Subsection NH—Class 1 Components in Elevated Temperature Service

2009 ◽  
pp. 409-445 ◽  
Keyword(s):  
Elevated Temperature ◽  
Class 1

Fire buckling curves for torsionally sensitive steel members subjected to axial compression

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Luca Possidente ◽  
Nicola Tondini ◽  
Jean-Marc Battini
Keyword(s):  
Elevated Temperature ◽  
Practical Interest ◽  
Statistical Investigation ◽  
Truss Structures ◽  
Design Standards ◽  
Torsional Buckling ◽  
Content Type ◽  
Steel Members ◽  
Class 1 ◽  
Flexural Torsional Buckling

PurposeBuckling should be carefully considered in steel assemblies with members subjected to compressive stresses, such as bracing systems and truss structures, in which angles and built-up steel sections are widely employed. These type of steel members are affected by torsional and flexural-torsional buckling, but the European (EN 1993-1-2) and the American (AISC 360-16) design norms do not explicitly treat these phenomena in fire situation. In this work, improved buckling curves based on the EN 1993-1-2 were extended by exploiting a previous work of the authors. Moreover, new buckling curves of AISC 360-16 were proposed.Design/methodology/approachThe buckling curves provided in the norms and the proposed ones were compared with the results of numerical investigation. Compressed angles, tee and cruciform steel members at elevated temperature were studied. More than 41,000 GMNIA analyses were performed on profiles with different lengths with sections of class 1 to 3, and they were subjected to five uniform temperature distributions (400–800 C) and with three steel grades (S235, S275, S355).FindingsIt was observed that the actual buckling curves provide unconservative or overconservative predictions for various range of slenderness of practical interest. The proposed curves allow for safer and more accurate predictions, as confirmed by statistical investigation.Originality/valueThis paper provides new design buckling curves for torsional and flexural-torsional buckling at elevated temperature since there is a lack of studies in the field and the design standards do not appropriately consider these phenomena.

Development of a Program for High-Temperature Design Analysis and Defect Assessment According to RCC-MRx

2018 ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Min-Gu Won ◽  
Nam-Su Huh ◽  
Woo-Gon Kim
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Personal Computer ◽  
Heat Exchangers ◽  
Fusion Reactor ◽  
Design Analysis ◽  
Design Evaluation ◽  
Web Based ◽  
Defect Assessment ◽  
Class 1

A program for a high-temperature design analysis and defect assessment has been developed for an elevated temperature evaluation according to the RCC-MRx for Generation IV and fusion reactor systems. The program, called ‘HITEP_RCC-MRx,’ consists of three modules: ‘HITEP_RCC-DBA,’ which computerizes the design-by-analysis (DBA) for class 1 components such as the pressure vessel and heat exchangers according to RB-3200 procedures, ‘HITEP_RCC-PIPE,’ which computerizes the design-by-rule (DBR) analysis for class 1 piping according to RB-3600 procedures and ‘HITEP_RCC-A16,’ which computerizes high-temperature defect assessment according to the A16 procedures. It is a web-based program, and thus can operate on a smartphone as well as on a personal computer once it is connected to the URL. The program has been verified with a number of relevant example problems on DBA, Pipe, and A16. It was shown from the verification works that HITEP_RCC-MRx with the three modules conducts a design evaluation and a defect assessment in an efficient and reliable way.

HITEP_RCC-MRx Program for the Support of Elevated Temperature Design Evaluation and Defect Assessment

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Min-Gu Won ◽  
Nam-Su Huh
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Design Evaluation ◽  
Piping System ◽  
Software Platform ◽  
Defect Assessment ◽  
Class 1 ◽  
Nuclear Component ◽  
Elevated Temperature Design ◽  
Integrated Software

An integrated software platform of high-temperature design evaluation and defect assessment for a nuclear component and piping system subjected to high-temperature operation in creep regime has been developed. The program, called “HITEP_RCC-MRx,” is based on French nuclear grade high-temperature design code of RCC-MRx and enables a designer to conduct not only elevated temperature design evaluation but also elevated temperature defect assessment. HITEP_RCC-MRx consists of three modules: “HITEP_RCC-DBA,” which is programmed for the design-by-analysis (DBA) evaluation for class 1 pressure boundary components such as the pressure vessel and heat exchangers according to the RB-3200 procedures; “HITEP_RCC-PIPE,” which is programmed for the design-by-rule (DBR) evaluation according to the RB-3600 procedures; and “HITEP_RCC-A16,” which is programmed for high-temperature defect assessment according to the A16 procedures. The program has been verified with a number of related example problems on modules of DBA, Pipe, and A16. It was shown from the verification examples that integrated software platform of HITEP_RCC-MRx is capable of conducting three functions of an elevated temperature design evaluation for pressure boundary components and for piping, and an elevated defect assessment in an efficient and reliable way.

Allowable Stress Criteria Based on the Onset of Third Stage Creep: An Historical Perspective

2015 ◽  
Author(s):  
Robert Jetter ◽  
J. E. Nestell ◽  
Mainak Sengupta
Keyword(s):  
Elevated Temperature ◽  
Task Force ◽  
Position Paper ◽  
Material Behavior ◽  
Allowable Stress ◽  
Current Time ◽  
Stress Criterion ◽  
Third Stage ◽  
Class 1 ◽  
Term Creep

This paper documents the basis for the current time dependent allowable stress criterion based on onset of third stage creep. The criterion is one of three that are used to develop allowable stresses for elevated temperature, Class 1, nuclear components*. The recommendation to consider third stage creep is part of a 1970 position paper prepared by one of the authors for the Task Force on Material Behavior of the Subgroup on Elevated Temperature Design. The position paper recommended that allowable stress/strain limits be set to preclude operation in third stage creep. This was based on the difficulty (at the time) of predicting the effects of multiaxial stresses on creep behavior and the possibility of through-wall cracks appearing before rupture. The principal references supporting this recommendation reported experimental results in which pressurized tubes failed almost exclusively before the onset of third stage creep. Also included are the reported results from a 1993 long term creep and rupture test of a nozzle-to-sphere model in which failure was also by small pinhole leaks prior to observed onset of third stage creep. In addition to excerpts from the above references, commentary from a current perspective is also provided.

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