Estimation of viscoelastic resistance and subduction profile of acrylic based pressure sensitive adhesive sheet subjected to wedge indentation

摘要

This paper aims to estimate the indentation resistance and deformation shape of a 0.5mm thickness acrylic Pressure Sensitive Adhesive (PSA) sheet subjected to a wedge indentation. As for the effect of apex angle of a wedge blade on the cutting characteristics of the PSA sheet, a 60° wedge blade was mainly investigated through experiments and numerical simulations, while the wedge angles of 42, 16° were discussed with respect to the subduction profile of wedged surface. For the sake of development of PSA deformation model, the Prony series based viscoelastic properties were determined by the shear stress relaxation test. Also, the equivalent Young's modulus was estimated by comparing with an out-of-plane compressive experiment and a Finite Element Method (FEM) based compressive simulation. Through the experimental wedge indentation using the 60° wedge blade, three stages of cutting load response were detected: (1) an exponential response, (2) an extremely increasing response based on the saturated inclined angle of subduction zone, and (3) a saturated gradient for the final stage. Furthermore, it was clarified that the proposed FEM model of viscoelastic-deformable sheet subjected to the 60° wedge indentation was applicable for simulating the cutting deformation for the early stage less than 60% of the thickness. The simulated inclined angle of subduction zone tended to be linearly increased with the indentation depth up to a certain extent, whereas the experimental inclined angle saturated to a constant for the indentation depth larger than 70% of the thickness. One of the reasons why the experimental cutting force was higher than the simulated result was explained as the wetting spreading effect due to the yield flow of PSA sheet. In the latter stage of indentation, the correlation between the mismatching of cutting line force and the mismatching of inclined angle of subduction zone was revealed.