Prediction of wear in a dumper truck body by coupling SPH-FEM and

DEM/FEM

Dan Forsström Pär Jonsén

Patric Waara

Agenda

• Background to the project • Field measurements • Modeling • Material model • Wear analysis • Ongoing work • Conclusion

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SSAB Light Weight Dumper Body

• Develop the free hanging concept

• Dumper body design • Wear resistant design • Investigate computer

wear simulations.

Wear results (SSAB Light Weight Dumper)

Max: 0,75 mm/1000h Mean: 0,50 mm/1000h

Max: 0,7 mm/1000h Mean: 0,4 mm/1000h

Max: 0,40 mm/1000h Mean: 0,30 mm/1000h

Max Mean: 0,3 mm/1000h

Running in: 337h Wear measurement : 480h Total operation time : 817h

Blast rock 55%

Primary crucher

45%

Rock size distribution

Results field measurements

• Ultrasonic thickness measurements on two designs.

• Similar work conditions on

both designs. • The analysis shows highest

at entrance on plate 1, 2.

Smoothed Particle Hydrodynamics (SPH) method

• Invented 1977

• Mesh free Lagrangian

• Particle representation

• Continuum method

• Extreme deformations

• Explicit time integration

• Available in LS-Dyna

2 ½0 1 2[3( )]vmf a a p a pσ= − + +

G [kPa] K [MPa] a0 [Pa2]

a1 [kPa]

a3

600 16.5 0 476 -0.1461

Granular material model

• Loaded with 35 tons of blasted granite.

• Constitutive relation to govern the

interaction between particles. • 50000 particles with the radius of

50 mm to simulate actual load case.

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Pressure distribution in a cross section Present dumber body SSAB Light weight dumper body

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SPH Smoothed particle hydrodynamics

Present dumber body SSAB Light weight dumper body

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Wear analysis

Present dumber body SSAB Light weight dumper body

Load intensity=∫ p v dt, p=pressure, v=velocity, t=time

Interpolated results Delauany triangulation

Wear in tipper body

• Field measurement on tipper body.

• DEM simulation to calculate the contact pressure.

• Discrete Element Method (DEM),Cundall (1971) • Alternating Newton’s 2:nd law and force

displacement law from contacts • Rigid particles • Granular material and fluids • Available in LS-Dyna

Discrete Element Method (DEM)

DEM-FEM model

Hertz Mindlin contact model

Unloading of a tipper body

Simulation on a tipper body

Results

Conclusion

• Two numerical method using SPH/FEM and DEM/FEM combination is used to predict the working condition of a dump truck.

• A correlation between the

pressure map from experimental measurements and numerical simulations are obtained.

• A realistic time scale

compared to the experimental measurements is used in all simulation.