effect of defect in am products airbus · airbus a320 nacelle hinge bracket was optimized,...

$: EFFECT OF DEFECT IN AM PRODUCTS Airbus · Airbus A320 nacelle hinge bracket was optimized, incorporating a topology optimization method process. • The fatigue and fracture analysis$
Dr.- Ing. Paola Caracciolo

email: [email protected]

EFFECT OF DEFECT IN ADDITIVE

MANUFACTURING PRODUCTS International Conference on Additive Manufacturing & 3D PrintingAdded Scientific Ltd – Nottingham (UK), 10 July 2018

• State of Additive Manufacturing (AM)

Historical Evolution of Application within Airbus

First Certified Titanium Part on Civil Aircraft

AM serial production

• Research Activities

Probabilistic Fracture mechanics on AM parts

Defects types and method of detection

Test case –Process chain

• Considerations and Remarks

Summary

10 July 2018 EFFECT OF DEFECT IN ADDITIVE MANUFACTURING PRODUCTS, Paola Caracciolo

• Commonly known as “3D-Printing” is the process of joining

materials to make objects from 3D model data, usually layer

upon layer, as opposed to subtractive manufacturing

methodologies.

• AM utilized in aircraft manufacturers are rapidly evolving and

are introduced also in the new aircraft designs, as well as

retrofits and repairs.

• In the vision to widely utilize AM within the next 5-10 years, a

continued research improvement is a key enabler in 3D printing

processes.

State of Additive Manufacturing (AM)


First Certified Titanium Part on Civil Aircraft –600 patents per year

1st twin-engine widebody aircraft,

A300

1st full fly-by-wire commercial

airliner

1st double decker airliner, A380

1st manufacturer to make

extensive use of composites

Industry FIRSTS

3D Printing

Image shows the 1st flying

3D printed metal part


Historical Evolution of Applications within Airbus

First Certified Titanium Part

on Civil Aircraft

First Optimised

Aluminium Structure

on Satellite

First EBM

Titanium

Structural Part

on Satellite

First Serial FDM

Polymer parts on

A350XWB

First use of SLA

models in Airbus

wind-tunnel

First SLS Polymer

Serial Parts on

Helicopters

Powder

Bed Fusion

Titanium

Directed Energy

Deposition

Titanium

Polymers

Composites

Powder Bed

Fusion

Aluminium

First Optimised

Aluminium RF Filter

on Satellite

First SLS Assembly

Tooling Applications

First application of SLS

to mitigate schedule

risk on flight test

First SLM

Titanium

Structural Part

on Satellite


Optimised PartsPowder Bed

Fusion

Titanium

3-D design

Manufacturing

AM Serial Production

The AM process discusses the general steps

involved in most additive manufacturing (AM)

procedures:

• Creating 3D computer design models,

• Converting those models to AM compatible file

formats, setting up and running an AM

machine, part removal and post-processing.

• Topology optimization

• Implementation

integration

10 July 2018

Assembly Line

EFFECT OF DEFECT IN ADDITIVE MANUFACTURING PRODUCTS, Paola Caracciolo

Research Activities

• AM is currently a comparatively expensive process, but this expense isacceptable in high-value applications where specialised materials areused or where it requires a complex design part.

• The design freedom meant that a significant proportion of weight couldbe saved in the part, while also reducing maximum stress and maintainingstiffness.

• As part of research into the benefits of AM manufacturing process, anAirbus A320 nacelle hinge bracket was optimized, incorporating atopology optimization method process.

• The fatigue and fracture analysis for Ti64 AM without HIP process forthe effect of defect in AM were investigated to identify the benefit ofprobabilistic damage technique.


Probabilistic Fracture mechanics on AM parts

Can a probabilistic approach address porosities, inclusions, lack of fusion, and other imperfections in AM?

To share the needs for quantifying and managing uncertainties throughout the product lifecycle an investigate of commercial tools are

running and compared within a simulation process:

1. Fatigue Assessment of AM parts: A new computational Frameworks based on CT-

scans, Pro-Face (Polytechnic of Milan -IT, EU)

2. Design Assessment of Reliability with Inspection, DARWIN (South West Research

Institute, USA)


Defects types & methods of detection

• Surface Quality

• Microstructure variability

• Powder Control

• Process Controls

>100 process parameters identified

Description & Formation

Foreign material in the part during

the manufacturing process. Foreign

material in feedstock powder or

metallization from heat shield

Impacts: mechanical

performance issue

Relevant Methods:

Destructive: Optical microscopy

NDT (Internal): X-Ray; CT; UT

Solid Inclusion


Cracks from Residual Stress,

observed in the bulk material.

Micro-cracking caused by internal

residual stress

Impacts: initial flows, mechanical

performance issue

Relevant Methods:


NDT (External) : ET - UT - Dye Penetrant

NDT (Internal): CT ; X-Ray

Cracks


Porosity from entrapped gas inside

particles.

Entrapped gas porosity in the particles

Cause: issue with beam power distribution

(un-melted powder)

Impacts: mechanical performance issue

Relevant Methods:


NDT : X-Ray; CT; UT

Gas CavitiesDescription & Formation

Material that has not been fused during

the process. Thicker layer of powder

due to recoating issue leading to partial

penetration of the beam. Potential fault

of the laser/electron beam.

Impacts: mechanical performance

issue, can initiate cracks during

fatigue cycling.

Relevant Methods:


NDT (Internal): CT ; X-Ray

Lack of Fusion


Test case: Process Chain


AIRBUS CONFIDENTIAL

Test case: Process Chain

Airbus Patents: 3D- SURFINEP000003109348A1, EP000003269848A1


Computed Tomography

AIRBUS CONFIDENTIAL10 July 2018 EFFECT OF DEFECT IN ADDITIVE MANUFACTURING PRODUCTS, Paola Caracciolo

Distribution of maximum defect in the sample gage volume from CT •Extreme value statistics: maximum defect size in larger volumes is well estimated. • Validation measuring

critical defects (always surface or subsurface). • The applied stress intersects the Kitagawa diagram defining a distribution of critical defect size. • The Pf of every element is the

probability that the maximum defect is larger than the critical one. • The weakest link is applied to all the elements. •To evaluate the experimental results concerning the limit

depending on initial crack sizes, the data is plotted in a Kitagawa-Takahashi diagram.

Fatigue assessment of AM part (Pro-FACE)

( Polytechnic of Milan- IT (S. Beretta, S. Romano,, Int. J. Fatigue. 94 (2017) 178–191))

Pro-Face: based on the Kitagawa diagram extended to finite life

Local failure probability Local critical defect

10 July 2018

Design Assessment of Reliability with Inspection (DARWIN)The zone-based probabilistic fracture mechanics could provide improvements compared to conventional approaches and that it well suited for AM.

(Software code developed by Southwest Research Institute (SwRI )

Darwin Tool: based on fracture mechanics from initial defect size up to failure

Stress model

Probability of failure

“Stress-Life-Defect size”

relationship

CT scan

Defect distribution

10 July 2018

10 July 2018

Fatigue Test

EFFECT OF DEFECT IN ADDITIVE MANUFACTURING PRODUCTS, Paola Caracciolo

Considerations and Remarks

• Probabilistic approaches should be implemented in case of failure of the deterministicmethod to address the missing issue without replacing traditional methods.

• In the study is emerged that a key input for the both probabilistic assessment is theanomaly distribution definition. How can we define it and what anomalies need to beconsidered and tackled by NDT and process control? (Crack initiation life from defects, Surfacedefect characterisation, anomaly distribution definition at coupon and part level etc…)

• Acceptable ranges of variation for the manufacturing parameters/materialanomalies distribution can be done using statistic distribution to determinate criticaldefect, propagation curve over all the crack regimes as well as propagation and stressthreshold.

• The study improve the optimization of design, the databases/allowable andhighlight limitation of AM quality with respect to industry specifications.

• Influence of different defect parameters on the fatigue resistance, further fracturemechanical investigations need to continued to be explored for new process.


Thank you

effect of defect in am products airbus · airbus a320 nacelle hinge bracket was optimized,...

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