Investigation of Vibration Modes of Double-lap Adhesive Joints: Effect of Slot

Adhesive joints represent a viable alternative to traditional joining methods. The analysis of frequencies and modal shapes is fundamental to predict the vibrational behaviour of a structural component subjected to dynamic stress. There are numerous studies in the literature to determine the trend of stresses in the bonded region. It has been proved that the introduction of a slot in the inner adherend allows to reduce the stress concentration at the edges of the adhesive region. In this paper, the influence of imperfections in the central adherend is investigated by FEM analysis. The FE software ANSYS©19 is used for the modal analysis of the double lap adhesive joints and the first five modes are considered. The results show the influence of Young’s modulus and density ratio on the natural frequencies, varying with the material. Moreover, the introduction of the imperfection is found to influence the vibrational behavior as the frequency increases. It is also observed that the mass reduction due to the introduction of the crack does not change the shape and modal frequency for the most significant modes, while it causes more important changes for the last vibrational mode. Therefore the introduction of the crack does not significantly change the dynamic behaviour of the joint and allows to realize a more even distribution of stresses, reducing the stress peaks values.