A crack in the vibrant structures can lead to premature failure if it is not identified in early stages. The failure rate increases as the crack growth increases due to the structure becomes weaker. Therefore, crack identification and type of crack is a key issue. The existence of cracks which influence the performance of structure as well as the vibration parameters such as; natural frequencies, mode shapes, stiffness and modal damping. Our current investigation is to model an inclined open edge crack in a cantilever beam and analyze the model using a finite element package, as well as experimental approach. A finite element model has been developed in this paper to analyze the variation of modal parameters according to the location, size and inclination of a crack in the cantilever beam having inclined edge crack. The proposed method is based on measured frequencies and mode shapes of the beam. The experiments are also carried out using specimens having inclined edge cracks of different depths, positions and crack inclinations to validate the FEA results achieved

In this paper authors discuss the advancements made over years in the passive constrained layer damping (PCLD) technique used for structural vibration control. To start with, the paper presents a brief literature survey on passive damping techniques using viscoelastic materials (VEM) emphasizing unconstrained layer damping (UCLD) followed by PCLD. The discussion on PCLD technique includes different mathematical models and experimental investigations related to it. Finally, the various design modifications proposed by the different researchers in order to improve the performance of conventional PCLD configuration in presented.

The present research aims to study the growth of the circular adhesion failure pre-existing at the interfaces of the strap adherend and the adhesive in a single lap joint. Three-dimensional nonlinear finite element analysis of adhesively bonded single lap joints made with high strength steel adherends under uniformly applied extension have been carried out. The interfacial stresses and strain energy release rate values, being indicative parameters, in the growth of the adhesion failures are computed in the vicinity of the pre-existing circular adhesion failure fronts when the load on single lap joint increases till failure. The magnitudes of the strain energy release rate are computed using the virtual crack closure technique. The results show that the sizes of the adhesion failure significantly influence the magnitudes of the interfacial stresses, the three modes of strain energy release rates and the load-bearing capacity of the single lap joint. The finite element analysis predicts that pre-embedded circular adhesion failures will not have grown from the pre-embedded circular adhesion failure front, instead the failure will be initiated from the overlap ends upon loading for the adhesive bonded single lap joint made with strong adherends and AV119 adhesive. The finite element analysis also proposes a method to calculate the strength of this type of joint configurations using the global shear strength of the adhesive and the intact bonded area. The finite element analysis predicted failure strength of the single lap joint is in good agreement with the experimentally obtained strength for the single lap joint containing pre-existing circular adhesion failure.