LS-DYNA recent developments

Recent Developments

Brian WainscottOasys LS-DYNA UK Users’ Meeting

January 28, 2016Solihull

• Introduction

• LS-OPT

• Elements

• ALE

• Implicit

• CFD

• Electromagnetics

• Particle Methods

• Metal Forming

• Frequency Domain

• Meshfree Methods

Outline

Explicit/Implicit

Heat Transfer

ALE & Mesh Free i.e., EFG, SPH, Airbag Particle

User InterfaceElements, Materials, Loads

Acoustics, Frequency Response, Modal Methods

Discrete Element Methods

Incompressible Fluids

CESE Compressible Fluids

Electromagnetics

Future: Control systems

LS-DYNA – Current Capabilities

Includes coupled Multi-Physics, Multi-Scale , and Multi-Stage in one Scalable Code

Multi-physics and Multi-stageStructure + Fluid + EM + Heat Transfer

Implicit + Explicit ….

Multi-scaleFailure predictions, i.e., spot welds

Multi-formulationslinear + nonlinear + peridynamics + …

The Neon crash model is courtesy of FHWA/NHTSA National Crash Analysis Center.

Single Model for Multiple DisciplinesManufacturing, Durability, NVH, Crash, FSI

LS-DYNA – One Code , One Model

LS-OPT

LS-OPT

• Simulation-based Multidisciplinary Optimization.

• Seamlessly integrated with LS-DYNA

• Interfaces with a large number of pre/post-processors & 3rd party solvers.

• Support web page: www.lsoptsupport.com

• The main analysis and optimization features of LS-OPT:

• Design Improvement and Optimization (MDO/MOO)

• System Identification

• Reliability-Based Optimization/Robust Design Optimization

• Outlier Analysis

• Network-based job scheduling

• Enhancements for Version 5.1 include interfaces for new solvers , enhanced modeling and optimization methods and enhanced graphical post-processing features.

LS-OPT MDO: Vehicle Crash and Body Dynamics

6 Crash Modes + Body Dynamics Mode:

- approximately 3 million element models

Allen Sheldon, Ed Helwig (Honda R&D)

LS-OPT Shape Optimization of Lower Bumper Stiffener

Design Vars: 4 Morphing Shapes

Objective: Min. weight

Constraints:

Ultrasim Failure Values < 0.6

All Ped Pro requirements fulfilled

Original contour

Baseline

Optimum: 7% mass reduction

Andreas Wuest (BASF)

Elements

Thick Shell: Types 5 & 7

• Thick Shells are like Solid Elements

• 8 nodes per element

• Assumed strain within the element

• Use the solid material models

• Thick Shells are like Shell Elements

• Layers in the thickness direction

• Type 5: 1 integration point per layer, VERY FAST!

• Type 7: 4 integration points per layer

Bridging Solids and Shells

thickness

thicknessthickness

Thick Shell: Types 5 & 7

• Thick Shells are NOT like Solid Elements

• Poor aspect ratio in the thickness direction

• Single element without stacking multiple solid elements

• More integration points through the thickness for bending

• Thick Shells are NOT like Shell Elements

• They are “thick” with a non-zero transverse normal stress

Bridging Solids and Shells

Shell Thick Shell Solid

A Clamped Square Plate subjected to a sudden point load at the center

4x4x1 10x10x1

Poor Aspect Ratio: Length = 1.0, Thickness = 0.02, Explicit Analysis

A: T-Shell Type 5 B: T-Shell Type 7

Thick Shell for T-Joint

Shell 16 Thick Shell 5Solid -2(Reference Solution)

490 Nodes198 Elems

Thick Shell 7

490 Nodes198 Elems

225 Nodes192 Elems

39325 Nodes30720 Elems

Non-conforming meshes

• Single layer of T-Shells for each panel

• Support variable thickness

• Support *CONTACT_TIED_NODE_SURFACEto tie non-conforming meshes between

panels

Models with different elements give consistent results.

Thick Shell for Composites

• Each layer has its own material property:

• Thickness, material type, fiber direction.

• Symmetric or Asymmetric lamination

• A first order shear deformation theory assumes:

• Transverse shear stress for each layer

• High order transverse shear strain for each layer

Sandwich panel Symmetric layers Asymmetric layers

High order Shear Stress for laminated composites

Parabolic Shear stressfor homogeneous materials

A Sandwich Beam under a Distributed Load

Case 1: Sandwich Beam Case 2: Asymmetric Beam

A/C: Solid Element B/D: Thick Shell

Material 1 (Red): E1=73.4 GPa Material 2 (Blue): E2=0.286 GPa E1/E2=257

Reference Solution: 36 solid elements through the thickness

One T-Shell element in the thickness12 layers within *PART_COMPOSITE

Case 1: Sandwich Beam

Remesh during runtime

Dynamic mesh refinement - initial horizontal crack

torque torque

opposite side of the crack


Dynamic mesh refinement - initial vertical crack

torque

initial vertical crack

Dynamic mesh refinement - initial horizontal crack

right

bending


Left

S-ALE Overview

• Structured ALE mesh automatically generated

• User specifies mesh spacing information along three directions

• Smaller input deck; Easier modifications to the mesh; Less I/O time.

• Shorter calculation time

• Sorting, searching faster and more efficient;

• SMP, MPP, MPP-Hybrid supported

• Redesigned algorithm enabled SMP parallelization and hence MPP Hybrid.

• Enhanced MPP efficiency

• More accurate and less memory

•A rewritten leaner, cleaner code using less memory to accommodate larger problems.

Solver MAX Memory (words) Clock Time (s)

ALE 414M 312

S-ALE 158M 199

* 48 CPU MPP Single Precision for a underwater explosion problem of 2.4M elements

S-ALE Time Saving

• Time saving in a Bridgestone tire rolling in mud model

ALE S-ALE Reduction

Total Time 30941s 20120s 34.97%

FSI 15449s 5726s 63%

Advection 7595s 6642s 12.55%

134400 ALE solid elements; Simulation time 2000ms.Single precision MPP 48 cpus without special decomposition

Implicit

Implicit update

• Rotational Dynamics

• available since R8.0

• adds additional stiffness terms due to rotations including Gyroscopic and spin softening

• Enable the study of vibration of rotating parts (turbine blades, propellers in aircraft and rotating disks in hard disk drives etc.).

• Campbell Diagrams can be generated to represent system's eigen-frequencies as functions of rotating speeds.

Implicit update

• Brake squeal

• Is the result of friction-induced vibration.

• Has been a challenging issue due to its immense complexity

• Complex eigenvalue analysis and transient analysis are the two

simulation methods used to investigate the brake squeal problem.

• With our complex eigensolver, LS-DYNA provides a multi-step

solution, a combination of the complex eigenvalue analysis and

transient analysis

disk

Pads (top and bottom)

Damping Ratio is defined as -2*Re(λ) / |Im(λ)|, where λis the eigenvalue. When negative, the mode is unstable.

Reuse of Symbolic Factorization

• Very Large Models in MPP can have wall clock time dominated by the Symbolic Factorization (a serial bottleneck we are still trying to fix)• Customer was using 1024 MPI processes and 6 SMP threads for a 7M node

version of this fan blade model.

• Symbolic Factorization was taking 2600 seconds (WCT)

• Numeric Factorization was taking 150 seconds.

• As a short term fix we have implemented two enhancements. • The first enhancement is to monitor the matrix structure from matrix

reformation to matrix reformation. If the matrix structure is the same from the last numeric factorization to the current one we reuse the symbolic factorization.

• The second enhancement is an MPP only feature. We predict the contact pattern for penalty based (non-tied) contact to allow small changes in the matrix structure due to changes in the contactbetween time steps.

• Reuse reduced WCT for time step by over 90%

A CFD solver for incompressible flows (ICFD solver).

Fully implicit.

Automatic volume mesh generation including boundary layer mesh.

Turbulence models for RANS/LES.

SMP and highly scalable MPP versions available.

Free surface flows

Porous media flow

Coupled to the structural and thermal solver

ICFD Solver Introduction

ICFD for Drag Analysis

• This study applies ICFD to unsteady flow analysis in the pitching motion of a 1/4 scale car model.

• The model was based on a real production car and obtained by smoothing the body surface relative to that of the actual vehicle, and by removing elements such as the engine compartment, underside components, and the suspension.

• Of primary interest is the difference between the aerodynamic forces acting on adynamic car model versus a stationary model.

• The results are validated through comparisons with those obtained by high accuracy academic CFD codes with a computational grid of 48 million elements.

“Analysis of Unsteady Aerodynamics of a Car Model in Dynamic Pitching Motion Using LS-DYNA® R7”, Yusuke Nakaeetc., 13th International LS-DYNA Users Conference

ICFD for Drag Analysis

• Static cases 1~3

• Dynamic cases

CFD + Thermal analysis example

CAD geometry Surface mesh

Automatic Volume meshing CFD + Thermal analysis

Results of CFD + Thermal Analysis

Thermal analysis for engine and exhaust.

Pressure contour Turbulent flow around a car

ICFD+FSI analysis

Structural pressure and Stress

ICFD – Pressure forces on a body

Fuel tank sloshing

Sloshing tank divided by a highly flexible Neoprene material

ICFD for porous media

• generalize Navier-Stokes equations to allow the definition of sub-domains with different permeability/porosity.

• The flow of a Newtonian fluid through a rectangular channel with a thick porous layer is considered

ICFD + Thermal for porous media


• It is known that the cooling-air flow passing through engine compartment, radiator interferes with external flow.

• This study performs CFD simulations of the car models with an engine compartment containing a radiator.

“Analysis of Unsteady Aerodynamics of a Car Model with Radiator in Dynamic Pitching Motion”, Y. Nakae, 10th European LS-DYNA Conference 2015


“Analysis of Unsteady Aerodynamics of a Car Model with Radiator in Dynamic Pitching Motion”, Y. Nakae, 10th European LS-DYNA Conference 2015

Isotropic and anisotropic porous media models

Free surface flow impacting on an a porous matrix made of three materials: two anisotropic materials immersed in a isotropic material.

EM and conjugate heat transfer: An electric current connected to the coil generates heat which is transferred to the fluid. The heat induces a flow motion due to natural convection.

ICFD – Conjugate Heat Transfer + EM

Electromagnetics

Electromagnetic solver in LS-DYNA

• Applications include:

• Magnetic Pulse Forming

• Magnetic Pulse Welding

• Induction welding

• Battery crash modeling

• Induction heating

• Resistive heating

• Electromagnetic spot welding

• Coil design and optimization

• Contact: rail gun, short circuits

• Generation of ultra high magnetic fields

Magnetic Metal Forming (MMF)

Use one sided die

(Optional - none

metallic die)

Can be combined

with any other

forming technology

Achieve higher

formability than

traditional methods

Can produce

Sharp corners and

fine details

Greatly reduced

springback and good

stress distribution

Die

Sheet

Blankholder

PunchCoilwindings

Combined deep drawing + MMF

Courtesy of Y. Kiliclar, IUL, TU Dortmund

movie_002.wmv

movie_002.wmv

Magnetic Pulse Welding

MPW is a solid state cold welding

generated by high speed collision between two metals at room temperature

Sub millisecond

weld time

Dissimilar

metals

High performance

joining,thinner

parts

No heat

affected zone

Different

shapes

Simulations are used to determinethe collision parameters (3D) to insure a good weld.

Courtesy of G. Mazars, Bmax, France

Particle Methods

*AIRBAG_PARTICLE – *CONTROL_CPM

*CONTROL_CPM

FORM NP2 NCPMTS CPMERR SFFDC

SFFDC : Scale factor of force decay constant (Default=1.0) Allowable arrange 0.01 to 100. (dev 97346)

Particle impact force is gradually applied to airbag segment by a special smoothing

function with the following form.

𝐹apply = 1 − 𝑒−𝑑𝑡

𝑆𝐹𝐹𝐷𝐶∗𝜏 ∗ 𝐹current + 𝐹stored

Where τ is the force decay constant stored in LS-DYNA.

SFFDC= 0.5 1.0 5.0

• Automatically shift all time dependent curves used in

– *AIRBAG_PARTICLE

– *MAT_FABRIC

Allow user to disable the bag by Tdeath

Allow user to set RIGID to DEFORMABLE switch

*AIRBAG_PARTICLE – *SENSOR_CPM_AIRBAG

*SENSOR_CPM_AIRBAG

$ CPMID SWITID TBIRTH TDEATH TDR FDEFPS RBPID

*AIRBAG_PARTICLE – IAIR=-1

IAIR=1 IAIR=-1

External Vent

• At the beginning of the bag inflation, the bag pressure may drop below

ambient pressure due to jetting. When IAIR=-1, it will allow external

vents to draw in outside air.

It gives better speed opening rolled bags by tracking the gas front.

It stores the number of collisions from resident air and inflator particles

and uses this data to track the inflator gas front and rolled region.

Inflator particles do not transfer energy to resident air particles, to prevent

prematurely deploying the rolled region. The energy of the initial air

should be small compared with the incoming energy.

The tracking algorithm can be switched off and all features will become

the same as IAIR=2.

IAIR=4 is not a replacement of IAIR=2.

*AIRBAG_PARTICLE – IAIR=4


IAIR=2

IAIR=4

Instances in time (42.5ms)Courtesy of Autoliv

Chamber 8 and 9


IAIR=2

42.5ms: Pressure history of chamber 8 and 9Courtesy of Autoliv

IAIR=4

*PARTICLE_BLAST– Real Gas Law

Set-up for free face tests Set-up for numerical simulation

D. Johansson et al., Int. Mining and Mineral Engineering, 2011

Explosive

Air

Front View Top View

140 mm

280 mm

8,10,12mm

Particle blast simulation of blast fragmentation of a mortar cylinder

Diameter of hole (mm) PETN strength (g/m)

Case1 12 40

Case2 10 20

Case3 8 20

Case4 8 10


Courtesy of Changping Yi , Luleå University of Technology


2ms 20ms5ms

C. Yi et al., 11th International Symposium on Rock

Fragmentation by Blasting, 2015

Local enlargement


Numerical Results Experimental Results

Xave(mm) Xmax(mm) Xave(mm) Xmax(mm)

Case1 8.37 48.36 8.30 40.4

Case2 18.08 54.59 15.13 48.3

Case3 17.75 46.36 14.94 52.4

Case4 28.50 56.70 25.49 78.1

C. Yi et al., 11th International Symposium on Rock Fragmentation by Blasting, 2015

1. Friction Stir Welding

2. SPH to SPH contact

SPH Enhancements

Double sided FSW 600 RPM, 1200 mm/min(plastic work and friction energy to heat)Courtesy of Kirk A. Fraser @ PredictiveEngineering

Temperature ContoursMaterial Mixing

Extended SPH thermal solver for SPH form 7 and 8

Friction Stir Welding

V

Multiple impacts with Keyword: SECTION_SPH_INTERACTION

Define the different type of interactions between SPH parts.

Metals withStandard interactions

Ceramic with node to node contacts

SPH Interaction

1. Discrete Element Sphere

2. Discrete Element Method with Bond

Discrete Element Method

*DEFINE_DE_TO_SURFACE_COUPLING

Node To Surface Coupling

INJECTION box as source of DES

Why a new N2S contact?• Consider rolling friction• Automatically treat liquid bridge for wet particles• Coupling considers traction force (use stationary segments to

model moving conveyor belt )

Throwing a pie in the face, Courtesy of Kazuya, Lancemore

*DEFINE_DE_TO_SURFACE_TIED

Tied Node to Surface Coupling

Wear prediction

Discrete Element Method (DEM)

Archard’s wear law:

A

vfWEARCh tn **

Form different shapes of particles using DEM

DEM Bond Type I Example

DE Bond Type

Simple links, truss or beam, etc…Peridynamics

Particle-particle interaction

Particle Gas

P1 P2BOND

1<->2

P3

P6

P5

P4DEM bond

DEM1) Node to Node

2) Node to Beam

3) Node to Segment

4) Node to Volume

Coupled Multi-Physics Solvers

Tank sloshing with fluid and vapor (node to node contact)Density ratio ~ 1000

SPH to SPH Contact

SPH and SPH Coupling

CPM and DES Contact

CPM and DES Coupling

Courtesy of Changping Yi , Luleå University of Technology

DES to Beam Contact

Node to Beam Coupling

DES to Segment Contact

Node to Surface Coupling

# of processors LS-DYNANational Lab DEM

Code

20 6158 6360

40 3733 4498

60 2669 3769

80 2152

Metalforming

Rigid Body Mesh Check/Fix

• Element Normal Check / fix

– Mesh generators are not always reliable in giving high quality tool mesh (very long, overlapped elements, with inconsistent element normals)

– Manual repair by user in pre-processor is time consuming and error-prone

– Simulation with bad elements has high possibility to get unrealistic results

• Physical offset of rigid tools

– In stamping simulation, it is common both upper and lower tools overlap each other in the home position

– Negative offset is used (MST is negative)

– With penetration, contact can be confused. Occasionally, unexpected results are obtained

• Keyword: *CONTROL_FORMING_AUTOCHECK

– automatically check and fix the rigid body mesh

– Automatically offset the rigid tool physically based on the MST values specified in contact definitions


• Example of automatic mesh repair

Section cut:

contact problem found

Section cut:

normal contact between the tools and

the blank

Adaptivity for Sandwich Structures

• Example of sandwich part structure

• Top and bottom layers use shell element

• Middle layer use solid element

• Elements in top layer share nodes with solid element in top surface

• Elements in bottom layer share nodes with solid element in bottom surface


Adaptive algorithmMesh refinement in the planeNo refinement in the thickness direction


• Example

Frequency Domain Analysis

Frequency Domain Analysis

• FRF

• SSD

• Random Vibration

• Response Spectrum Analysis

• BEM Acoustics

• FEM Acoustics

• SSD Fatigue

• Random Fatigue

• NVH of automotives and air planes

• Acoustic design and analysis

• Defense industry

• Fatigue of machines and engines

• Civil and hydraulic engineering

• Earthquake engineering

Applications

Velocity

Acoustic Impedance

Pressure

New boundary conditions for FEM acoustic features

Use acoustic Impedance boundary condition

to model the sound absorbing material (like

the interior surface of roof or floor)

Use pressure boundary condition to

model the window or other openings

cv

pz

n

Characteristic impedance

FEM Acoustics

FEM Acoustics – Pressure Boundary

0 pressure b.c. to model

the opened window

In this example, the opened window is

simulated using 0 pressure boundary

condition. The blue area in the d3acs

pressure plot clearly indicates the 0

pressure zones.

No. of Nodes: 114221

No. of elements: 643619

FEM Acoustics – Acoustic Eigenvalue Analysis

Mode LS-DYNA Other software

1 3.93144E-06 6.698696E-06

2 8.10808E+01 8.108078E+01

3 1.25457E+02 1.254568E+02

4 1.47780E+02 1.477799E+02

5 1.52190E+02 1.521901E+02

6 1.72872E+02 1.728723E+02

7 1.98448E+02 1.984481E+02

8 2.08590E+02 2.085895E+02

9 2.14581E+02 2.145808E+02

10 2.23230E+02 2.232297E+02A closed compartment model

Eigenvector for the 2nd mode

LS-DYNA

*FREQUENCY_DOMAIN_ACOUSTIC_FEM

_EIGENVALUE

aiaiia NiMK ,1][2

aiaaa FpMCjK ][2

New databases:

•EIGOUT_AC

•D3EIGV_AC

Other software

FEM Acoustics – Acoustic Eigenvalue Analysis

Mode LS-DYNA Other software

1 6.79551E+01 6.795506E+01

2 1.03346E+02 1.033460E+02

3 1.47853E+02 1.478530E+02

4 1.58211E+02 1.582106E+02

5 1.74781E+02 1.747807E+02

6 1.87460E+02 1.874595E+02

7 2.10906E+02 2.109057E+02

8 2.14993E+02 2.149934E+02

9 2.28861E+02 2.288609E+02

10 2.50667E+02 2.506669E+02

A compartment model with

windows open

Eigenvector for the 1st mode

LS-DYNA Other software

R

eAp

ikRi

zyxiki Aep

*FREQUENCY_DOMAIN_ACOUSTIC_INCIDENT_WAVE

Spherical wave Plane wave

Card 1 1 2 3 4 5 6 7 8

Variable TYP MAG XC YC ZC

Type I F F F F

Default 1 None None None None

MAG Magnitude of the incident sound wave

GT.0: constant magnitude,

LT.0: |MAG| is a curve ID, which defines the frequency dependent magnitude. See

*DEFINE_CURVE.

VARIABLE DESCRIPTION

BEM Acoustics – Incident Acoustic Wave

Use frequency dependent magnitude in acoustic incident wave

Acoustic fringe plot

*FREQUENCY_DOMAIN_ACOUSTIC_FRINGE_PLOT_{OPTION}

Options:

PART

PART_SET

NODE_SET

SPHERE

PLATE

Existing structure components

LS-DYNA generates mesh automatically

Results (D3ACS):

• Real part of acoustic pressure

• Imaginary part of acoustic pressure

• Absolute value of acoustic pressure

• Sound Pressure Level (dB)

Supported by LS-PrePost 4.2 and above

Purpose:

Define field points for acoustic pressure computation and use D3ACS binary database to visualize the pressure distribution.

Acoustic fringe plot

R = 5000 mm

DENSITY = 15

No. of new nodes: 1178

No. of new elements: 1176

*FREQUENCY_DOMAIN_ACOUSTIC_FRINGE_PLOT_{SPHERE}

Equivalent Radiated Power (ERP) calculation

nnFF VVcERP 2

1

Calculation of ERP is a simple and

fast way to characterize the structure

borne noise. It gives the user a good

look at how panels contribute to total

noise radiation. It is a valuable tool in

early phase product development.

The ERP density is defined as

S

abs dSERPERP

The ERP absolute is defined as

*FREQUENCY_DOMAIN_SSD_{ERP}

)/(log10 10 refabsdB ERPERPERP

The ERP in dB is defined as

ERP calculation results are saved in

• Binary database

d3erp

• ASCII xyplot files ERP_abs ERP_dB

ERP calculation example

For a simplified engine model, a

constant horizontal acceleration 0.02g

is given on the base, for the range of

frequency 10-1000 Hz.

ERP density (d3erp)

ERP calculation example

ERP density (d3erp)Nodal force applied at

engine attachment point

With ERP, one can

study the contribution

to the radiated noise

from each panel.

SSD Fatigue

New stress index for SSD fatigue analysis

*FREQUENCY_DOMAIN_SSD_FATIGUE

Card 3 1 2 3 4 5 6 7 8

Variable STRTYP NOUT NOTYP NOVA

Type I I I I

Default 1 1 1 1

STRTYP Stress index used in fatigue analysis:

EQ.0: Von Mises stress,

EQ.1: Maximum principal stress,

EQ.2: Maximum shear stress.

VARIABLE DESCRIPTION

STRTYP=0

(Von Mises)

Peak damage

ratio 1.705

STRTYP=1

(Max principal)

Peak damage

ratio 1.585

STRTYP=2

(Max shear)

Peak damage

ratio 1.518

New

Statistical Energy Analysis (ongoing development)

*FREQUENCY_DOMAIN_SEA_SUBSYSTEM*FREQUENCY_DOMAIN_SEA_CONNECTION*FREQUENCY_DOMAIN_SEA_INPUT_POWER

1 10 100 1.e3 1.e4 2.e4

Deterministic(FEM/BEM)

Statistical(SEA)

SEA is a statistical method for studying

vibration and acoustics in high frequency

ranges, without using elements or mesh.

In SEA a system is represented in terms

of a number of coupled subsystems and

a set of linear equations are derived that

describe the input, storage, transmission

and dissipation of energy within each

subsystem.

Frequency (Hz)

Subsystem i

(Ei, i)

Subsystem j

(Ej, j)

Pi

Pid

Pj

Pjd

Pij

Pji

SEA model of 2 subsystems

Statistical Energy Analysis example

Simplified passenger compartment

Loading is given on Floor Fender_right_front Fender_left_front Windshield

Meshfree Methods

• Adaptive FEM/EFG solid is available for Implicit thermo-mechanical coupled analysis.• Allows local refinement and has high accuracy. • Is suitable for forging and extrusion simulations with spring-back analysis.

Work piece

Top tool

Effective plastic strain contour

Adaptive FEM/EFG Solid Method

98

(b)(a) (c)

Comparison of pressure contours: (a) displacement-based meshfree Galerkin method (b) displacement-based meshfree Galerkin method with pressure smoothing and (c) presented method.

• Available for explicit and implicit analyses.• 5-noded Meshfree-enriched Finite element

method (MEFEM) is inf-sup stable.• Only available in LS-DYNA.

Courtesy of Yokohama Rubber Co.

MEFEM Method for Unit Cell Composite Analysis

Discrete Dislocation Dynamics (DDD) Method

• Mobility: mobbcc0

• One initial dislocation line:

• Glide plane:

• Burger vector:

• Shear modulus: 1

Poisson’s ratio: 0.305

• Dislocation core radius: 288.7

Annihilation distance: 144.3

• Applied stress field

• largest time step 1.0e7

• Mesh size between

110

111

3

2 1

10 2 1

1 1

111

1000,2000

• Developed for discrete dislocation analysis for applications IC industry.• Works for single crystal materials.• Only available in LS-DYNA.

Courtesy of Taiwan Semiconductor Manufacturing Company

Frank-Read Source

Shear Band

Temperature field

von Mises stress

Courtesy of Taiwan Semiconductor Manufacturing Company

• Developed for continuous dislocation analysis for applications IC industry.• Works for single crystal materials.• Will be available in LS-DYNA soon.

Single Crystal Plasticity Method

Effective Plastic Strain contour

Von Mises stress contour

Contact Force

A Low-speed Ball Penetrating through a Metal Plate

• Pure particle method.• Using existing FEM mesh.• No element/particle erosion or manual cut of the model.• Time steps do not drop.

Bottom view

Top view

EPS Contour

• Allows non-uniform FEM mesh and multiple SPG parts.

Upper plate Lower plate


Self-pierce Riveting (SPR) Analysis

Cutting Speed = 10 m/s

Explicit Dynamic Analysis

Aluminum

ρ0=2.7×10-6 kg/mm3

E=78.2GPa

v=0.3

σy=0.29(1+125ep)0.1

Strain-based failure criteria εfail = 0.5

Low-speed Oblique Metal Cutting Analysis

Time-Punch Force

Pressure Contour (Cross-section view)

∆t=7.69~8.16 ×10-8

Effective Stress Contour (Cross-section view)

Hole Punching in Metal

FDS model

Rigid

Constant v

Solid plates (SPG)



Courtesy of Ford Motor Co.

Single Layered Flow-drilling Screw (FDS) Analysis

FDS model

Rigid

Constant v

Solid plates (SPG)




Two-Layered Flow-drilling Screw (FDS) Analysis


• Allows multiple cracks.• Allows sharing nodes with

FEM

Metal Tearing Test

LS-DYNA recent developments

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