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...

this paper presents the effects of geometric tolerances on the rotating shafts natural frequencies. due to modeling the tolerances, a code is written in matlab 2013 software that produces deviated points. deviated points are controlled by different geometric tolerances, including cylindricity, total run-out and coaxiality tolerances. final surfaces and models passing through the points are crea...

determination of allowable free span length plays a crucial role in design of offshore pipelines. the seabed intervention cost and safety of an offshore pipelines project are largely influenced by pipelines free spanning during the project life time. different criteria are proposed by both the current designing guidelines and researchers there is however lack of comprehensive assessment of inde...

in the present paper, the modal analysis on a full finite element model of an off-road vehicle. this vehicle was modeled in the catia software and then meshed in the hypermesh software. the free vibration analysis was conducted by the abaqus software. by applying an external displacement, the forced vibration analysis was also performed. as a result, natural frequencies and shape modes were ext...

wide range of planar structures in new technologies has attracted special consideration. in this research vibration behavior of plates with non-linear edges is investigated by means of finite difference (fd) method. for this issue, classical and analytical solutions for plates with linear edges were analyzed and mutual equations, needed for numerical calculation were extracted. by expanding the...

OVERVIEW The efficacy of modal analysis in detecting and localizing damage is debated based on sensitivity concerns – modal frequencies are extremely insensitive to small changes in local parameters and geometry. Convincing evidence of sensitivity issues is vast, and here we cite a single field study of a 163 ft. long, 10 ft. deep experimental test girder from an I40 bridge in Bernalilo County ...

In Operational Modal Analysis, the modal parameters (natural frequencies, damping ratios and mode shapes) obtained from Stochastic Subspace Identification (SSI) of a structure, are afflicted with statistical uncertainty. For evaluating the quality of the obtained results it is essential to know the appropriate confidence intervals of these figures. In this paper we present algorithms that autom...

Telemedicine can be used to create virtual environments for the collaboration of patient, physicians, and medical staff. Multi modal presentation is increasingly used to improve human-computer interface. In this paper we present a multimodal interactive environment for EEG/MEG data presentation based on Internet technologies and a virtual reality user interface (VRUI). In addition to visualizat...

The transfer function of a linear mechanical system can be defined in terms the quadruplet state-space matrices (A,B,C,D) that identified from input and output measurements with subspace-based identification methods. estimation has been well studied literature both theoretical practical viewpoints. Nonetheless, algorithm for uncertainty quantification its errors resultant parametric is missing ...

We apply a new method of modeling Porro prism resonators, using the concept of rotating loss screens, to study stable and unstable Porro prism resonator. We show that the previously observed petal--like modal output is in fact only the lowest order mode, and reveal that a variety of kaleidoscope beam modes will be produced by these resonators when the intra--cavity apertures are sufficiently la...