Ratcheting assessment of AISI 316L stainless steel welded pipe joint
Thesis (Ph.D (Mechanical Engineering))
| Главный автор: | |
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| Формат: | Диссертация |
| Язык: | English |
| Опубликовано: |
Universiti Teknologi Malaysia
2023
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| Предметы: | |
| Online-ссылка: | http://openscience.utm.my/handle/123456789/221 |
| _version_ | 1825623363307962368 |
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| author | Moslemi, Navid |
| author_facet | Moslemi, Navid |
| author_sort | Moslemi, Navid |
| collection | OpenScience |
| description | Thesis (Ph.D (Mechanical Engineering)) |
| first_indexed | 2024-03-05T17:33:31Z |
| format | Thesis |
| id | oai:openscience.utm.my:123456789/221 |
| institution | Universiti Teknologi Malaysia - OpenScience |
| language | English |
| last_indexed | 2024-03-05T17:33:31Z |
| publishDate | 2023 |
| publisher | Universiti Teknologi Malaysia |
| record_format | dspace |
| spelling | oai:openscience.utm.my:123456789/2212023-04-18T16:00:27Z Ratcheting assessment of AISI 316L stainless steel welded pipe joint Moslemi, Navid Pipelines—Welding Thesis (Ph.D (Mechanical Engineering)) Welded pipes are extensively used in engineering piping networks. Ratcheting damage has not been accurately predicted theoretically and by numerical simulation, hence they were insufficient understanding on ratcheting responses in the presence of the welding process effects. This deficiency of the design method may be the reason for many unexpected fatigue failures. The main objective of these experimental and numerical studies is to assess the influence of welding effects on the ratcheting behavior of AISI 316L stainless steel welded pipe joints. The welding effects that are of interest were welding residual stress and weld geometry and hardening effect. Two major phases of work were taken to reach the final understanding on ratcheting. The first part concerned calibrating the ratcheting parameters and the second part addressed the comparison of ratcheting behavior between welded and un-welded pipes. The initial task was to observe the mechanical response of seamless AISI 316L stainless steel pipes in symmetrically cyclic strain control uniaxial test followed by monotonic uniaxial test in order to determine parameters which were used in the Chaboche ratcheting model in the Finite Element software ANSYS®. From the experimental hysteresis and post-stabilized monotonic stress plastic-strain curves, the Chaboche parameters were optimized using the Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) codes in MATLAB®. The PSO method presented higher efficient results and was subsequently used to calculate the parameters using an accurate elastic limit. The comparison of ratcheting between experimental and numerical simulation demonstrates that adopting post-stabilized monotonic curve rather than hysteresis curve with accurate elastic limit improved ratcheting prediction significantly. Following this, the effect of residual stress of Gas Tungsten Arc Welding (GTAW) circumferential butt-welded joint of AISI 316L stainless steel pipes on ratcheting was evaluated. The welding heat source was analyzed for evaluation of induced residual stresses. High quality full scale welding was carried out and the strains were measured using hole drilling technique. The strain readings were validated with numerical results obtained from FE simulation using Goldak model in SYSWELD® software. The residual stresses from SYSWELD® were adopted in subsequent numerical ratcheting analysis, using Chaboche model in ANSYS®, and the results were compared with ratchetings tests on welded and un-welded pipes. HYPERMESH® processor was employed to generate the same meshing for both SYSWELD® and ANSYS®. The final results show that weld geometry and welding residual stress contributed to the axial and hoop ratcheting rate of welded pipes in comparison to un-welded pipes. The present study demonstrates that the proposed methods able to simulate residual stresses from a welding process, to introduce the residual stresses as initial stresses in ANSYS®, to generate optimized ratcheting parameters from mechanical tests, to build accurate Chaboche model and to run ratcheting analysis in ANSYS®. The correlation with ratcheting tests prove that the methods used are efficacious and can be implemented on other welded and un-welded piping components. Faculty of Engineering - School of Mechanical Engineering 2023-04-18T07:08:33Z 2023-04-18T07:08:33Z 2019 Thesis Dataset http://openscience.utm.my/handle/123456789/221 en application/pdf application/pdf Universiti Teknologi Malaysia |
| spellingShingle | Pipelines—Welding Moslemi, Navid Ratcheting assessment of AISI 316L stainless steel welded pipe joint |
| title | Ratcheting assessment of AISI 316L stainless steel welded pipe joint |
| title_full | Ratcheting assessment of AISI 316L stainless steel welded pipe joint |
| title_fullStr | Ratcheting assessment of AISI 316L stainless steel welded pipe joint |
| title_full_unstemmed | Ratcheting assessment of AISI 316L stainless steel welded pipe joint |
| title_short | Ratcheting assessment of AISI 316L stainless steel welded pipe joint |
| title_sort | ratcheting assessment of aisi 316l stainless steel welded pipe joint |
| topic | Pipelines—Welding |
| url | http://openscience.utm.my/handle/123456789/221 |
| work_keys_str_mv | AT mosleminavid ratchetingassessmentofaisi316lstainlesssteelweldedpipejoint |