Session: SE-09-01 Advanced Seismic Evaluation and Code - 1

Paper Number: 107707

107707 - A Study on Reliability of Piping System Supported by Elastic-Plastic Support Subjected to Unsteady Seismic Waves 

Large earthquakes occur frequently in Japan and overseas, and the seismic design of mechanical structures is important.
A new seismic guideline was issued for nuclear power plants in Japan in 2006.
The old guideline was designed with a certain degree of safety factor in mind.
However, there is a risk of destruction or damage in the event of a huge earthquake, so the new guideline aims to evaluate that risk.
In addition, piping systems are important components of large-scale plants such as power plants and chemical plants.
In recent years, elasto-plastic supports with nonlinear hysteresis characteristics, such as supports using plastic deformation of lead, have begun to be put to practical use as damping devices for piping systems.
So far, the authors have conducted research on seismic design methods for piping systems supported by elasto-plastic supports based on probabilistic theory.
However, white noise is mainly used from the viewpoint of probability theory, and there are not many studies based on probability theory when unsteady artificial seismic waves that are closer to real seismic waves are input.
Furthermore, there have been few studies on the difference in support behavior due to the characteristics of seismic waves.
Therefore, in this study, we introduce a model in which an L-shaped piping system is supported by elasto-plastic supports, and input unsteady artificial seismic waves.
A stationary stochastic Gaussian noise is weighted by a deterministic function with seismic frequency characteristics, and this is taken as an input acceleration wave.
This seismic wave is made with reference to characteristics of the Taft earthquake.
As indices, the reliability of the pipings based on the stress on the pipings, and energy absorption rate by the support are employed.
The response of piping subjected to non-stationary artificial seismic waves is investigated and compared to the response subjected to stationary Gaussian noise on the basis of these indices.
The reliability of the piping system is lower than that of white noise with the same power when non-stationary artificial seismic waves are input.
The energy absorption rate of supports reduces comparing with that of the white noise.

 

Presenting Author: Atsuhiko Shintani Osaka Metropolitan Univ.

Presenting Author Biography: Atsuhiko Shintani received the Doctoral degree at Kyoto Institute of Technology in Japan in 1997.
He is currently Professor in Osaka Metropolitan University in Japan.
His research areas are vibration engineering, seismic engineering, flow-induced vibration, stability of dynamic system, application of vibration, human engineering, and so on.

Authors:

Atsuhiko Shintani Osaka Metropolitan Univ.
Chihiro Nakagawa Osaka Metropolitan University
Tomohiro Ito Independent Author