Adhesives Mechanical Properties, Technologies and Economic Importance

In this book, some interesting technologies and applications dedicated to adhesives are presented and discussed. First, the interference fitted and adhesively bonded joints are extensively studied as an effective means to increase the transferable load while reducing both the weight and the stress level of the joined components. In such type of joints, the influence of the assembly technique on the shear strength of the joints has been investigated. Therefore, the shear strength of hybrid joints realised by 'press fitting', by 'shrink fitting' or by 'cryogenic fitting' were compared in order to suggest the best way of joining both for technological and economic importance. Then, some design aspects for practical application (for instance in the automotive steel wheel) were analysed. The adhesive and interference contributions to the resultant resistance of the hybrid joint were carried out with particular attention to the phenomena occurring at the interface. The effect of the adhesive nature, its curing technology and its mechanical response were strongly related to the type of adhesive exploited. Also, the static and fatigue strength properties of press fitted and adhesively bonded joints was studied by considering their Engagement Ratio, which is the ratio between the coupling length and the coupling diameter. Coupling and decoupling tests have been performed both on press-fitted and adhesively bonded specimens and on pin-collar samples, considering four different levels for the Engagement Ratio.