Introduction Importance of stabilizing composite materials

FAAFAA

Regulatory Policy for Composite Material ControlPresented at 8/8/02 FAA/NASA Workshop (Chicago, IL)

• Introduction– Importance of stabilizing composite materials– FAA approach for safety & certification initiatives

• Material procurement and processing– Qualification databases and documentation– Material procurement spec– Parts of process spec used to support material control

• Timeline• Industry standards• Summary

Larry IlcewiczNRS, Composites

Presented by L. Ilcewicz at 8/8/02 FAA/NASA Workshop for Composite Material Control

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Importance of Stabilizing Composite Materials

• Stable source of raw material is needed for continued safe and reliable use of composites in aircraft products– Expanding applications, including the use of composites in

other industries, is driving material supplier developments– Current composite aircraft industry approaches have some

differences versus metal

• Industry standards and shared databases are currently being pursued for traditional material forms– Initial FAA policy drafted in 2000– Experiences to date have lead to the current efforts in

developing guidelines and regulatory policy– Pursuit of shared databases span all aircraft product forms


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Ongoing Composite Safety & Certification Initiatives*

Objectives

1) Work with industry, other government agencies, and academia to ensure safe and efficient deployment of composite technologies being pursued for use in aircraft

2) Update policies, advisory circulars, training,

and detailed background used to support standardized composite engineering practices

* Formal planning efforts started in 1999 to address issues associated with increasing composite applications


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FAA Approach to Composite Safety and Certification Initiatives

InternalPolicies

FocusedRE&D

NewTechnologyConsiderations

CertificationProjects

Industry Interface

Evolving Mature

PolicyMemos

AdvisoryCirculars

Rules & General

Guidance

DetailedBackground

Training (Short Courses, IVTs)

Public Documents(e.g., Mil-Hdbk-17, Contractor Reports)

Time

FARs


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Regulatory Policy for Material Procurement and Processing

• Qualification databases & specifications are needed to ensure a stable raw material source for aircraft products

• Qualification databases and specifications should include:– Process control document (proprietary to the supplier)– Process spec for cured test panels used in developing the material

qualification database and continuous QC – Test reports for chemical, physical and mechanical properties

needed to characterize the material (with details of specific test specimen fabrication and tests)

– Qualification data for a minimum of three material batches– Storage & shipping limitations– Material procurement spec


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Regulatory Policy for Material Procurement and Processing, cont.

• Material procurement spec– Qualification data should be a statistical basis for equivalency (for

new users and changes) and QC acceptance requirements– Documentation and databases for material characteristics should

exist for each unique material– Property drift (including upward shifts) in “key characteristics (KC)”

& “key process parameters (KPP)” should be minimized by SPC– Reduced test sampling rates may be adopted if KC and KPP data

indicate necessary levels of process control– Process to evaluate different levels of change in material production

should be outlined– Material packaging and shipping must maintain material control

through delivery


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• Corners of the process window should be investigated by appropriate means to ensure related material controls

• Process spec– Process documentation and technician training should be

adequately detailed to ensure repeatable fabrication

– Quality assurance monitoring procedures are needed for equipment, materials, facilities and tooling

– Methods of inspection should be consistent with those used for production parts


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• Design details & manufacturing scaling issues representative of aircraft structure will require additional processing documentation beyond that used in material control– An understanding of these issues are needed such that the process

methods used to support material QC don’t miss KC and KPP essential to the product producibility and structural performance

• Consistent and repeatable industry engineering practices would benefit compliance with requirements essential for base material control– Recommendations to pursue standardization with

SAE Committee P, Mil-Handbook-17 and ASTM


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Static Strength SubstantiationCritical Issues for Composite Designs

• Integration of structural design detail with repeatable manufacturing processes– Material & process control are essential prerequisites to current efforts

for advanced analyses and more efficient building block testing

• Design details, manufacturing flaws and service damage, which cause local stress concentration, drive static strength margins– Dependency on tests– Scaling issues

• Environmental effects– Temperature– Moisture content

• Maintenance inspection and repair


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Scheduled Timeline for Efforts Related to Material Control

• Draft policy on material & process specs for internal FAA review, Sept. 2002– Disposition of internal comments, Dec. 2002– Publication in Federal Registrar, Feb. 2003– 30 days for public comment– Disposition of external comments, June 2003– Final publication, 2003

• Continued support to SAE, Mil-Handbook-17 material standardization efforts (timeline, TBD)

• FAA consideration of TSO– Industry and FAA acceptance, 2002– Draft TSO for first selected material form, 2003– Policy, guidance and training for first selected material form, 2004 – Release of initial composite TSO, late 2004 or 2005


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What is Needed for Implementationof a TSO for Composite Materials

• Industry and FAA acceptance of the concept– Agreement on data requirements needed to control

composite materials– Additional responsibilities given to material suppliers– FAA oversight and delegation of a more efficient system– Agreement on what constitutes minor and major changes

for each composite material form considered

• Support from Mil-Handbook-17, SAE and ASTM• Associated FAA policy and guidance• FAA workforce trained on the use of composite TSO


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standards and provide overall coordination– http://www.mil17.org/– Data Utilization Working Group

• SAE Committee P to establish/approve material and process specifications

• ASTM D30 to establish/approve standard test methods

Important U.S. Standards Organizations*

Stephen [email protected]

Curtis R. [email protected]

* Must interface with international standards groups to achieve optimum efficiency


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Workshop Summary• Consistent and stable materials are crucial to the safe use of composites for

expanding applications with aircraft structure– Associated databases and M&P specs may be shared within the industry– Pre-requisite to industry initiatives for more efficient composite structural

development

• Draft recommendations and guidelines have been developed for composite material procurement and process specifications– Your inputs will be considered to change the documents before release

• Related FAA policy will be drafted later this year

• Future efforts by standards organizations can help facilitate the approval of shared databases and M&P specs

• FAA plans continued work in this area as related to industry directions in aircraft applications

Introduction Importance of stabilizing composite materials

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