Misalignment effect on stress concentration of thickness mismatched plate structures

Liu, Xuesong; Song, Wenping; Yan, Zhongjie; Wang, Qiang; pan, Haibo

doi:10.1016/j.prostr.2016.06.256

Cited by 6 publications

(3 citation statements)

References 2 publications

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“…The finite element method (FEM) was used to investigate local stress concentrations due to the misalignment of welded structures and determine the effect of geometric variables. The existence of a cope hole was found to influence the peak stress surrounding the transition zone [22]. From all the previous research mentioned above, there has not been a study on the misalignment effect in PCHEs under high-temperature conditions.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Mechanical Integrity Analysis of a Printed Circuit Heat Exchanger with Channel Misalignment

Simanjuntak

Lee

2020

Applied Sciences

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Printed circuit heat exchangers (PCHEs), which are used for thermal heat storage and power generation, are often subject to severe pressure and temperature differences between primary and secondary channels, which causes mechanical integrity problems. PCHE operation may result in discontinuity, such as channel misalignment, due to non-uniform thermal fields in the diffusion bonding process. The present paper analyzes the mechanical integrity, including the utilization factors of stress and deformation under various channel misalignment conditions. The pressure difference of the target PCHE is 19.5 MPa due to the high pressure (19.7 MPa) of the steam channel in the Rankine cycle and the low pressure (0.5 MPa) of molten salt or liquid metal in the primary channel. Additionally, the temperature difference between channels is around 25 °C, however the average temperature is around 500 °C. The PCHE has a relatively large primary channel measuring approximately 3 x 3 mm, and a steam channel measuring 2 x 1.5 mm. The finite element method (FEM) is applied to determine the stress by changing the misalignment to below 30% of the primary channel width. It was found that the current PCHE is operable up to 700 °C in terms of the ASME code under these design conditions. Additionally, the change of utilization factor due to the misalignment increases, but is still under the ASME acceptance criteria of 700 °C; however, it violates the criteria at 725 °C, which is the allowable temperature condition. Therefore, the mechanical integrity of the PCHE with low-pressure molten salt or liquid metal and a high-pressure steam channel is acceptable in terms of utilization factor.

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Section: Boundary Conditionsmentioning

confidence: 99%

Mechanical Integrity Analysis of a Printed Circuit Heat Exchanger with Channel Misalignment

Simanjuntak

Lee

2020

Applied Sciences

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“…A thorough investigation focussing on the detailed effects of weld location in the plate, its length over width ratio and load magnitude by the use of analytical approaches is published in [3]. Further studies incorporating finite element simulation runs focus on more complex assemblies such as panel structures in ships or girth welds for pipelines [4,5].…”

Section: Introductionmentioning

confidence: 99%

Analysis of fatigue notch effect due to axial misalignment for ultra high-strength steel butt joints

et al. 2019

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The majority of fatigue tests of welded specimens is based on shop-made samples generally exhibiting minor misalignment. Due to the challenge of ensuring misalignment-free joints in industrial manufacturing processes, investigations focussing on the effect of misalignment on the fatigue strength are important. Therefore, this paper deals with the influence of axial misalignment on the fatigue resistance of butt-welded ultra high-strength steel specimen. In addition, the effect of high frequency mechanical impact treatment (HFMI) on the fatigue performance is researched. In the course of the experimental investigations, specimens exhibiting three different levels of axial misalignment are manufactured. Fatigue tests at a stress ratio of R = 0.1 in as-welded condition reveal a significant drop in fatigue strength with increasing axial misalignment. Fatigue assessments of the as-welded test results based on nominal, structural and effective notch stress approach are performed taking into account the sampledependent misalignment factor. The given equations enable an improved consideration of axial misalignment regarding to fatigue strength. The HFMI treatment increases the fatigue strength compared with the as-welded state; the detrimental effect of misalignment is less pronounced. A comparison to the current IIW guideline for HFMI treatment reveals a conservative assessment if IIW-recommended FAT values for as-welded condition are applied.

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“…Fazzini et al [21] em seu trabalho sobre avaliação de fadiga nos tubos soldados em formato helicoidal identificaram o problema de desalinhamento entre as soldas interna e externa e as consequências que esse problema pode desencadear sobre a concentração de tensão. Já para Farhat [23] e Liu et al [24], o desalinhamento entre os cordões de solda pode causar redução na resistência a impacto e influência na vida útil de fadiga. Porém, em alguns casos essa falta de alinhamento é considerada aceitável a depender da aplicação [25].…”

Section: Análise De Macrografiaunclassified

Soldagem Helicoidal de Tubos Produzida em Campo do Aço ASTM A-1018 e sua Correlação com Características Mecânicas e Microestruturais das Juntas Soldadas

et al. 2018

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Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution Non-Commercial, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que sem fins comerciais e que o trabalho original seja corretamente citado.Resumo: Um problema diversas vezes encontrado na produção de tubos está relacionado ao seu transporte dificultado por suas grandes dimensões. Atrelado a isso, a soldagem de campo é complexa e muitas vezes onerosa. Um processo de fabricação alternativo para tubulações é o processo de formação de tubos com costura helicoidal. Este trabalho propõe estudar as características microestruturais e realizar uma avaliação mecânica destas soldas executadas em campo do aço ASTM A1018. Para alcançar o objetivo do trabalho foram utilizados dois tubos de aço fabricados com chapas de espessura de 12,5 mm e diâmetro nominal de 1200 mm, através do equipamento adaptado para a soldagem em campo pelo processo de soldagem por arco submerso. Após soldagem dos tubos, foram retiradas amostras destes para efetuar as análises de micrografia, macrografia, composição química, dobramento e dureza. A principal diferença apresentada entre as amostras foi o aumento da ferrita acicular e redução da ferrita primária de contorno de grão com o decréscimo do aporte térmico nas microestruturas formadas tanto na zona fundida como na ZTA como apresentado. Observou-se, ainda, mudanças na geometria dos cordões de solda. Por fim, identificou-se que o principal parâmetro que influência nas mudanças microestruturais apresentadas é a corrente de soldagem. Palavras-chave: Tubos helicoidais; Soldagem por arco submerso; Caracterização microestrutural e mecânica.Abstract: A problem commonly found in the production of tubes is related to transportation due its large dimensions. This fact, makes field welding a complex and often costly operation.. An alternative fabrication process for pipes is the process of forming tubes with helical welds. This work proposes to study the microstructural characteristics and perform a mechanical evaluation of these welds performed in field of ASTM A1018 steel tubes. In order to reach the aim, two steel tubes manufactured from sheets with a thickness of 12.5 mm and a nominal diameter of 1200 mm were welded by the process of submerged arc welding through the equipment adapted for field welding. Subsequently, samples were taken to perform characterization by microanalysis. Chemical composition, bending and hardness tests were also conducted. The main difference between the samples was the increase of the acicular ferrite and reduction of the primary ferrite of the grain boundary with the decrease of the thermal contribution in the microstructures formed in the molten zone as in the ZTA as presented. Also, changes in the geometry of the weld beads were observed. Finally, it was identified that the main parameter that influences the microstructural changes presented is the welding current.

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Misalignment effect on stress concentration of thickness mismatched plate structures

Cited by 6 publications

References 2 publications

Mechanical Integrity Analysis of a Printed Circuit Heat Exchanger with Channel Misalignment

Mechanical Integrity Analysis of a Printed Circuit Heat Exchanger with Channel Misalignment

Analysis of fatigue notch effect due to axial misalignment for ultra high-strength steel butt joints

Soldagem Helicoidal de Tubos Produzida em Campo do Aço ASTM A-1018 e sua Correlação com Características Mecânicas e Microestruturais das Juntas Soldadas

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