Browsing by Author "Sousa, Jorge Augusto Dias"
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- Numerical Thermomechanical Analysis of Scarf Adhesive JointsPublication . Sousa, Jorge Augusto Dias; Campilho, Raul Duarte Salgueiral GomesGiven the industrial demands presented nowadays, adhesive bonding is a concept that goes towards the needs of the future. It is a process that is evolving too fast in order to keep up with it. It is replacing other traditional methods, not only because of its improved stress distribution and improved stiffness, but also because it can be used in high strength and lightweight structures at lower cost and easier production, among other advantages. Adhesive joints can come in different formats such as lap joints, butt joints or strap joints, just to name a few. The scarf adhesive joint belongs to the butt joints type configuration and it allows smoother surfaces, and some research has been done to this type of joint. Most structures must endure challenging conditions and temperature can be a disruptor of performance. Thus, this dissertation aims to study the effect of temperature in adhesive joints and understand the material and geometric factors that can influence it. The focus will be on scarf adhesive joints in a numerical thermo-mechanical analysis. Temperature has a significant effect on the adhesive and on the interface of the adhesive joint. The thermal effects will be studied in scarf joints with various scarf angles, from 3.43° to 45°, with three different adhesives, the Araldite® AV138 (brittle epoxy), the Araldite® 2015 (reasonable ductile epoxy) and the Sikaforce® 7752 (ductile polyurethane). With the support of the Abaqus software and cohesive zone modelling, a two-step thermo-mechanical analysis will be used to determine the temperature effects and understand the respective joint behaviour. The main conclusions of the present work are as follows: • The lower the scarf angle, the higher the bonded area; therefore, the joint strength increases; • The higher the temperature, the higher the joint displacement to failure; • Temperature also influenced stress levels (both shear and peel), and this effect is more noticeable as scarf angles are increased; • Temperature does not affect maximum force; • Cohesive Zone Modelling is a precise technique in predicting strength of various joint configurations and adhesives.