Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 72 for “"mode shape"”.
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The Effect of Sensor Mass, Sensor Location, and Delamination Location of Different Composite Structures Under Dynamic Loading
… along the specimen, including the bending mode node line locations. The free vibration of the composite structure was forced through a harmonic horizontal vibration test using an Unholtz-Dickie shake system. A sinusoidal sweep input was considered for the test. The dynamic response of the …
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Development of Small-Footprint Large-Amplitude Tripod (three lambda) Mode Traveling Wave Generator
… of generating a traveling wave of three lamda mode shape (i.e. of three crests and three troughs) along the circumference of both end faces to provide stable, non-rocking drive for ultrasonic micromotors. The FEA results revealed that the said mode shape can be realized with a short aluminum …
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Seismic Design and Evaluation of Multistory Buildings Using Yield Point Spectra
… indices (IDIs) are estimated using deformed shapes of the building based on the first mode shape and combinations of the first and second mode shapes.
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Dynamic Analysis of Modified Structural Systems (Eigenvalues, Vibrations, Frequencies)
… of the changes in the frequency of vibration and mode shape of a structure due to changes in the physical system. Such changes may consist of variations of the structural properties of a given system or even of the addition of new degrees of freedom.
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MATLAB implementation of an operational modal analysis technique for vibration-based structural health monitoring
… to the dynamic responses from two finite element models of simply-supported beams and their modal frequencies and shapes were extracted. The first three modal frequencies were obtained with less than 6 percent error from the actual values and the fundamental mode shape values obtained contained …
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Compressive buckling of a clamped circular plate on an elastic foundation not in attachment
… studied with regard to it's behavior in the 2nd mode shape. Two regions of action are controlled by two differential equations of the fourth order which were solved in terms of the Bessel functions. The relations between the foundation modulus and the buckling load were found from two …
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Model Updating Using Neural Networks
Accurate models are necessary in critical applications. Key parameters in dynamic systems often change during their life cycle due to repair and replacement of parts or environmental changes. This dissertation presents a new approach to update system models, accounting for these changes. The …
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Physically constrained maximum likelihood (PCML) mode filtering and its application as a pre-processing method for underwater acoustic communication
Mode filtering is most commonly implemented using the sampled mode shape or pseudoinverse algorithms. Buck et al [1] placed these techniques in the context of a broader maximum a posteriori (MAP) framework. However, the MAP algorithm requires that the signal and noise statistics be known a priori. …
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The analysis of rigid-viscoplastic plane structures subjected to large impulsive loading
… account. Computational advantage is obtained by modelling this behaviour by a homogeneous viscous constitutive relation, as the rigid phase is absent. As opposed to the standard displacement method finite element formulation where interpolation functions describing the velocity field across …
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Multichannel maximum entropy method of spectral analysis applied to offshore structures
… are calculated. These estimates are then used in mode shape identification of a triple decked, single caisson offshore platform. The superiority of the multichannel Maximum Entropy Methods relative to conventional spectral analysis techniques in calculating these cross-spectral estimates and …
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Acoustic boundary condition estimation in a near-scale gas-turbine combustor
… operation, and a finite element method-based model of the combustion chamber. Results of a theoretical analysis are presented which show that the method is capable of accomplishing its mission. An observation of particular significance is the lack of sensitivity of the pressure mode shape to …
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Physically constrained maximum likelihood (PCML) mode filtering and its application as a pre-processing method for underwater acoustic communication
Mode filtering is most commonly implemented using the sampled mode shape or pseudoinverse algorithms. Buck et al placed these techniques in the context of a broader maximum a posteriori (MAP) framework. However, the MAP algorithm requires that the signal and noise statistics be known a priori. …
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Buckling response of symmetrically laminated composite plates having a trapezoidal planform area
… composite plates having a planform area in the shape of an isosceles trapezoid. The loading is assumed to be inplane and applied perpendicular to the parallel ends of the plate. The tapered edges of the plate are assumed to have simply supported boundary conditions, while the parallel ends are …
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Modeling of the UNLV-Aro light-weight robot using Lagrange's assumed mode method, symbolic manipulation, and numerical simulation
This thesis modeled the dynamics of the UNLV-ARO serially connected light-weight robot. The two outer-most links of the robot exhibited flexible behavior in the in-plane and the out-of-plane directions. Lagrangian mechanics were used to model this system. Assumed modes method was used to …
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Thermal Post-Buckling and Vibration Analysis of Thermally Buckled Antisymmetrically Laminated Beams Using a 20 DOF Finite Element
… for the critical temperature. The scaled first mode shape was used as the trial displacement vector for post-buckling deflection analysis, which employed a Newton-Raphson type iterative procedure. Once the final static deflection was achieved, the dynamic part of the equation of motion was used …
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A Theoretical and Experimental investigation of Nonlinear Vibrations of Buckled Beams
… of a buckled beam around its first buckling mode shape are investigated. Frequency-response curves characterizing single-mode responses of the beam under a primary resonance are generated using both approaches and contrasted with experimentally obtained frequency-response curves. It is shown …
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Forced Vibration Testing and Analysis of Pre- and Post- Retrofit Buildings
… FVT, comparing that behavior to computational model predictions, and determining the necessary level of detail to include in the computational modeling. Forced vibration testing (FVT) of two stiff-wall/flexible-diaphragm buildings yielded natural frequencies and mode shapes for the two …
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A vibration-based bridge scour monitoring technique
… has been studied primarily using numerical modelling simulations of a hypothetical integral bridge with piled foundations. Only one modal parameter – natural frequency – was investigated in most of these studies and it was predicted to change by up to double-digit percentages due to scour. …
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Structural elements with mathematically defined surfaces for enhanced structural and acoustic performance
… approach is to design panels formed into the shape of a mode shape to reduce detrimental modal dynamics. The effects of combining the two-dimensionally curved designs with constrained layer damping is also investigated. Further, it is also the goal of this research that these panels can be …
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