Interfacial Instability of Two Bonded Elastic Bodies Driven by Interface or Bulk Residual Stress

Inspired by recent research interest in the interface wrinkling of bonded materials in diverse areas of 3D printing, the present work studies the interfacial instability of two bonded elastic bodies driven by negative interfacial tension or compressible bulk residual stress. For interfacial instability modes decaying exponentially with distance from the interface, the present model is formulated for two bonded elastic half-spaces with a planar interface under plane strain. An explicit expression is given for the wavenumber of interfacial instability driven by negative interfacial tension, and a critical condition is derived for interfacial instability driven by compressive bulk residual stress. The derived results are validated with comparison to known results on surface instability of an elastic half-space, and the role of shear modulus ratio and Poisson’s ratios of two bonded elastic bodies in interfacial instability, an issue to be addressed in literature, is studied with specific reference to material parameters used in some areas of 3D printing.