Updating a CAE model (FEM or CFD) to the experimental acquired shape is a key step in the Quality Assessment Process. A workflow based on RBF mesh morphing is proposed and demonstrated on a research case: the wind tunnel test article of the European FP7 project RIBES. www.rbf-morph.com

1. RBF update of CAE models
on actual manufactured
shapes
Prof. Marco Evangelos Biancolini – University of Rome “Tor
Vergata”

2. Outline
Feb 2017RBF Morph
2
 Robust design
concepts
 Update of CAE
model of
manufactured part
 Standard methods
 RBF methods
 RIBES wing
example

3. Robust design concepts
Feb 2017RBF Morph
3
 The actual manufactured shapes represent the
nominal geometry within a prescribed tolerance
 The effect on performances can be predicted in
advance (mesh morphing and RS method are typically
adopted)
 The effect on performances can be evaluated after
manufacturing (an update of CAE models is required!)
 The same concepts can be applied to parts that passed
QA (i.e. deviations within prescribed tolerances) as well
to off-design parts (for instance repaired ones)

4. CAE update workflow
 Main advantages
 No need to generate a new CAD
 No need to generate a new mesh
 Cloud of acquired points can be
directly filtered using RBF
 An STL can be used as input
 Fast process that keeps the same
mesh
 Main disadvantages
 RBF filtering technique has to be
mastered
 Computational intensive
 Main advantages
 Accurate geometry quality
control
 Updated CAD available
 Main disadvantages
 Highly skilled CAD user
required
 CAD reconstruction is a long
and complex process
 Remesh required
 Comparison with baseline
CAE mesh requires
interpolation
Feb 2017
4
RBF Morph
RBF based CAD based

5. CAE based
Feb 2017RBF Morph
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 Acquired geometry available as:
 a cloud of points (usually automatic
triangulation and filtering available)
 regular points scanned on 3d-curves (curve
fitting)
 New surfs can be built as:
 automatic multipatch
 parametric surfaces
 Once the new CAD is built the CAE model
has to be regenerated (new mesh and set-
up)

6. RBF based
Feb 2017RBF Morph
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 Acquired geometry available as:
 a cloud of points (usually automatic
triangulation and filtering available)
 regular points scanned on 3d-curves (curve
fitting)
 Direct surface mesh update:
 Experimental points are projected onto the
original CAD
 A field moving points from original to acquired
position results
 The field is filtered using RBF regression
(rbf4noisy)

7. RBF based
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 CAD acquired surf update:
 Direct projection on CAD entities in RBF Morph ACT
for Workbench
 STL projection on meshes in RBF Morph SA/Fluent
Add On
 FEA mesh update:
 Updated surfaces are controlled
 RBF set-up for mesh morphing completed using
RBF Morph
 A quick comparison between original and actual geo
can be conducted on the same FEA model

8. RIBES EU Project
 Radial basis functions at fluid Interface Boundaries to
Envelope flow results for advanced Structural analysis
 JTI-CS-2013-GRA-01-052
Feb 2017
8
RBF Morph

9. RIBES test article
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 WT test article built as an aeronautical wing box.
Manufacturing fidelity is tricky, especially at the leading edge
because of the thickness of the skin.

10. RIBES test article
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 The shape of the manufactured part has been recorded using
a contact profilometer at 8 cross sections of the airfoil, some
noise is observed in the experimental data.

11. RIBES test article
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 A new CAD has been manually defined by fitting the 8 curves
(filtering out the noise) and connecting them in the span
direction.

12. RIBES test article
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 The update of the
volume mesh can be
achieved using the
new CAD.
 RBF Morph (ACT
Extension for WB)
interact with the BREP
(multiple surfaces,
virtual topology can be
considered)
 Projection works with a
single face projection

13. RIBES test article
Feb 2017RBF Morph
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 The update of the
volume mesh can be
achieved using the
new CAD.
 RBF Morph (ACT
Extension for WB)
interact with the BREP
(multiple surfaces,
virtual topology can be
considered)
 Projection works with a
single face projection

14. RIBES test article
Feb 2017RBF Morph
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 The update of the volume
mesh can be achieved
using the new CAD.
 RBF Morph (Stand Alone
and Fluent Add On )
comes with a projection
tool based on the implicit
surface
 The airfoil has been split
in 3 surfaces (double wall
issues at trailing edge)

15. RIBES test article
Feb 2017RBF Morph
15
 The update of the volume
mesh can be achieved
using the new CAD.
 RBF Morph (Stand Alone
and Fluent Add On )
comes with a projection
tool based on the implicit
surface
 The airfoil has been split
in 3 surfaces (double wall
issues at trailing edge)

16. RIBES test article
Feb 2017RBF Morph
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 The update of the volume
mesh can be achieved
using the new CAD.
 RBF Morph (Stand Alone
and Fluent Add On )
comes with a projection
tool based on the implicit
surface
 The airfoil has been split
in 3 surfaces (double wall
issues at trailing edge)

17. RIBES test article
Feb 2017RBF Morph
17
 The update of the volume
mesh can be achieved
using the new CAD.
 RBF Morph (Stand Alone
and Fluent Add On )
comes with a projection
tool based on the implicit
surface
 The airfoil has been split
in 3 surfaces (double wall
issues at trailing edge)

18. RIBES test article
Feb 2017RBF Morph
18
 The update of the volume
mesh can be achieved
using the new CAD.
 RBF Morph (Stand Alone
and Fluent Add On )
comes with a projection
tool based on the implicit
surface
 The airfoil has been split
in 3 surfaces (double wall
issues at trailing edge)

19. RIBES test article
Feb 2017RBF Morph
19
 The update of the volume
mesh can be achieved
using the new CAD.
 RBF Morph (Stand Alone
and Fluent Add On )
comes with a projection
tool based on the implicit
surface
 The airfoil has been split
in 3 surfaces (double wall
issues at trailing edge)

20. RIBES test article
Feb 2017RBF Morph
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 A direct method which
consists in RBF filtering
the acquired points
(rbf4noisy) can be used
 Experimental points are
projected onto the
baseline CAD to create a
field
 The field is filtered
according to the retained
spatial wavelength

21. RIBES test article
Feb 2017RBF Morph
21
 A direct method which
consists in RBF filtering
the acquired points
(rbf4noisy) can be used
 Experimental points are
projected onto the
baseline CAD to create a
field
 The field is filtered
according to the retained
spatial wavelength

22. RIBES test article
Feb 2017RBF Morph
22
 A direct method which
consists in RBF filtering
the acquired points
(rbf4noisy) can be used
 Experimental points are
projected onto the
baseline CAD to create a
field
 The field is filtered
according to the retained
spatial wavelength

23. Geometries comparison
RBF Morph
CAD

24. CAD RBF
Morph
CL 0.3132 0.3135
CD 145.9 dc 144.8 dc
Aerodynamic solutions
CAD
RBF Morph
Pressure

25. Related topics
Feb 2017RBF Morph
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 RBF4ARTIST a system that allows to use an haptic
device to directly insert individual control points
https://youtu.be/74yjd7ZWcNk
 RBF4METRO a system for compensation of
metrological data (correction field defined using CAE)
 Robust design using mesh morphing to define a
shape parametric CAE model
 Local update of a large dead mesh using local CAD
(original and target) and RBF

26. Conclusions
Feb 2017RBF Morph
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 RBF technology can simplify and shorten the
update of the CAE model onto the actual
measured shape
 Powerful RBF noise filtering tools available
 Final Update of the CAE model using mesh
morphing
 To learn more about RBF technology of RBF
Morph consider a visit of our web site www.rbf-

27. biancolini@ing.uniroma2.it
Many thanks for your kind
attention!
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