Phononic crystals and acoustic metamaterials have unique properties, such as the existence of band gaps, which give them huge potential in many applications, such as vibration isolation, acoustic cloaking, acoustic lensing, and more. Many methods have been proposed to determine the band structure of these materials but almost all require a model of the structure. In this paper, an inverse method to calculate the band structure of one dimensional periodic structures based on Bloch wave boundary conditions and wave superposition is introduced. The proposed method only requires the frequency responses measured at a small number of points within the structure. This allows the band structures to be determined experimentally using simple equipment, like a shaker and accelerometers. The band structure of a simple bi-material beam was calculated in this study as a demonstration of the method, and the results were found to be in agreement with calculations made using the transfer matrix method. The proposed method was then extended to predict the response of a finite periodic bi-material beam with arbitrary boundary conditions using only the band structure and components of the eigenvectors; some resonance peaks were observed within the band gaps and these were found to be caused by the reflection of the waves at the boundaries. The effects of the number of unit cells on the transmissibility of a beam were investigated. It was found that the transmissibilities within the band gaps can be estimated to be directly proportional to the number of unit cells. Lastly, an attempt was made to extend the method to two and three dimensional periodic structures and the wave superposition method was found to be able to measure a portion of the dispersion surface of two dimensional structures with a fair degree of accuracy, especially at lower bands. Errors and scatter are present at high frequencies caused by more waves significantly affecting the responses of the system. This issue can be alleviated by taking measurements further away from the boundaries or increasing the number of waves considered. However, the key limitation of the method for two- and three-dimensional periodic structure is that it can only measure a portion of the dispersion surface or volume

An advanced hybrid joining technology for joining metal and composite is introduced. Protrusions formed on the surface of the metal by electron beam are embedded into carbon fibre reinforced polymer layers and thus forms an integrated joint. The performance of a joint produced using such method was found to be better than traditional joints. In this paper, the properties of two different patterns of protrusions, including a linear pattern and a cylindrical pattern were studied by uniaxial tensile testing of double lap composite structures using digital image correlation. The distributions of strains in the composites tested varied and were found to be influenced by the shape of the protrusions which also resulted in different failure modes. The joints with a linear pattern failed between laminate layers, whereas the joints with a cylindrical pattern fractured at the interface of metal and composite. Furthermore, the tensile properties such as the ultimate tensile strength and elongation to failure of the joint with the linear pattern were around twice the value of the joint with the cylindrical pattern. Consequently, the performance of hybrid joints can be improved significantly by optimising the protrusion pattern