Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 6 — Influence of Damper Properties on Vibration Control Performance

2018 ◽  
Author(s):  
Keisuke Minagawa ◽  
Kiyoshi Aida ◽  
Go Tanaka ◽  
Satoshi Fujita
Keyword(s):  
Viscous Fluid ◽  
Vibration Control ◽  
Power Plants ◽  
Vibration Suppression ◽  
Thermal Power ◽  
Sensitivity Analyses ◽  
Thermal Power Plants ◽  
Control Performance ◽  
Support Structures ◽  
Long Duration

Coal-fired thermal power generation became a very important power source in Japan after Great East Japan Earthquake [1]. Therefore improvement of seismic reliability of the coal-fired thermal power plants is required, because occurrence of very large earthquakes is expected in Japan. Boilers of coal-fired power plants are usually suspended from the upper end of support structures in order to allow thermal expansion of the boilers [2], so boilers easily sway during earthquakes. In order to suppress the vibration, stoppers made of steel are generally installed between boilers and their support structures. Although stoppers made of steel are effective for vibration suppression, further countermeasure for earthquakes having long duration and many aftershocks is required. Authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP2017, the basic performance of the proposed damper was presented [3–5]. In this paper, damper properties were adjusted in order to improve vibration control performance of the damper. Influence of damper properties on the performance was investigated by sensitivity analyses. In addition, influence of dispersion of damper properties was also investigated. Long period and long duration earthquake waves were considered in the analyses.

Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 3 — Evaluation of Vibration Control Performance

2017 ◽  
Author(s):  
Keisuke Minagawa ◽  
Kiyoshi Aida ◽  
Go Tanaka ◽  
Satoshi Fujita
Keyword(s):  
Viscous Fluid ◽  
Vibration Control ◽  
Shear Force ◽  
Power Plants ◽  
Thermal Power ◽  
Response Analysis ◽  
Thermal Power Plants ◽  
Control Performance ◽  
Support Structures ◽  
Analysis Model

After Great East Japan Earthquake in 2011, the base load power in Japan was shifted from nuclear power to coal-fired thermal power. Stable electricity supply is one of important infrastructure, so improvement of seismic reliability of coal-fired thermal power plant and related structures is very important. Boiler structures in coal-fired thermal power plants are generally high-rise structures, and boilers in the structures are usually hung on the top of the structures in order not to restrict thermal expansion. Therefore boilers easily vibrate by earthquakes. In order to suppress vibration of boilers during earthquakes, stoppers made of steel are installed between boilers and support structures. The stoppers have simple mechanism and dissipate vibration energy by plastic deformation of steel material. However, further improvement of vibration control performance is required from the viewpoint of above-mentioned social requirements and recent large earthquakes such as the Great East Japan Earthquake, the Kumamoto earthquake in 2016 and so on. This study proposes an application of a damper using viscous fluid to boilers of coal-fired power plants. The damper is set between boilers and support structures. There are many examples of application of the damper using viscous fluid to buildings and civil engineering structures. Therefore the application of the damper to boilers will be effective. In this paper, a seismic response analysis using an analysis model of a boiler structure is conducted. The analysis model has plural stoppers or plural dampers. The response analysis result is evaluated from the viewpoint of vibration control performance. In other words, story shear force of the support structure is evaluated. In addition various limitations such as the maximum stroke of the dampers are taken into account. As a result, story shear force of the support structure with the proposed damper is smaller than that of the structure with the conventional stopper made of steel, so the proposed damper has high vibration control performance.

Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 7 — Evaluation of Lifetime Using Experimental Design Method

2019 ◽  
Author(s):  
Kiyoshi Aida ◽  
Keisuke Minagawa ◽  
Go Tanaka ◽  
Satoshi Fujita
Keyword(s):  
Experimental Design ◽  
Viscous Fluid ◽  
Power Plants ◽  
Design Method ◽  
Thermal Power ◽  
Great East Japan Earthquake ◽  
Thermal Power Plants ◽  
Support Structures ◽  
Long Duration ◽  
Experimental Design Method

Abstract In 2011, Great East Japan Earthquake that was the largest earthquake in Japanese history occurred. The earthquake had large acceleration, long duration and a lot of aftershocks, and coal-fired thermal power plants were damaged by the earthquake. Boiler structures in coal-fired thermal power plants are generally high-rise structures, and boilers are simply suspended from the top of the support structures in order not to restrict thermal expansion. Therefore boilers are easy to vibrate. In order to suppress vibration of boilers during earthquakes, stoppers are generally set between boilers and support structures. The stoppers are made of steel, and dissipate vibration energy by plastic deformation. However aseismic requirements for thermal power plants have been increased as a result of the Great East Japan Earthquake. Thus authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP 2017, the basic performance of the proposed damper was presented. In PVP 2018, influence of dispersion of damper properties was also investigated. In addition, seismic response analyses using various earthquakes that include long period and long duration earthquake waves were carried out. As a result of previous investigations, it was confirmed that the proposed damper has good performance in its lifetime. However, parameters of dampers were selected manually. Therefore, influence of parameters of dampers on the lifetime were evaluated theoretically by using the experimental design method in this paper. The experimental design method is one of the effective techniques for research such as investigation of the influence of the habitat environment on the growth of crops. The selection of damper parameters is complex optimization, because so many variables need to be optimized. Therefore the experimental design method is suitable technique for the evaluation of damper parameters. This paper evaluates lifetime of dampers from the viewpoint of the experimental design method.

Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 8 — Evaluation of Vibration Control Performance Using Experimental Design Method

2019 ◽  
Author(s):  
Keisuke Minagawa ◽  
Kiyoshi Aida ◽  
Go Tanaka ◽  
Satoshi Fujita
Keyword(s):  
Experimental Design ◽  
Viscous Fluid ◽  
Vibration Control ◽  
Seismic Performance ◽  
Power Plants ◽  
Design Method ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Control Performance ◽  
Experimental Design Method

Abstract After Great East Japan Earthquake, coal-fired thermal power generation is a very important power source in Japan. In addition, Hokkaido Eastern Iburi Earthquake occurred in Japan in 2018, and damage of coal-fired thermal power plants by this earthquake caused blackout in very wide area. Therefore improvement of the seismic performance of the thermal power plants is a very important issue. In general boilers of coal-fired power plants are suspended from the upper end of support structures in order to allow thermal expansion of the boilers. Therefore boilers are structures that easily sway by earthquakes. In order to suppress the vibration, stoppers made of steel are generally installed between boilers and their support structures. Although stoppers made of steel can suppress the vibration effectively and economically, further improvement of seismic performance is required from the viewpoint of abovementioned issue. Therefore authors have proposed and developed a vibration control damper for coal-fired power plants instead of the stopper made of steel. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP 2017, the basic performance of the proposed damper was presented. In PVP 2018, influence of dispersion of damper properties was also investigated. In addition, seismic response analyses using various earthquakes that include long period and long duration earthquake waves were carried out. As a result of previous investigations, it was confirmed that the proposed damper has good performance in its lifetime. However, parameters of dampers were selected manually. Therefore, influence of parameters of dampers on the vibration control performance were evaluated theoretically by using the experimental design method in this paper. The experimental design method is one of the effective techniques for research such as investigation of the influence of the habitat environment on the growth of crops. The selection of damper parameters is complex optimization, because so many variables need to be optimized. Therefore the experimental design method is suitable technique for the evaluation of damper parameters. This paper will evaluate vibration control performance from the viewpoint of the experimental design method.

Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 5 — Influence of Damper Properties on Lifetime

2018 ◽  
Author(s):  
Kiyoshi Aida ◽  
Keisuke Minagawa ◽  
Go Tanaka ◽  
Satoshi Fujita
Keyword(s):  
Viscous Fluid ◽  
Seismic Response ◽  
Power Plants ◽  
Thermal Power ◽  
Great East Japan Earthquake ◽  
Thermal Power Plants ◽  
Support Structures ◽  
Long Duration ◽  
Fluid Dampers ◽  
Viscous Fluid Dampers

In 2011, Great East Japan Earthquake that is the largest earthquake ever observed in Japan occurred. The earthquake had large energy, long duration and many aftershocks, and coal-fired thermal power plants were damaged by the earthquake [1]. Boiler structures in coal-fired thermal power plants are generally high-rise structures, and boilers are simply suspended from the top of the support structures in order to allow thermal expansion, so boilers easily vibrate [2]. In order to suppress vibration of boilers during earthquakes, stoppers are generally set between boilers and support structures. The stoppers are made of steel, and dissipate vibration energy by plastic deformation. However aseismic requirements for thermal power plants have been increased as a result of the Great East Japan Earthquake. Thus authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP 2017, the basic performance of the proposed damper was presented [3–5]. In this paper, influence of damper properties on lifetime of the damper was investigated by seismic response analyses. In addition, lifetime of dampers for long period and long duration earthquake waves were investigated by seismic response analyses.

Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 2 — Evaluation of Lifetime

2017 ◽  
Author(s):  
Kiyoshi Aida ◽  
Keisuke Minagawa ◽  
Go Tanaka ◽  
Satoshi Fujita
Keyword(s):  
Viscous Fluid ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Response Analysis ◽  
Thermal Power Plants ◽  
Support Structures ◽  
Analysis Model ◽  
Large Numbers ◽  
Plastic Displacement

In 2011, Great East Japan Earthquake that is the largest earthquake ever observed occurred. The earthquake had large energy, long duration time and many aftershocks. Huge tsunami caused nuclear accidents. At present, a large number of nuclear power plants in Japan have not been operated yet. Then the base load power in Japan was shifted from nuclear power to coal-fired thermal power. Therefore it is very important to improve aseismic performance of coal-fired thermal power plants. Boiler structures in coal-fired thermal power plants are generally high-rise structures. In addition its combustion temperature is very high, so boilers are simply suspended from the top of the support structures in order to allow thermal expansion. Therefore boilers easily vibrate. In order to suppress vibration of boilers during earthquakes, stoppers are set between boilers and support structures. The stoppers are made of steel, and dissipate vibration energy by plastic deformation. However aseismic requirements for thermal power plants against large earthquakes having large numbers of repeat counts have been increased. Then authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper made of steel, and it is able to perform in earthquakes with relatively large numbers of repeat count. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In this paper, a seismic response analysis using an analysis model of a boiler structure is conducted. The analysis model has plural stoppers or plural dampers. The response analysis result is arranged to investigate lifetime of the stoppers or the dampers. The accumulated plastic displacement of each stopper or damper is used for the evaluation. As a result, it was confirmed that the proposed damper has high durability compared with conventional stopper made of steel.

Improvement of Seismic Resistance Performance of Thermal Power Plants by Applying Vibration Control Dampers

2017 ◽  
Author(s):  
Koki Fushimi ◽  
Satoshi Fujita ◽  
Keisuke Minagawa
Keyword(s):  
Vibration Control ◽  
Power Plants ◽  
Thermal Power ◽  
Analytical Models ◽  
Earthquake Resistance ◽  
Response Analysis ◽  
Thermal Power Plants ◽  
Support Structure ◽  
Large Numbers ◽  
Resistance Performance

Improving earthquake resistance of power plants has been important since Great East Japan earthquake occurred in 2011. In particular, thermal power plants accounted for most of the current Japanese power supply. Thus, improving earthquake resistance of the thermal power plants has been paid attention than other power plants. In current coal-fired power plants, boilers are simply suspended from the top of the support structures. Therefore, boilers easily vibrate. In order to suppress vibration of boilers during earthquakes, stoppers made of steel are installed between a boiler and its support structure. The stoppers dissipate vibration energy by plastic deformation. Therefore, the stoppers are effective in earthquakes with relatively small numbers of repeat counts, but may not effect in earthquakes with relatively large numbers of repeat counts. Then we propose installation vibration control dampers in support structure to suppress more the vibration and perform also in the repetition of earthquakes. In this paper, a seismic response analysis using analytical models of the boiler structure is conducted. In addition, a vibration control damper suitable for installed in the support structure are considered. As a result, a rectangle hysteresis damper is suitable as vibration control damper for the support structure.

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