Ebook: New Frontiers in Light Metals

The INALCO 2010 Conference “New Frontiers in Light Metals” is the eleventh in a series of aluminium conferences organised since 1979. It will consist of keynote lectures by invited speakers as well as oral presentations of papers submitted by attendees.

The 1st International Conference of welded products and constructions with aluminium alloys was held at Cleveland, USA in 1979 and established as INALCO at the 2nd conference held in Munich, Germany in 1982. Since then these conferences have been held every 3 years at different locations all over the world.

With the 2010 INALCO Conference “New Frontiers in Light Metals” we want to emphasize the many challenges that face the industry today and the creative and innovative solutions that are developed by the industry and the research institutes to remain competitive in the light metals world that is becoming more global every year. We have also widened the scope of the conference by including contributions on magnesium technology.

The programme of the 3 day conference consists of two plenary sessions and 12 parallel sessions. The topics of the parallel sessions are:

• Advanced Joining

• Materials Technology

• Surface

• Architecture

• Structural Design

• Transport & Automotive

In connection with the conference programme an exhibition of new developments is organised. Furthermore an excursion programme is added to the programme to give exposure to interesting aluminium applications in the Netherlands. The proceedings of INALCO 2010 will be available both on CD and in print at the start of the conference.

The symposium committee gratefully acknowledge the support of the many sponsors and exhibitors to make the symposium possible. As symposium chairmen we would like to acknowledge in particular Messrs Rein van de Velde and Rudolf de Ruijter for their enthusiastic support in planning and organising the conference. Also the cooperation of the members of the symposium committee has been very fruitful in identifying relevant new technical areas and potential contributors.

Finally I would like to gratefully acknowledge the speakers and authors for their contributions to make the symposium a success.

Prof. Laurens Katgerman, Symposium Chairman, Department of Materials Science and Engineering, Delft University of Technology, the Netherlands

Prof. Frans Soetens, Symposium Chairman, Department of Architecture, Building and Planning, Eindhoven University of Technology, the Netherlands

This paper demonstrates the potential for aluminium to contribute to the creation of high quality contemporary architecture, throughout the globe. Architecture that is durable and beautiful, providing comfort and human well-being. It examines how the architectural profession can learn from its own experiences and benefit from technology transfer from other industries. The paper also explores the responsible sourcing of construction products and divergent views on recycled content. The case study architecture will be drawn from the author's own practice and key international exemplars, identifying the potential for aluminium to contribute to human ecology.

The basic principles and the continuing development of friction technologies are described with particular emphasis on friction stir welding (FSW) variants from the perspective of discovery, invention and innovation. This paper further outlines the feasibility work that has been carried out to develop self-reacting (bobbin) stir welding for welding 25mm thick aluminium alloy material.

With the advent of the 2010 Aluminum Association's Specification for Aluminum Structures, structural engineers will be required to design using new stability provisions. Second-order effects, including P-Δ and P-δ moments, will need to be directly accounted for in the analysis. Factors known to accentuate these effects, such as geometric imperfections and member inelasticity, will also need to be considered. This paper provides an overview of these provisions and describes a study that investigated their effectiveness.

Can there be an end to the continuously growing primary aluminium industry and can the recycling industry catch up or even replace it? It all depends on the global demand for aluminium products in let's say 40 years from now and what will happen with the almost endless stream of aluminium products to the end of its life cycle.

It seems that if there is a political wish to do it, an expanding recycling industry can boost jobs, reduce CO2 emission big time and balance it out with the primary industry.

An overview of the status quo in the field of façade design and construction is given, related to the core aspects energy, efficiency and individuality. In a second part the research, executed by the Façade Research Group at the TU Delft is described and the relevant and influencing research topics for design decisions in architecture are described:

- Opportunities for integrated façade solutions.

- The refurbishment of façade and cladding systems and how they can be updated in relation to the use and design of the building.

- The influence of embodied energy in façade and cladding constructions for the design.

- Chances for new additive production technologies in the field of façades and cladding.

Two twin aluminium domes have been erected within the thermo-electrical power plant of the Italian Electrical Department (ENEL) in Torreveldaliga Nord near Civitavecchia (Italy).

They are two reticular space structures shaped as geodetical domes (with 144 m diameter and 50 m high) made of aluminium alloy tubes and stainless spherical nodes, according to the MERO system. The two domes are the largest built in Europe and surely ones of the largest in the World. Their function is for coal storage, according to the requirements of the thermo-electrical power plant.

The aluminium alloy 6082 T6 has been selected in order to obtain both a mechanical strength comparable with the one of steel and a corrosion resistance compatible with the aggressive environment, being the plant located close to the Tirreno sea cost.

The design of the domes has been done following the Eurocode 9, also considering the “design assisted by test” approach. In fact, a series of tests has been planned in order to qualify the structural behaviour of each material, component and substructure. The global behaviour has been analysed by means of sophisticated numerical models and wind tunnel tests have been also done, being the wind load effect more severe than the earthquake for this type of structure, also thanks to the lightness of the structural material.

During erection, very comprehensive quality control and qualification tests have been planned. The final proof tests on the whole structure, both static and dynamic, confirmed the satisfactory behaviour of the domes in good agreement with the numerical prediction.

This challenging application demonstrates once again that aluminium alloys are excellent structural materials with a strength-to-weight ratio more than twice the one of steel and in addition the good corrosion resistance allows avoiding any protective coating. Non negligible economical advantages have been obtained for the structure itself, the foundation dimensions and, last but not least, the maintenance cost. The two aluminium domes represent a clear example in which this aluminium solution can be competitive versus a steel one.

Laser welding of aluminium alloys was performed with high power YAG, fiber or disk laser. Interaction between laser and plume, laser absorption, welding phenomena and weldability were investigated by using such lasers. The absorption of a focused fiber laser in aluminum alloy was found to be higher at high powers and low welding speeds than that in stainless steel.

Hybrid welding of A5052 alloy with YAG, fiber or disk and MIG arc was performed to understand welding phenomena, the mechanisms of weld penetration, porosity formation and prevention, etc. The conditions for the production of sound deep welds were clarified. Furthermore, the addition of the other filler wire during hybrid butt-joint welding was also investigated, and the effect of the increase in gap tolerance was confirmed.

Aluminum-to-steel joining was performed. It was confirmed that the joints with three weld beads were fractured in the base metal and possessed high strength. Moreover, the laser joining of PET plastic to aluminium alloy was also carried out using a diode laser under various conditions. High tensile strengths of lap weld joints were obtained when the laser was irradiated on an aluminum alloy sheet. It was observed that the PET sheet on the aluminum alloy plate was melted and chemically bonded through the oxide film on the base aluminium alloy. This novel bonding technique was applied to bond an aluminium alloy sheet to a steel one. It was consequently confirmed that the joint of aluminium alloy and steel with PET intermediate sheet was high.

Joints of high tensile aluminum alloys can enhance design flexibility for various structures. Al-Cu alloy is an extensively used high tensile material. However, the conventional fusion welding of Al-Cu alloy is less weldable than Al-Mg alloys.

In the present study, YAG laser, Disk laser Plasma welding and friction stir welding are produced for Al-4%Cu alloys of 0.8 mm in thickness. This research has been investigated by tensile, hardness and impact tests, and observation of imperfection and microstructure. Weldability of Disk laser beam welds is higher than other power beam processes. Mechanical properties are influenced beam quality. Weld metals are shown fine structure and segregation of element is not recognized. Friction stir welds shows high impact properties and fracture position of drop impact test is base metal.

For the purpose of improving the defects of conventional friction welding method, new friction welding technology has been examined. That is, conventional friction welding can make only joint with round and relatively small cross section, and further it cannot obtain the joint of many combinations of dissimilar materials. New method has intermediate material for translational friction between joint specimens. After the intermediate material generates the friction heat, it is removed instantaneously and upset process begins to weld the specimens for joint. In this study, the experimental results for principal certification for this technology are reported. Several materials were examined for intermediate specimen and joints, in addition factors on the friction heat such as friction pressure and motion of the intermediate material were investigated.

It is well known that aluminum castings are hard to weld due to imperfections. However, they have several advantages and are therefore often used in industry. Nowadays, large components of medical equipments and automobile vehicles are manufactured using castings.

Imperfections during casting cannot completely be avoided. Mechanical properties of welded coupons are the subject of this paper after introducing some imperfections during casting.

For pull-over, the fastener's head is pulled completely through a metal sheet. The 2005 Aluminum Design Manual includes an equation for nominal pull-over strength. This was based on testing using thin aluminum (1.02 mm maximum). Later, other testing indicated that this equation becomes increasingly conservative as thickness increases beyond 1.02 mm. A new equation has been developed that is in substantially better agreement with tests that used prescribed hole sizes and aluminum thicknesses of 1.02 mm and greater.

The thermal aspect of the jig for friction stir welding (FSW) in a commercial application with a self-reaction pin tool (SRPT) is described. The influence of the heat conduction through the jig is examined by the finite element simulation and the welding experiment. In a particular case, the increase of the heat conduction can increase the risk of weld imperfection. Adopting the preferable spacing of the jig determined by the numerical simulation prevents the imperfection and achieves stable welding.

A numerical method has been proposed to estimate transient temperature distribution in friction welding of aluminum alloys. The temperature distribution was calculated with a finite element method using the measured rotation speed, friction pressure, upset pressure and burn-off length. The calculated heat input and temperature were compared with the measurement results. It has been shown that the transient temperature characteristic could be calculated quantitatively by this numerical method which allows the deformation of two similar base materials.

Non-orthogonal high-rise buildings are emerging with an increasing degree of geometrical variation. As yet no scheme categorises data on the basis of the overall geometries of such buildings. The author proposes an easily accessible morphological scheme which for example, nables data to be retrieved on sustainable performance of the distinctive building shapes or façade build-up.

The shaping of most non-orthogonal high-rises is related to developments in modeling software. The morphological scheme is based on software manipulations to describe shaping, not on mathematical formulae. As software develops, new ways of generating and new shapes emerge. In onsequence the shaping scheme gradually will be updated. The scheme is illustrated by examples of overall shaping and materialization trends.

This paper examines the carbon impact of double-skin facades in office buildings in the UK context. It establishes the initial carbon cost of double-skin facades through increased material quantities, and outlines the timeframe within which these are offset through reduced heating, cooling and ventilation requirements during operation. The paper also examines the role aluminium and recycled materials play in reducing the carbon impact of the facade.

In this paper, elastic interactive local buckling formulas of box section and channel section are established according to classic differential equation of plate stability. Formulas calculating restraint coefficient of adjacent plate parts are also derived. Based on the effective thickness method adopted by current code of various countries treating stiffened plate and non-stiffened plate, the restraint coefficient is then introduced to account for the restraining action exerted by adjacent plate element and its effect on the bearing capacity of cross section. Finally, non-linear finite element analyses are employed to predict the ultimate strengths of box section and channel section under uniform compression, and the results are compared with the approximate approach developed in this paper. It is found that the plate assembly effect does exist when local buckling takes place, and the results given by the approach in this paper are inclined to be safe in most cases.

Design models are required to assess the behaviour in fire of aluminium structures. These models need to be validated by comparison with test. Up to now tests results are only available for (small scale) individual components. This paper provides the results of tests carried out on frames. A finite element model in combination with a sophisticated constitutive model are used to simulate the test. The results of the simulations agree with that of the tests at room and elevated temperatures.