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- 1 -Copyright © 1994~2010 by THEME Engineering, Inc.

Multi-Physics Capability of LS-DYNA®

Theme Engineering, Inchttp://www.theme-eng.co.kr


ONE CODE STRATEGY

Combine the multi-physics capabilities

• Explicit/Implicit solver• Heat Transfer• ALE• EFG, SPH, Airbag particle method• Acoustics • Interfaces for users, i.e., elements, materials, loads• Incompressible fluids (version 980)• CESE compressible fluid solver (version 980)• Electromagnetics (version 980)

into one scalable code for solving highly nonlinear transient problems to enable the solution of coupled multi-physics and multi-stage problems.


LS-DYNA APPLICATIONS

Automotive• Crash and Safety• Durability• NVH

Aerospace• Bird strike

• Containment• Crash

Manufacturing• Stamping• Forging

Structural• Earthquake safety• Concrete structures

Electronics• Drop analysis• Package design• Thermal

Defense• Weapon design• Blast response• Penetration• Underwater shock analysis

Others • Biomedical• Sports• Consumer products• Etc.


LS-DYNA Version 971 R4 & R5


IMPLICIT

MPP Implicit Improvement

- Ex) 6 cylinders with contacts / 1,014,751 nodes / 921, 600 solids 3,034,944 order of Linear Algebra Problem

*CONTROL_IMPLICIT_STATIC_CONDENSATION

- Superelement can run with Reduced Linearized model

- Superelement can export Nastran DMIG to LS-DYNA binary

- *ELEMENT_DIRECT_MATRIX_INPUT_{BINARY}

*CONTROL_IMPLICIT_MODES

- Define constraint/attachment and extract eigen mode

- Craig-Bampton linear representation using constraint and eigenmodes

No. of Processors

Elapsed Time Speed Up

4 36911

8 18443 2.0

16 9012 2.0

32 5263 1.7

64 3073 1.7

128 2313 1.3


• Contact

1. Heat transfer by the GAP

2. Radiation

3. Heat transfer by the CONTACT

*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_THERMAL_FRICTIONCID

Heat Transfer


• Cooling Method 1 : Cooling by the boundary condition

LCID : Temp VS Time

* BOUNDARY_TEMPERATURE_OPTIONNSID / NID LCID CMULT LOC

Cooling

• Cooling Method 2 : Bulkflow

Fluid Flow

Pipe / Die

Fluid flow

Bulk Node

Surface Layer

Contact


ALE(FSI) Updates

*ALE_AMBIENT_HYDROSTATIC, *INITIAL_HYDROSTATIC_ALE

- Initializing and prescribing hydrostatic pressure in ALE liquids

*CONTROL_ALE2D

- Implemented ALE2D (Plane Strain, Surface Weighted Axisymmetric) and mapping to ALE3D


ALE Updates

ALE ambient type5

- Coupled with *LOAD_BLAST_ENHANCED where in pressure and velocity BC applied to ALE Ambient

LOAD_BLAST_ENHANCED

- BLAST=1 : Hemispherical surface burst2 : Spherical free-air burst 3 : Air Burst - Moving non-spherical warhead, 4 : Air Burst - Ground reflected wave, Mach stem wave


EFG & SPH Updates

EFG(Element Free Galerkin) Updates

• Adaptive Remeshing

- Implicit/Explicit, Solids/Shells, SMP/MPP

• MPP Thermal solver : Adaptive Solids

• EFG Fracture capability : Tetra element

• Switch EFG Formulation by time and other parameters

• Mesh free shells

- Adaptive remeshing, *MAT_ADD_EROSION

- Ex) Full Car NCAC Crash model with 100% EFG Shells

SPH(Smooth Particle Hydrodynamics) Updates

- Add thermal effects for 2D and 3D SPH elements : *MAT_T01 (*MAT_THERMAL_ISOTROPIC)

- Add 3D SPH elements avalable for *MAT_022 (*MAT_COMPOSITE_DAMAGE)


AIRBAG

Corpuscular Particle Method (CPM)

• Gas Dynamics(Gas mixtures)

- Particle-to-structure momentum transfer option

- Moving point sources and multiple inflators

- Airbag deployment in moving vehicle

- Robust contact algorithms for tightly folded bags

- Fabric porosity

- Treat external and internal vents

- Blockage considered for porosity and venting

- Switch from particle method to control volume to save CPU time

- SMP/MPP


ACOUSTIC SOLVER

*BOUNARY_ELEMENT_METHOD_ACOUSTIC

- BEM (Accurate)

- Rayleigh, Kirchhoff methods (Approximate method)

FFT

LS-DYNA nonlinear FEM analysis

Velocity (pressure) in time domain

Velocity (pressure) in frequency domain

Rayleigh KirchhoffBEM

Sound pressure (Pa), SPL (dB) for target points

Velocity in frequency domain given by user

Model information

FEM part34412 Nodes

27616 Solid elements

BEM part6313 Nodes

6272 Shell elements

Frequency range1,000 – 20,000 hz


LS-DYNA Version 980


INCOMPRESSIBLE FLOW SOLVER

• 3-D time-accurate incompressible Navier-Stokes

• Error Control, Automatic Meshing, Adaptive Remeshing

• MPP implementation

• Separate meshes for fluid and structure

• Weak and Strong FSI coupling

• Coupling to explicit and implicit structural solvers

• Multi-fluid and Free-Surface flows

• Turbulent model : LES and RANS models

LS-DYNA Version 980

g = (0,0,-1)

Density=0.5

Density=0.1

Free Surface (P=0)

Free Slip

Bubble Drop: High Resolution Interface Capturing and Adaptive Re-Meshing


COMPRESSIBLE FLOW SOLVER

• CESE (Conservation Element and Solution Element) - by Dr. Chang, NASA, 1991

• Applications :

- All speed compressible flows (subsonic, hypersonic)

- Especially for high speed flows with complex shock patterns

- Acoustics (noise), Chemical reaction flows, Cavitating flows

• Advantages of CESE method for compressible flow :

- Flux conservations in space and time (locally & globally)

- 2nd order accurate

- Novel & simple shock-capturing strategy

- Both strong shocks and small disturbances

- Boundary conditions can be implemented easily & accurately

• Current Status

- Codes : SMP/MPP implementation

- Flows : Compressible inviscid & viscous flows

- Meshes : Hexahedra, wedges, tetrahedra

- BCs : Regular BCs (solid, open, inflow, outflow, symmetric)Moving or Rotating solid boundaries for viscous flows (in tangential directions)

LS-DYNA Version 980


ELECTROMANETIC SOLVER

• Methods :

- BEM only

- Full coupling between the FEM (solid) and the BEM (air)

- FEM(Solid) + FEM(Air) method with automatic remeshing of air mesh

• Fully coupled with the mechanics and the thermal solver

• Shells, Hexahedra, Wedges, Tetrahedra

• Adaptivity

• Extra Boundary Conditions (Symmetric, periodic, etc)

• MPP Implementation

• EOS for conductivity vs temperature

• Outputs : Current density, EM field, Lorentz force, Vector potential, Joule Loss, etc

• Applications : EM Sheet forming, Hemming, Welding etc.

LS-DYNA Version 980


Update Hybrid III Rigid-FE & H3 50

17

• Model stability and response improved

• Customer feedback incorporated

• Further improvements planned


LS-DYNA Information

www.lstc.com/lspp

LS-Prepost Download & Online

Tutorial #1~17

www.feainformation.com

Download Application avi file

multi-physics capability of ls-dyna - pace | · pdf filels-dyna information ls-prepost...

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