Seismic Qualification of Piping Systems by Detailed Inelastic Response Analysis: Part 1 — A Code Case for Piping Seismic Evaluation Based on Detailed Inelastic Response Analysis

2017 ◽  
Author(s):  
Masaki Morishita ◽  
Akihito Otani ◽  
Tomoyoshi Watakabe ◽  
Izumi Nakamura ◽  
Tadahiro Shibutani ◽  
...  
Keyword(s):  
Strain Amplitude ◽  
Seismic Design ◽  
Equivalent Strain ◽  
Design Rule ◽  
Design Evaluation ◽  
Response Analysis ◽  
Inelastic Response ◽  
Inelastic Analysis ◽  
Piping Systems ◽  
Equivalent Strain Amplitude

A Code Case in the framework of the Nuclear Codes and Standards of Japan Society of Mechanical Engineers (JSME) is currently under development to incorporate seismic design evaluation methodologies for piping systems by detailed inelastic response analysis and strain-based fatigue criteria as an alternative design rule to the current rule, in order to provide a more rational seismic design evaluation by taking directly the response reduction due to plasticity energy absorption into account. The Code Case provides two strain-based criteria; one is a limit to maximum amplitude of equivalent strain amplitude derived from detailed analysis and the other is a limit to the fatigue usage factor also based on the equivalent strain amplitude. The Code Case also provides an evaluation method by simplified inelastic analysis with an additional damping taking the response reduction due to plasticity into account. Some discussions are provided on the adequacy of additional damping in the simplified inelastic analysis and the safety margin and reliability of fatigue evaluation by the detailed inelastic response analysis provided in the Code Case.

A JSME Code Case on Piping Seismic Design Based on Inelastic Response Analysis and Strain-Based Fatigue Criteria

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Masaki Morishita ◽  
Akihito Otani ◽  
Izumi Nakamura ◽  
Tomoyoshi Watakabe ◽  
Tadahiro Shibutani ◽  
...  
Keyword(s):  
Strain Amplitude ◽  
Seismic Design ◽  
Safety Margin ◽  
Equivalent Strain ◽  
Design Rule ◽  
Design Evaluation ◽  
Response Analysis ◽  
Inelastic Response ◽  
Inelastic Analysis ◽  
Equivalent Strain Amplitude

Abstract A Code Case in the framework of the Nuclear Codes and Standards of Japan Society of Mechanical Engineers (JSME) has been published to incorporate seismic design evaluation methodologies for piping systems by detailed inelastic response analysis and strain-based fatigue criteria as an alternative design rule to the current rule, in order to provide a more rational seismic design evaluation by taking directly the response reduction due to plasticity energy absorption into account. The Code Case provides two strain-based criteria: one is a limit to maximum amplitude of equivalent strain amplitude derived from detailed analysis and the other is a limit to the fatigue usage factor also based on the equivalent strain amplitude. Some discussions are provided on the adequacy of additional damping in the simplified inelastic analysis and the safety margin and reliability of fatigue evaluation by the detailed inelastic response analysis provided in the Code Case.

Seismic Qualification of Piping System by Detailed Inelastic Response Analysis: Part 2 — A Guideline for Piping Seismic Inelastic Response Analysis

2017 ◽  
Author(s):  
Akihito Otani ◽  
Tadahiro Shibutani ◽  
Masaki Morishita ◽  
Izumi Nakamura ◽  
Tomoyoshi Watakabe ◽  
...  
Keyword(s):  
Strain Amplitude ◽  
Seismic Design ◽  
Seismic Analysis ◽  
Equivalent Strain ◽  
Design Rule ◽  
Design Evaluation ◽  
Response Analysis ◽  
Piping System ◽  
Inelastic Response ◽  
Equivalent Strain Amplitude

A Code Case in the framework of JSME Nuclear Codes and Standards is currently being developed to incorporate seismic design evaluation of piping by detailed elastic-plastic response analysis and strain-based fatigue criteria as an alternative design rule to the current rule, in order to provide a more rational seismic design evaluation. The Code Case provides two strain-based criteria; one is a limit to maximum amplitude of equivalent strain amplitude derived from detailed analysis and the other is a limit to the fatigue usage factor also based on the equivalent strain amplitude. A guideline for piping seismic analysis based on inelastic response analysis is also being developed as a mandatory appendix for the code case. The guideline provides the methodology to obtain the elastic and plastic strains in seismic response and contains descriptions for analysis code, FE modeling including material property definition, time history analysis method, damping, seismic input condition and verification and validation method. This paper introduces the outlines of them.

Application of JSME Seismic Code Case by Elastic-Plastic Response Analysis to Practical Piping System

2018 ◽  
Author(s):  
Akihito Otani ◽  
Satoru Kai ◽  
Naoaki Kaneko ◽  
Tomoyoshi Watakabe ◽  
Masanori Ando ◽  
...  
Keyword(s):  
Seismic Design ◽  
Evaluation Methodology ◽  
Design Rule ◽  
Design Evaluation ◽  
Response Analysis ◽  
Piping System ◽  
Plastic Response ◽  
Seismic Code ◽  
Elastic Plastic ◽  
Piping Systems

A Code Case in the framework of JSME Nuclear Codes and Standards is being developed to incorporate a seismic design evaluation methodology for piping by means of advanced elastic-plastic response analysis methods and strain-based fatigue criteria. The Code Case as an alternative seismic design rule over the current rule will provide a more rational seismic design evaluation than the current criteria. This paper demonstrates an application result of the JSME Seismic Code Case to an actual complex piping system. The secondary coolant piping system of Japanese Fast Breeder Reactor, Monju, was selected as a representative of the complex piping systems. The elastic-plastic time history analysis for the piping system was performed and the piping system has been evaluated according to the JSME Seismic Code Case. The evaluation by the Code Case provides a reasonable result in terms of the piping fatigue evaluation that governs seismic integrity of piping systems. Moreover, it is found that the supporting forces and the response accelerations of the piping system obtained by the elastic-plastic response analysis also become more rational results than those with the current elastic response analysis. The contradiction of two requirements in piping design, flexibility for thermal expansion and rigidity for seismic response, can be effectively relaxed by use of the Code Case being developed.

Seismic Qualification of Piping Systems by Detailed Inelastic Response Analysis: Part 3 — Variation in Elastic-Plastic Analysis Results on Carbon Steel Pipes From the Benchmark Analyses and the Parametric Analysis

2017 ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Morishita ◽  
Masaki Shiratori ◽  
Tomoyoshi Watakabe ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Evaluation Procedure ◽  
Response Analysis ◽  
Seismic Load ◽  
Inelastic Response ◽  
Elastic Plastic ◽  
Analytical Results ◽  
Plastic Analysis ◽  
Piping Systems ◽  
Parametric Analyses

It is recognized that piping systems used in nuclear power plants have a significant amount of the safety margin, up to the point of boundary failure, even when the input seismic load exceeds the allowable design level. The reason is attributed to the large strength capacity of the piping systems in the plastic region. In order to establish an evaluation procedure, in which the inelastic behavior of piping systems is considered in a rational way, a task group activity under the Japan Society of Mechanical Engineers (JSME) has been conducted. As a deliverable of this activity, a Code Case in the framework of the JSME Nuclear Codes and Standards is now being developed. The Code Case provides the strain-based criteria, an evaluation procedure using the response-spectrum based inelastic analysis, and detailed inelastic response analysis based on a finite element model. For developing the Code Case, inelastic benchmark and parametric analyses of the tests of a pipe element and piping system made of carbon steel were conducted to investigate the variation of the elastic-plastic analyses results. Based on these analytical results, it is assumed that setting the yield stress has a significant influence on the inelastic analytical results, while the work hardening modulus in the bi-linear approximation of the stress-strain curve has little influence. From the results of the parametric analyses, it is confirmed that the variation in the analytical results among the analysts would be reduced by having a unifying analysis procedure. In this paper, the results of the parametric analyses and the variation in the elastic-plastic analysis are discussed.

Appropriate Damping on Seismic Design Analysis for Inelastic Response Assessment of Piping

2018 ◽  
Author(s):  
Tomoyoshi Watakabe ◽  
Masaki Morishita
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Response Spectrum ◽  
Response Assessment ◽  
Design Analysis ◽  
Stress Factors ◽  
Design Rule ◽  
Inelastic Analysis ◽  
Current Design ◽  
Seismic Design Method

The current seismic design rule on piping assumes elastic analysis without the effect of response reduction due to plasticity, although some degree of plasticity is allowed in its allowable limits. Damping for the seismic design analysis is conservatively determined depending on the number of supports and thermal insulation conditions. These conservative assumptions lead to large amount of design margin. Based on such recognition, to provide a more rational seismic design method, a new Code Case for seismic design of piping is now under development in the framework of JSME Nuclear Codes and Standards as an alternative rule to the current design rule. The Code Case provides detailed inelastic analysis with using shell or solid FEA models as a more rational method. Simplified analysis with an additional damping taking the response reduction due to plasticity into account is now under consideration to incorporate the convenience in design. In this study, a series of analysis was made to see the adequacy of the simplified inelastic analysis. Design margins contained in the current design analysis method composed of response spectrum analysis and stress factors was quantitatively assessed in the view point of additional damping.

Method for Estimating Maximum Response for Seismic Design of Multiple Supported Elastic-Plastic Piping Systems

2015 ◽  
Author(s):  
Akira Sone ◽  
Tomoyuki Matsuda ◽  
Arata Masuda
Keyword(s):  
Nonlinear System ◽  
Seismic Design ◽  
Maximum Response ◽  
Response Analysis ◽  
Simple Method ◽  
Plastic Characteristic ◽  
Nonlinear Properties ◽  
Input System ◽  
Piping Systems ◽  
The One

This study describes a simple method to estimate the maximum response in the seismic response analysis of multi-input nonlinear system. There are many studies on the response analysis of a system having nonlinear properties, such as elasto-plastic characteristic, but they are intended for the one input system because they cannot be applied to multi-input system. On the other hand, a simple method for estimating the multi-input response analysis can also be proposed, which is applied to a linear system, but they cannot be applied to a nonlinear system. However, the importance of seismic design in consideration of both nonlinear and multi-input problems has been increasing in recent years. Therefore, we propose a simple method for estimating the maximum response of multi-input system with elasto-plastic characteristic in the present study.

P075 Response Analysis for Seismic Design of Multiple Supported Elastic-Plastic Piping Systems

2016 ◽  
Vol 2016.91 (0) ◽  
pp. 448
Author(s):  
Takuya SHIOMI ◽  
Tomoyuki MATSUDA ◽  
Ranma OKAZAKI ◽  
Nanako MIURA ◽  
Akira SONE
Keyword(s):  
Seismic Design ◽  
Response Analysis ◽  
Elastic Plastic ◽  
Piping Systems

Dislocation Structures of Duplex Stainless Steel in Uniaxial and Biaxial Cyclic Loading

2005 ◽  
Vol 482 ◽  
pp. 179-182 ◽  
Author(s):  
Martin Petrenec ◽  
Veronique Aubin ◽  
Jaroslav Polák ◽  
Suzanne Degallaix
Keyword(s):  
Stainless Steel ◽  
Stress Response ◽  
Cyclic Loading ◽  
Slip System ◽  
Duplex Stainless Steel ◽  
Strain Amplitude ◽  
Equivalent Strain ◽  
Wall Structures ◽  
Equivalent Strain Amplitude

Austenitic-ferritic duplex stainless steel has been subjected to uniaxial and biaxial nonproportional cyclic loading with the same equivalent strain amplitude. The dislocation structures in specimens fatigued to fracture using both types of loadings were studied and compared. Uniaxial cyclic loading, both in austenitic and in ferritic grains, produces simple structures due to activation of predominantly one slip system. Non-proportional cyclic loading results in formation of cell and wall structures and thus in higher stress response of the material.

Seismic Qualification of Piping Systems by Detailed Inelastic Response Analysis: Part 4 — Second Round Benchmark Analyses With Stainless Steel Piping Component Test

2017 ◽  
Author(s):  
Tomoyoshi Watakabe ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Morishita ◽  
Tadahiro Shibutani ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Seismic Design ◽  
Analysis Procedure ◽  
Response Analysis ◽  
Analysis Method ◽  
Element Analysis ◽  
Inelastic Response ◽  
Current Design ◽  
Steel Piping

Some studies concerning ultimate strength of piping under seismic loads concluded that there is a large design margin until failure, even if the stress calculated based on the current design method does not satisfy design criteria. To provide a more rational seismic design, a new Code Case for seismic design of piping is now under development in the framework of JSME Nuclear Codes and Standards. The Code Case incorporates a dynamic elastic-plastic analysis procedure by employing finite element analysis as an alternative to the current design analysis method of elastic assumption. To confirm the applicability of inelastic response analysis, benchmark analyses have been conducted. In the first round benchmark, a carbon steel elbow analysis was performed. In this report, a second round benchmark with a stainless steel elbow and tee is introduced. The second benchmark aims to establish an analysis procedure for stainless steel piping and tee piping of complicated shapes. The second benchmark results provided a practical analysis method for stainless steel piping, and the Code Case was expanded so that it could be applied not only to carbon steel piping but also to stainless steel piping. The second benchmark also challenged analyses of a tee having complicated geometry. These results provide some important knowledge, and they will be included in the Code Case.

Nuclear Fatigue Analysis Codified Design Rules: Comparison of Cyclic Plasticity Effects

2015 ◽  
Author(s):  
Claude Faidy ◽  
Andrew Wasylyk
Keyword(s):  
Strain Amplitude ◽  
Task Force ◽  
Cyclic Plasticity ◽  
Elastic Plastic ◽  
Inelastic Analysis ◽  
Code Comparison ◽  
Life Evaluation ◽  
Piping Systems ◽  
Fatigue Life Evaluation ◽  
Nuclear Association

Large uncertainties exist in fatigue life evaluation using existing elastic stress analysis. The usage factor is obtained by comparison of strain amplitude evaluation on different points of the components and the fatigue S-N curve of the material. This paper will review existing codified rules in major nuclear Codes that are proposed as simplified elastic-plastic analysis of strain amplitude. The different formulas proposed by the different Codes are described with their own background document and compared on typical cases. Methods are based on simplified elastic-plastic approach (elastic analysis plus correction factor) with associated material data. The Code comparison includes nuclear Codes, as ASME Boiler and Pressure Vessel Code Section III, French RCC-M and RCC-MRx and German KTA; Russian PNAEG Code and JSME rules are also considered based on specific English version of the Codes for fatigue rules. Two types of components are concerned by the comparison: vessels and piping systems. All these Codes are proposing different Ke and Kv rules based on different assumption. Finally, a first set of recommendation to perform reference inelastic analysis will be presented to improve existing codes on an harmonized way, associated to analytical recommendations, all material properties needed and criteria to apply this modern methods. This review is mainly done in World Nuclear Association (WNA), Cooperation in Reactor Design Evaluation and Licensing (CORDEL) Working Group, Codes & Standards Task Force.

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