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Weld bonding of aluminium autobody structures offers automotive vehicle manufacturers the opportunity of achieving significant weight reduction, compared to equivalent steel structures. Further, this is achievable using volume production manufacturing methods. This paper considers all key aspects of the weld bonding process, in particular the equipment requirements and the factors that are important in reliably achieving satisfactory structures. Methods of minimising damage to the adhesive bondline and assessment of spot weld quality are discussed. Using experience gained from extensive weld bonding trials, suitable parameters for robust weld bonding are recommended.

A proven design and manufacturing system for building automotive structural frames and unibody structures in adhesively bonded sheet aluminum is described. The system, which was developed to be compatible with established procedures and facilities for building spot-welded steel vehicles, allows the weight of such vehicle body structures to be reduced by almost half, yet provides structures of similar rigidity, excellent resistance to fatigue and corrosion attack and has been proven through evaluation tests carried out on replicas of production cars built using the technology. While developed for manufacturing automobile structures from adhesively bonded stamped sheet, adaptation of this technology to the construction of adhesively bonded perimeter and tubular structural frames is also described.

Experiments have been carried out on the collapse behavior, the energy absorption and the flexural stiffness of adhesively bonded, spot-welded and weld-bonded aluminum box structural assemblies and the results compared with those for equivalent spot-welded mild steel structures. It has been found that weld-bonded aluminum box beams can exhibit specific energy absorptions that are three times greater than those for the mild steel beams and, hence, show that aluminum vehicle structures which typically can be built at about half the weight of steel structures, should nevertheless have more than adequate impact resistance. In flexural testing, the results suggest that the overall stiffness improvements of bonded structures may be a combination of improved beam stiffness, and superior connections between structural elements.