ABSTRACT

In bonding processes, the final distribution of the adhesive in the gap depends on the compressing normal load, velocity and kinematics, the adhesive properties, but above all on the initial adhesive distribution. The latter is also largely responsible for trapped air and the adhesive squeezes 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 the aforementioned model towards shear rate-dependent viscosity, a phenomenon crucial for most industrial adhesives. 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 verification, studies are performed on two academic examples: a rectangular, and a circular propagation. The results are compared with analytical solutions and CFD simulations. A very good agreement of pressure (deviations below 1.5%), and velocity profiles (deviations below 5%), 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.

摘要

在粘合过程中，粘合剂在间隙中的最终分布取决于压缩法向载荷、速度和运动学、粘合剂特性，但最重要的是取决于初始粘合剂分布。后者也是造成空气滞留和粘合剂在边缘挤出的主要原因。最近开发了一个模型，用于模拟粘合接头压缩过程中的流动。本文将上述模型扩展到与剪切速率相关的粘度，这是一种对大多数工业粘合剂至关重要的现象。除了牛顿流体的假设之外，还使用了幂律和安田定律的近似值。为此，在现有模型中添加了另一个用于确定流动剖面的从属牛顿方法。大范围剪切速率的流变测量可作为参考。为了验证，对两个学术示例进行了研究：矩形传播和圆形传播。将结果与解析解和 CFD 模拟进行比较。对于所有场景和流动规律，压力（偏差低于 1.5%）和速度剖面（偏差低于 5%）的一致性非常好。该模型开发的长期目标是预测复杂应用模式的粘合剂压缩流动。对于所有场景和流动规律，被发现。该模型开发的长期目标是预测复杂应用模式的粘合剂压缩流动。对于所有场景和流动规律，被发现。该模型开发的长期目标是预测复杂应用模式的粘合剂压缩流动。