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Tags   Composite     DSTO     Environmental     Materials     Testing  
DSTO-TR-0657 Accelerated Environmental Testing of Composite Materials.pdfDownload 

Accelerated Environmental Testing of Composite Materials

DSTO-TR-0657 Accelerated Environmental Testing of Composite Materials

This report addresses material durability and strength issues for composite materials
in RAAF aircraft operating under Australian climatic conditions. The effects of the
natural environment during both flight and ground storage are assessed. Methods
which may be used to simulate these effects in the laboratory in shorter time frames
are outlined. Such information may be vital in formulating life-extension strategies and
anticipating material problems well in advance. This report does not address issues
related to corrosion or the effects of chemical acfiOn on materials such as fuels or
hydraulic fluids.

The environmental conditioning of composite materials is an important aspect of their
certification for use in aircraft structures. The mechanical properties of composite
materials such as boron/ epoxy and graphite/ epoxy degrade in the natural
environment and particularly under hot/ wet conditions. It is important to understand
these effects in order to design confidently and Certify composite structures. There are
numerous mechanisms which act to degrade the matrix and in some cases, the fibre
itself. Changes in material properties over time may also need to be quantified. This
can be difficult since real-time environmental testing of a composite in a natural
environment may take many years to complete.

Both graphite / epoxy and boron/ epoxy materials are currently used by the RAAF on a
number of aircraft. Boron/ epoxy material is primarily used in adhesively bonded
repairs or reinforcements such as on the F~111 upper wing—pivot fitting. Large
boron/ epoxy doublers were also fitted to the lower wing pivot fitting during original
manufacture. Graphite / epoxy material is used extensively on the surfaces of the F/ A-
18 aircraft such as the main wing skins, horizontal stabilator and vertical fins.
Understanding the way in which these materials will perform in the future is vital
knowledge for the supportability of the RAAF fleet.

Creating accelerated testing environments which replicate the effects of long-term
natural environmental exposure and flight mission profiles can significantly reduce
testing time and give advance warning of material problems which may arise in the
future. It must be stressed that such tests must be carried out carefully to avoid
exposing the material to conditions it may never see in service. It is therefore
important to accurately define the conditions the material will be exposed to in the first

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Microsoft Excel Spreadsheets

FREE ANALYSIS SPREADSHEETS 3 Over the last 10 years we have developed hundreds of spreadsheet tools to help us with our structural analysis work. We have made these available through the Abbott Aerospace web site and the XL Viking project. We have now brought them into the technical library. They have been updated, improved and the collection has been expanded to cover more analysis methods than ever before.

The XL-Viking Add-In for Excel

XL-Viking 2 We created the XL-Viking Excel add-in to satisfy our own need to make Excel a better engineering tool. XL-Viking shows your Excel Formula in a way that makes sense and brings essential new functionality to Microsoft Excel by providing an additional user interface and easy to use functions.

The Indispensable Tool For Engineers, Mathematicians, Scientists, Accountants and Teaching Professionals!


Technical Papers & Reports

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Market Analysis and Market Information

Our newest addition to the library is an on-going series of articles on the aircraft and aerospace market. These are part quantitative and part qualitative and introduce a new aspect to the competencies within Abbott Aerospace.