Development and validation of a compression flow model of non-Newtonian adhesives

In bonding processes, the final distribution of the adhesive in the gap depends on the loading process during compressing, the adhesive properties, but above all on the initial adhesive distribution. The latter is also largely responsible for trapped air and the adhesive squeeze out at the edges. A model has recently been developed for the simulation of the flows during compression processes in adhesively bonded joints. This paper extends aforementioned model towards shear rate-dependent viscosity, a phenomenon crucial for most industrial adhe-sives. Besides the assumption of a Newtonian fluid, approximations of a power-law and a Yasuda law are used. For this purpose, a further subordinate Newton method for determining the flow profiles is added to the existing model. Rheological measurements over a wide range of shear rates serve as a reference for the different flow laws tested. For the validation, studies are performed on two academic ex-amples: a rectangular, and a circular propagation. The results are compared with analytical solutions and CFD simulations. A very good agreement of pressure, and velocity profiles, for all scenarios and flow laws was found. The long-term goal of this model development is the prediction of adhesive compression flows for complex application patterns.