Adherend surface roughness effect on the mechanical response of adhesive joints

TL;DR

This study investigates how adherend surface roughness influences the mechanical strength of adhesive joints through experimental testing, revealing that roughness can enhance adhesion energy depending on specific parameters.

Contribution

It provides new experimental insights into the relationship between surface roughness and adhesive joint strength, considering factors like adhesive thickness and loading rate.

Findings

Surface roughness can increase adhesion energy.

The effect depends on the ratio of adhesive thickness to roughness.

Roughness effects vary with loading rate.

Abstract

The present contribution focuses on the effect of adherend surface roughness on the strength of adhesive joints, which are particularly cost-effective and extensively applied in a wide range of industrial applications. However, the reliability of such solutions is a critical concern for the integrity of commercial products. To gain a deeper understanding on the effect of roughness, an extensive experimental campaign is proposed, where thermoplastic substrates are produced with a specified roughness, whose characterization has been performed using a confocal profilometer. Elastic strips are then bonded onto such substrates using Silicone adhesive while controlling the adhesive thickness. Peeling tests are finally carried out and the effects of joint parameters such as surface roughness, adhesive thickness, and loading rate are discussed in detail. Eventually, it is demonstrated that the surface roughness can increase the adhesion energy of joints depending on the value of a ratio between the adhesive thickness and the root mean square elevation of roughness.