Mechanics of planar variable-curvature interconnects for stretchable electronics

Abstract Stretchable variable-curvature interconnects, such as two-dimensional spirals, offer certain advantages over widely used serpentine and horseshoe designs with constant curvatures in terms of stretchability and coverage. A clear understanding of the nonlinear stretching mechanics of variable-curvature interconnects is essential for its optimization and application. This work develops a unified mechanics model based on finite deformation theory for general interconnects defined by parametric curves. Theoretical predictions for stretched configurations, effective tensile stress, and maximum strain are validated by finite element analysis. The effects of geometric shape parameters on the mechanical responses and stretchability of sinusoidal-serpentine and sinusoidal-spiral interconnects are thoroughly investigated. This work provides certain insights for designing stretchable, planar interconnects for advanced flexible electronics.