Mechanical characterisation of graded single lap joints using magnetised cork microparticles

• Type: Chapter or Part of a Book
• Date: 2020

Authors

da Silva, CI (Author) Other; Barbosa, AQ (Author) Other; Marques, JB (Author) Other; Ricardo Carbas (Author) FEUP; Marques, EAS (Author) FEUP; Abenojar, J (Author) Other; da Silva, LFM (Author) FEUP

Indexing

Scopus - 1 Citation

Other information

Authenticus ID: P-00S-244

DOI: 10.1007/978-981-15-2957-3_11

Abstract (EN): One of the main problems associated with adhesive joints is the existence of stress concentrations (shear and peel) at the ends of the overlap, reducing joint performance. This is especially valid for the most common joint geometry¿the single lap joint (SLJ). Therefore, a main area of investigation in the field of adhesive bonding is the uniformisation of the stress distribution along with the adhesive bondline, in order to decrease those stress accumulations at its ends, achieving stronger and lighter joints. The main goal of this work was to develop a functionally modified adhesive, where the mechanical properties vary gradually along the overlap. With an adequate application of magnetic fields, using a customised apparatus, magnetised cork microparticles, initially uniformly distributed within a resin, were strategically placed along the bondline of an adhesive joint, being then nonuniformly distributed along the entire overlap area. This results in a gradual variation of the mechanical properties along the overlap, decreasing the stress concentrations and leading to a more uniform stress distribution on the overlap region. The adhesive stiffness varies along the overlap, being maximum in the middle and minimum at the edges of the overlap region. Therefore, the influence of the amount of magnetised cork microparticles was assessed. Tensile tests were performed for bulk specimens and SLJs, along with SEM analysis of the particles and the correspondent fracture surfaces of the bulk specimens. Additionally, glass transition temperature measurements were carried out. According to experimental testing result, the inclusion of these particles enhances the joint performance for both graded joints and joints with a uniform particle distribution, when compared to joints bonded with neat resin. It was also possible to manufacture graded joints with distinct mechanical behaviour, which is dependent on the amount of magnetised particles being considered. © Springer Nature Singapore Pte Ltd. 2020.

Language: English

Type (Professor's evaluation): Scientific