the relevant scale for mechanical modelling in additive ... · the relevant scale for mechanical...

The relevant scale for mechanical modelling in additive manufacturing

technologiesSofiane Guessasma1 & Sofiane Belhabib2

1INRA, research unit BIA, Nantes, France sofiane.guessasma@inra.fr

2IUMR CNRS GEPEA, University of Nantes, France sofiane.belhabib@univ-nantes.fr

Basics of FE simulation in structural mechanics

Complex load/geometry + simple mechanical law

Complex mechanical response + simple load configuration

Complexity in both mechanical law + configuration

Fused filament (FDM)

Stereolithography

Droplet-based

Materialdiscontinuity

Source of complexity: material discontinuities

Mechanical response in additive manufacturing

Mechanical response in additive manufacturing

Mechanical response in additive manufacturing

Mechanical response in additive manufacturing

Comsol model:Handelling raster effect filament crossing sequence +45°/‐45°

Regular meshing (2.7 M dof)

Building direction

X’

Y’

Z

In‐plane (XY)

XY

Fused Deposition modelling: printing angle

Local property distribution

Topological law: Young’s modulus = 45°

= 30°= 0°

1.00

1.051.101.151.201.251.30

E (GPa)

Compression behaviour

Heteregeneous strain field

Positive strain Poisson’s expansion

Crack opening (mixed mode)

Explaining effect of raster on performance

Comsol predictions

3D imaging

CAD-based modelling:

Compression performance of

cellular structures

Comparison between FE and

experimental Young’s moduli

Strain field100 150 200 250 300 350 400100

150

200

250

300

350

400

Pre

dict

ed (M

Pa)

Experimental (MPa)

Filament-based simulation R²=0.87 Design-based simulation R²=0.46

Perfect matching

100 150 200 250 300 350 400100

150

200

250

300

350

400

Pre

dict

ed (M

Pa)

Experimental (MPa)

Filament-based simulation R²=0.87 Design-based simulation R²=0.46

Perfect matching

100 150 200 250 300 350 400100

150

200

250

300

350

400

Pre

dict

ed (M

Pa)

Experimental (MPa)

Filament-based simulation R²=0.87 Design-based simulation R²=0.46

Perfect matching

Heterogeneous strain field based on implementation of Filament-trajectory

Filament-based modelling: Best

fit to experimental

conditions

Conclusions

Relevant scale for FE modelling in additive manufacturing : microstructural heterogeneity

Conclusions Filament-based FE simulation: lack of cohesion

between filament + process-induced porosity

Conclusions Unrealistic predictions from CAD-based models

Conclusions Complex deformation mechanisms guided by

process conditions (printing angle)