Development on Rubber Bearings for Sodium-Cooled Fast Reactor: Part 6 — Proposal of New Type of Hysteresis Model for Ultimate Behavior

2017 ◽  
Author(s):  
Tsuyoshi Fukasawa ◽  
Shigeki Okamura ◽  
Tomohiko Yamamoto ◽  
Tomoyoshi Watakabe
Keyword(s):  
Seismic Response ◽  
Hysteresis Loops ◽  
Response Analysis ◽  
Hysteresis Model ◽  
Seismic Response Analysis ◽  
Restoring Force ◽  
Proposed Model ◽  
New Type ◽  
Rubber Bearings ◽  
Hysteresis Characteristics

This paper describes a new type of hysteresis model applied for seismic response analysis, which provides restoring force characteristics containing various types of hysteresis loops generated by calculating differential equations, based on static breaking tests regarding thick rubber bearings. In order to reduce residual risk, there is increasing necessity to accurately predict seismic response against both design-basis ground motion and ground motion exceeding design-basis. This process of seismic response prediction is called seismic Probabilistic Risk Assessment (PRA). In general, a restoring force of rubber bearing under large deformation due to a major earthquake has strong non-linear characteristics containing the hysteresis loops. To improve the accuracy of seismic response predictions up to the ultimate behavior in PRA, a new hysteresis model to be applicable up to the breaking point in horizontal and vertical directions is proposed by the authors. The features of the proposed hysteresis model are as follows: (1) The hysteresis characteristics obtained by the proposed model have smooth curves as substantive hysteresis loops measured in breaking tests. (2) The various types of hysteresis characteristics can be captured efficiently as initial value problems since the proposed model, consisting of differential equations, directly allows the skeleton function, and unaffected by hysteresis law such as Masing law. This paper indicates applicability of the proposed hysteresis model to seismic response analysis through comparison of results of the static breaking test with results of analytical, and also describes the breaking mode obtained by the seismic response analysis.

scholarly journals Seismic Response Analysis and Evaluation of Laminated Rubber Bearing Supported Bridge Based on the Artificial Neural Network

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Bingzhe Zhang ◽  
Kehai Wang ◽  
Guanya Lu ◽  
Weizuo Guo
Keyword(s):  
Seismic Response ◽  
Seismic Damage ◽  
Response Analysis ◽  
Seismic Demand ◽  
Vertical Load ◽  
Demand Model ◽  
Seismic Response Analysis ◽  
Seismic Demands ◽  
Seismic Demand Model ◽  
Rubber Bearings

Laminated rubber bearings are commonly adopted in small-to-medium span highway bridges in earthquake-prone areas. The accurate establishment of the mechanical model of laminated rubber bearings is one of most critical steps for the bridge seismic response analysis. A new constitutive model of bearing based on the artificial neural network (ANN) technique is established through the static cyclic test of laminated rubber bearings, considering the bearing initial stiffness, friction coefficient, and other parameters such as the bearing sectional area, height, loading velocity, vertical load, and aging time. Combined with the ANN method, the ANN-based bridge seismic demand model is built and applied to the rapid evaluation of the bridge seismic damage. The importance of the bearing affecting design factors in the bridge seismic demands are ranked. The results demonstrated that the dimensions of the bearing and vertical load are the main factors affecting the bearings constitutive model. Based on the partial dependency analysis with the ANN-based bridge seismic demand model, it is concluded that the height of bearing is the key design parameter which affects the bridge seismic response the most. The ANN seismic demands model can fit the complex function relationship between various factors and bridge seismic response with high precision, so as to achieve the rapid evaluation of bridge seismic damage.

Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 1 — Proposal of Analytical Models Based on Loading Tests

2018 ◽  
Author(s):  
Tsuyoshi Fukasawa ◽  
Shigeki Okamura ◽  
Takahiro Somaki ◽  
Takayuki Miyagawa ◽  
Masato Uchita ◽  
...  
Keyword(s):  
Seismic Response ◽  
Analytical Model ◽  
Three Dimensional ◽  
Analytical Models ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Natural Period ◽  
Isolation System ◽  
Loading Tests ◽  
Rubber Bearings

This paper describes that the analytical model for the three-dimensional isolation system [1], which consists of thick rubber bearings, disc springs and oil dampers, is created through loading tests. The new-type analytical models of each element are proposed to improve the prediction accuracy of the seismic response analysis. The concept of the three-dimensional isolation system has been proposed to ensure the structural integrity for large reactor vessels. The primary specifications of the three-dimensional isolation system are a horizontal natural period of 3.4 s and a vertical natural period of 0.33 s. The investigations of horizontal isolation performances have been conducted for the various types of isolation devices, beginning with rubber bearings, whereas the previous studies focused on the vertical isolation performances are only a few. Hence, isolation characteristics, such as restoring force and damping force, should be clarified by loading tests using vertical seismic isolation elements, and analytical model to assess the seismic response should be identified on the basis of the loading test results. This paper presents a new analytical model with providing of the differential equations to improve the prediction accuracy and demonstrates the seismic performance, including beyond-design-basis ground motion, for the three-dimensional isolation system by the seismic response analysis.

Influence of Mullins and hardening effects of seismic isolation rubber bearings on the seismic response

2021 ◽  
Author(s):  
Hiroshi Shimmyo ◽  
Tolga Onal ◽  
Shozo Nakamura ◽  
Kazuya Tokunaga
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Hysteresis Loops ◽  
Highway Bridges ◽  
Restoring Force ◽  
Two Factors ◽  
Product Test ◽  
Rubber Bearings ◽  
Isolated Bridges ◽  
Force Displacement

<p>In the current Specifications for Highway Bridges of the Japan Road Association, a bilinear force- displacement relationship is recommended as the hysteresis loops of the seismic isolation rubber bearings for the dynamic structural analysis of seismically isolated bridges. However, it has been confirmed that the restoring force characteristics of the actual devices are different from the bilinear model due to the Mullins effect and the hardening phenomenon of the rubber under large shear strains. In this study, the effect of these two factors on the seismic response of a bridge is investigated through the dynamic analysis with the tri-linear double target model considering the factors. The parameters of the model are obtained from product test results of lead-plugged laminated rubber bearings and high-damping laminated rubber bearings.</p>

Research and Development of Vibration Control Device by Using Displacement Amplification Mechanism

2008 ◽  
Author(s):  
Tomoyoshi Watakabe ◽  
Satoshi Fujita ◽  
Toshio Omi ◽  
Hiroshi Kurabayashi ◽  
Keiji Ogata
Keyword(s):  
Vibration Control ◽  
Seismic Response ◽  
Small Amplitude ◽  
Control Device ◽  
Response Analysis ◽  
Control Performance ◽  
Seismic Response Analysis ◽  
Loading Test ◽  
New Type ◽  
Amplification Mechanism

Many types of dampers have been developed as seismic technique for architectural buildings, and some of these devices have been applied in Japan. In recent years, these dampers begin to be applied to the low-rise structures having the natural frequency in higher range. However, the deflection of low-rise structures is small, and the performance of damper isn’t obtained against small amplitude vibrations. In this study, the new type of damper which has the displacement amplification mechanism has been developed to solve the above problem. To amplify the displacement by applying the principle of leverage, the damper can achieve good performance even if the deformation transmitted to damper is small. This paper reports on the results obtained from loading test of the proposed damper and the vibration control performance of the proposed damper which was investigated by seismic response analysis.

A Practical Model for Nonlinear Seismic Response Analysis of Jacket Type Fixed Offshore Platforms

2006 ◽  
Author(s):  
Mehrdad Kimiaei ◽  
Ali Akbar Aghakouchak ◽  
Mohsen Ali Shayanfar ◽  
M. Hesham El Naggar
Keyword(s):  
Seismic Response ◽  
Response Analysis ◽  
Winkler Foundation ◽  
Offshore Platforms ◽  
Seismic Response Analysis ◽  
Practical Procedure ◽  
Nonlinear Seismic Response ◽  
Lateral Response ◽  
Proposed Model ◽  
Soil Structures

Offshore platforms in seismically active areas should be designed to survive severe earthquake excitations with no global structural failure. In seismic design of offshore platforms, it is often necessary to perform a dynamic analysis that accounts for nonlinear pile soil structures interaction effects. This paper summarizes an inexpensive and practical procedure compatible with readily available structural analysis software (ANSYS) for estimating the nonlinear lateral response of fixed offshore platforms resting on flexible piles subjected to seismic loading. In the proposed model, piles and jacket members are modeled using BNWF (Beam on Nonlinear Winkler Foundation) and FE (Finite Element) approaches respectively in an integrated model. In this paper, nonlinear seismic response analysis of an existing sample offshore platform has been performed and sensitivity of the results to the model main parameters is investigated.

Nonlinear Seismic Response Analysis of Concrete Perforated Brick Masonry Building

2012 ◽  
Vol 160 ◽  
pp. 87-91
Author(s):  
Wei Jun Yang ◽  
Ming Sheng Duan ◽  
Ming Juan Yin
Keyword(s):  
Seismic Response ◽  
Inflection Point ◽  
Nonlinear Dynamic Analysis ◽  
Linear Interpolation ◽  
Brick Masonry ◽  
Response Analysis ◽  
Force Model ◽  
Masonry Building ◽  
Seismic Response Analysis ◽  
Restoring Force

In order to grasp the seismic performance of the concrete perforated brick masonry building, nonlinear dynamic analysis is used for seismic response analysis of multi-storey building. In the degradation of trainer restoring force model,it is proposed that the yield moment of the inflection point is calculated by linear interpolation, the unloading time of inflection point is calculated by the precise non-iterative, which approach to improve the accuracy and efficiency of nonlinear analysis. Example shows: concrete perforated brick masonry structure in the 7-degree multi-zone can be widely used.

SEISMIC RESPONSE ANALYSIS OF THE BUILDING FOUNDATION BASED ON THE DEFORMATION PERFORMANCE TESTS OF PHC-PILE

1999 ◽  
Vol 5 (9) ◽  
pp. 71-76
Author(s):  
Takao MATSUMURA ◽  
Shinichiro ASANO ◽  
Jun YAMADA ◽  
Masao KOBA ◽  
Koji ITO ◽  
...  
Keyword(s):  
Seismic Response ◽  
Response Analysis ◽  
Performance Tests ◽  
Seismic Response Analysis ◽  
Building Foundation
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