Lap joints configuration

P(2) Instead of butt joints a strap, scarf or lap joint configuration shall be used (see Figure 5.41). The joint design is then undertaken according to the procedures for strap or scarf joints respectively. When using strap configurations the adherend ends shall also be bonded. 

In practice, it is not always possible to use the preferred double-lap joint configuration. Instead, the single-lap configuration, shown schematically in... 

The geometry used in these analyses consisted of the single lap Joint configuration with a relatively short overlap of 12.5 mm. In a parallel experimental programme, any spew fillet that had been formed on manufacture of the Joints was machined off subsequent to the adhesive curing, so this was also removed in the model. 

Apart from the physical problem of actually being able to assemble components sufficiently well to make an effective joint, there are several practical considerations which should be taken into account. For example, when two components have to be assembled using a lap-joint configuration the slight indentation of one part may allow the more accurate placement of the other. Similarly, care must be taken with the... 

In contrast with the co-cured single lap joint, tensile load bearing capacity of the co-cured double lap joint decreases as the stacking angle of the composite adherend increases. Sint e the co-cured double lap joint has symmetrical configuration, it is important to consider the out-ofplane shear stress rather than the out-of-plane peel stress in designing the joint. 

Figures 12 and 13 show interfacial out-of-plane transverse and shear stress distributions of the co-cured double lap joints with [0]i6t and [ 45]4s stacking sequences along the interfaces between steel and composite adherends, respectively. It is important to consider interfacial out-of-plane shear stress rather than interfacial out-of-plane transverse stress because of the compressive stress distribution due to the symmetric configuration of the co-cured double lap...

Fig. 1.3 Joint configurations for friction stir welding, (a) Square butt, (b) Edge butt, (c) T-butt joint, (d) Lap joint, (e) Multiple lap joint. (f) T-lap joint, (g) Fillet joint. Source Ref 14...

Freeney et al. (Ref 21) evaluated the effect of process parameters on FSSW of AA5052 using a plunge-type FSW machine. Sheets with two different thicknesses were used. The dwell time and revolutions per minute were process variables. Lap-shear tests were performed in two-sheet and three-sheet configurations to determine the influence of processing parameters on the mechanical properties of lap-joint friction stir spot welds. 

For laminate thicknesses greater than 5 mm, joint configurations other than single-lap or double-lap are recommended, as with greater thicknesses these configurations become inefficient. 

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