We describe a polarization-selective beam splitter by a sandwiched grating, which can fulfill the high efficiency element for TE polarization and the two-port output for TM polarization. The modal method and the rigorous coupled-wave analysis (RCWA) are employed together to optimize the polarization-selective beam splitter. According to the modal method, the grating duty cycle and period are di...

We study the boundary controllability problem for a multilayer Rao-Nakra sandwich beam. This beam model consists of a Rayleigh beam coupled with a number of wave equations. We consider all combinations of clamped and hinged boundary conditions with the control applied to either the moment or the rotation angle at an end of the beam. We prove that exact controllability holds provided the damping...

There is a growing interest in developing non-destructive damage detection methods for damage assessment of composite structures, especially in the aerospace and marine industries. Although damage detection of composite laminates has been widely investigated, little work has been carried out on sandwich composite configurations. A technique using the Lipschitz exponent, which is estimated by wa...

This paper deals with the active vibration control of beam like structures with distributed piezoelechic sensor and actuator layers bonded on top and bottom surfaces of the beam. A finite element model based on Euler-Bernoulli beam theory has been developed. The contribution of the piezoelectric sensor and actuator layers on the mass and stiffness of the beam is colisidered. Three types of clas...

We consider a three layer Rao-Nakra sandwich beam with damping proportional to shear included in the core layer. We prove that eigenvectors of the beam form a Riesz basis for the natural energy space. In the damped case, we are able to give precise conditions under which solutions decay at a uniform exponential rate. We also consider the problem of boundary control using bending moment and late...

ACKNOWLEDGEMENT It gives me immense pleasure to express my deep sense of gratitude to my supervisor Prof. Tarapada Roy and Prof. Haraprasad Roy for their invaluable guidance, motivation, constant inspiration and above all their ever cooperating attitude enabled me in bringing up this thesis in present elegant form.

The method for calculating the deflection of a web-core sandwich panel in its weak direction is based on complex shell and plate theory. A simple method was presented by assuming inflection points are located at the mid-span of the facing plate segment between two adjacent web cores. It also assumes that an inflection point also exists at the midheight of the web core. Based on these assumption...