LS-DYNA
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LS-DYNA is an advanced general-purpose multiphysics simulation software package developed by the former Livermore Software Technology Corporation (LSTC), which was acquired by Ansys in 2019. 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 Finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical models, mathematical modeling. Typical problem areas of interest include the traditional fields of structural ...
(FEA) using explicit time integration. LS-DYNA is used by the
automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...
,
aerospace Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial, and military applications. Aerospace engineering consists of aeronautics and astron ...
,
construction Construction are processes involved in delivering buildings, infrastructure, industrial facilities, and associated activities through to the end of their life. It typically starts with planning, financing, and design that continues until the a ...
and
civil engineering Civil engineering is a regulation and licensure in engineering, professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads ...
,
military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. Militaries are typically authorized and maintained by a sovereign state, with their members identifiable by a d ...
,
manufacturing Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of the secondary sector of the economy. The term may refer ...
, and
bioengineering Biological engineering or bioengineering is the application of principles of biology and the tools of engineering to create usable, tangible, economically viable products. Biological engineering employs knowledge and expertise from a number ...
industries.


History

LS-DYNA originated from the 3D FEA program DYNA3D, developed by Dr. John O. Hallquist at
Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a Federally funded research and development centers, federally funded research and development center in Livermore, California, United States. Originally established in 1952, the laboratory now i ...
(LLNL) in 1976. DYNA3D was created in order to simulate the impact of the Full Fuzing Option (FUFO) or "
Dial-a-yield Variable yield, or dial-a-yield, is an option available on most modern nuclear weapons. It allows the operator to specify a weapon's yield, or explosive power, allowing a single design to be used in different situations. For example, the Mod-10 ...
" 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. Though the FUFO bomb was eventually 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 In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer. Since a computer, at base, only ...
was released into the
public domain The public domain (PD) consists of all the creative work to which no Exclusive exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly Waiver, waived, or may be inapplicable. Because no one holds ...
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 The Cray-1 was a supercomputer designed, manufactured and marketed by Cray Research. Announced in 1975, the first Cray-1 system was installed at Los Alamos National Laboratory in 1976. Eventually, eighty Cray-1s were sold, making it one of the ...
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 VAX (an acronym for virtual address extension) is a series of computers featuring a 32-bit instruction set architecture (ISA) and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century. The V ...
/ VMS,
IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...
,
UNIX Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
, COS operating system compatibility. At this point, DYNA3D became the first code to have a general single surface contact algorithm.
Metal forming In metalworking, forming is the fashioning of metal parts and objects through mechanical deformation; the workpiece is reshaped without adding or removing material, and its mass remains unchanged. Forming operates on the materials science princ ...
simulation and composite analysis capabilities were added to DYNA3D in 1987. This version included changes to the shell elements, and
dynamic relaxation Dynamic relaxation is a numerical method, which, among other things, can be used to do " form-finding" for cable and fabric structures. The aim is to find a geometry where all forces are in equilibrium. In the past this was done by direct modelling ...
. 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. In 2019, LSTC was acquired by Ansys, Inc.


Typical uses

Nonlinear means at least one (and sometimes all) of the following complications: * Changing
boundary condition In the study of differential equations, a boundary-value problem is a differential equation subjected to constraints called boundary conditions. A solution to a boundary value problem is a solution to the differential equation which also satis ...
s (such as contact between parts that changes over time) * Large deformations (for example the crumpling of
sheet metal Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Thicknesses can vary significantly; extremely thin sheets are considered foil (metal), foil or Metal leaf, leaf, and pieces thicker than 6 mm (0.25  ...
parts) * Nonlinear materials that do not exhibit ideally
elastic Elastic is a word often used to describe or identify certain types of elastomer, Elastic (notion), elastic used in garments or stretch fabric, stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rub ...
behavior (for example
thermoplastic A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular weight. The polymer chains as ...
polymers A polymer () is a substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, b ...
) Transient dynamic means analyzing high speed, short duration events where
inertia Inertia is the natural tendency of objects in motion to stay in motion and objects at rest to stay at rest, unless a force causes the velocity to change. It is one of the fundamental principles in classical physics, and described by Isaac Newto ...
l
force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...
s are important. Typical uses include: * Automotive crash (deformation of
chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of a manufactured object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...
,
airbag An airbag is a vehicle occupant-restraint system using a bag designed to inflate in milliseconds during a collision and then deflate afterwards. It consists of an airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. ...
inflation,
seatbelt A seat belt, also known as a safety belt or spelled seatbelt, is a vehicle safety device designed to secure the driver or a passenger of a vehicle against harmful movement that may result during a collision or a sudden stop. A seat belt reduce ...
tensioning, ...) * Explosions (underwater
mine Mine, mines, miners or mining may refer to: Extraction or digging *Miner, a person engaged in mining or digging *Mining, extraction of mineral resources from the ground through a mine Grammar *Mine, a first-person English possessive pronoun M ...
s,
shaped charge A shaped charge, commonly also hollow charge if shaped with a cavity, is an explosive charge shaped to focus the effect of the explosive's energy. Different types of shaped charges are used for various purposes such as cutting and forming metal, ...
s, ...) * Manufacturing (sheet metal stamping, ...)


Characteristics

LS-DYNA consists of a single executable file and is entirely command-line driven. Therefore, all that is required to run LS-DYNA (besides some licensing infrastructure) is a command shell, the appropriate executable for the computer's architecture, an input file, and enough free disk space to store the results. Input files use a simple
ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...
format and thus can be prepared using any
text editor A text editor is a type of computer program that edits plain text. An example of such program is "notepad" software (e.g. Windows Notepad). Text editors are provided with operating systems and software development packages, and can be used to c ...
. Many third-party simulation environments integrate some LS-DYNA preprocessing capabilities. LSTC also develops its own preprocessor
LS-PrePost
which is freely distributed, runs without a license, and can also be used for viewing and postprocessing simulation results. 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'
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 used in 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. However the main strength of the software lies in highly nonlinear simulations of high-speed events, preferably involving the deformation of sheet metal. (For example a car crashing into a
traffic barrier Traffic barriers (known in North America as guardrails or guard rails, in Britain as crash barriers, and in auto racing as Armco barriers AK Steel (formerly Armco) genericized trademark) keep vehicles within their roadway and prevent them from co ...
.) Several variants of algorithms and multiphysics expansions were added to use these core capabilities in special fields. (For example the
deep drawing Deep drawing is a sheet metal forming process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch. It is thus a shape transformation process with material retention. The process is considered "dee ...
of steel sheets by electromagnetic forces or by explosives.) One example of a simulation that involved a unique combination of several features is the
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
JPL The Jet Propulsion Laboratory (JPL) is a federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by California Institute of Technology (Caltech) researche ...
Mars Pathfinder ''Mars Pathfinder'' was an American robotic spacecraft that landed a base station with a rover (space exploration), roving probe on Mars in 1997. It consisted of a Lander (spacecraft), lander, renamed the Carl Sagan Memorial Station, and a ligh ...
landing, which simulated the gas and fabric of inflating
airbag An airbag is a vehicle occupant-restraint system using a bag designed to inflate in milliseconds during a collision and then deflate afterwards. It consists of an airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. ...
s around the spaceship, and the subsequent impact and bouncing of the assembly on the martian soil. LS-DYNA's analysis capabilities: * Full 2D & 3D capabilities * Nonlinear dynamics * Rigid body dynamics * Quasi-static simulations *
Normal modes A normal mode of a dynamical system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation. The free motion described by the normal modes takes place at fixed frequencies. ...
* 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 (
MADYMO MADYMO (MAthematical DYnamic MOdels) is a software package for the analysis of occupant safety systems in the automotive and transport industries. The software was developed by the Netherlands Organization for Applied Scientific Research (TNO) a ...
, Cal3D) * Underwater shock *
Failure analysis Failure analysis is the process of collecting and analyzing data to determine the cause of a failure, often with the goal of determining corrective actions or liability. According to Bloch and Geitner, ”machinery failures reveal a reaction chain ...
* Crack propagation * Real-time
acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician ...
* Implicit springback * Multi-physics coupling * Structural-thermal coupling * Adaptive remeshing * SPH (
Smoothed particle hydrodynamics Smoothed-particle hydrodynamics (SPH) is a computational method used for simulating the mechanics of continuum media, such as solid mechanics and fluid flows. It was developed by Gingold and Monaghan and Lucy in 1977, initially for astrophysic ...
) * DEM (
Discrete element method A discrete element method (DEM), also called a distinct element method, is any of a family of numerical methods for computing the motion and effect of a large number of small particles. Though DEM is very closely related to molecular dynamics, t ...
) * EFG ( Element Free Galerkin) * Radiation transport * EM (
Electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...
)


Material Library

LS-DYNA's comprehensive library of material models: *
Metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...
s *
Plastics Plastics are a wide range of synthetic or semisynthetic materials composed primarily of polymers. Their defining characteristic, plasticity, allows them to be molded, extruded, or pressed into a diverse range of solid forms. This adaptab ...
*
Glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...
*
Foam Foams are two-phase materials science, material systems where a gas is dispersed in a second, non-gaseous material, specifically, in which gas cells are enclosed by a distinct liquid or solid material. Note, this source focuses only on liquid ...
s *
Fabric Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, and different types of fabric. At first, the word "textiles" only referred to woven fabrics. However, weaving is no ...
s *
Elastomer An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus (E) and high failure strain compared with other materials. The term, a portmanteau of ''ela ...
s *
Honeycomb A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic cells built from beeswax by honey bees in their beehive, nests to contain their brood (eggs, larvae, and pupae) and stores of honey and pol ...
s *
Concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...
&
soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
s *
Viscous Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup h ...
fluids * User-defined materials


Element Library

Some of the element types available in LS-DYNA: * Beams (standard, trusses, discrete, cables, and welds) (with over 10 beam element formulations) * Discrete Elements ( Springs and Dampers) * Lumped
Inertia Inertia is the natural tendency of objects in motion to stay in motion and objects at rest to stay at rest, unless a force causes the velocity to change. It is one of the fundamental principles in classical physics, and described by Isaac Newto ...
s * Lumped
Mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...
es *
Accelerometer An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration (the rate of change (mathematics), rate of change of velocity) of the object relative to an observer who is in free fall (tha ...
s *
Sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...
s *
Seat Belts A seat belt, also known as a safety belt or spelled seatbelt, is a vehicle safety device designed to secure the driver or a passenger of a vehicle against harmful movement that may result during a collision or a sudden stop. A seat belt reduce ...
** Pretensioners ** Retractors ** Sliprings * Shells (3, 4, 6, and 8-node including 3D shells, membranes, 2D
plane stress In continuum mechanics, a material is said to be under plane stress if the stress (mechanics), stress vector is zero across a particular plane. When that situation occurs over an entire element of a structure, as is often the case for thin plates ...
,
plane strain Plane most often refers to: * Aero- or airplane, a powered, fixed-wing aircraft * Plane (geometry), a flat, 2-dimensional surface * Plane (mathematics), generalizations of a geometrical plane Plane or planes may also refer to: Biology * Pl ...
, and
axisymmetric Rotational symmetry, also known as radial symmetry in geometry, is the property a shape has when it looks the same after some rotation by a partial turn. An object's degree of rotational symmetry is the number of distinct orientations in whic ...
solids) (with over 25 shell element formulations) * Solids (4 and 10-node
tetrahedron In geometry, a tetrahedron (: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular Face (geometry), faces, six straight Edge (geometry), edges, and four vertex (geometry), vertices. The tet ...
s, 6-node
pentahedron In geometry, a pentahedron (: pentahedra) is a polyhedron with five faces or sides. There are no face-transitive polyhedra with five sides and there are two distinct topological types. With regular polygon faces, the two topological forms are th ...
s, and 8-node
hexahedron A hexahedron (: hexahedra or hexahedrons) or sexahedron (: sexahedra or sexahedrons) is any polyhedron with six faces. A cube, for example, is a regular hexahedron with all its faces square, and three squares around each vertex. There are seven ...
s) (with over 20 solid element formulations) * SPH 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


Applications


Automotive crashworthiness & occupant safety

LS-DYNA is 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 A seat belt, also known as a safety belt or spelled seatbelt, is a Automotive safety, vehicle safety device designed to secure the driver or a passenger of a vehicle against harmful movement that may result during a collision or a sudden stop. ...
*
Slip ring A slip ring is an electromechanical device that allows the transmission of Electric power, power and electrical Signal, signals from a stationary to a rotating structure. A slip ring can be used in any Electromechanics, electromechanical system ...
s * Pretensioners * Retractors *
Sensors A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...
*
Accelerometers An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration (the rate of change of velocity) of the object relative to an observer who is in free fall (that is, relative to an inertia ...
*
Airbags An airbag is a vehicle occupant-restraint system using a bag designed to inflate in milliseconds during a collision and then deflate afterwards. It consists of an airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. ...
* Hybrid III dummy models * Inflator models


Sheetmetal forming with LS-DYNA

One of LS-DYNA's 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 used by the aerospace industry to simulate
bird strike A bird strike (sometimes called birdstrike, bird ingestion (for an engine), bird hit, or bird aircraft strike hazard (BASH)) is a collision between an airborne animal (usually a bird or bat) and a moving vehicle (usually an aircraft). The term ...
, jet engine blade containment, and structural failure. Aerospace applications for LS-DYNA include: * Blade containment * Bird strike (windshield, and engine blade) * Failure analysis


Military and defense applications

LS-DYNA is used extensively by researchers from military and defense. Some of these applications include: *
Explosion An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated ...
s (underwater Naval mine, shaped charges) * Projectile Penetration * Rail Gun * Warhead Design * Shockwave modelling


Oil and gas industry

LS-DYNA is used in oil and gas industries to perform fatigue analysis on offshore structures, failure analysis of ships under the event of collision, and simulate fluid structure interactions. LS-DYNA applications for oil and gas industry include: * Jacket Platform Analysis * Sloshing Analysis * Ice Impact * Wave and
Tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
Impact


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 engineering * Failure analysis * Sports equipment (golf clubs, golf balls, baseball bats, helmets) * Civil engineering (offshore platforms, pavement design)


References


External links


LSTC Company Website

Papers from European and International LS-DYNA User Conferences

Examples and Class Notes for Download

Training and Class Notes for Download

Download for Windows
{{CAE software Finite element software Finite element software for Linux Public-domain software with source code