Journal of Adhesion, Vol.80, No.3, 203-221, 2004
Experiments and inelastic analysis of the loop tack test for pressure-sensitive adhesives
The loop tack test is studied experimentally and numerically using a model system. The ends of a steel strip are clamped together, giving a teardrop shape, and the loop is pushed downward onto an acrylic foam tape and then pulled upward off the tape. In the finite element analysis, the strip is represented by beam elements and a bilinear elastic-plastic constitutive law. The traction-separation relationship for the pressure-sensitive adhesive (PSA) is modeled with a trapezoidal cohesive zone. Viscoelastic behavior of the PSA is included in one case. Curves of the pulling force versus the top displacement (i.e., tack curves) exhibit a sharp peak just before separation of the loop from the strip. The effects of the PSA parameters, contact length, loop length and thickness, and loading rate are investigated. The numerical results compare more favorably with the experimental results than do those from a previous elastic analysis.
Keywords:loop tack;pressure sensitive adhesive;finite element analysis;elastic foundation;viscoelastic foundation