Rate-dependent cohesive zone modeling and experimental validation for viscoelastic sensor-embedded interfaces

Abstract

The mechanical behavior of viscoelastic interfaces in sensor-embedded systems exhibits strong rate dependence, directly influencing adhesion performance and structural integrity. Existing cohesive zone models (CZMs) inadequately capture the interplay between viscoelastic bulk deformation and interfacial damage evolution, particularly under dynamic loading. This study proposes a novel rate-dependent CZM framework integrating viscoelastic liner mechanics to decouple bulk deformation from true interfacial behavior. A trilinear stress-strain relationship (weak/strong nonlinear strengthening and damage softening) was identified through multi-rate uniaxial tensile experiments on polyimide (PI)/hydroxyl-terminated polybutadiene (HTPB) interface specimens. Key innovations include a methodology to isolate interfacial cohesion parameters via Prony series-based viscoelastic decoupling and finite element validation. Results demonstrate exponential rate dependence of cohesive strength (1.19–1.58 MPa) and critical displacement (0.89–0.67 mm) across 10–70 mm/min loading rates, with stress intensification during damage propagation. The model aligns closely with experiments at low strain rates, while discrepancies at high rates highlight viscoelastic relaxation effects. This work advances interface mechanics by resolving the coupling of bulk and interfacial responses, offering a universal framework for adhesion analysis in flexible sensor systems.