Comparison of Full-Scale and Numerical Model Dynamic Responses of Norströmsgrund Lighthouse

2014 ◽  
Author(s):  
Wojciech Popko
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Measurement Data ◽  
Structural Response ◽  
Full Scale ◽  
Dynamic Responses ◽  
Soil Stiffness ◽  
Time Histories ◽  
3D Numerical Model ◽  
Abaqus Software

This paper compares dynamic response of the Norströmsgrund lighthouse and its numerical implementation in Abaqus software. The dynamic response of the full-scale structure was analyzed based on the accelerometers data, which were correlated with ice loading time histories that were recorded from the load panels surrounding the structure. The full-scale measurement data come from the Measurements on Structures in Ice (STRICE) project. A 3D numerical model of the lighthouse, based on the solid elements was setup in Abaqus. Such aspects as soil stiffness and sand filling of caissons were accounted for to more accurately mimic behavior of the real structure. The eigen-frequency response of the numerical model was tuned to correspond with the structural response of the full-scale lighthouse. The numerical model was equipped with a set of load panels on which pre-defined time histories of the full-scale loading were applied. Then, its response was compared with the response of the Norströmsgrund lighthouse.

Experimental Study on Hydroelastic Impact of One Wedge With Stiffened Panels

2017 ◽  
Author(s):  
Chuanrui Dong ◽  
Huilong Ren ◽  
Ning Liu ◽  
Qiang Wang
Keyword(s):  
Dynamic Response ◽  
Structural Response ◽  
Space Distribution ◽  
Stiffened Panels ◽  
Structure Dynamic ◽  
Time Space ◽  
Slamming Load ◽  
Time Histories ◽  
Entry Velocity ◽  
Free Drop

In this paper, two wedges with deadrise angle 45 degrees made of steel and aluminum alloy respectively was designed and a series of free-drop model tests were carried out, we recorded time histories of water-entry velocity of models, slamming pressures on outer surface of stiffened panels and stress response of the structures. The time space distribution of slamming load and characteristic of structure dynamic response were studied. And through comparison analysis of slamming loads between two model’s corresponding measuring points, the effect of hydroelastic on slamming loads were discussed. Finally, an equivalent static analysis method to determine the structural response of hull structures under slamming loads was presented by analyzed the slamming loads and structure dynamic response that got from experiment combined with finite element method.

Dynamic Response in ALF Aggregate Base Asphalt Pavement

2011 ◽  
Vol 97-98 ◽  
pp. 40-44 ◽  
Author(s):  
Chuan Yi Zhuang ◽  
Ai Qin Shen ◽  
Lin Wang
Keyword(s):  
Dynamic Response ◽  
Compressive Stress ◽  
Asphalt Pavement ◽  
Compressive Strain ◽  
Full Scale ◽  
Dynamic Responses ◽  
Traffic Load ◽  
Dynamic Strain ◽  
Strain Response ◽  
Soil Pressure

In order to evaluate pavement dynamic responses accurately under truck loading, the full-scale asphalt pavement accelerated loading facility (ALF) was used. 10 strain gauges and 2 soil pressure cells were installed; temperature sensors were also installed in the different depth of the HMA layer. Pavement response was measured under real traffic load with ALF. The measured pavement responses are compared between the pavement sections to evaluate the effects of various experimental factors, such as axle load, speed, et al. Dynamic strain at the bottom of HMA layer and vertical compressive stress on the top of the subgrade were examined in the full-scale testing road, the regression models between dynamic response and axle load, dynamic response and speed were put forward respectively. Studies show that there is not only tensile strain but also compressive strain in the dynamic response, and the strain response is in the station of tension and compression alternation. Under the intermediate temperature, the strain response at the bottom of the asphalt layer is increased linearly with the increase of axle load and the vertical compressive stresses at the top of the subgrade is also increased with the increase of axle load. Speed has a great effect on strain response at the bottom of HMA layer, and has little effect on vertical compressive stress, it affects the loading duration of stress only. The destroy for the pavement by low speed and heavy load is more serious than that is normal.

Structural Response Due to Blade Vane Interaction

1984 ◽  
Vol 106 (1) ◽  
pp. 50-56 ◽  
Author(s):  
R. L. Jay ◽  
J. C. MacBain ◽  
D. W. Burns
Keyword(s):  
Dynamic Response ◽  
Structural Response ◽  
Analytical Description ◽  
Rotor Blades ◽  
Dynamic Responses ◽  
Strain Gages ◽  
Bladed Disk ◽  
Forcing Function ◽  
The Difference ◽  
Strong Dynamic

The structural response of a bladed turbine disk due to excitation from an upstream stator row was measured using strain gages. Rig testing performed in a realistic aerodynamic environment was preceded by a static vibratory search in which individual blade frequencies and system modes were identified by strain response and holography. In the rig testing special emphasis was placed on identifying the dynamic response resulting from the interaction between the vanes and blades. An analytical description of the forcing function which results from the difference between the number of blades and the number of vanes is presented and correlated with detailed blade responses both in terms of amplitude and interblade phasing. In particular, the combination of 26 inlet vanes and the 30 rotor blades yielded strong dynamic responses in two modes of the four diametral family. The experimental results augmented by the analytical formulation of excitation created by the difference in vane and blade numbers have conclusively identified a mechanism for large blade dynamic response which should be considered in the design phase of bladed disk systems.

scholarly journals Dynamic Response Analysis of a Semi-Submersible Floating Wind Turbine in Combined Wave and Current Conditions Using Advanced Hydrodynamic Models

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5820 ◽  
Author(s):  
Takeshi Ishihara ◽  
Yuliang Liu
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Wave Spectrum ◽  
Full Scale ◽  
Dynamic Responses ◽  
Offshore Wind Turbine ◽  
Response Analysis ◽  
Water Tank ◽  
Hydrodynamic Models ◽  
Wide Range

In this study, advanced hydrodynamic models are proposed to predict dynamic response of a floating offshore wind turbine (FOWT) in combined wave and current conditions and validated by laboratory and full-scale semi-submersible platforms. Firstly, hydrodynamic coefficient models are introduced to evaluate the added mass and drag coefficients in a wide range of Reynolds numbers. An advanced hydrodynamic model is then proposed to calculate the drag force of cylinder in combined wave and current conditions. The proposed model is validated by the water tank tests in the current-only, wave-only and current-wave conditions and is used to investigate the effect of current on the dynamic response of FOWT. Finally, the full-scale semi-submersible platform used in the Fukushima demonstration project is investigated. It is found that the predicted dynamic responses of platform by the proposed hydrodynamic models are improved by the directional spreading function of the sea wave spectrum and show favorable agreement with the field measurement.

Nonlinear dynamic response and bifurcation of asymmetric rotor system supported in axial-grooved gas-lubricated bearings

2021 ◽  
pp. 146134842110527
Author(s):  
Sha Li ◽  
Yanjun Lu ◽  
Yongfang Zhang ◽  
Hongbo Luo ◽  
Song Wang ◽  
...  
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Rational Function ◽  
Nonlinear Dynamic ◽  
Rotor System ◽  
Dynamic Responses ◽  
Function Model ◽  
Nonlinear Dynamic Response ◽  
Asymmetric Rotor ◽  
The Rational Function Model

Dynamic characteristics of the asymmetric rotor system supported in axial-grooved gas-lubricated bearings are studied. In order to solve nonlinear dynamic response of rotor system effectively, a hybrid numerical model is established by coupling the motion equation of rotor with the rational function model of the gas film forces. The rational function model of the gas film forces of gas-lubricated bearing is established based on vector fitting theory. By using the hybrid numerical model, the repeated calculations of the unsteady Reynolds equation and gas film forces are avoided; the continuous rotor trajectory and the dynamic gas film forces can be calculated simultaneously; and for the rotor system supported in the same bearings, the computing cost can be saved effectively. The nonlinear dynamic responses of asymmetric rotor system supported in axial-grooved gas-lubricated bearings are investigated by trajectory diagrams, frequency spectrum, Poincaré maps, and time series. The bifurcations are analyzed by the bifurcation diagrams with different rotating speeds and mass eccentricities. The dynamic behaviors of the asymmetric rotor system appear complex nonlinear dynamic phenomenon and specific bifurcation characteristics.

Identification of Spudcan Fixity for a Jack-Up Rig

2009 ◽  
Author(s):  
T. N. Thanh ◽  
C. G. Koh ◽  
Y. S. Choo
Keyword(s):  
Element Model ◽  
Dynamic Responses ◽  
Random Wave ◽  
Improved Genetic Algorithm ◽  
Worst Case ◽  
Soil Stiffness ◽  
The North ◽  
Time Histories ◽  
Set Up ◽  
Jack Up

To estimate soil stiffness parameters under spudcan foundations and assess the performance of a jack-up rig, a strategy for identifying spudcan fixity of a jack-up rig based on the measured acceleration responses is developed. The finite element model of a jack-up rig is set up, in which the interaction of soil and a spudcan foundation is modeled as a system of horizontal, vertical, and rotational elastic springs. The ‘measured’ acceleration responses along each leg is archived by simulating the jack-up under a selected storm loading in the North sea, including random wave, current and wind loadings. The random wave loading is calculated using JONSWAP water surface elevation spectrum in conjunction with Morison’s equation. The spudcan fixity of a jack-up rig is effectively identified using an improved genetic algorithm (GA) method. The identification strategy proposed works by matching the time histories of the measured accelerations up with those of the numerical simulated accelerations through an objective function in GA. The results indicate that the soil stiffness parameters under spudcan foundations are exactly identified in noise free case. Error less than 1.2% in identified rotational and vertical spring stiffnesses of interest is archived with the worst case of 10% noise and only two acceleration measurements at hull. In addition, it is observed that the vertical and rotational stiffness parameters are more accurately identified than the horizontal one. The identified stiffness values of spudcan fixity help to enhance the understanding of jack-up foundation behavior and improve the operational envelop for a specific jack-up design. With full-scale measurements of environmental conditions and dynamic responses of a jack-up rig, this strategy can be employed to verify recent findings on the conservatism of predicting soil stiffness parameters.

Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

Prediction of an actual RPM and engine power of an LNGC based on full-scale measurement data

2018 ◽  
Vol 147 ◽  
pp. 496-516 ◽  
Author(s):  
Youngjun You ◽  
Jaehan Kim ◽  
Min-Guk Seo
Keyword(s):  
Measurement Data ◽  
Full Scale ◽  
Engine Power
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