Current Search: Department of Civil, Environmental and Geomatics Engineering (x) » Structural dynamics (x)
View All Items
- Title
- Rain-wind-induced cable vibrations in cable-stayed bridges.
- Creator
- Calle, Oscar F., Reddy, Dronnadula V., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
This research is aimed at investigating and analyzing the rain-windinduced cable vibration phenomena experienced in cables of cable-stayed bridges and also the countermeasures employed by engineers to mitigate the large-amplitude vibration problem reported by various researchers around the world. In order to investigate the problem of the water rivulet creation at the top of the cable surface, a single-degree-of-freedom (SDOF) analytical model was developed and analyzed. This thesis studies...
Show moreThis research is aimed at investigating and analyzing the rain-windinduced cable vibration phenomena experienced in cables of cable-stayed bridges and also the countermeasures employed by engineers to mitigate the large-amplitude vibration problem reported by various researchers around the world. In order to investigate the problem of the water rivulet creation at the top of the cable surface, a single-degree-of-freedom (SDOF) analytical model was developed and analyzed. This thesis studies the aerodynamic instability of cables in cable-stayed bridges by doing literature review of a typical in-situ test, developing a single degree-of-freedom (SDOF) analytical model, and an ANSYS finite element model. Furthermore, a linear viscous damper that acts as a countermeasure to the large amplitudes of vibration is reported and analyzed. The suppression characteristics and damper effectiveness of such countermeasure are summarized.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004271, http://purl.flvc.org/fau/fd/FA00004271
- Subject Headings
- Bridges -- Aerodynamics, Bridges -- Vibration -- Prevention, Cable stayed bridges -- Maintenance and repair, Damping (Mechanics), Structural dynamics, Vibration -- Mathematical models, Wind resistant design
- Format
- Document (PDF)
- Title
- Reliability-based fatigue design of marine current turbine rotor blades.
- Creator
- Hurley, Shaun., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
The study presents a reliability-based fatigue life prediction model for the ocean current turbine rotor blades. The numerically simulated bending moment ranges based on the measured current velocities off the Southeast coast line of Florida over a one month period are used to reflect the short-term distribution of the bending moment ranges for an idealized marine current turbine rotor blade. The 2-parameter Weibull distribution is used to fit the short-term distribution and then used to...
Show moreThe study presents a reliability-based fatigue life prediction model for the ocean current turbine rotor blades. The numerically simulated bending moment ranges based on the measured current velocities off the Southeast coast line of Florida over a one month period are used to reflect the short-term distribution of the bending moment ranges for an idealized marine current turbine rotor blade. The 2-parameter Weibull distribution is used to fit the short-term distribution and then used to obtain the long-term distribution over the design life. The long-term distribution is then used to determine the number of cycles for any given bending moment range. The published laboratory test data in the form of an ε-N curve is used in conjunction with the long-term distribution of the bending moment ranges in the prediction of the fatigue failure of the rotor blade using Miner's rule. The first-order reliability method is used in order to determine the reliability index for a given section modulus over a given design life. The results of reliability analysis are then used to calibrate the partial safety factors for load and resistance.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3183123
- Subject Headings
- Turbines, Blades, Materials, Fatigue, Marine turbines, Mathematical models, Composite materials, Mathematical models, Structural dynamics
- Format
- Document (PDF)
- Title
- Numerical simulation and prediction of loads in marine current turbine full-scale rotor blades.
- Creator
- Senat, Junior., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
Marine current turbines are submerged structures and subjected to loading conditions from both the currents and wave effects. The associated phenomena posed significant challenge to the analyses of the loading response of the rotor blades and practical limitations in terms of device location and operational envelopes. The effect of waves on marine current turbines can contribute to the change of flow field and pressure field around the rotor and hence changes the fluid forces on the rotor....
Show moreMarine current turbines are submerged structures and subjected to loading conditions from both the currents and wave effects. The associated phenomena posed significant challenge to the analyses of the loading response of the rotor blades and practical limitations in terms of device location and operational envelopes. The effect of waves on marine current turbines can contribute to the change of flow field and pressure field around the rotor and hence changes the fluid forces on the rotor. However, the effect of the waves on the rotor depends on the magnitude and direction of flow velocity that is induced by the waves. An analysis is presented for predicting the torque, thrust, and bending moments resulting from the wave-current interactions at the root of rotor blades in a horizontal axis marine current turbine using the blade element-momentum (BEM) theory combined with linear wave theory. Parametric studies are carried out to better understand the influence of important parameters , which include wave height, wave frequency, and tip-speed ratio on the performance of the rotor. The periodic loading on the blade due to the steady spatial variation of current speeds over the rotor swept area is determined by a limited number of parameters, including Reynolds number, lift and drag coefficients, thrust and torque coefficients, and power coefficient. The results established that the BEM theory combined with linear wave theory can be used to analyze the wavecurrent interactions in full-scale marine current turbine. The power and thrust coefficients can be analyzed effectively using the numerical BEM theory in conjunction with corrections to the tip loss coefficient and 3D effects., It has been found both thrust and torque increase as the current speed increases, and in longer waves the torque is relatively sensitive to the variation of wave height. Both in-plane and out-of-plane bending moments fluctuate significantly and can be predicted by linear wave theory with blade element-momentum theory.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3172695
- Subject Headings
- Marine turbines, Mathematical models, Structural dynamics, Fluid dynamics, Rotors, Design and construction
- Format
- Document (PDF)
- Title
- Blast/explosion resistant analysis of composite steel girder bridge system.
- Creator
- Zhou, Fang., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
The design of bridge structures to resist explosive loads has become more of a concern to the engineering community. This thesis proposes a method to evaluate the effects of conventional blast loads on a two span continuous composite steel girder bridge system. The bridge design is based on AASHTO LRFD method. Resistance capacities of bridge deck and composite steel girder are calculated according to AASHTO specifications. Equivalent blast pressures on the bridge components are obtained....
Show moreThe design of bridge structures to resist explosive loads has become more of a concern to the engineering community. This thesis proposes a method to evaluate the effects of conventional blast loads on a two span continuous composite steel girder bridge system. The bridge design is based on AASHTO LRFD method. Resistance capacities of bridge deck and composite steel girder are calculated according to AASHTO specifications. Equivalent blast pressures on the bridge components are obtained. Response and performance of concrete deck, steel girders, and supporting piers are evaluated under typical blast loads. The blast induced force in the bridge components are computed in the static analyses for varying amounts of TNT. The blast effects in the supporting pier are determined using both static and dynamic analyses. Further research needs to be done in the dynamic analysis of the bridge system subjected to blast loads.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/227976
- Subject Headings
- Steel, Structural, Testing, Bridges, Design and construction, Structural dynamics
- Format
- Document (PDF)