AIAA Non Deterministic Approaches (NDA)

Proposal to create theAIAA NDA Technical Committee

toAIAA New Initiatives Subcommittee

9 January 2007

Prepared by Ben Thacker, Chair NDA Working Group, bthacker@swri.org, 210/522-3896

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Need for an NDA Technical Committee

• NDA Working Group in active existence since 2004– Over 30 members– Operating according to TC guidelines– 7 successful NDA forums, 1 successful NDA

conference• Non-deterministic or probabilistic

methods now recognized in other societies– SAE, ASME, ASCE, SEM, and ASQ

• NDA Conference requires TC-level support to ensure enduring stream of high quality leadership

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What is NDA?

• Non-Deterministic Approaches are methods, philosophies and approaches that seek to address the effect of inherent and systematic uncertainties in engineered systems.

• NDA is rapidly gaining ground as preferred methods for analysis and design with potentially high payoffs (cost, safety, etc.) in aeronautical, aerospace, and other many other related applications.

• NDA is currently part of the Structures TC

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AIAA NDA – When, Why and How?

• 1st NDA Forum at 40th SDM in 1999 (St Louis, MO)

• Bring together NDA related work throughout the aerospace community

• Expose critical NDA issues• Provide direction for future NDA

research

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Background

• Successfully conducted 7 consecutive NDA Forums (’99-’05) and one full conference (’06)

• NDA Conference approved in 2006– Called the 8th NDA Conference to reflect our 7

previous forums

• 9th NDA Conference planned for 2007 in Waikiki, Hawaii– 52 accepted abstracts organized into 9 sessions

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NDA-WG Scope

• The NDA Working Group supports AIAA technical activities that advance the relevant art, science and cross-cutting technologies required for the successful application of non-deterministic approaches to aerospace systems.

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NDA Working GroupGoals

1. Organize NDA Conference in support of the SDM

2. Ensure quality leadership for NDA Conference3. Serve as the focal point for NDA technologies

in AIAA4. Coordinate AIAA activities on NDA with other

organizations5. Coordinate NDA activities with other AIAA

technical committees6. Transfer NDA technology to AIAA membership

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NDA-WG Leadership

• Chair – Ben Thacker (rotate out 4/07)• Vice Chair – Chris Pettit (rotate in 4/07)• Secretary – Jason Pepin• Liaisons

– MDO – Romero– ASA – Wallace– ASCE – Mahadevan– Structures TC – Hilton– ASME – Pepin/Romero– SAE – Ghiocel– Adaptive Structures TC – Chamis

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NDA Conference Leadership

Year General Chair Technical Chair

2008, TBD Sankaran Mahadevan

TBD

2007, Hawaii Mike Enright Sankaran Mahadevan

2006, Newport Chris Pettit Mike Enright

2005, Austin Levon Minnetyan Chris Pettit

2004, Palm Springs

Christos Chamis Levon Minnetyan

2003, Norfolk Christos Chamis Levon Minnetyan

2002, Denver Christos Chamis Levon Minnetyan

2001, Seattle Suren Singhal Christos Chamis

2000, Atlanta Suren Singhal Christos Chamis

1999, St Louis Suren Singhal Christos Chamis

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Sustained Performance of the NDA Conference

3437

5254

36

56

62

58

52

0

10

20

30

40

50

60

70

1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

No.

of

Acc

epte

d P

aper

s

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2004 NDA Forum Session Titles

• Sampling Methods• Code Verification• Response Surface Methods• Model Validation• Dynamic Systems• Flight Applications• Materials and Design Safety Factors• Reliability-Based Design Optimization• Fatigue and Fracture

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Current Roster – 31 Members

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NDA-WG Makeup

10

13

6

2

0

2

4

6

8

10

12

14

Gov Aca Ind Org

Category

Nu

mb

er

of

Me

mb

ers

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NDA-WG Bulletin Board

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Why Create an NDA TC?

• Growing interest• “Place at the table”• Natural evolution of

NDA activities in AIAA• As a technology, NDA

is different from yet integral to other key SDM TC’s:– Structures– Materials– Structural Dynamics– MDO– Survivability– Adaptive Structures

NDA serves a unique purpose

Number of Papers at SDM NDA Forum

0

10

20

30

40

50

60

70

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

YearN

um

be

r o

f P

ap

ers

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Support

• Betty Guillie emailed proposal to all AIAA TC chairs on 12/5/2006

TC For Against Undecided

Ground Test

Space Operations and Support

Solid Rockets

Management

Survivability

Meshing, Visualization, and Computational Environments

Aircraft Operations

Balloons

Fluid Dynamics

Structures

Summary of Responses

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Support, cont’d

• Mark Melanson, Ground Test TC– No objections or known overlap

• Mike Mattis, Space Operations and Support– The SOSTC has no scope issues and

believes that Non-Deterministic Approaches would be a good addition to the Technical Committees

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Support, cont’d

• I-Shih, Solid Rockets– There is no objection from Solid

Rockets Technical Committee to creating a new NDA Technical Committee

• J. Stephen Rottler, Management– There is no overlap between the

proposed NDA TC and the TCM • Ron Dexter, Survivability

– I reviewed your proposal and do not see any conflicts or overlap

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Support, cont’d

• John Chawner, Meshing, Visualization, and Computational Environments– MVCE - in the persons of John Chawner

(chair) and John Dannenhoffer (vice chair) is OK with formation of the NDA TC

• Brian Baxley, Aircraft Operations– …there does not appear to be any scope

overlap of the proposed TC with the Aircraft Operations TC.

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Support, cont’d• Henry Cathey, Balloon Systems

– “On the whole, the responses were very positive”– One member commented:

• "It seems to me that the use of NDA to obtain a result is of interest to many disciplines.  However, should the method itself be represented in AIAA is a TC?  The safety folks use this to create flight rule for our balloons which is important.  But is the probability theory itself in need of representation?  I think not."

– My response to member (via Cathey) on 12/15/06• Non-deterministic Approaches (NDA) are much more than probability theory. NDA

encompass the field we call "uncertainty quantification" and it includes techniques such as probability theory, fuzzy sets, possibility theory, evidence theory, convex models, info-gap theory, etc. Even if NDA meant only probability theory, application of probability theory to structural/mechanical/thermal problems requires efficient and accurate algorithms and analysis strategies. Thus, applied probability theory itself is still a very active area of research and development, and will continue to be as we ask it to solve ever increasingly challenging problems.

• The proposed NDA TC is technology oriented as opposed to application oriented, which may be fueling the confusion. Many of our members and conference attendees are engineers working at aerospace companies who are faced with problems that can only be solved using NDA. Others are methods developers. Solutions to current and challenging reliability problems go way beyond what's available in standard probability textbooks, and that's precisely where NDA are required. Our TC brings these two groups together, as well as supports many of the other areas within AIAA (structures, materials, dynamics, etc.)

• There could be a viewpoint issue/problem here as well. If you are only an occasional user of basic probability theory, you may not be aware of the broad and rapidly growing field of NDA driven by the needs of industry. I'm not sure if this is the case here, but I have run into before.

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Support, cont’d

• Thomas Beutner (chair) & Peter Hartwich, (chair-elect), Fluid Dynamics– Non-deterministic are relevant to structures, to fluids,

to thermal sciences. Thus, there's inherent overlap with established TCs

– If the goal of this TC is to sponsor a conference that will collocate with structures, then is a new TC needed?

– AIAA's total membership is stable if not decaying. In this general environment, is it advisable that AIAA keeps creating new TCs?

– [Hartwich] In summary, my vote is against establishing an NDATC.

– [Beutner] I suggest tabling the decision on a new TC for now and utilizing the existing TC structure to advance NDA and create a sustainable annual or biennial conference

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Support, cont’d• Mary Mahler, Structures

– With full consensus from the membership and friends of the AIAA Structures Technical Committee, it is my pleasure to announce that the Structures TC fully endorses the formation of the Non-Deterministic Approaches Technical Committee for AIAA. I have talked to the senior membership and there is total agreement that the NDA Working Group had added a valuable aspect to the aerospace industry.  It is a technology that has come into its own right and should be a technical committee for AIAA.  With this area of interest only growing in interest and research and practice in production, the group that has several senior members and is under the current leadership of Dr. Ben Thacker should be a technical committee of AIAA.

The members of the Structures TC had no reservations of this endorsement.

If there are any questions or further details to this endorsement, please feel free to contact me.  We look forward to working with Ben and the soon-to-be NDA TC in the future.

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Recommendation

Establish the NDA Technical Committee