Joint overlap

The contact resistance can be minimized by increasing the pull of the fasteners. Increasing the area of overlap may not reduce the contact resistance, unless the number of fasteners is also increased. It is mandatory to maintain a certain minimum contact pres.stire per unit area of the joint overlap. An average contact pressure at around 40-55 kg/cm is considered adequate. For the purpose of easy application, it is expressed in terms of bolt torque, depending upon the area of overlap and the number of fasteners, as specified in Table 29.1. 

The same sort of considerations allow one to determine matrix elements. Eet ui(l) v n) = T be another orbital product. There is a joint overlap matrix between the v- and m-functions ... 

The 8 x 9 in panels stressed by mounting on a steel bending frame to get 0.25-in deflection at the center of a 6-in span V -in joint overlap is at center of span. 

Increasing the overlap length has virtually no benefit in reducing the maximum stress. The analysis shows that the stress in the central zone is reduced to zero. From an adhesive performance point of view, an area of low stress means that the joint will not suffer from creep under load. Reduction in joint overlap by 35 mm... 

Secure metal with metal bands at butt joint overlaps and between joints. Field-Applied Metal Jacket... 

Volkersen [28] presented a continuum mechanics approach to analyse the shear-lag configuration of the single lap joint. However, there were limitations to his analysis, most significant of which was its failure to account for the effect of the bending moments induced by the eccentricity of the applied load. Nor did it account for the adherend shearing, and it predicted the maximum shear stress to occur at the free surface at the end of the joint overlap. As this is a free surface, the shear stress here should, in practice, be zero. 

A loaded lap joint tends to produce high stresses at the ends of the joints due to the slight eccentricity of the force line. Excessive joint overlap also increases the stress concentrations at the joint ends. 

Equivalent von Mises stress along the middle of the joint overlap in an aluminium-epoxy single lap joint conditioned at 50°C/95% r.h. (Jumbo, 2007)... 

From the shear stress distribution curve in Figure 5.4 we can see that the highest stress is at the ends of the bond and by increasing the joint overlap there is no significant change in the strength of the bond. 

Figure 5.4 The joint strength does not increase linearly with joint overlap due to...

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