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on a universal testing frame and the normal force (which was monitored by a loadcell) was applied through
hydraulic jacks. The material under examination was a carbon fibre/epoxy resin composite (HTA/6376) in a
quasi-isotropic configuration and aircraft grade aluminium (T2024). Both these materials are used extensively in
the aerospace industry. The baseline COF of these materials was determined using Herzian contact through the
use of a cylindrically shaped specimen. Several adaptations were incorporated into the rig to closely simulate
actual bolted joint conditions (e.g. the use of washers and countersunk bolts). An extensive test series was conducted
to quantify the COF that exists between the laps for various bolt pre-loads (i.e. increasing levels of bolt
torque). Tests were also conducted to investigate if protruding head bolts, countersunk head bolts, and washers
had any effect on the COF at the shear plane of the joint.
11
Title: Machining of Composites with Abrasive Waterjets
Authors: Mr R. Möller
Flow Europe GmbH
Time: November 3, 2009 2:20 pm
Room: Lumen
It is widely known that composite materials offer significant strength-toweight advantages over metals. These advantages
couldn’t be more evident than as seen in the increasing use of composite materials on commercial and
military aircraft. Where airframes were traditionally constructed of metal, structures such as the fuselage, wings,
and the empennage (vertical and horizontal stabilizers), are now made of composite materials.
The Boeing 787, for instance, with delivery beginning in 2008 will be 50% composite structure by weight. In
comparison, the 777, which entered service just over ten years ago, is only 10% composite structure by weight.
AIRBUS, with it’s A350XWB, is considering an all composite fuselage and wing. The military’s F-22 Rapture
aircraft contains approximately 60% composite structure.
With the increased use of composite materials on primary aircraft structures comes the greater need for technological
improvements in the production of those structures. The obvious factors driving this need includes: 1)
Consistent high product quality due to the potential for imminent catastrophic aircraft failure if a structure fails inflight;
2) Lower processing and materials cost since the $/LB cost of composite structures compared to structures
made from conventional metals (such as aluminum) have historically prevented the use of composites on aircraft;
3) Shorter processing times in light of forecasted order and build rates of new aircraft.
Abrasive waterjet (AWJ) cutting is one technology enabling the realization of all three of the above factors, provides
several advantages over conventional cutting methods, and is the preferred method for cutting composite
structures.
Abrasive Waterjet (AWJ) Technology
When water is pressurized up to 60,000 pounds (or more) per square inch (psi) and forced through a tiny
opening, it can cut a variety of soft materials including food, paper and baby diapers, rubber and foam. When
small amounts of abrasive particles, such as garnet, are mixed into the jet stream, the resulting „abrasive waterjet“
can cut virtually any hard material such as metal, composites, stone and glass. …
Title: Metal-ceramic interpenetrating composites obtained by metal infiltration into
gelcast alumina foams
Authors: Dr M. Potoczek, Prof. R.Sliwa
Rzeszow University of Technology
Time: November 3, 2009 2:40 pm
Room: Lumen
Looking for strong and light materials to adopt as elements of aeronautical construction, the composite based
on foams infiltrated by light metals have been analysed. In order to obtain the porous alumina material a new
method of manufacturing of porous ceramics known as “gelcasting of foams” was applied. The gelcast alumina
foams were used as preforms for AlCu5 alloy infiltration by pressure technique. The results of apparent density,
percentage of theoretical density, open and total porosity of alumina foams are presented. SEM observations of
alumina foams are the base for looking for the best solution for manufacturing such kind of composite material.
The alumina foams were typically composed of approximately spherical cells interconnected by circular windows.
Spherical pores were associated with well-densified polycrystalline struts The presence of well-densified
struts is the main microstructure difference between the gel-casting technique and another method of manufacturing
of highly porous ceramics, known as a replication process. One of the drawbacks of the replication process
is the tendency to leave hollow struts, causing lowering of the mechanical properties. …
12
Title: New Economic Solutions for Drilling and Milling of CFRP and Low Force Drilling of
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