Boeing’s Certifiable Primary Structural Bonding Initiative March 16, 2010 • Principal Investigator & Requirements Dev
Marc J. Piehl
ATF Structures
• Robust Bonding Materials and Processes
Kay Blohowiak
TF M&PT
• Non-Destructive Inspection
Dick Bossi
STF NDE
• Design and Analysis
Matt Dilligan
Senior Analyst
• Sustainment / Repair
Rusty Keller
TF Supportability
Additional Boeing Key Team Members Will Grace, Gerry Mabson, Mark Wilenski, Derek Fox, Alan Prichard, Charlie Saff, Eric Cregger, Doug Frisch, Gerardo Pena, Eugene Dan-Jumbo BOEING is a trademark of Boeing Management Company. Copyright © 2009 Boeing. All rights reserved.
Agenda Engineering, Operations & Technology | Boeing Research & Technology
Structural Technology
• Bonding Certification Approach Development at Boeing • AMTAS related tasks and their Impacts on Boeing -UW Prof. Brian Flinn -FIU Dwayne McDaniel -UW Prof. Kuen Lin (FAA Technical Monitors Curtis Davies, Larry Ilcewicz and David Westlund) • Bonding Path Forward in AMTAS-Boeing relationship
Copyright © 2009 Boeing. All rights reserved.
Boeing Approach to Bonding Certification Engineering, Operations & Technology | Boeing Research & Technology
Bonded Certification Requirements Approach
Material Select
Structural Technology
Fabricate
Final Configuration and Process Validate Design Type Certificate Production Certificate Airworthiness Certificate
Linked Requirements P P L
*
Develop Comprehensive Certification Approach for Bonded Primary Structure
Increasing lap length > L1 * – Increases the “zero" stress trough length – Does not increase area under shear stress diagram
Affordable Bonding Processes
L1
Bond length – L
Advanced Design / Analysis
FTA 1.2 Area 3
Area 2
Area 1 1.0
Fail Damage Parameter
Joint strength P
τ
Supportability and Repair
0.8
0.6
0.4
AREA 1
AREA 2
AREA 3
0.2
Pass 0.0 0
5
10
15
20
25
30
Single Pulse Fluence (J/cm2)
Advanced NDE Techniques LBID Copyright © 2009 Boeing. All rights reserved.
35
40
45
Reliable Bonding Processes Parameters
Fault Tree Analysis Bonded Skin to Rib Joint Engineering, Operations & Technology | Boeing Research & Technology
Structural Technology
UE: Significant Weak Bond Region in Rib to Lower Skin Bond AND
52. Bond Strength Test Fails to Detect Weak Bond
51. NDI Fails to Detect Weak Bond Characteristic
Weak Interface OR
Cure Problem 42. Interface is Contaminated During Adhesive Placement on skin
AND
49. Improper Cure
50. Cure Check Fails
Adhesive Error
Wrong or Out of Date Adhesive
33. Incorrect Adhesive
41. Surface Energy Check Fails
AND
OR 30. Bad Adhesive
35. QA Check Fails
OR
AND
Bad Adhesive
32. Storage Degrades Adhesive
AND
Improper– Lower Skin Surface
46. Bond is Contaminated During Placement of Rib
31. Receiving Test Fails
Improper Rib Surface
34.Out of Date Adhesive
36.Skin Surface Damage in Retrieval
AND
39.Surface in not cleaned or contaminated by cleaning process
40. Surface is contaminated during wait
47. Surface Energy Check Fails OR
Incorect Grit Blast Incorrect or Contaminated Surface Below Rib Peel Ply
Rib Peel Ply Left AND
44. Peel Ply Not Removed
43. Damage Rib Surface to be Bonded
46. Rib Surface is Contaminated During Wait
37. Incorrect Texture
Improper skin surface
AND
38. QA Check Fails
45. QA Check Fails
Fault Tree Analysis provides both data to assess the critical bonding parameters and flexibility to optimize the reliability Copyright © 2009 Boeing. All rights reserved.
Reliable Bonding Materials and Processes Engineering, Operations & Technology | Boeing Research & Technology
Boeing Need:
Structural Technology
AMTAS Support:
Controlled Process Parameters • Assess effects of process parameter changes •Materials aging: shelf-life and storage conditions •Batch-to-batch differences •Out-time effects •Tape vs. fabric •Thermal and hydrothermal conditioning •Cure conditions
•Define key factors for making good/poor bonds •How to predict material surface prep compatibility •Develop correlation between surface contact angle and bond quality •In-line contact angle surface analysis
Efficient In-Line QC Methods • Develop techniques to assess quality of bonding steps in mfg •In-line surface preparation assessment tools •Analytical tools to assess surface chemistry •Process control as measured by surface features or materials condition
Copyright © 2009 Boeing. All rights reserved.
•AFM Tool •Detect contamination on surface •Map laminate surface •Electrochemical Tool •Contamination detection •In-field tool development
Robust Bonding M&P Collaborative Activity Engineering, Operations & Technology | Boeing Research & Technology
•Guidance on requirements •Facilitate collaboration
FAA / FARS and Requirements
•Test feasibility of test methods •Evaluate method limits Feasibility trials• •List of typical contaminants •Mfg limitations & constraints •Specifications •Materials used •Evaluation of robustness Copyright © 2009 Boeing. All rights reserved.
•Guidance on reqmts •Facilitate collaboration
•Understanding new capabilities •Reporting of progress •Show feasibility of approach
•Understanding new capabilities •Reporting of progress •Show feasibility of approach
FIU / Miami
Structural Technology
AMTAS: Bonded Structure Community of Practice
Boeing Needs and Requirements
University of WA
•Eval effects of parameter changes •Define theory behind surf changes •Evaluate method limits •Define materials of interest •Define process parameters to be investigated •Specifications •Evaluation of robustness
Arrestment Feature Performance Advanced Analysis and Testing Engineering, Operations & Technology | Boeing Research & Technology Leg modulus E=10 MSI Feature spacing = 1.5” Crit bending strain = 0.010000 Feature bending and shear stiffness ignored
Required Disbond Arrest Feature Diameter for Mode 1 (DCB) 0.6
M
EI
2t
0.5
EI
Structural Technology
Analysis Techniques for Arrestment Feature Performance Stiff Beam for Feature Preload
M
Required feature dia (in)
t
Thermoplastic E=0.5 MSI, σ = 15 ksi
0.4
Spring: Kmoment, Kshear, Kaxial
Above line leg fails bending 0.3
Titanium E=16 MSI, σ = 160 ksi
Below line feature fails tension
Contact Element: EAtension, EItension, EAcompression, & EIcompression
0.2
Steel E=30 MSI, σ = 220 ksi
0.1
Shank Properties: E, A, I, α, G
0 0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Leg thickness (in)
2.00
Displacement to Propagate Crack Length [in]
Stiff Beam for Feature Preload
Titanium, Diam. = 0.25 in (T1) Titanium, Diam. = 0.0625 in (T2) Titanium, Diam. = 0.125 in (T3) Composite, Diam. = 0.125 in (T4) Composite, Diam. = 0.25 in (T5) Composite Pin, Diam. = 0.125 in (T8) Composite Pin, Diam. = 0.25 in (T9) Leg Fails In Bending Above This Dispacement
1.80 1.60 1.40
Fastener (Fastener) Details Feature
1.20 1.00
w
t/2
t 0.80
t/2
w
0.60
L1
0.40
L2
L3
Pure Mode 1 Loading
0.20 0.00 0
0.02
0.04
0.06
0.08
0.1
0.12
Crack Length Behind Fastener [in]
Arrestment Features are a key parameter to certifying Transport Bonded Primary Structure Copyright © 2009 Boeing. All rights reserved.
Disbond / Delamination Arrest Mechanisms Engineering, Operations & Technology | Boeing Research & Technology
Mode I: FEM vs. Analytical Fracture Analysis
Mode I
Structural Technology
Mode II: FEM vs. Analytical Fracture Analysis
General Loading
Mode II
Design Curves - Identify key variables for design, opt. and certification Copyright © 2009 Boeing. All rights reserved.
Path Forward - AMTAS / Boeing Relationship Engineering, Operations & Technology | Boeing Research & Technology
Boeing Needs Damage Tolerance Crack Arrest Fail safety
Certification of Bonded Primary Structure
Structural Technology
AMTAS Activity
Understand design requirements and specify criteria
Project 1 – disbond arrestment modeling
Understand Bonding Process and convert to process criteria
Project 3 – surface characterization
Process Control Establish process reliability value Surface energy
In-Line Quantitative QC tools Bond strength verification In-service requirements Repair Copyright © 2009 Boeing. All rights reserved.
Implement Manufacturing Controls Life cycle
Project 6 – surface probe development Project ? Project ?
Engineering, Operations & Technology | Boeing Research & Technology
Copyright © 2009 Boeing. All rights reserved.
Structural Technology
