A Degradable Mode I Cohesive Zone Model Developed for Damage and Fracture Analysis of Dissimilar Composite/Metal Adhesive Joints Subjected to Cyclic Ageing Conditions

M. Moazzami, A. Akhavan-Safar, M. R. Ayatollahi, J. A. Poulis, L. F. M. Da Silva, Sofia Teixeira de Freitas
October 2023
Cite DOI

Abstract

Adhesive joints are frequently exposed to cyclic ageing conditions during their service life, which can have a substantial impact on the mechanical properties of both the adhesive and the substrates. The safe life philosophy, commonly employed in the design of bonded joints, underscores the importance of obtaining an accurate estimate of the adhesive’s durability. Therefore, it is essential to enhance the predictive capabilities of the adhesive’s mechanical behavior under cyclic ageing conditions. This research aims to expand the use of quasi-static cohesive zone modelling (CZM) for damage and fracture analysis of dissimilar adhesive joints subjected to cyclic ageing environments. The first step involved measuring the mechanical properties of the adhesive through tensile tests on unaged and cyclically aged dogbone specimens, considering their moisture content and ageing cycles. Based on the results, a degradable CZM was developed. To validate the numerical model, dissimilar double cantilever beam specimens (DCBs) of glass fibre reinforced polymer (GFRP) and aluminium were manufactured and tested before and after ageing. The load-displacement curves of the bi-materials bonded joints were successfully predicted using the developed model where the properties of the material are defined as a function of the moisture uptake and ageing cycles at each material element. The obtained results showed that after 4 ageing cycles, the maximum load of DCB specimens decrease considerably.

Type
Journal article
Publication
Theoretical and Applied Fracture Mechanics
Cohesive Zone Modelling Cyclic Ageing Dissimilar Adhesive Joints Mode I Moisture Diffusion
Sofia Teixeira de Freitas
Sofia Teixeira de Freitas
Principal Investigator

Sofia Teixeira de Freitas researches the structural integrity of bonded and layered materials to enable durable, sustainable structures. She is also an accredited group facilitator, committed to building academic environments grounded in cooperation and inclusion—key to overcoming technological limits and addressing the challenges of a truly sustainable society.