Development of the Guideline on Inelastic Analysis for Design

Author(s):  
Yoshihiko Tanaka ◽  
Hiroshi Shibamoto ◽  
Kazuhiko Inoue ◽  
Naoto Kasahara ◽  
Masanori Ando ◽  
...  

The guideline on inelastic analysis for design, one of the key items of Fast Reactor Design Standard (FDS), is being developed. The basic policies of this guideline are as follows: (a) to emphasis conservative analysis output rather than nominal value representing actual behavior, (b) to clarify the applicable area for assurance of conservative results. With such concepts, it would be possible that the guideline provides useful explanations on the manner of analysis and estimation in the form of concrete examples of design as well as general rules (somehow vague). As the first step of the guideline development, the following five issues to be solved were extracted: 1) applicable area, 2) selection of constitutive equation, 3) modeling method of the load history, 4) ratchet strain and creep fatigue damage evaluation methods by inelastic analysis and 5) example design problems to check users’ analysis quality and to complement the general rules. In parallel, inelastic analyses with the promising constitutive equations were applied by way of trial to obtain rough presumption on their effects on structural design of the components. As a result, all inelastic analyses provided smaller cumulative strains and equivalent strain ranges than the existing design method based on elastic analysis, suggesting advantage of introducing them into actual design.

2012 ◽  
Vol 602-604 ◽  
pp. 1818-1821
Author(s):  
Jun Liu ◽  
Cong Dong Ji

Progressive die has been widely used in product manufacturing field. This paper proposed a NX-based computer server support design method. The equivalent stress, resilience, equivalent strain, attenuation, and forming were analyzed in detail. The key technology of confirming blank dimension and stock layout of server support were explicated clearly.


2020 ◽  
Vol 20 (2) ◽  
pp. 229-238 ◽  
Author(s):  
Yonggil Jeong ◽  
Taeuk Kang

In this study, we developed a program for detention pond sizing based on Excel in order to improve user convenience. The program includes a function for the derivation of flood hydrograph that was embodied by using the rational method hydrograph for connecting the design of the stormwater pipe. The design method of a permeable detention pond that is a kind of low impact development (LID) technique was also implemented. In addition, the operation of the program was found to be stable, and various discharge structures such as weir, pump, and pipe could be easily conducted using the engine of the stormwater management model (SWMM). The developed detention pond sizing program was applied to the actual design. Subsequently, similar results were derived by comparing with the actual design, and it was found that the program was appropriate.


2014 ◽  
Vol 945-949 ◽  
pp. 306-309
Author(s):  
Ting Jian Dong ◽  
Jin Chen ◽  
Hua Peng Ding

Against the sticking patch design problems of pass damage of aircraft skin repair, by using the calculation method of mechanical analysis, the stress analysis of pass damage is completed. The calculation methods are used quantitatively to determine the sticking patch dimension of pass damage repair, which is compared with analysis sticking patch design method calculated by the repair empirical equation of aircraft skin of Airline Company. The reason of error is analyzed and the measure to correct empirical equation method is put forward. The optimization of the critical parameters of pass damage empirical equation is completed.


Author(s):  
S W Kim ◽  
J S Park

An optimum design methodology is presented for point-to-point motion control servo systems in which d.c. permanent magnetic motors are used as the main actuators. Emphasis is focused on establishing a series of comprehensive decision-making practices in dealing with three major design subjects: determination of the velocity profile, optimization of the speed reduction ratio, and selection of the motor. Finally, a practical design example is discussed to illustrate how the suggested design methodology may be applied to actual design problems.


2021 ◽  
Author(s):  
M. C. Messner ◽  
T.-L. Sham

Abstract The rules for the design of high temperature reactor components in Section III, Division 5, Subsection HB, Subpart B (HBB) of the ASME Boiler and Pressure Vessel Code contain two options for evaluating the deformation-controlled design limits on strain accumulation and creep-fatigue: design by elastic analysis and design by inelastic analysis. Of these options design by inelastic analysis tends to be less overconservative and produce more efficient designs. However, the HBB currently does not provide approved material models for use with the inelastic analysis rules, limiting their widespread use. A nonmandatory appendix has been developed to provide general guidance on appropriate material models and provide reference material models suitable for use with the design by inelastic analysis approach. This paper describes a viscoplastic model for Alloy 617 suitable for use with the HBB rules proposed for incorporation into the new appendix. The model represents the high temperature creep, creep-fatigue, and tensile response of Alloy 617 and accurately accounts for rate sensitivity across a wide range of temperatures. The focus in developing the model was on capturing key features of material deformation required for accurately executing the HBB rules and on developing a relatively simple model form that can be implemented in commercial finite element analysis software. The paper validates the model against an extensive experimental database collected as part of the Alloy 617 Code qualification effort as well as against specialized experimental tests examining the effect of elastic follow up on stress relaxation and creep deformation in the material.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Ricardo Duarte ◽  
Jean-Pierre Nadeau ◽  
Antonio Ramos ◽  
Michel Mesnard

The orthosis is considered a class 1 medical device which often originates from a nonstructured development process. As these devices are mainly developed by small- and medium-sized enterprises, with no standard research method, the result can be an unadapted device which may not respond to the user’s needs and which in the short term may be abandoned. One way to solve this problem is to define and apply standard rules and procedures throughout the development/design process. Although methodologies may solve the “empiricism” in orthosis design problems, these design strategies are not applied during orthosis development due to the particularities of this field and the difficulties in linking the required knowledge and the actors that may be present during the orthosis development. The objective of this work is to develop a methodology to structure the orthosis design process that takes into account both the device life cycle and the different stakeholders involved in the design process. A case study was used to validate the proposed methodology. It was applied to the development of an orthosis to treat a specific postural disorder called camptocormia, also known as bent spine syndrome. This disorder is characterized by the anteroflexion of the trunk and especially affects elderly people. Contrary to scoliosis, the characteristics of camptocormia are not permanent, which means that the patient is able to straighten his posture. A postural brace is used to treat this disorder which enables the patient to redress and maintain the correct upright posture of the trunk.


Author(s):  
Sho Ikeda ◽  
Masakazu Sato ◽  
Naoto Kasahara

Fast Breeder Reactors and chemical plants that is operated at elevated temperature must be designed considering creep deformation in addition to elastic-plastic deformation. Especially at structural discontinuities, strain concentration induced by stress-strain redistribution reduces creep-fatigue strength. For this reason, a design method is needed for appropriately evaluating inelastic behavior at a structural discontinuity. As one of simplified methods with elastic analysis, a rational method with Stress Redistribution Locus (SRL) has been studied during recent years. Previous studies have shown that SRL does not depend on constitutive equations or on the magnitude of loading. And through the elastic-plastic-creep analysis of a one-dimensional pipe model, it was revealed that there was a relation between stress-strain redistribution and the size of elastic core. The purpose of this study is to clarify the mechanism of stress-strain redistribution in complex structures like actual components. Multi-dimensional stress-strain distribution and multiaxial stress occur in those structures. For considering those effects, inelastic analyses on perforated plate were performed and the relation between the region of elastic cores and SRL was examined. Then, it was revealed that SRL could be divided into two parts. One half is affected by the region of elastic core and the other half depends on the loading type. Furthermore, this paper proposes the new SRL method based on the mechanism and validates the method.


Author(s):  
Wen Wang ◽  
Xiaochun Zhang ◽  
Xiaoyan Wang ◽  
Maoyuan Cai

Abstract The structural integrity of reactor components is very essential for the reliable operation of all types of power plants, especially for components operating at elevated temperature where creep effects are significant and where components are subjected to high-temperature alteration and seismic transient loading conditions. In this article, a molten salt storage tank in high temperature thorium molten salt reactor (TMSR) is evaluated according to ASME-III-5-HBB high temperature reactor code. The evaluation based on 3D finite element analyses includes the load-controlled stress, the effects of ratcheting, and the interaction of creep and fatigue. The thermal and structural analysis and the application procedures of ASME-HBB rules are described in detail. Some structural modifications have been made on this molten salt storage tank to enhance the strength and reduce thermal stress. The effects of ratcheting and creep-fatigue damage under elevated temperature are investigated using elastic analysis and inelastic analysis methods for a defined representative load cycle. In addition, the strain range and the stress relaxation history calculated by elastic and inelastic methods are compared and discussed. The numerical results indicate that the elastic analysis is conservative for design and a full inelastic analysis method for estimating input for creep-fatigue damage evaluation need to be developed.


Author(s):  
Heramb P. Mahajan ◽  
Tasnim Hassan

Abstract Current ASME Section III, Division 5 code provides elastic, simplified inelastic and inelastic analysis options for designing nuclear power plant components for elevated temperature service. These analyses methods may fail to capture the complex creep-fatigue response and damage accumulation in materials at elevated temperatures. Hence, for analysis and design of the nuclear power plant components at elevated temperature, a full inelastic analysis that can simulate creep-fatigue responses may be needed. Existing ASME code neither provides guidelines for using full inelastic analysis nor recommends the type of constitutive model to be used. Hence, a unified rate-dependent constitutive model incorporating a damage parameter will be developed, and its parameters for base metal will be determined. In addition, a full inelastic analysis methodology using this model to analyze the creep-fatigue performance of components for nuclear power applications will be developed. Base metal 800H (BM800H) data are collected from literature to determine constitutive material model parameters. The parameter determination methodology for a constitutive model is discussed. The optimized parameter set for BM 800H at different temperatures will be presented in the paper. Recommendations are provided on the constitutive model selection and its parameter determination techniques. In the future, this work will be continued for diffusion bonded Alloy 800H (DB800H) material, and obtained parameters will be compared.


Author(s):  
Tomoyoshi Watakabe ◽  
Masaki Morishita

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.


Sign in / Sign up

Export Citation Format

Share Document