We present an experimental validation of a recently proposed solution to the problem of finding the input torque command that provides rest-to-rest motion in a given time for a one-link flexible arm. The basic idea is to design an auxiliary output such that the associated input-output transfer function has no zeros. Planning a smooth interpolating trajectory for this output imposes a unique res...

ABSTRACT In the presentwork finite element method and fuzzy-KSOM hybrid technique are used for localization of damagepresent in form of cracks in the cantilever beam. The presence of cracks in the beam like structures is a serious threat to the performance as well as integrity of structures and itschange the modal indics e.g. natural frequencies and mode shapes of the structures.The glass fiber...

We present a modal theory of self-trapping spatially incoherent light beams in any general nonlinear media. We find that a self-trapped incoherent beam induces a multimode waveguide which guides the beam itself by multiply populating the guided modes. The self-trapping process alters the statistics of the incoherent beam, rendering it localized. We find the conditions for self-trapping (“existe...

How much do model errors influence the closed loop performance? This question is investigated for the control problem of designing active damping of vibrations in a viscoelastic cantilever beam. The beam is physically modeled using Fourier transformed Euler-Bernoulli beam equations. For control design the standard LQG technique is employed, and two different finite order models are used. One is...

Crack identification is a very important issue in mechanical systems, because it is a damage that if develops may cause catastrophic failure. In the first part of this research, modal analysis of a multi-cracked variable cross-section beam is done using finite element method. Then, the obtained results are validated usingthe results of experimental modal analysis tests. In the next part, a nove...

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...

The following study deals with the updating the finite element model of structures using the operational modal analysis. The updating process uses an evolutionary optimization algorithm, namely bees algorithm which applies instinctive behavior of honeybees for finding food sources. To determine the uncertain updated parameters such as geometry and material properties of the structure, local and...

This thesis is devoted to the study of transverse modes in large-mode-area (LMA) fibers. It highlights the importance of transverse spatial-hole burning (TSHB) effect in LMA multimode fibers through experiments and simulations. The measured beam-quality factor decreases until the gain becomes saturated in an amplified spontaneous emission (ASE) source based on an Yb-doped LMA multimode fiber. A...

The damage identification study presented in this article leveraged a full-scale sub-component experiment conducted in the Charles Lee P owell Structural Research Laboratories at the University of California, San Diego. As a payload project attached to a quasi-static test of a full-scale composite beam, a high-quality set of lowamplitude vibration response data was acquired from the beam at var...

Measurement of dynamic responses plays an important role in structural health monitoring, damage detection and other fields of research. However, in aerospace engineering, the physical sensors are limited in the operational conditions of spacecraft, due to the severe environment in outer space. This paper proposes a virtual sensor model with partial vibration measurements using a convolutional ...