simulation of advanced processes: welding & additive manufacturing cases studies

VIRFAC | The Virtual Factory

Finite Element Simulation of

Advanced Processes

Case Studies:

Welding & Additive Manufacturing

Copyright GeonX © 2014

Dr. Laurent D’Alvise

CEO & co-founder

www.geonx.com

[email protected]

TABLE OF CONTENTS

Cladding example

Welding example

Global picture

Virfac® | www.geonx.com

To control parts deformations during manufacturing …

Improving quality mastering before launching production !

To control residual stresses generated during manufacturing …

Assessing the impact of manufacturing on life and durability !

To understand the complex phenomena occurring during manufacturing and

the influence of process operating conditions …

Reducing scrap and improving cash return !

WELDING SIMULATION : WHY ?

© 2012-2014 GeonX – All rights reserved


OUR VISION

Physics simulation and modelling will help achieving these goals

GeonX is building the integrated Virtual Factory that will enable production

engineers to simulate before making !

NOT an expert tool for expert engineers

BUT a powerful software tightly integrated with manufacturing

machines and modern computing capabilities.


LET’S TAKE AN EXAMPLE !

Virfac® | www.geonx.com © 2012-2014 GeonX – All rights reserved

INPUT DATA From: Tanker Components: 2 Stiffened Panels (AH36) Dimensions: 3,48 x 16 m Thickness: 13 mm Weld Length: 16 m Objective: control distortions


Live visualization of temperature, deformations,

stresses, metallurgical transformations, etc.

TYPICAL OUTPUTS

1

-6

Y [mm]


TYPICAL OUTPUTS

Final deformation of the stiffened panels after 1 weldline operation.

Possibility to optimize the welding sequence, operating conditions, clamping

system, jig positions, etc. in order to minimize deformations.

Particularly well suited when the structure is complex and with a high number

of welds.

VIRTUAL WELDING, OR

ADVANCED WELDING SIMULATION


Welding objectives:

• Minimization of distortions

• Minimization of residual stresses (crack prediction)

• Optimization of weld joint properties (hardness) and microstructure

• Verification of weldability or defaults

Operating conditions to tune/optimize:

• the welding speed/energy

• the welding sequence

• the clamping or fixture setup

• and other operating conditions, if any

OUT

IN

IN Virtual

Welding OUT


Private Belgian company incorporated in October 2012

Specialized scientific and industrial software editing

Development of a new generation manufacturing software:

• The Virtual Factory, Virfac® powered by Morfeo: powerful user-interface (since 2012)

• Morfeo (Manufacturing ORiented Finite Element tOol): parallel FE solver (since 2003 in partnership with Cenaero)

The Virtual Factory Virfac® addresses the following processes:

•Fusion & Friction Welding (LBW, EBW, FSW, IFW, etc.)

•Additive Manufacturing (Cladding, etc.)

•Advanced Machining

•Damage tolerance and durability

•Welding → In-service behavior (crack propagation)

•For large industrial mechanical components

•Specifically designed for High Performance Computing systems

•Extensively tested on industrial and demanding applications

•Within the industrial environment (mimetic)

GEONX IN A NUTSHELL

GEONX SOFTWARE PRODUCT


Morfeo Virfac®


VIRFAC® IN A NUTSHELL


CAD modelling

Parasolid kernel library (Siemens PLM)

Import and export of Parasolid native file (x_t, xmt_txt, xmt_bin, x_b, …)

Model transformation (intersection, union, scaling, rotation, translation, etc.)

CAD geometry entities management (creation, destruction, …)

Import of other CAD format: translators for CATIA, Pro-E, IGES and STEP

Discrete model importer with cleaning functionalities

Meshing:

DISTENE MeshGems on Parasolid model for :

Surface triangulation

3D tetrahedra meshing

Size control – Face – Edge – Node – Curvature

Anisotropic meshing

Extruded unstructured meshes

Partnership with Beta-System (ANSA mesher)

TABLE OF CONTENTS

Cladding example

Welding example

Global picture


The present study aims to:

1. Use Virfac Welding for an application representative aerospace interests

2. Simulate the welding process on a exhaust carter and display distortions taking place

during the welding operations

3. Verify the influence of the welding sequence on the residual distortions

4. Compare two modelling approaches from a computing performance and accuracy

standpoints

Welding sequence n°1

Welding Sequence n°2


Transient Thermo-Mechanical analysis

Inherent Strain Method

EXAMPLE N°1 - OBJECTIVES


A “fake” exhaust carter was designed for non-confidentiality purposes:

1. External diameter : 200 mm

2. External ring thickness : 12 mm

3. Number of welds : 16

4. Nominal sequence: shown hereafter


APPLICATION DESCRIPTION


Experimental data:

1. Material : steel

2. Clamping system : central core

3. Welding process : LBW

4. Welding power : 800 W

Nominal welding sequence:

1. Distortions are magnified 40 times

2. External ring strongly deformed

3. Visible rotation of the part

4. Twist of the carter

5. Computation time: 21 minutes


RESULTS


Influence of the operating conditions:

1. Welding parameters

2. Clamping system

3. Welding sequence


MINIMIZATION OF DISTORTIONS


Influence of the welding sequence:


MINIMIZATION OF DISTORTIONS


Influence of the welding sequence:

Changing the welding sequence leads to a reduction of distortions:

• This information may be useful to address quality issues

• This information is available through a virtual environment prior any experimental test

• Timeframe for obtaining such results on this simple application:

Set the model with Virfac: ~4 hours

Computation time: 21 minutes per simulation

• Process optimization is possible within a virtual environment: Virfac Welding Scheduler

• Further results in terms of residual stresses and metallurgy are also possible:

full transient methodology : Virfac Welding Designer


PROCESS OPTIMIZATION

TABLE OF CONTENTS

Cladding example

Welding example

Global picture


The present lecture aims to:

1. Apply Virfac to laser cladding simulation and predict distortions after corrective

machining.

2. Demonstrate the feasibility and pertinence of manufacturing chaining simulation.

3. Perform sensitivity studies on the operating conditions and check the influence on

quality criteria in terms of residual distortions.


EXAMPLE N°2 - OBJECTIVES


Machining

Simple (for validation purposes) additive manufacturing application (laser

cladding: tube on support) followed by machining.

Additive Layer Manufacturing

Distortions, Residual Stresses and

Metallurgy from the T/M/M simulation

Final part within

geometrical tolerances


APPLICATION DESCRIPTION

• Large excursions of temperature • Cycling heat load over one location • Cycling material melting & solidification • Large excursions of material properties • Important metallurgical transformations

Export : • Final geometry • Residual stresses


MA -

Corrective Machining

The present study aims to setup a demonstrator of process chaining simulation.

The following questions will be addressed:

1. How far the ALM part will be from the nominal geometry ?

2. How will the machining process influence the distortions of the final part ?

3. Which tolerance will be reached after machining ?

Important notice: this numerical model will be used as a simulation demonstrator and not yet for experimental validation purposes (see perspectives).

ALM -



WORK PLAN



Stage n°1: Additive Layer Manufacturing

1. Operating conditions:

Tube on plate: ext.diam. 52.4 mm, length 25 mm, thickness 2.2 mm

Material: Inconel 718

Number of cladding layers: 14

Loading speed: 13.3 mm/s

Loading time: 172 s

Post-ALM cooling time (on threshold 20°C): 1579 s

2. Modelling hypothesis:

Thermo-Mechanical-Metallurgical coupling

Transient analysis

HEXAhedra elements conforming to the clad

Automatic mesh elements’ activation according to a moving box of selection

Heat loading: energy density applied in the activated FE elements (volume)

Thermal properties as a function of temperature

Mechanical properties as a function of temperature (Elasto-Plastic # Power Law)

Distributed Multi-Processing analysis: 12 processors

SIMULATION DESCRIPTION - ALM


ALM sequence:

Same starting point for each layer

Same loading direction for all layers

SIMULATION RESULTS - ALM


Residual distortions (after ALM + cooling):

Comparison against the nominal geometry

Cross section parallel to the ALM start

Deflection at the top of the tube: -0.637 mm

Maximum deflection (radial): -0.755 mm

δtop = -0.637 mm

δmax = -0.755 mm

Cross section



Alternative layer sequences:

Influence on residual distortions

Configuration T2:

Same start for each layer

Alternating loading direction from one layer to the next

Configuration T3:

90° shift start for each layer

Same loading direction for all layers

Configuration T4:

90° shift start for each layer

Alternating loading direction from one layer to the next

i

i+1

i

i+1



i

i+1 Cross section

δtop = -0.475 mm

δmax = -0.594 mm

Reference (configuration T1): δtop = -0.637 mm δmax = -0.751 mm

Configuration T2:



δtop = -0.66 mm

δmax = -0.747 mm

Cross section


Configuration T3:



δtop = -0.577 mm

δmax = -0.700 mm

Cross section

i

i+1


Configuration T4:




Stage n°2: Machining

1. Operating conditions:

Tube on plate: deformed from the Additive Manufacturing process

Geometry: Configuration T2 selected

Machining process: surface finish (cylindrical shape)

Thickness of removed material: 0.2, 0.4, 0.6 mm

Objective: flat surfaces

2. Modelling hypothesis:

Deformed mesh from the upstream analysis (ALM)

Residual Stresses mapped from the upstream process (ALM)

Mechanical analysis based on XFEM

Cutting passes represented by Level-Sets

Computation time : several minutes

Machining

Mesh’’

MODELLING DESCRIPTION


Machining thickness sensitivity:

Effect of machining on residual distortions

Without Stress Relief Heat Treatment

The 0.6 mm thickness leads to flat external surfaces

Thickness (mm)

Rtop

(mm)

Rmin

(mm)

Tolerance (mm)

0.2 25.882 25.775 0,107

0.4 25.798 25.776 0.022

0.6 25.592 25.599 0.007

i

i+1 Cross section


Machining

Flat surface

SIMULATION RESULTS - MA

FURTHER DETAILS

Contact details

Dr. Laurent D’Alvise

Mail: [email protected]

Skype: geonx_

Visit: www.geonx.com

Follow us on Twitter: @geonx_


simulation of advanced processes: welding & additive manufacturing cases studies

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