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A Study on Vibration Isolation in a Wind Turbine Subjected to Wind and Seismic LoadingVan der Woude, Chad January 2011 (has links)
The primary loading on wind turbines is in the lateral direction and is of a stochastic nature, due to wind and seismic forces. As turbines grow larger, they experience proportionally larger lateral forces. Large forces require larger section sizes and overall weight of the turbine. The objective of this study is to investigate the use of vibration isolation as a structural control measure to minimize the overall wind and seismic forces transmitted to the turbine. Passive control systems such as tuned mass dampers have previously been proposed to mitigate response to wind loading but have not generally been evaluated under seismic loading.
This thesis discusses the potential use of a non-linear vibration isolator just below the wind turbine nacelle to decrease the structural response of the turbine under wind and seismic loading. The structural idealization of the wind turbine structure and the applied loading are presented. The force-displacement properties of the vibration isolator are discussed and the equations of motion are modified to include the isolator.
A finite element model is created which includes wind and seismic loading and incorporates a vibration isolator. Simulations are performed to determine a number of key structural response variables without the vibration isolator, and with a vibration isolator having varied force-displacement properties. The changes in those key response variables are presented and discussed. It is concluded that vibration isolation is a viable method for reducing structural response of wind turbines. Some practical concerns and areas of future research are discussed.
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Coupling of two natural complex systems: earthquake-triggered landslidesGhahramani, Masoumeh January 2012 (has links)
This thesis contains two main parts. The first part presents a database compiling 137 landslide-triggering earthquakes (LTEs) worldwide, with magnitudes greater than the minimum observed threshold for causing landslides (M4.5), for the period of 1998 -2009. Our data sources include a comprehensive review of the existing literature on earthquake-triggered landslides (ETLs), and also a USGS-based earthquake catalog (PAGER-CAT) that contains information on earthquake-triggered secondary events. Only 14 earthquakes out of the 137 seismic events induced significant numbers of landslides (>250). We compared the number of ETLs with the total number of earthquakes with M ≥ 4.5 (n=68,734) during the same period of time. The results show that only 0.2 % of ETLs and only 4.5% of earthquakes of M > 6 resulted in landslide. In addition, we compiled a database of 37 large-scale landslides, involving initial failure volumes of greater than 20 Mm3 that occurred worldwide between 1900 to 2010. The database contains large-scale earthquake-triggered (n ETLs=18) and non-earthquake-triggered landslides (n NETLs=20), i.e., ca. 50% of large-scale landslides were induced by seismic activity. Surprisingly, the volume-temporal frequency curves of ETLs and NETLs show almost identical slopes and intercepts. Thus, for a given volume, the annual frequency of ETLs is almost identical to that of NETLs in the 110 year period. In contrast to previous studies, this thesis found that the volume of the largest landslide triggered by a given landslide-triggering earthquake is not a function of earthquake magnitude. Peak ground motions (PGA, PGV, and PSA) were calculated for the 18 large-scale ETLs at the site of each occurrence and the resulting values show a correlation with the volume of landslides below the threshold of ca. 80 Mm3. Above this threshold, the relationship between peak ground motions and ETL volume shows complex and nonlinear behavior. The results suggest that 1) other special conditions are required for significant earthquake-triggered landslides to occur, and 2) that very large earthquake-triggered landslides (volume greater than 80 Mm3) result from complex progressive failure mechanisms initiated by seismic shaking (i.e., above this threshold volume, landslide volume is independent of PGA, PGV, and PSA).
A detailed analysis of the two 1985 Nahanni earthquakes and the North Nahanni rockslide triggered by the first main shock is carried out in the second part of the study. The North Nahanni rockslide, Northwest Territories, Canada was triggered by the earthquake of M=6.6 on October 5th, 1985. The slide occurred in a Palaeozoic carbonate sequence along a thrust fault, which partly follows bedding and partly cuts across bedding. The sliding surface within the limestone consisted of two planes; the lower plane dipped at 20° while the upper plane dipped at 35°. Slope stability analysis is performed using discontinuum numerical modeling. Static slope stability analyses indicate that the sliding rock was marginally safe for the sliding surface friction angles of 24o or higher. Dynamic analyses of the co-seismic movements are conducted by applying a series of sinusoidal waves to the base of the model. The amplitudes of the October earthquake's seismic waves are estimated using strong motion data available from the second main shock. The results, from the dynamic analysis indicate that the slope becomes unstable for given seismic inputs at a specific range of friction angles (24o to 30o) for the sliding surface and the deformation behavior of the North Nahanni rock masses is dependent on the frequency of the seismic signals. Because the static slope stability analysis showed that the slope was close to instability prior to the seismic shaking, we suggest that the 1985 Nahanni earthquake operated as a trigger event that accelerated the occurrence of the slide. This finding supports our earlier results of the global scale study, which showed that the triggering event does not change the general trend of the frequency-volume distribution of landslides; however, it can accelerate the occurrence of slope failure.
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The Macroeconomic Effects of the Chilean Earthquake 2010Lundgren, Viktoria January 2012 (has links)
The purpose of this paper is to analyze the macroeconomic effects of the earthquake that struck Chile in 2010 and the impact it had on the Chilean economy. It is a narrative case study of a small, open emerging economy and the timeframe is short term. Like other studies made about macroeconomic effects of a natural disaster, it is surprising to find how fast a country can so rapidly recover from a big devastation like the Chilean earthquake 2010. The final economic impact depends on the structural conditions of the economy and the economic policy mix undertaken to handle the short-term effects. The paper shows that despite the big disaster, Chile showed great resilience to the adverse shook due to its sound finances and effective countercyclical policies.
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Synthesis of earthquake ground motions for the new madrid seismic zoneDrosos, Vasileios A. 01 December 2003 (has links)
No description available.
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Probabilistic Assessment of Non-Ductile Reinforced Concrete Frames Susceptible to Mid-America Ground MotionsCelik, Ozan Cem 29 June 2007 (has links)
The infrequent nature of earthquakes in the Central and Eastern United States (CEUS), and the fact that none with intensity comparable to the New Madrid sequence of 1811 12 or the Charleston earthquake of 1886 has occurred in the past century, have caused the earthquake hazard in the region to be ignored until quite recently. The seismic performance of reinforced concrete (RC) frames in the CEUS, which have primarily been designed for gravity load effects, is expected to be deficient when subjected to earthquakes that are judged, in recent seismological research, as being plausible in the New Madrid Seismic Zone (NMSZ). The objective of this study is to develop a set of probability-based tools for efficient uncertainty analysis and seismic vulnerability and risk assessment of such gravity load designed (GLD) RC frames and to use these tools in evaluating the seismic vulnerability of RC frames that are representative of the building inventory in Memphis, TN the largest population center close to the NMSZ.
Synthetic earthquake ground motions for the CEUS that are available from two different Mid-America Earthquake (MAE) Center projects were used in the finite element-based simulations for determining the seismic demand on the GLD RC frames by nonlinear time history analysis (NTHA). A beam-column joint model was developed to address the deficiencies in the joints of GLD frames and was incorporated in the finite element structural models. Seismic fragilities were derived for low-, mid-, and high-rise GLD RC frames. Various sources of uncertainty were propagated through the analysis, and their significance for fragility assessment was examined. These fragilities were used to evaluate the vulnerability of the RC frame inventory in Memphis, TN with regard to performance-based design objectives, defined in terms of performance levels associated with reference earthquake hazard levels. This performance appraisal indicated that GLD RC frames do not meet the life safety and collapse prevention performance objectives that are found in recent building codes and guidelines for performance-based earthquake engineering.
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Chinese NGOs and Wenchuan Earthquake: The Role and the Functional AnalysisChen, Jui-wen 27 June 2012 (has links)
Human society in the 21st century, population pressures brought about by globalization, the unequal distribution of environmental hazards, and a variety of public issues become not by the traditional government alone; has been, non-governmental organization (NGO) in the global the role in a variety of topics, are the key to lead the relationship between state and society in the discussions of civil society and international governance, the NGO has become increasingly critical, even in order to achieve democracy, with human rights, a indicators.
After 1978, the Communist Party power succession by designated has passed three generations. 2012, mainland China's power struggle with severe economic test can reveal the opportunity for Chinese mainland state machine transition is not yet known; But no matter how, recalling the moment in 2008, it was a in the north hosting the Olympic Games to the international community show the elements of national power, surprisingly actually first in the Southern earthquake relief shown.
The Corporatism defined the mode of interdependence between the NGOs and the government is built on the concept of exchange, of which the most important connotation is the country's laws, institutions and regulations; the organization can not just exist with its own objectives and efficiency relevant professional space must comply with the external specification, which includes the cultural system, moral values. National units the role of classification screening system for the development of mainland China NGO, the NGO in the process of development, whether it can have more than "Legitimacy" is even more important.
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Neuro-fuzzy model of superelastic shape memory alloys with application to seismic engineeringOzbulut, Osman Eser 15 May 2009 (has links)
Shape memory alloys (SMAs) have recently attracted much attention as a smart
material that can be used in passive protection systems such as energy dissipating
devices and base isolation systems. For the purpose of investigating the potential use of
SMAs in seismic engineering applications a soft computing approach, namely a neurofuzzy
technique is used to model dynamic behavior of CuAlBe shape memory alloy
wires. Experimental data are collected from two test programs that have been performed
at the University of Chile. First, in order to evaluate the effect of temperature changes
on the behavior of superelastic SMA wires, a large number of cyclic, sinusoidal, tensile
tests are conducted at various temperatures. Second, to assess dynamic effects of the
material, a series of laboratory experiments are conducted on a scale model of a three
story model of a building that is stiffened with SMA wires and given excitation by a
shake table.
Two fuzzy inference systems (FISes) that can predict hysteretic behavior of
CuAlBe wire have been created using these experimental data. Both fuzzy models
employ a total of three input variables (strain, strain-rate, and temperature or prestress)
and one output variable (predicted stress). Values of the initially assigned membership
functions for each input are adjusted using a neural-fuzzy procedure to accurately predict
the correct stress level in the wires. Results of the trained FISes are validated using test
results from experimental records that had not been previously used in the training
procedure. Finally, numerical simulations are conducted to illustrate practical use of these
wires in a civil engineering application. In particular, dynamic analysis of a single story
frame and a three story benchmark building that are equipped with SMA damping
elements are conducted. Then, an isolated bridge that utilizes a linear rubber bearing
together with SMA elements is analyzed. Next, in order to show recentering ability of
SMAs, nonlinear time history analysis of a chevron like braced frame is implemented.
The results reveal the applicability for structural vibration control of CuAlBe wire whose
highly nonlinear behavior is modeled by a simple, accurate, and computational efficient
FIS.
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The Effect of Emotional Intelligence on Crisis Management : The Example of Nantou Area School Teachers in 921 Earthquake CatastropheHSUEH, HSU-I 07 June 2001 (has links)
Abstract
The purpose of the study was to explore the relationship between emotional intelligence and crisis management, and to examine the important effect of emotion implementation on daily life. The study investigates the predictive effect of different background variables of emotional intelligence on crisis management. Further, emotional intelligence can influence the policies or actions taken for any crises.
The subjects were 162 teachers from Nantou Area in 921 Earthquake Catastrophe in Taiwan. The instruments used in the study included ¡uemotional intelligence questionnaire¡vand ¡ucrisis management questionnaire¡v. The data was analyzed by the statistics methods of frequency distribution, person's correlation, t-test, one-way ANOVA, MANOVA, canonical correlation and stepwise multiple regression.
The major findings were as follows:
1.The level of emotional intelligence and crisis management of Earthquake Catastrophe Area School Teachers are medium.
2.For emotional intelligence, emotion management, there were significant differences among variables of faith¡Bteaching experience¡Bthe top academic degrees on emotional intelligence, but gender¡Bage¡Bposition and school scope were not.
3.As to crisis management, there were significant differences among variables of gender¡Bteaching experience¡Bthe top academic degrees on crisis management, but age¡Bfaith¡Bposition and school scope were not .
4.There were significant differences of crisis management due to different emotional intelligence measures.
5.The result of canonical correlation analysis revealed that perceived emotional intelligence was significantly associated with crisis management by a canonical variable. The one
canonical relation coefficient is .294.
6.The variables of emotional intelligence could significantly predict crisis management.
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A Study on Industry Reconstruction Strategy in Area of 921 Earthquake Disaster.Yu, Chi-Wei 22 July 2003 (has links)
Abstract¡G
Taiwan has been suffering from a series of severe earthquake disaster. Especially in 921 Earthquake. To deal with such a disastrous situation, government implemented the new plans for the quake-ravaged areas, such as the guiding principle of 921 disaster recovery. This study is attempted to program Industry Reconstruction of post- earthquake in the disaster area. The research method of this research is consisted of data analysis and SWOT Analysis.
The research results have indicated:
1.The government plays an important role in the process of Industry Reconstruction.
In the entire process of industry reconstruction, from the rescue at the early stage to the replacement of industry reconstruction, it is inevitably that the role of government would be the main influence of industry reconstruction effectiveness. However, in the meanwhile, because of the urge of becoming a member of WTO, it had caused the rate of the unemployment increased and some small businesses closing down. People had economically undertaken all the domestic pressures of becoming a member of WTO, and yet now the government had to face another problem, industry reconstruction in the quake-ravaged areas. It seems that it would be much harder for the government to overcome all at once, therefore, a series of well-related policy is needed, such as the guiding of job-shifted for farmers and style-shifted of agriculture, the strategic alliance of the agriculture association, the promotion of Tourism and the construction of the specific industry in the quake-ravaged areas. Those policies should be concerned in regarding to post-earthquake recovery.
2.The people participation in the reconstruction progress
After 921 earthquake, it is obviously that government had difficulty to undertake all issues domestically and internationally. Therefore, it found that the participation of people in the post earthquake recovery would be necessary. Indeed, with the participation of people, it can speed up the process of the recovery. As a result, the participation of people in the quake- ravaged areas was seriously required to the re-development of the specific local industry.
3.The style-shifted of industry and resource integration
Since Taiwan had put efforts on becoming a member of WTO in order to increase its products more competitive in the atmosphere of international trade, the style-shifted of Industry would be necessary in avoidance to elimination of the potential domestic industry. For example, when the style-shifted, from agriculture to agricultural Industry, had occurred, the needs of machines in Agriculture would be increased in order to reduce the cost of agriculture production. As a consequence, the agriculture production would become more competitive in international trade and it would increase GDP in a sense. Therefore, promoting the number of experts in relation to the knowledge of agriculture from government would be the prior in order to increase the competitiveness in international trade.
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Design of an Earthquake Proof One Family House : A house in alternative construction material, made for slum areas in Medellin, ColombiaFabisch, Anna, Karlsson, Anders January 2007 (has links)
<p>One of mankind’s most important needs is the need for shelter. All around the world people live in lack of this basic need. Colombia is a South American country heavily burdened by civil war for many years. This has led to that many people have moved to the larger cities with large slum areas and bad living conditions. This thesis is aiming to give a solution to the problem with bad housing and it is performed in cooperation with Ankarstiftelsen. Ankarstiftelsen is a Swedish charity organisation that works with the suffering people in various places in Colombia.</p><p>This thesis examines the possibility to build a house in a sandwich technique with a core of rigid plastic foam and a skin material of fibre reinforced plastic. The construction should be as easy as possible to manufacture, and the construction is also intended to be self carrying. The final proposition is to build the house using polyurethane rigid foam as the core, and a glass fibre reinforced polyester as the skin. This combination combines good mechanical behaviour with a relatively low price.</p><p>Tests have been performed to evaluate the constructions ability to withstand some basic loads, with the help of computer aided engineering. The program that has been used to create a model is ProEngineer, and the application ProMechanica has been used to perform the analysis. The loads that have been tested are: gravity loads, wind loads, maintenance loads and earthquake loads. Colombia is located in the so called Pacific Ring of Fire, where earthquakes are a bitter reality. The Colombian building code is, as a result of this, much focused on the issue of earthquake safety. The Colombian building code has been used in order to create reliable earthquake testing models.</p><p>The authors come to the conclusion that the house is possible to build with the given data. However, further investigations regarding manufacturing techniques and practical tests have to be made before the house can be built in reality.</p>
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