A HOLISTIC APPROACH TO QUALITY MANAGEMENT FOR … · Nezami, Fuhr, Schierle, Cherif, Middendorf: Holistic development of high quality composite parts based on automated preforming

A HOLISTIC APPROACH TO QUALITY MANAGEMENT FOR COMPOSITE FORMING PROCESSES

June 2016

Dr. Farbod Nezami

28.09.2017 | 2Fuhr | Nezami | Schierle

Composite Forming: Reliable, fast, effective, but…

Sour

ce: A

irbus

, Boe

ing,

ETZ

, Dai

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r

• High lot size• Cost sensible

• Complex shaped geometries• Small sectioned parts• Packaging- & design demands

Geometry Process

Fast formingprocesses

What to do aboutquality?

How can we improve the quality of preforms with an holistic quality approach?

1. Parts free of wrinkles and reduction of fiber distortions (“waviness”)2. Influencing of fiber orientation and shear angles3. Assess the resulting mechanics4. Validate our approach?


The Complexity of Composite Forming

• Textiles show specific forming modes and characteristics.

• Complex Geometries consisting of radii, curvature, edges.

• Formability can be influenced by Process factors too.

• These interactions define the resulting Mechanics of the structure.

Every development has to be regarded as a holistic system of all aspects

Textiles

GeometryProcess

Mechanics


An Holistic Quality Approach to Preforming

„Planning quality“

„Realizing quality“

„Ensuring quality“

„Analysing quality“

MethodsProcess SelectionMaterial SelectionProcess FeasibilityDraping simulation

MethodsActive manipulationAutomationTool design

MethodsOptical analysisNon-destructive testingQuality criteria

MethodsComposite FEASensitivity studiesProcess factors

Textiles & Geometry

Process

Validation

Mechanics

Definition of local quality criteria

Process optimization

Draping effects


Material characterization with process induced factors:Shear-Tension Coupling

BA

Membrane tensionNo wrinkles at 55°

Tension freeWrinkles at 55°


Material characterization with process induced factors:Fiber waviness due to interactions

Forming Limit Diagram

Fiber waviness

In-plane damage


Definition of a Forming Limit Diagram for Interaction Defects

Textiles

GeometryProcess


Recent developments in prediction of fiber waviness

• The first chapter of the quality approach showed us that:– There is an interlink between tension (process) and wrinkling (textile)– There is an interaction of layers towards each other which can cause fiber waviness

• Draping simulation can be used to investigate the risk of wrinkles and fiber waviness







MethodsProcess SelectionMaterial SelectionProcess Feasibility




Textiles & Geometry

Process

Validation

Mechanics



Draping effects


Integration of forming defects of composite forming to FEA analysis

Nezami, Fuhr, Schierle, Cherif, Middendorf: Holistic development of high quality composite parts based on automated preforming in JEC magazine no. 103, March 2016, Special JEC World

3D Plot of fiber orientationdue to forming FEA modelling Analysis of forming effects

Draping simulation











Textiles & Geometry

Process

Validation

Mechanics



Draping effects


Integration of previous steps into process development

Reduction of interaction force and fiber waviness by oscillations

Mechanical actuatorsReduction of wrinkling due to local application

of tensile forces


Application: Mercedes-Benz AMG Backlid

Cut-out optimization and ply clamping

Transfer to active interlayers

Multilayer draping with activeinterlayers

Orientation 0°

Orientation 45°

Clamping

Cut / Dart

Clamping

Different material draw-in and

clampingnecessary!

0/90° top layer

Homogenous Blank Holder Force

Ply-specific clamping

Piezo actuatorsfor oscillations

• Reduction of the size ofwrinkles by 81,5%

• Complete suppressionof interaction baseddefects











Textiles & Geometry

Process

Validation

Mechanics



Draping effects


Validation and Assessment of Measures by Optical Fiber Measurement System

1Local AnalysisDefinition of critical spots

2Definition of robot coordinates

Analysis of- Fiber orientations- Gaps- Validation of draping simulation

4

VALIDATION &ASSESSMENT

3 Capturing


Conclusions

• To increase quality of parts being produced by composite forming an holistic approach is necessaryas interlinks of domains drive overall quality

• Early stage material characterization can help to identify dominant quality drivers• In preforming it was found that wrinkles can be suppressed by local tensioning, but risk of

interaction defects like fiber waviness can increase hereby. Therefore reduction of normal contactforces is necessary.

• This was realized by the utilization of active interlayers which can actively control tensioning andreduce interlayer friction by oscillations

• Optical fiber measurement systems were applied to validate the results of draping simulations andassess the quality improvement due to process improvements

Documents

A HOLISTIC APPROACH TO QUALITY MANAGEMENT FOR … · Nezami, Fuhr, Schierle, Cherif, Middendorf: Holistic development of high quality composite parts based on automated preforming