Geometries and rigidities involving the presence of more than one neutral axis during finite (plane-strain) bending of a multilayered elastic (incompressible) block make numerically stiff the differential equations governing the incremental problem necessary to investigate diffuse-mode instabilities. We have developed a compound matrix method to solve these cases, so that we have shown that the presence of two neutral axes occurs within sets of parameters where the elastic system may display

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... g-wavelength bifurcation modes. Following the predictions of the theory, we have designed and realized qualitative experiments in which these modes become visible.