Bonded-riveted joints

P(l) Bonded-riveted joints are, from the design point of view, identicai to bonded-bolted Joints and shall be dealt with accordingly. 

REPRESENTATIVE BONDED/RIVETED JOINT ON SUPPORTING SUBSTRUCTURE... 

Bonding can eliminate crevices that often lead to crevice corrosion in riveted joints. 

Sealants are used by the aircraft industry to form flexible adherent barriers that will withstand chemical attack. The major uses are seals around riveted joints, fileting on overlapping bonded surfaces, and sealing fuel tanks. They also find some application with electrical components for protection from moisture and vibration. 

The traditional view of lap joint failure is old and familiar and was, in essence, employed by Fairbairn(36) who considered the failure mode of riveted joints on iron bridges. However, the topic of bonded lap shear joints is probably best reviewed in detail by... 

The ability to join thin substrates If thin pieces of, for example, aluminium are joined using rivets, the final component is susceptible to a tearing failure through the substrate which emanates at the rivet and its associated hole in the substrate. Any tensile load across the riveted joint (as seen in Fig. 19) is maximised at the point where the rivet enters the skin. Thus, when die substrate is thin, this can readily lead to crack and/or tear initiation and failure of the structure. Using bonding technology within these components eliminates these bearing stresses and minimises the chance of premature failure. 

Improved stiffness [left) and stress distribution [right] at adhesively bonded joints in relation to riveted Joints... 

Pirondi A, Moroni F (2009) Clinch-bonded and rivet-bonded hybrid joints application of damage models for simulation of forming and failure. J Adhes Sci Technol 23 1547... 

As already mentioned, adhesive bonded structural joints are automatically sealed against leakage and corrosion in addition to providing strength, Conventional bolted or rivetted joints may also be sealed by structural adhesives applied during assembly, in which case they improve the stiffness of the structure as well as performing the sealing function. 

Transition Joints. Use of explosion-clad transition joints avoids the limitations involved in joining two incompatible materials by bolting or riveting. Many transition joints can be cut from a single large-area flat-plate clad and deflvered to limit the temperature at the bond interface so as to avoid undesirable diffusion. Conventional welding practices may be used for both similar metal welds. 

Bonding enables stresses to be distributed over large areas in the joint, thus avoiding the local stress concentrations present in riveted or spot-welded joints which can reduce fatigue resistance. 

Figure 1.2 Power transmission in riveted (screwed) and bonded joints.

It has been shown that in comparison with spot welds, rivets and a variety of selfpiercing mechanical fastenings, toughened structural adhesives may yield single lap shear joints of superior energy absorption when used to bond aluminium alloy sheet the findings were confirmed in tests on full-size bonded vehicles (see Toughened adhesives, Structural adhesives). 

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