Abstract
For the connection parts of engineering structures, the actual boundary conditions lie between the ideal simply-supported and clamped conditions. It is difficult, however, to define the boundary conditions clearly. In addition, material properties of many structures, e.g. perforated plates, are rather difficult to determine. In this dissertation, dynamic behaviors of full flat plates and shells, perforated plates and shells, printed circuit boards (PCB) as well as shadow masks on the elastic support were investigated by the hybrid method which is a combination of the experimental and numerical methods. The amplitude fluctuation electronic speckle pattern interferometry (AF-ESPI) technique was utilized to obtain the vibration fringe patterns of those plates and shells. The modal assurance criterion (MAC) was used to compare the experimental and numerical results to obtain the equivalent boundary conditions and material properties. The difference between the experimental and numerical model can be reduced via the sensitivity testing and correlation coefficient. After tuning the selected parameters, the natural frequencies obtained are in good agreement with the experimental results. In addition, curve-fitting method was utilized to confer the relationship of the mass remnant ratio to parameter ratio. The functions obtained from the curve fitting can be used to predict the equivalent material properties and natural frequencies of the perforated plates of the diagonal and rectangular arrays. By using the tuned boundary conditions and material properties, the state of stress of the structures can then be calculated reasonably.