Inelastic Seismic Test of the Small Bore Piping and Support System: Part 3 — Simulation Analysis for the Piping Seismic Test

2008 ◽  
Author(s):  
Eiji Shirai ◽  
Kazutoshi Eto ◽  
Akira Umemoto ◽  
Toshiaki Yoshii ◽  
Masami Kondo ◽  
...  
Keyword(s):  
Support System ◽  
Simulation Analysis ◽  
Local Strain ◽  
System Model ◽  
System Response ◽  
Piping System ◽  
Inelastic Behavior ◽  
Inelastic Response ◽  
Strain Behavior ◽  
Safety Margins

Seismic safety is one of the major key issues of nuclear power plant safety in Japan. It is demonstrated that nuclear piping possesses large safety margins through the small bore piping and support system test, consisted of three dimensional piping, supports, U-bolts, and concrete anchorages, using the E-defense vibration table of National Research Institute for Earth Science and Disaster Prevention, Hyogo Earthquake Engineering Research Center at Miki city, by the extremely higher seismic excitation level [1, 2]. A simulation analysis for the piping system is described with a focus on the inelastic behavior of the support to the whole piping system response, and the subsequent interaction when both piping and support shows inelastic behavior. The analysis for the inelastic response of the piping seismic test was conducted using the FEM program ABAQUS. It requires a large amount of time to carry out a strain behavior analysis of the localized piping element and also calculate the dynamic inelastic response of the whole piping system, simultaneously. Therefore the following two steps analysis method is proposed. (Step 1) Seismic response analysis of the piping system. (Step 2) Evaluation for local strain of elbows. The simplified piping system model is adopted to solve the non-linear dynamic response both of the supports and elbows of the piping system in (Step 1). On the other hand, the piping system model with partially detailed elbow shell elements is applied to evaluate local strain behavior of the elbow in (Step 2).

Inelastic Seismic Test of the Small Bore Piping and Support System: Part 1 — Seismic Proving Test of the Small Bore Piping System

2008 ◽  
Author(s):  
Eiji Shirai ◽  
Kazutoshi Eto ◽  
Akira Umemoto ◽  
Toshiaki Yoshii ◽  
Masami Kondo ◽  
...  
Keyword(s):  
Support System ◽  
Nuclear Power ◽  
Three Dimensional ◽  
System Response ◽  
Piping System ◽  
Inelastic Behavior ◽  
Seismic Safety ◽  
Plant Safety ◽  
Safety Margins ◽  
Support Element

Seismic safety is one of the major key issues of nuclear power plant safety in Japan. It is demonstrated that nuclear piping possesses large safety margins in the various piping ultimate test reports. But it is appeared that there still remain some technical uncertainties about the phenomenon when both piping and supports show inelastic behavior in the extremely high seismic excitation level. In order to obtain the influence of the inelastic behavior of the support to the whole piping system response, and the subsequent interaction when both piping and supports show inelastic behavior, the following two tests have been started. • Support element test: Load-displacement characteristics of the support system including U-bolt, support itself and concrete anchorage are obtained by the forced displacement test. • Seismic proving test of piping system: The small bore piping and support system consisted of three dimensional piping, supports, U-bolts, and concrete anchorages will be excited on the table by the extremely higher seismic level. This paper introduces the major results of seismic proving test of piping and support system. The support element test results is presented in the paper of part 2, and the simulation analyses of these tests are summarized in the paper of part 3 [1, 2].

Seismic Design Margin of the Piping and Support System: Part 3—Evaluation of Seismic Margin of the Piping System

2010 ◽  
Author(s):  
Eiji Shirai ◽  
Takanori Yamada ◽  
Kazutoyo Ikeda ◽  
Toshiaki Yoshii ◽  
Masami Kondo ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Support System ◽  
Earthquake Engineering ◽  
Nuclear Power ◽  
System Response ◽  
Piping System ◽  
Linear Modeling ◽  
Safety Margins ◽  
Non Linear

Seismic safety is one of the major key issues of nuclear power plant safety in Japan. It is demonstrated that nuclear piping possesses large safety margins through the piping and support system test, which consisted of three dimensional piping, supports, U-bolts, and concrete anchorages, using the E-defense vibration table of National Research Institute for Earth Science and Disaster Prevention, Hyogo Earthquake Engineering Research Center, on extremely high seismic excitation level [1,2,3]. In the above test, the non-linear hysteretic behaviors of the support are quite complicated, but the dissipated energies introduce large damping effects on the piping system response. In order to evaluate the inelastic behavior of the support with respect to the whole piping system response, the following simulation methodology for the support re-evaluation is proposed. 1) Non-linear modeling of the support: • Failure mode and failure capacity of each support. • Simplified non-linear modeling of each support. 2) Simulation Analysis of the piping and support system: • Considering the non-linearity both of the supports and elbows in the piping system. 3) Evaluation of seismic margin: • Focused on the failure level for the support system, and the fatigue damage for the strain range of the piping. The limit state analysis of the typical piping system of a nuclear power plant is presented in this paper, and it is demonstrated that these evaluations of the seismic margins would give important insight into the support reinforcement program on the seismic re-evaluation work.

Influence of Local Wall Thinning and Support Stiffness in Piping Systems on Safety Assessments for Dynamic Loading

2014 ◽  
Author(s):  
Klaus Kerkhof ◽  
Fabian Dwenger ◽  
Gereon Hinz ◽  
Siegfried Schmauder
Keyword(s):  
Stress Analysis ◽  
Response Spectrum ◽  
System Response ◽  
Piping System ◽  
Load Bearing ◽  
Wall Thinning ◽  
Safety Margins ◽  
Piping Systems ◽  
Bearing Behavior ◽  
Local Wall Thinning

The load bearing behavior of piping systems depends considerably on support distances and stiffness as well as cross section characteristics. Stiffness of supports can often be defined only with difficulty by applying simplified procedures or guidelines based on assumptions. Load cases can be estimated quite well, but the safety assessment of a piping system can only be as reliable as the system model can realistically describe the present support stiffness or imperfections e.g. local wall thinning. As a consequence, the prediction of the system response may be poor. It is likely that calculated frequencies differ from natural frequencies determined experimentally. These frequency shifts lead to unrealistic predictions of stress analysis. Examples for overestimations and underestimations of stress analysis are given regarding the load case earthquake, depending on whether the frequency shift runs into or out of the plateau of the applied floor response spectrum. The influence of local wall thinning on modal characteristics is investigated. Conservative estimations of the influence on the load bearing behavior regarding severe local wall thinning are given. For fatigue checks the linear response of an experimental piping system is calculated and safety margins are demonstrated by comparing calculated with experimental results.

Seismic Proving Test of Ultimate Piping Strength: Simulation Analysis of Simplified Piping System Test

2003 ◽  
Author(s):  
Kenichi Suzuki ◽  
Y. Namita ◽  
H. Abe ◽  
I. Ichihashi ◽  
Kohei Suzuki ◽  
...  
Keyword(s):  
Large Scale ◽  
Simulation Analysis ◽  
Safety Margin ◽  
Response Analysis ◽  
Piping System ◽  
Seismic Safety ◽  
Strain Behavior ◽  
Critical Elements ◽  
Seismic Design Code ◽  
Piping Systems

The six-year program for the Seismic Proving Test of Ultimate Piping Strength has been running since 1998 with the following objectives: i) to clarify the elasto-plastic response and ultimate strength of nuclear piping, ii) to ascertain the seismic safety margin of the current seismic design code for piping, and iii) to assess new allowable stress rules. To resolve outstanding technical issues before proceeding on to a seismic proving test of a large-scale piping system, a series of preliminary tests of materials, piping components and simplified piping systems is intended. A simulation analysis related to the simplified piping system test is described with a focus on the methodology of the non-linear dynamic response analysis of the whole piping system and the strain behavior of the localized critical elements, such as elbows and nozzles.

Research on Modulation Multiplexing System and Technique Employing Tilted Grating

2013 ◽  
Vol 397-400 ◽  
pp. 1643-1647
Author(s):  
Hui Bo Wang ◽  
Zhi Quan Li
Keyword(s):  
Delay Time ◽  
Large Scale ◽  
Intelligent System ◽  
Simulation Analysis ◽  
Response Speed ◽  
Signal Frequency ◽  
System Response ◽  
Photodiode Array ◽  
Speed Simulation ◽  
Demodulation Method

A dual demodulation technique based on tilted grating and InGaAs photodiode array is proposed; using the coupling modes of the cladding, a wavelength demodulation method with the tilted grating as the spectroscopic device is realized. This method can achieve that the demodulation of the channel in which the sensing information changed and the optimization of collection rules of the system. Two tunable F-P filters scan and demodulate the sensing path simultaneously to further improve the system response speed. Simulation analysis and experiments results indicate that the average demodulation time is 40ms and the average signal frequency can reach 15Hz. In addition, the demodulation bandwidth is 40nm, and its wavelength demodulation precision can reach 20pm. The system has advantages of the shorter delay time, and the demodulation time is immune to the number of channels, etc.. Therefore, this system is able to meet the smart requirement of some complex systems and large scale distributed intelligent system.

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