilities of LS-DYNA in an attempt to create a universal tool for most simulation needs.
Typical uses
Nonlinear means at least one (and sometimes all) of the following complications:- Changing boundary conditions (such as contact between parts that changes over time)
- Large deformations (for example the crumpling of sheet metalSheet metalSheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material...
parts) - Nonlinear materials that do not exhibit ideally elasticElasticity (physics)In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
behavior (for example thermoplasticThermoplasticThermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
polymers)
Transient dynamic means analyzing high speed, short duration events where inertia
Inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...
l force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
s are important. Typical uses include:
- Automotive crash (deformation of chassisChassisA chassis consists of an internal framework that supports a man-made object. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame with the wheels and machinery.- Vehicles :In the case of vehicles, the term chassis means the...
, airbagAirbagAn Airbag is a vehicle safety device. It is an occupant restraint consisting of a flexible envelope designed to inflate rapidly during an automobile collision, to prevent occupants from striking interior objects such as the steering wheel or a window...
inflation, seatbelt tensioning, ...) - Explosions (underwater mineNaval mineA naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
s, shaped chargeShaped chargeA shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
s, ...) - Manufacturing (sheet metal stampingStamping (metalworking)Stamping includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. This could be a single stage operation where every stroke of the press produce the desired form on the sheet...
, ...)
Characteristics
LS-DYNA consists of a single executable file and is entirely command line driven. Therefore all that is required to run LS-DYNA is a command shell, the executable, an input file, and enough free disk space to run the calculation. All input files are in simple ASCIIASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
format and thus can be prepared using any text editor
Text editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
. Input files can also be prepared with the aid of a graphical preprocessor
Preprocessor
In computer science, a preprocessor is a program that processes its input data to produce output that is used as input to another program. The output is said to be a preprocessed form of the input data, which is often used by some subsequent programs like compilers...
. There are many third party software products available for preprocessing LS-DYNA input files (e.g.TrueGrid). LSTC also develops its own preprocessor, LS-PrePost, which is freely distributed and runs without a license. Licensees of LS-DYNA automatically have access to all of the program's capabilities, from simple linear static mechanical analysis up to advanced thermal and flow solving methods. Furthermore they have full use of LSTC's LS-OPT software, a standalone design optimization and probabilistic analysis package with an interface to LS-DYNA.
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 variety of physical events. An example of a simulation that involves a unique combination of features is the NASANASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
JPL Mars Pathfinder
Mars Pathfinder
Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...
landing which simulated the space probe's use of airbags to aid in its landing.
LS-DYNA's analysis capabilities:
- Full 2D & 3D capabilities
- Nonlinear dynamics
- Rigid body dynamics
- Quasi-static simulations
- Normal modes
- Linear statics
- Thermal analysis
- Fluid analysis
- Eulerian capabilities
- ALE (Arbitrary Lagrangian-Eulerian)
- FSI (Fluid-Structure Interaction)
- Navier-Stokes fluids
- Compressible fluid solver, CESE (Conservation Element & Solution Element)
- FEM-rigid multi-body dynamics coupling (MADYMOMADYMOMADYMO stands for MAthematical DYnamic MOdels. It is a software package developed by TASS , headquartered in Rijswijk, the Netherlands. It a leading design & analysis software for occupant safety systems in the transport industry....
, Cal3DCal3DCal3D is a skeletal animation based 3D character animation library written in C++ in a platform-/graphic API-independent way. Originally designed to be used in a 3D client for Worldforge, it evolved into a stand-alone product which can be used in many different kinds of projects...
) - Underwater shock
- Failure analysisFailure analysisFailure analysis is the process of collecting and analyzing data to determine the cause of a failure. It is an important discipline in many branches of manufacturing industry, such as the electronics industry, where it is a vital tool used in the development of new products and for the improvement...
- Crack propagation
- Real-time acousticsAcousticsAcoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics...
- Implicit springback
- Multi-physics coupling
- Structural-thermal coupling
- Adaptive remeshing
- SPH (Smoothed particle hydrodynamicsSmoothed particle hydrodynamicsSmoothed-particle hydrodynamics is a computational method used for simulating fluid flows. It has been used in many fields of research, including astrophysics, ballistics, volcanology, and oceanography...
) - EFG (Element Free GalerkinMeshfree methodsMeshfree methods are a particular class of numerical simulation algorithms for the simulation of physical phenomena. Traditional simulation algorithms relied on a grid or a mesh, meshfree methods in contrast use the geometry of the simulated object directly for calculations. Meshfree methods exist...
) - Radiation transport
- EM (ElectromagnetismElectromagnetismElectromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
)
Material Library
LS-DYNA's comprehensive library of material models:- MetalMetalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s - Plastics
- GlassGlassGlass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
- FoamFoam-Definition:A foam is a substance that is formed by trapping gas in a liquid or solid in a divided form, i.e. by forming gas regions inside liquid regions, leading to different kinds of dispersed media...
s - FabricFabricA fabric is a textile material, short for "textile fabric".Fabric may also refer to:*Fabric , the spatial and geometric configuration of elements within a rock*Fabric , a nightclub in London, England...
s - ElastomerElastomerAn elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...
s - HoneycombHoneycombA honeycomb is a mass of hexagonal waxcells built by honey bees in their nests to contain their larvae and stores of honey and pollen.Beekeepers may remove the entire honeycomb to harvest honey...
s - ConcreteConcreteConcrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
& soilSoilSoil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s - Viscous fluids
- User-defined materials
Element Library
Some of the element types available in LS-DYNA:- BeamsBeam (structure)A beam is a horizontal structural element that is capable of withstanding load primarily by resisting bending. The bending force induced into the material of the beam as a result of the external loads, own weight, span and external reactions to these loads is called a bending moment.- Overview...
(standard, trusses, discrete, cables, and welds) (with over 10 beam element formulations) - Discrete Elements (SpringsSpring (device)A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...
and DampersShock absorberA shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. It is a type of dashpot.-Nomenclature:...
) - Lumped InertiaInertiaInertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...
s - Lumped MassMassMass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
es - AccelerometerAccelerometerAn accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...
s - SensorSensorA sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...
s - Seat BeltsSeat beltA seat belt or seatbelt, sometimes called a safety belt, is a safety harness designed to secure the occupant of a vehicle against harmful movement that may result from a collision or a sudden stop...
- Pretensioners
- Retractors
- Sliprings
- Shells (3, 4, 6, and 8-node including 3D shells, membranes, 2D plane stress, plane strain, and axisymmetric solids) (with over 25 shell element formulations)
- Solids (4 and 10-node tetrahedronTetrahedronIn geometry, a tetrahedron is a polyhedron composed of four triangular faces, three of which meet at each vertex. A regular tetrahedron is one in which the four triangles are regular, or "equilateral", and is one of the Platonic solids...
s, 6-node pentahedronPentahedronIn geometry, a pentahedron is a polyhedron with five faces. Since there are no face-transitive polyhedra with five sides and there are two distinct topological types, this term is less frequently used than tetrahedron or octahedron....
s, and 8-node hexahedronHexahedronA hexahedron is any polyhedron with six faces, although usually implies the cube as a regular hexahedron with all its faces square, and three squares around each vertex....
s) (with over 20 solid element formulations) - SPHSmoothed particle hydrodynamicsSmoothed-particle hydrodynamics is a computational method used for simulating fluid flows. It has been used in many fields of research, including astrophysics, ballistics, volcanology, and oceanography...
Elements - Thick Shells (8-node)
Contact 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
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 to tool or experimentally test a prototype, thus saving time and expense.LS-DYNA's specialized automotive features:
- Seatbelts
- Slip ringSlip ringA slip ring is a method of making an electrical connection through a rotating assembly. Slip rings, also called rotary electrical interfaces, rotating electrical connectors, collectors, swivels, or electrical rotary joints, are commonly found in electric motors, electrical generators for AC...
s - Pretensioners
- Retractors
- Sensors
- Accelerometers
- Airbags
- Hybrid III dummy models
- Inflator models
Sheetmetal forming with LS-DYNA
One of LS-DYNA's most widely used applications is sheetmetal 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
Aerospace industry applications
LS-DYNA is widely used by the aerospace industry to simulate bird strikeBird strike
A bird strike—sometimes called birdstrike, avian ingestion , bird hit, or BASH —is a collision between an airborne animal and a man-made vehicle, especially aircraft...
, jet engine blade containment, and structural failure.
Aerospace applications for LS-DYNA include:
- Blade containment
- Bird strike (windshield, and engine blade)
- Failure analysis
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 (heart valves)
- Metal cutting
- Earthquake engineeringEarthquake engineeringEarthquake engineering is the scientific field concerned with protecting society, the natural and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels...
- Failure analysis
- Sports equipment (golf clubs, golf balls, baseball bats, helmets)
- Civil engineering (offshore platforms, pavement design)
External links
- LSTC Company Website
- LS-DYNA and d3VIEW blog by Suri Bala d3VIEW is a web-based tool that "extracts information from LS-DYNA generated “d3hsp” files and presents it in a concise, user-friendly format" online. The blog also contains further documentation on LS-DYNA, such as a history and outlook on LS-DYNA by Dr. Benson.
- LS-DYNA Support Site
- Papers from European and International LS-DYNA User Conferences
- Examples and Class Notes for Download
- Information on Performance on different Hardware
- LS-PrePost Site Free download of LS-PrePost for creating LS-DYNA input files and evaluating LS-DYNA output. The website also has extensive documentation and tutorials.
- NCAC Finite Element Model Archive Contains dozens of free models of vehicles, highway barriers, benchmark models, and more for use with LS-DYNA.