micro molding
Wear simulation of tribosystems Dr. Vishwanath Hegadekatte University of Karlsruhe
Prof. Norbert Huber
GKSS Forschungszentrum Geestacht GmbH Hamburg University of Technology
Abaqus Germany User Conference 2007 Baden-Baden, Germany 18 Sept 2007 SFB 499 · Design, production and quality assurance of molded micro-components made from metals and ceramics Dr. V. Hegadekatte: Wear simulation of tribosystems 1
Contents
1.
Motivation and strategy
2. Numerical Tools: GIWM, WP, UM 3. Pin-on-disc tribometer 4. Twin-disc tribometer 5. Summary
Dr. V. Hegadekatte: Wear simulation of tribosystems
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Motivation
SFB 499 Model System: Micro-planetary gear train
Micromachines are finding a wide variety of applications High surface to volume ratio High operating speeds Wear is a critical factor which can limit their life span Dr. V. Hegadekatte: Wear simulation of tribosystems
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GIWM (Global Incremental Wear Model) V. Hegadekatte et al., Tribology Letters, 2006, 24, 51 - 60.
FN ΔV = k Δs H = k D FN Δs Δh = k D pΔs FN p= 2 πai
Assumptions Archard’s wear law FN u= Average contact pressure over circular contact area 2 EC ai Assumes axisymmetric wear on pin surface Normal elastic displacement taken into account (Oliver & Pharr, 1992) Linear wear integrated over sliding distance Dr. V. Hegadekatte: Wear simulation of tribosystems
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Wear-Processor (WP) Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Update Update Surface Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
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Wear-Processor (WP) Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Update Update Surface Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
Wear-Processor (WP) Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Update Update Surface Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
Wear-Processor (WP) Pin Wear
Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Update Update Surface Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
Wear-Processor (WP) Pin Wear
Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Disc Wear Surface Update Update Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
Wear-Processor (WP) Pin Wear
Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Disc Wear Surface Update Update Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
Wear-Processor (WP) Wear Processor
FEM FEM (ABAQUS) (ABAQUS) Update Update Surface Surface Topography Topography (Re-meshing) (Re-meshing)
Compute Compute Wear Wear
V. Hegadekatte et al., Modelling Simul. Mater. Sci. Eng., 2005, 13, 57 - 75.
Dr. V. Hegadekatte: Wear simulation of tribosystems
UMESHMOTION (UM)
Δh = k D pΔs
User-defined subroutine in ABAQUS For defining motion of nodes in an Adaptive Meshing constraint node set Eulerian analysis for sweeping the nodes Material quantities are remapped using Lax-Wendroff method Equilibrium is corrected by re-solving the last time increment
Dr. V. Hegadekatte: Wear simulation of tribosystems
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Pin-on-disc: GIWM V. Hegadekatte et al., Tribology Letters, 2006, 24, 51 - 60.
Prediction
Fit
Si3N4 in Air GIWM can fit pin-on-disc experimental results GIWM can also predict pin-on-disc experimental results when load is doubled Dr. V. Hegadekatte: Wear simulation of tribosystems
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WC-Co in Water
hexperiment
hGIWM
Wear Depth, h
Friction Coefficient, µ
GIWM: Water lubrication
Normal Load,
Dr. V. Hegadekatte: Wear simulation of tribosystems
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Pin-on-disc: WP & GIWM
Si3N4 in Air
V. Hegadekatte et al., Tribology Letters, 2006, 24, 51 - 60.
Dr. V. Hegadekatte: Wear simulation of tribosystems
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Twin-disc
Dr. V. Hegadekatte: Wear simulation of tribosystems
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Twin-disc
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: UMESHMOTION (UM) For one rotation, θ = 2π
hi +1 = hi + k D
prdθ ∫ θ =0
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: UMESHMOTION (UM) For one rotation, θ = 2π
hi +1 = hi + k D
prdθ ∫ θ =0
For a given time increment of Δti θ =2π
Δti | (V1 −V2 ) | hi+1 = hi + kD prdθ ∫ 2πr θ =0 Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: UMESHMOTION (UM) For one rotation, θ = 2π
hi +1 = hi + k D
prdθ ∫ θ =0
For a given time increment of Δti θ =2π
Δti | (V1 −V2 ) | hi+1 = hi + kD prdθ ∫ 2πr θ =0 Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: UMESHMOTION (UM) For one rotation, θ = 2π
hi +1 = hi + k D
prdθ ∫ θ =0
For a given time increment of Δti θ =2π
Δti | (V1 −V2 ) | hi+1 = hi + kD prdθ ∫ 2πr θ =0 Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM & UM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM & UM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM & UM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM & UM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM, UM & WP
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM, UM & WP
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: GIWM, UM & WP
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: Expt. & GIWM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: Expt. & GIWM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: Expt. & GIWM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Twin-disc: Expt. & GIWM
Dr. V. Hegadekatte: Wear simulation of tribosystems
Micro Planetary Gear Train: WP
Dr. V. Hegadekatte: Wear simulation of tribosystems
Summary Experiment Verification
GIWM
Wear-Processor / UMESHMOTION
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• •
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Fast tool for quick identification Wear Model (Global Scale) Limitations – Geometries, wearing surface
• •
Wear Model (Local Scale) Ideal for studies of local effects Different Geometry Computationally Expensive
Verify each other Dr. V. Hegadekatte: Wear simulation of tribosystems