Field Measurement of Dynamic Instability of a 50-Ton Tainter-Gate

2007 ◽  
Author(s):  
Keiko Anami ◽  
Noriaki Ishii ◽  
Charles W. Knisely ◽  
Tatsuya Oku
Keyword(s):  
Theoretical Model ◽  
Degrees Of Freedom ◽  
Dynamic Instability ◽  
Test Results ◽  
Model Studies ◽  
Coupled Mode ◽  
Excited Vibration ◽  
Concurrent Development ◽  
2D And 3D ◽  
Maintenance Plan

The 2-degrees-of-freedom coupled-mode self-excited vibration of Tainter gate has been demonstrated in hydraulic model studies of 2D and 3D gate models. The concurrent development of a theoretical model has permitted the prediction that some full-scale Tainter-gates could be potentially susceptible to this coupled-mode self-excited vibration. However, there are many people who regard with suspicion the prediction that a massive Tainter-gate might actually undergo this type of vibrations. In response to these skeptics, this paper presents the test results from an actual operational 50-ton Tainter-gate to determine its propensity for large-amplitude self-excited vibration. Further, the previously developed theoretical analysis was applied to the tested gate to uncover an essential dynamic instability for this installation, as well as to provide a framework for the design of a retrofit and an optimized maintenance plan.

Vibration Tests With a 1/13-Scaled 3-D Model of the Folsom Dam Tainter-Gate and Its Prediction by Theory

2006 ◽  
Author(s):  
Keiko Anami ◽  
Noriaki Ishii ◽  
Charles W. Knisely ◽  
Robert V. Todd ◽  
Tatsuya Oku
Keyword(s):  
Dynamic Instability ◽  
Vibration Test ◽  
Test Results ◽  
Bending Vibration ◽  
Coupled Mode ◽  
Basic Assumptions ◽  
Vibration Tests ◽  
D Model ◽  
Theoretical Analyses ◽  
Made In

This study presents 3-D model gate vibration test results demonstrating violent spontaneous vibrations and validating the basic assumptions made in previously published theoretical analyses. First, the design of a 1/13-scaled 3-D model of Folsom dam Tainter-gate is presented, in which the streamwise natural bending vibration mode of the skinplate, measured in the field vibration tests on the remaining Folsom gate, is shown to be correctly replicated with the aid of FEM simulations. Secondly, in-air and in-water vibration test results with the 1/13-scaled 3-D model are presented, reproducing the intense coupled-mode self-excited vibrations. Thirdly, test results are plotted on a theoretically calculated stability criterion diagram to confirm the validity of the theoretical analysis. Finally, the intense dynamic instability of the Folsom gate, which could have caused its failure, is presented.

Coupled-Mode Dynamic Instability of Tainter Gates With Parallel Bending Vibration of the Skinplate

2010 ◽  
Author(s):  
Keiko Anami ◽  
Noriaki Ishii ◽  
Takuma Tsuji ◽  
Tatsuya Oku ◽  
Masaru Goto ◽  
...  
Keyword(s):  
Dynamic Instability ◽  
Laboratory Model ◽  
Dynamic Coupling ◽  
Bending Vibration ◽  
Coupled Mode ◽  
Excited Vibration ◽  
Rotational Vibration ◽  
The Usa ◽  
Vibration Mechanism ◽  
Vibration Tests

As part of the investigation of the dynamic instability of the gate closely related to the Folsom Dam Tainter-gate failure, and in order to assure the dynamic stability of the gate, the field vibration tests on three full-scale operational Tainter-gates were conducted. From these tests, the possible existence of another coupled-mode self excited vibration mechanism, which involves the dangerous dynamic coupling of the whole gate rigid-body rotational vibration with a “parallel” bending vibration of the skinplate was suggested. This paper presents the mechanism of the suggested coupled-mode self-excited vibration, theoretical analysis for the suggested dynamic instability, and 2-dimensional laboratory model tests results. Further, the need for retrofit countermeasures for Tainter gates which are currently installed in both Japan and the USA and susceptible to this dangerous coupled-mode dynamic instability is emphasized.

Experimental and analytical investigation on the in-plane dynamic instability of arches owing to parametric resonance

2017 ◽  
Vol 24 (19) ◽  
pp. 4419-4432 ◽  
Author(s):  
Airong Liu ◽  
Zhicheng Yang ◽  
Hanwen Lu ◽  
Jiyang Fu ◽  
Yong-Lin Pi
Keyword(s):  
Parametric Resonance ◽  
Dynamic Instability ◽  
Damping Ratio ◽  
Analytical Investigation ◽  
Engineering Practice ◽  
Test Results ◽  
Periodic Load ◽  
Shallow Arches ◽  
Excitation Frequencies ◽  
Critical Regions

When an arch is subjected to a periodic load, it may lose in-plane stability dynamically owing to parametric resonance. Previous investigations have been concentrated on in-plane dynamic buckling of pin-ended shallow arches. However, in engineering practice, fixed arches with different rise-to-span ratios are often encountered. Little research on in-plane dynamic instability of deep fixed arches has been reported in the literature. This paper is concerned with experimental and analytical investigations for in-plane dynamic instability of fixed circular arches with rise-to-span ratios 1/8–1/2 under a central periodic load owing to parametric resonance. Experiments are carried out to determine the in-plane frequency and damping ratio of arches, to investigate critical regions of frequencies and amplitudes of the periodic load for in-plane dynamic instability of arches, and to explore effects of the rise-to-span ratio and additional weights on dynamic instability. The analytical method for determining the region of excitation frequencies and amplitudes of the periodic load causing in-plane instability of the arch is established using the Hamilton’s principle by accounting for effects of additional concentrated weights. Comparisons of analytical solutions with test results show that they agree with each other quite well. These results show that the rise-to-span ratio significantly influences the bandwidth of regions of critical excitation frequencies for in-plane dynamic instability of arches. The critical frequencies of the periodic load and their bandwidth increase with a decrease of the rise–span ratio of the arch, whereas the corresponding amplitude of the periodic load decreases at the same time. It is also found that the central concentrated weight influences in-plane dynamic instability of arches significantly. As the weight increases, the critical frequencies of excitation and their bandwidth for in-plane dynamic instability of arches decreases, whereas the corresponding amplitude of excitation increases.

Analytical Model for Rockfall Protection Galleries - a Blind Prediction of Test Results and Conclusion

2011 ◽  
Vol 82 ◽  
pp. 722-727 ◽  
Author(s):  
Kristian Schellenberg ◽  
Norimitsu Kishi ◽  
Hisashi Kon-No
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Test Results ◽  
Blind Prediction ◽  
Proposed Model ◽  
Input Parameters ◽  
Scale Test ◽  
Definition Of ◽  
Protective Structures ◽  
Cushion Layer

A system of multiple degrees of freedom composed out of three masses and three springs has been presented in 2008 for analyzing rockfall impacts on protective structures covered by a cushion layer. The model has then been used for a blind prediction of a large-scale test carried out in Sapporo, Japan, in November 2009. The test results showed substantial deviations from the blind predictions, which led to a deeper evaluation of the model input parameters showing a significant influence of the modeling properties for the cushion layer on the overall results. The cushion properties include also assumptions for the loading geometry and the definition of the parameters can be challenging. This paper introduces the test setup and the selected parameters in the proposed model for the blind prediction. After comparison with the test results, adjustments in the input parameters in order to match the test results have been evaluated. Conclusions for the application of the model as well as for further model improvements are drawn.

Research on Network Communication Model of Intelligent Ship Handling Simulator

2011 ◽  
Vol 97-98 ◽  
pp. 787-793 ◽  
Author(s):  
Shen Hua Yang ◽  
Guo Quan Chen ◽  
Xing Hua Wang ◽  
Yue Bin Yang
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Communication Process ◽  
Network Communication ◽  
Communication Model ◽  
Test Results ◽  
Six Degrees Of Freedom ◽  
Model Based ◽  
Hydraulic Servo ◽  
Ship Handling

Due to the target ship in the traditional ship handling simulator have not the ability to give way to other ships automatically to avoid collision, this paper put forward a new idea that bringing the hydraulic servo platform, six degrees of freedom ship mathematical model, the actual traffic flow, researching achievement of automatic anti-collision in research of the new pattern ship handling simulator, and successfully develop the Intelligent Ship Handling Simulator(ISHS for short). The paper focuse on the research on the network communication model of ISHS. We took the entire simulator system as three relatively independent networks, proposed a framework of communication network that combined IOCP model based on TCP with blocking model based on UDP, and gave the communication process and protocols of system. Test results indicate that this is an effective way to improve the ownship capacity of ship handling simulator and meet the need of multi-ownship configuration of desktop system of ship handling simulator.

Numerical Investigation of the Influence of Friction Coefficient on Brake Groan

2010 ◽  
Vol 44-47 ◽  
pp. 1923-1927 ◽  
Author(s):  
Xian Jie Meng
Keyword(s):  
Nonlinear Dynamics ◽  
Friction Coefficient ◽  
Degrees Of Freedom ◽  
Equilibrium Points ◽  
Static Friction ◽  
Kinetic Friction ◽  
Dynamics Model ◽  
Excited Vibration ◽  
Nonlinear Dynamics Model ◽  
The Stability

A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the stability of vibration system at the equilibrium points is analyzed using the nonlinear dynamics theory. Finally the numerical method is taken to study the impacts of friction coefficient on brake groan. The calculation result shows that with the increase of kinetic friction coefficient /or the decrease of difference value between static friction coefficient and kinetic friction coefficient can prevent or restrain self-excited vibration from happening.

scholarly journals WAVELESS APPROXIMATION THEORIES OF GRAVITY

2008 ◽  
Vol 17 (02) ◽  
pp. 265-273 ◽  
Author(s):  
JAMES A. ISENBERG
Keyword(s):  
Gravitational Field ◽  
Gravitational Radiation ◽  
Elliptic Equations ◽  
Degrees Of Freedom ◽  
Dynamic Instability ◽  
Accurate Approximation ◽  
Time Step ◽  
Einstein Theory ◽  
Physical Systems ◽  
Theories Of Gravity

The analysis of a general multibody physical system governed by Einstein's equations is quite difficult, even if numerical methods (on a computer) are used. Some of the difficulties — many coupled degrees of freedom, dynamic instability — are associated with the presence of gravitational waves. We have developed a number of "waveless approximation theories" (WAT's) which repress the gravitational radiation and thereby simplify the analysis. The matter, according to these theories, evolves dynamically. The gravitational field, however, is determined at each time step by a set of elliptic equations with matter sources. There is reason to believe that for many physical systems, the WAT-generated system evolution is a very accurate approximation to that generated by the full Einstein theory.

Parametric Resonance Characteristics of Woven Fiber Metal Laminated Plates

2019 ◽  
Vol 11 (04) ◽  
pp. 1950034 ◽  
Author(s):  
Elluri Venkata Prasad ◽  
Shishir Kumar Sahu
Keyword(s):  
Parametric Resonance ◽  
Degrees Of Freedom ◽  
Dynamic Instability ◽  
Parametric Instability ◽  
Laminated Plates ◽  
Load Factor ◽  
Harmonic Loading ◽  
Resonance Behavior ◽  
Fiber Metal ◽  
Ply Orientation

The present investigation deals with the assessment of parametric resonance behavior of new aircraft material, i.e., woven fiber metal laminated (FML) plates subjected to in-plane static and harmonic loading using finite element (FE) technique and Bolotin’s method. In this analysis, a four-node isoparametric element with five degrees of freedom per node is adopted. Based on the first-order Reissner–Mindlin theory, the parametric instability of FML plate subjected to in-plane harmonic loading is examined. A MATLAB code is developed for the parametric study on the dynamic stability of FML plates. The reliability of present formulation is checked by comparing numerical results obtained from present FE analysis with the published researches in the field. The influences of several factors, viz. static load factor, aspect ratio, length-to-thickness ratio, number of layers, ply orientation and boundary conditions on the dynamic instability regions are discussed. Significant variations of these factors on dynamic instability zones of FML plates are observed. The instability zones can be used as guidelines for the prediction of the dynamic behavior of FML plates.

The role of cholesterol in membrane activity of digitonin: Experimental and theoretical model studies

2020 ◽  
pp. 114598
Author(s):  
Beata Korchowiec ◽  
Maria Janikowska-Sagan ◽  
Klaudia Kwiecińska ◽  
Anna Stachowicz-Kuśnierz ◽  
Jacek Korchowiec
Keyword(s):  
Theoretical Model ◽  
Membrane Activity ◽  
Model Studies
Sign in / Sign up

Export Citation Format

Share Document