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.

Verification of a Finite Element Analysis Procedure for Modeling the Nonlinear, Monotonic In-Plane Behavior of 4 Inch, Schedule 10, Stainless Steel, 90° Elbows

2003 ◽  
Author(s):  
James K. Wilkins
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Nonlinear Behavior ◽  
Shell Element ◽  
Analysis Procedure ◽  
Hoop Strain ◽  
Element Analysis ◽  
Butt Welding ◽  
Strain Data

A project has been conducted to verify a finite element analysis procedure for studying the nonlinear behavior of 90°, stainless steel, 4 inch schedule 10, butt welding elbows. Two displacement controlled monotonic in-plane tests were conducted, one closing and one opening, and the loads, displacements, and strains at several locations were recorded. Stacked 90° tee rosette gages were used in both tests because of their ability to measure strain over a small area. ANSYS shell element 181 was used in the FEA reconciliations. The FEA models incorporated detailed geometric measurements of the specimens, including the welds, and material stress-strain data obtained from the attached straight piping. Initially, a mesh consisting of sixteen elements arrayed in 8 rings was used to analyze the elbow. The load-displacement correlation was quite good using this mesh, but the strain reconciliation was not. Analysis of the FEA results indicated that the axial and hoop strain gradients across the mid-section of the elbow were very high. In order to generate better strain correlations, the elbow mesh was refined in the mid-section of the elbow to include 48 elements per ring and an additional six rings, effectively increasing the element density by nine times. Using the refined mesh produced much better correlations with the strain data.

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.

Evaluation of Stiffness and Stress of External Fixators with Curved Acrylic Connecting Bars

2000 ◽  
Vol 13 (02) ◽  
pp. 65-72 ◽  
Author(s):  
R. Shahar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Axial Compression ◽  
External Fixator ◽  
External Fixators ◽  
Analysis Method ◽  
Lateral Bending ◽  
Element Analysis ◽  
The Finite Element Analysis

SummaryThe use of acrylic connecting bars in external fixators has become widespread in veterinary orthopaedics. One of the main advantages of an acrylic connecting bar is the ability to contour it into a curved shape. This allows the surgeon to place the transcortical pins according to safety and convenience considerations, without being bound by the requirement of the standard stainless steel connecting bar, that all transcortical pins be in the same plane.The purpose of this study was to evaluate the stiffness of unilateral and bilateral medium-sized external fixator frames with different curvatures of acrylic connecting bars. Finite element analysis was used to model the various frames and obtain their stiffness under four types of load: Axial compression, four-point medio-lateral bending, fourpoint antero-posterior bending and torsion. The analysis also provided the maximal pin stresses occurring in each frame for each loading condition.Based on the results of this study, curvatures of acrylic connecting bars of up to a maximal angular difference between pins of 25° will result in very similar stiffness and maximal pin stresses to those of the equivalent, uniplanar stainless steel system. In both unilateral and bilateral systems the stiffness decreases slightly as angulation increases for axial compression and medio-lateral bending, increases slightly for torsion and increases substantially for antero-posterior bending.External fixator systems with curved acrylic connecting bars are commonly used in veterinary orthopaedics. This paper evaluates the biomechanical performance of such systems by applying the finite element analysis method. It shows that external fixators with curved acrylic connecting bars exhibit stiffness and maximal pin stresses which are similar to those of the standard stainless steel system.

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.

Analysis and Control of Maglev Flywheel Rotor in the Wind Generator

2012 ◽  
Vol 608-609 ◽  
pp. 513-516
Author(s):  
Hua Chun Wu ◽  
Xu Jun Lv ◽  
Gao Gong
Keyword(s):  
Reduction Method ◽  
Response Analysis ◽  
Analysis Method ◽  
Element Analysis ◽  
Lqr Control ◽  
Finite Element Analysis Method ◽  
Wind Generator ◽  
Simulation Results ◽  
And Control ◽  
Flywheel Rotor

The application of maglev flywheel in wind generator is investigated. The dynamics analysis of maglev flywheel rotor has been performed including the critical speed analysis and unbalance response analysis, which took into account the gyroscopic effect by using of finite element analysis method. Based on the model reduction method, the modeling and LQR control of maglev flywheel rotor is presented, the simulation results show stable levitation and good levitated rotation.

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.

Analysis on Aseismic Performance of the Beijing Yintai Center

2010 ◽  
Vol 163-167 ◽  
pp. 3872-3877
Author(s):  
Zhi Qiang Zhang ◽  
Ai Qun Li ◽  
Yong Sun ◽  
Meng Ya Huang
Keyword(s):  
Seismic Behavior ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Response Analysis ◽  
Analysis Method ◽  
Element Analysis ◽  
Plastic Analysis ◽  
Earthquake Action ◽  
Rare Earthquake ◽  
Three Dimensional Finite Element

In this study, the seismic behavior of the main tower building of Beijing Yintai Center is presented with regard to the dynamic characteristics analysis and seismic response analysis. Firstly, by means of three-dimensional finite element analysis software, the dynamic properties and seismic responses under frequent earthquake action of the structure are obtained, respectively. It can be seen that the structure has a rational arrangement for structural elements and has a good seismic behavior. Then, the seismic behavior of the structure is studied through the dynamic elasto-plastic analysis method and static elasto-plastic analysis method under rare earthquake. Analysis results of both analysis methods show that the behavior of the structure accords with the earthquake performance objectives and the structure would not collapse under the rare earthquake action.

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.

Study on Acoustic System Designing of Two Dimensional Ultrasonic Polishing without Abrasives

2010 ◽  
Vol 455 ◽  
pp. 283-287
Author(s):  
Chuan Shao Liu ◽  
Jian Xin Zheng ◽  
Y.F. Liu
Keyword(s):  
Modal Analysis ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Response Analysis ◽  
Two Dimensional ◽  
Acoustic System ◽  
Analysis Method ◽  
Element Analysis ◽  
Harmonic Response Analysis ◽  
Aided Design

Acoustic system is the core component of power ultrasonic, which is designed by traditional analytic method and modal analysis with finite element analysis method. And component of the step-like horn with rectangular sections and tool head used in two dimension ultrasonic polishing without abrasives are studied, and the calculating results and modal analysis results are consistent on the whole. The harmonic response analysis for the component of horn and tool head is carried out and the three dimensional coordinates of the vibrating node on the tool head with maximal displacement are obtained. The fitting result shows that the moving trajectory of such node is ellipses, which meets the experimental requirement well. So a new way for designing acoustic system of two dimensional ultrasonic vibration through combining theoretical calculation with computer aided design may be applied.

Method for Predicting Mixing Tee Thermal Fatigue in Carbon Steel Based on Austenitic Stainless Steel Operating Experience

2009 ◽  
Author(s):  
Robert O. McGill ◽  
David O. Harris ◽  
Ken Wolfe
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Austenitic Stainless Steel ◽  
Thermal Fatigue ◽  
Operating Experience ◽  
The United States ◽  
Pressurized Water ◽  
Short Period ◽  
Water Reactors ◽  
Steel Piping

Over the past ten years, a significant amount of research has been conducted regarding mixing tee thermal fatigue in pressurized water reactors prompted by the leakage event at Civaux Unit 1 in 1998. The plant experienced a leak in the reactor residual heat removal system piping after a short period of operation during plant start-up. An evaluation as to the cause of the leakage concluded that mixing of hot and cold fluid upstream from the failed austenitic stainless steel elbow resulted in thermal fatigue cracking. Recently, an assessment of susceptibility to this thermal fatigue mechanism in boiling water reactors in the United States was completed. The piping systems in these reactors where the potential for thermal mixing exists are predominantly constructed of carbon steel. Thus, an analytical model was developed for predicting mixing tee thermal fatigue in carbon steel piping based on the austenitic stainless steel piping operating experience at Civaux. This paper describes how the model was developed and presents some general findings.

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