Shear lag approximation

Fig. 16 Modeling of the stress distribution in a cracked film with plasticity at the interface using the shear lag approximation, (a) linear evolution of the normal stress along the characteristic slip length r/2 and (b) sharp evolution of the interfacial shear stress x. along the characteristic slip length r/2.

By taking into account the yielding of the substrate near the film-substrate interface, Hu and Evans [10] derived within a so-called shear lag approximation the following formula... 

Fig. 17. Shear lag predictions for shear stresses within adhesive layer joining two dissimilar adherends having different coefficients of thermal expansion. Thinner bond lines result in more significant peaks in shear stress. Bending is ignored for this shear lag approximation.

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