A general model of hard and soft interfaces with damage

In recent years, adhesive bonding became a very common assembly technique in many industrial sectors, such as aeronautical, civil, energetic, automotive and biomedical engineering, as an alternative to conventional joining techniques, such as welding and riveting. Adhesive bonding provides several advantages, including reduced stress concentrations, higher corrosion resistance, water tightness, and the ability to join materials with dissimilar properties. In this paper, a general model of interfaces is presented. This model includes hard (the stiffness of the adhesive is of the same order as that of the substrates) or soft (the stiffness of the adhesive is lower than that of the substrates) interfaces. The model takes into account a damage parameter. The adhesive material is obtained by homogenizing a micro-cracked media. The porosity (or crack density) of the medium is chosen as the damage parameter. An evolution law based on the standard material theory is introduced. Academic examples are presented to show the evolution of the mechanical parameters and the relevance of the model.