A HOLISTIC APPROACH TO QUALITY MANAGEMENT FOR COMPOSITE FORMING PROCESSES

Transcription

1 A HOLISTIC APPROACH TO QUALITY MANAGEMENT FOR COMPOSITE FORMING PROCESSES Dr. Farbod Nezami June 2016

2 Composite Forming: Reliable, fast, effective, but Geometry Process Source: Airbus, Boeing, ETZ, Daimler Complex shaped geometries Small sectioned parts Packaging- & design demands What to do about quality? High lot size Cost sensible Fast forming processes 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 angles 3. Assess the resulting mechanics 4. Validate our approach?

3 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. Textiles Mechanics Process Geometry These interactions define the resulting Mechanics of the structure. Every development has to be regarded as a holistic system of all aspects

4 An Holistic Quality Approach to Preforming Process optimization Validation Process Ensuring quality Mechanics Realizing quality Textiles & Geometry Analysing quality Planning quality Process Selection Material Selection Process Feasibility Draping simulation Composite FEA Sensitivity studies Process factors Active manipulation Automation Tool design Optical analysis Non-destructive testing Quality criteria Draping effects Definition of local quality criteria

5 Material characterization with process induced factors: Shear-Tension Coupling A B Membrane tension No wrinkles at 55 Tension free Wrinkles at

6 Material characterization with process induced factors: Fiber waviness due to interactions Fiber waviness In-plane damage Forming Limit Diagram

7 Definition of a Forming Limit Diagram for Interaction Defects Textiles Process Geometry

8 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

9 An Holistic Quality Approach to Preforming Process optimization Validation Process Ensuring quality Mechanics Realizing quality Textiles & Geometry Analysing quality Planning quality Process Selection Material Selection Process Feasibility Composite FEA Sensitivity studies Process factors Active manipulation Automation Tool design Optical analysis Non-destructive testing Quality criteria Draping effects Definition of local quality criteria

10 Integration of forming defects of composite forming to FEA analysis 3D Plot of fiber orientation due to forming FEA modelling Analysis of forming effects Draping simulation 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

11 An Holistic Quality Approach to Preforming Process optimization Validation Process Ensuring quality Mechanics Realizing quality Textiles & Geometry Analysing quality Planning quality Process Selection Material Selection Process Feasibility Composite FEA Sensitivity studies Process factors Active manipulation Automation Tool design Optical analysis Non-destructive testing Quality criteria Draping effects Definition of local quality criteria

12 Integration of previous steps into process development Mechanical actuators Reduction of interaction force and fiber waviness by oscillations Reduction of wrinkling due to local application of tensile forces

13 Application: Mercedes-Benz AMG Backlid Transfer to active interlayers Multilayer draping with active interlayers Cut-out optimization and ply Orientation clamping0 Cut / Dart Clamping Clamping Piezo actuators for oscillations 0/90 top layer Homogenous Reduction Blank of Holder the size Force of wrinkles by 81,5% Complete suppression of interaction based defects Orientation 45 Different material draw-in and clamping necessary! Ply-specific clamping

14 An Holistic Quality Approach to Preforming Process optimization Validation Process Ensuring quality Mechanics Realizing quality Textiles & Geometry Analysing quality Planning quality Process Selection Material Selection Process Feasibility Composite FEA Sensitivity studies Process factors Active manipulation Automation Tool design Optical analysis Non-destructive testing Quality criteria Draping effects Definition of local quality criteria

15 Validation and Assessment of Measures by Optical Fiber Measurement System Analysis of - Fiber orientations - Gaps - Validation of draping simulation 4 1 Local Analysis Definition of critical spots 2 Definition of robot coordinates 3 Capturing VALIDATION & ASSESSMENT

16 Conclusions To increase quality of parts being produced by composite forming an holistic approach is necessary as 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 contact forces is necessary. This was realized by the utilization of active interlayers which can actively control tensioning and reduce interlayer friction by oscillations Optical fiber measurement systems were applied to validate the results of draping simulations and assess the quality improvement due to process improvements