Numerical Coupling Dem Fem-minecrush 2010 Ragc v2

8/4/2019 Numerical Coupling Dem Fem-minecrush 2010 Ragc v2

http://slidepdf.com/reader/full/numerical-coupling-dem-fem-minecrush-2010-ragc-v2 1/39

Nicolas Spogis, Ph.D.; Daniel Nasato, Eng.ESSS Brasil – www.esss.com.br

Rafael Angelo Tozzo, Eng.VALE – www.vale.com

Andrés González - M.Sc. ; Víctor SandovalESSS Chile – www.esss.cl

NUMERICAL COUPLING BETWEEN DEM (DISCRETEELEMENT METHOD) AND FEA (FINITE ELEMENTS

ANALYSIS).

http://www.esss.com.br/

http://www.vale.com/

http://www.esss.cl/

http://www.esss.cl/


http://www.esss.com.br/



Nicolas Spogis, Ph.D.Business ManagerE-mail: [email protected]

Daniel Nasato, Eng.Business AnalystE-mail: [email protected]

Rafael Angelo Tozzo, Eng.Mechanical EngineeringE-mail: [email protected]

Authors

Andrés González, M.Sc.Account ManagerE-mail: [email protected]: +56 (2) 946 -1941Cel: +56 (9) 9319-1576

Víctor SandovalNew Business Manager

E-mail: [email protected]: +56 (2) 946 -1941Cel: +56 (9) 9319-1593

www.esss.cl www.vale.com

mailto:[email protected]





http://www.esss.cl/



http://www.esss.cl/








FlorianópolisBrazil

São PauloBrazil

Rio de JaneiroBrazil

SantiagoChile

ESSS at a Glance

ESSS develops, markets, and supports

engineering simulation software to shorteningand improve product development cycles in abroad range of industries, by technologytransfer or providing simulation services.

WHAT WE DO

SINCE 1995 LOCATIONS

15 years providing the most comprehensivesimulation solutions to the market.

NEW OFFICES



VALE at a Glance

• Vale is the world’s second-largestmining and metal company in market

value, with assets of more than

US$ 100 billion.

• Vale is the global leader in the

production and export of iron ore.• In 2006, Vale became the world’s

largest nickel producer after the

acquisition of the Canadian company

Inco.

• Vale is a global company

headquartered in Brazil, with a

workforce of over 100,000 employees,

including outsourced workers.



1º

- Objectives

2º

- DEM Method

3º

- EDEM ANSYS Coupling

4º

- Validation & Real Case

5º

- Conclusions

Agenda



Objectives

• Develop an 1-way coupling between

Discrete Element Method (DEM) and

Finite Element Method (FEM).

• Propose a numerical validation to

evaluate the method accuracy.

• Simulate a transfer chute using the

developed method to solve a realproblem.



1º- Objectives

2º - DEM Method

3º - EDEM ANSYS Coupling

4º- Validation & Real Case

5º - Conclusions



• Governing equations for the translational and rotational

motion of particle i with mass m i and moment of inertia I i :

DEM Method - Mathematics

• vi and ωi are the translational and angular velocities of particle i ,

• Fc ij and Mij are the contact force and torque acting on particle i by particle j

or walls,

• Fnc ik is the noncontact force acting on particle i by particle k or other

sources,

• Ff i is the particle –fluid interaction force on particle i,

• Fg i is the gravitational force.



• To detect contacts between particles and structure, EDEM splits the

geometry in triangular surface mesh (StL file format), a 3-dimensional

surface geometry;

• The surface is tessellated or broken down logically into a series of

small triangles (facets);

• Each facet is described by a perpendicular direction and three points

representing the vertices (corners) of the triangle.

DEM Contact Detection



Track each

particle andboundary element

Detect contact

between elements

Calculate contact forces oneach particle

Calculate bodyforces acting on

each particle:gravity, fluid drag,electrostatic, …..

Update particle accelerationand velocity

Update particle and boundaryelement positions

DEM Method - Basic Numerical Cycle



1º- Objectives

2º - DEM Method



5º - Conclusions



EDEM-ANSYS Coupling

• EDEM was used as Discrete Element Method (DEM) tool and ANSYSwas used as Finite Element Method (FEM) tool.



EDEM-ANSYS 1-way couplingSetup ANSYS Model Run EDEM Model

Export EDEM

LoadsCreate Named

Surface

Interpolate Loads

Python Script

And ANSYS APDL

Solve and EvaluateANSYS Results



EDEM-ANSYS coupling methods

• 1-Way DEM-FEA

– Coupling - Steady State

– Static Structural Analysis

• 1-Way DEM-FEA

– Coupling - Transient – Transient Structural Analysis

• 2-Way DEM-FEA

– Coupling - Transient

Developed

Under development

Force

Displacement



• Load is transferred from EDEM to ANSYS using a conservative

interpolation;

• Each element face is divided into n number of IP faces, where n is the

number of nodes on the face;

• IP faces are converted onto a two-dimensional polygon;

• Polygons on the sending side are intersected with the IP polygons on

the receiving side;

• The polygon intersection creates many overlapped areas used totransfer loads between the two sides.

Interpolation Method



• During interpolation, the total force balance over the surface is

preserved.

• For loss less data transfer between particle and structural code, both

numerical models must be coincident in space

Interpolation Method



1º- Objectives

2º - DEM Method



5º - Conclusions



Validation Tests

• It was built a small box with 1x1x1m in EDEM and it was created 2000

particles with 40mm diameter and 2500kg/m3 density;

• It was performed 3s of simulation to ensure that particles have no

velocity in Y direction;

• Total forces (X, Y and Z) and surface mesh nodes position are

exported from EDEM in a single time step.

• Force on Y direction calculated on EDEM was compared with

analytical results.



Validation Tests

• Test 1 - ANSYS coarse mesh,

EDEM coarse mesh

• Test 2 - ANSYS intermediate mesh,

EDEM coarse mesh

• Test 3 - ANSYS refined mesh,EDEM coarse mesh

Analytical EDEM force Test 1 - Coarse Test 2 - Intermediate Test 3 - Refined

Force Y (N) 1643,8 1645,8 1575,2 1617,6 1663,5

Error % 0,1 4,3 1,7 1,1



• Case Vale – Mina de Brucutu

Industrial Application

Modeling of ore flows and

loads on transfer‐chutes.

A case study for Vale Brucutu

using EDEM and Ansys.



Geometry

•

Geometry directly importedfrom CAD on ACIS (.sat)format.

•Simulation:•Conveyor belt•Transfer chute•Vibrating screens

•Dynamics:•Sinusoidal translation

•Sinusoidal rotation•Moving plane (for belt)



• Mass flow: 8492 t/h

• Conveyor velocity: 3.52 m/s

• Particle diameter: 25 mm

• Particle shape: Single sphere

• Dynamic repose angle: 20˚

• Static repose angle: 30˚

• Moisture: 8%

• Iron Ore density: 2500kg/m³

• Ore / Ore Interaction:• Coeff. of Restitution: 0.4

• Static friction: 0.65

• Rolling friction: 0.1

•

Ore / Belt Interaction (rubber):• Coeff. of Restitution 0.3



• Ore / Structure Interaction (steel)• Coeff. of Restitution 0.3



Material properties



EDEM Factory

•Mass Flow:•8492 t/h – 2.3589 ton/s•Aprox. 30000 particles/s



Conveyor dynamics

Belt Angle Vtotal Vy VzSlice 1 18,919 3,520 m/s -3,330 m/s 1,141 m/s

Slice 2 19,658 3,520 m/s -3,315 m/s 1,184 m/s

Slice 3 9,890 3,520 m/s -3,468 m/s 0,605 m/s

Cylinder Radius 0,659 m

Perimeter 4,141 m

Vtotal 2,816 m/s

RPS 0,680

RPM 40,805



Screen dynamics

x y z

Right Screen 6,87 7,92994 11,9179 996 16,6 0,5697

Left Screen 2,086 7,8384 12,0042 996 16,6 0,4988

6 DOF centerRPM Hz Angle



EDEM Results



EDEM Results

High impact velocities zones – Wear and structural problems.



EDEM Results



Screen force distribution

High impact velocities zones(up to 7 m/s) on screen.

Wear and structural problems.

High forces on chute discharge.



Unbalanced forces

Unbalanced forces on screen generated bywrong chute discharge.



Time varying forces

-8000,00

-6000,00

-4000,00

-2000,00

0,00

2000,00

4000,00

6000,00

0,00 5,00 10,00 15,00 20,00 25,00 30,00

Total Force X (N)

-15000,00

-10000,00

-5000,00

0,00

5000,00

10000,00

15000,00

20000,00

0,00 5,00 10,00 15,00 20,00 25,00 30,00

Total Force Y ( N)

-140000,00

-120000,00

-100000,00

-80000,00

-60000,00

-40000,00

-20000,00

0,00

20000,00

0,00 5,00 10,00 15,00 20,00 25,00 30,00

Total Force Z ( N)



0

10000

20000

30000

40000

50000

60000

1 2 3 4 5 6

T o t a l F o r c e

( N )

X direction bin group

Total force on screen width

30.05

30.10

30.15

30.20

30.25

30.30

30.35

30.40

30.45

30.50

• Unbalanced forces; – Picks reaches 20 times higher forces

between one extreme to another.

Force Distribution

• EDEM can split the domain into smallfraction (Bins) to do local analysis;

– Domain was split into 8 regions in X-direction, in order to investigate unbalancedforces.

EDEM ANSYS coupling Conservative



EDEM-ANSYS coupling – ConservativeInterpolation

The developed scripts and macros automatically interpolatesEDEM forces (normal and tangential) on the structural

elements.



Total Deformation Equivalent Strain

Static Structural Analysis

The Static Analysis performed shows stresses& Strains under the yield limit OK



Modal AnalysisMode 1 - 3.3647 Hz Mode 2 - 6.874 Hz Mode 3 - 14.121 Hz

Mode 4 - 21.454 Hz Mode 5 - 25.309 Hz Mode 6 - 26.261 Hz



FFT – Fast Fourier TransformationMode 1 - 3.3647 Hz

-8000.00

-6000.00

-4000.00

-2000.00

0.00

2000.00

4000.00

6000.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Total Force X (N)

-15000.00

-10000.00

-5000.00

0.00

5000.00

10000.00

15000.00

20000.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Total Force Y (N)

-140000.00

-120000.00

-100000.00

-80000.00

-60000.00

-40000.00

-20000.00

0.00

20000.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Total Force Z (N)

3.2031

3.3984

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

0 1 2 3 4 5

FFT Magnitude X

3.2031

3.3984

3.5938

0

100000

200000

300000

400000

500000

600000

700000

800000

0 1 2 3 4 5

FFT Magnitude Y

3.203125

3.359375

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

5000000

0 1 2 3 4 5

FFT Magnitude Z

RESONANCE !!!



1º- Objectives

2º - DEM Method



5º - Conclusions

Bulk Handling & Structural Problems?!



Bulk Handling & Structural Problems?!...Coupled SIMULATION can solve them!

Structural Problems

(FEA Simulation)

Bulk Handling Problems

(DEM Simulation)Coupled Problems

Static & Dynamic effects of

ore in equipment

Material Degradation &

SegregationUnbalanced Load

Inadequate SupportsChute Clogging & Uneven

Feed

High Ore impact in the

equipment Structure

Fatigue Cracking Conveyor Belt misalignmentEquipment Weight reduction Energy Efficiency

Wrong Springs (screens) Screen Performance

Mineral Crushing

(Particle Breakage)

Spillage & Dust

Rats Holes in Discharges



Conclusions

DEM can solve industrial bulk

material handling problems.

FEA can solve structural analysis

problems.

DEM-FEA coupling can give the right

structure for the

best particle flow!

Documents

Numerical Coupling Dem Fem-minecrush 2010 Ragc v2