In this study, an analytical approach based on the energy method is used to estimate the force required to expand tubes for different die shapes. The proposed method calculates the driving force by the volume energy change and working effect ratio instead of depending on the contact pressure and the shape of the contact surface in the previous studies. The new approach greatly reduces the difficulty of the analysis and simplifies the calculation. Since the accurate stress distribution in the transition zone is essential for determining the working effect factor, a new analytical approach with self-adaption is also introduced to estimate the strain and stress distribution in the transition zone of an expanding tube, and the contact position between die and tube can also be obtained by this approach. In this study, three finite element models as a numerical approach are used to develop an axisymmetric model including multiple linear kinematic hardening behavior to confirm the approach. Additionally, copper and steel 3/8 inch tubes are expanded with oval dies on a designed test workbench with different boundary conditions. The tangential, longitudinal strains and driving force are monitored and recorded during the expansion process. Finally, the results from the three approaches show a very good agreement.
{"title":"A Method of Evaluating the Driving Force and Stresses During Tube Die Expansion","authors":"Zijian Zhao, A. Bouzid, Linbo Zhu","doi":"10.1115/1.4056604","DOIUrl":"https://doi.org/10.1115/1.4056604","url":null,"abstract":"\u0000 In this study, an analytical approach based on the energy method is used to estimate the force required to expand tubes for different die shapes. The proposed method calculates the driving force by the volume energy change and working effect ratio instead of depending on the contact pressure and the shape of the contact surface in the previous studies. The new approach greatly reduces the difficulty of the analysis and simplifies the calculation.\u0000 Since the accurate stress distribution in the transition zone is essential for determining the working effect factor, a new analytical approach with self-adaption is also introduced to estimate the strain and stress distribution in the transition zone of an expanding tube, and the contact position between die and tube can also be obtained by this approach.\u0000 In this study, three finite element models as a numerical approach are used to develop an axisymmetric model including multiple linear kinematic hardening behavior to confirm the approach. Additionally, copper and steel 3/8 inch tubes are expanded with oval dies on a designed test workbench with different boundary conditions. The tangential, longitudinal strains and driving force are monitored and recorded during the expansion process.\u0000 Finally, the results from the three approaches show a very good agreement.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47872238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sanlong Zheng, Yiqi Zhang, Jiawei Xu, Bingbing Chen, Pengfei Wang, Yang Liu
The knockdown factor (KDF), which characterizes the difference between the actual buckling pressure and the classical theoretical pressure of shallow spherical shells under external pressure. By scanning six shallow spherical shells, the geometric characteristics of the shells were analyzed, and a geometric model was established based on the Fourier series. 720 sets of shallow spherical shells under external pressure were simulated using the proposed Fourier series model and simulation method. The influence of the yield strength, geometrical parameter λ, dimensionless parameters radius-thickness ratio R/t, and the imperfection-thickness ratio e/t on KDF were studied, and the highly discrete characteristics of KDF were reproduced. The results showed that the proposed method has a better predictive effect on KDF, which is significantly improved over the "Eigemode imperfections" method. KDF is not only related to λ and e/t, but is also affected by the yield strength and R/t. The lower envelopes of KDF were obtained when e/t was is less than 1.0 and 2.0. The NASA SP-8032 curve corresponds to the lower envelope of KDF when e/t is less than 8.0, and the curve is below the lower envelope of KDF when e/t is less than 1.0 and 2.0. As stipulated in the pressure vessel standard, the KDF obtained by NASA SP-8032 will be conservative for design conditions with e/t less than 1.0 or 2.0, and appropriate adjustment should be considered.
{"title":"Research on the Buckling Load of Clamped Spherical Caps Under External Pressure: Analyzed by the Fourier Series Model with Initial Geometric Imperfections","authors":"Sanlong Zheng, Yiqi Zhang, Jiawei Xu, Bingbing Chen, Pengfei Wang, Yang Liu","doi":"10.1115/1.4056509","DOIUrl":"https://doi.org/10.1115/1.4056509","url":null,"abstract":"\u0000 The knockdown factor (KDF), which characterizes the difference between the actual buckling pressure and the classical theoretical pressure of shallow spherical shells under external pressure. By scanning six shallow spherical shells, the geometric characteristics of the shells were analyzed, and a geometric model was established based on the Fourier series. 720 sets of shallow spherical shells under external pressure were simulated using the proposed Fourier series model and simulation method. The influence of the yield strength, geometrical parameter λ, dimensionless parameters radius-thickness ratio R/t, and the imperfection-thickness ratio e/t on KDF were studied, and the highly discrete characteristics of KDF were reproduced. The results showed that the proposed method has a better predictive effect on KDF, which is significantly improved over the "Eigemode imperfections" method. KDF is not only related to λ and e/t, but is also affected by the yield strength and R/t. The lower envelopes of KDF were obtained when e/t was is less than 1.0 and 2.0. The NASA SP-8032 curve corresponds to the lower envelope of KDF when e/t is less than 8.0, and the curve is below the lower envelope of KDF when e/t is less than 1.0 and 2.0. As stipulated in the pressure vessel standard, the KDF obtained by NASA SP-8032 will be conservative for design conditions with e/t less than 1.0 or 2.0, and appropriate adjustment should be considered.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43549275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Feenstra, T. Sawadogo, Bruce A. W. Smith, Victor Janzen, Helen Cothron
The tubes in the U-bend region of a recirculating type of nuclear steam generator are subjected to cross-flow of a two-phase mixture of steam and water. There is a concern that these tubes may experience flow-induced vibration, including the damaging effects of fluidelastic instability. This two-part series of papers presents the results of flow-induced vibration experiments performed by Canadian Nuclear Laboratories for the Electric Power Research Institute (EPRI) using the Multi-Span U-Bend test rig. The tube bundle is made of 22 U-bend tubes of 12.7 mm (0.5 in) diameter, arranged in a rotated triangular configuration with a pitch-to-diameter ratio of 1.5. The test rig was equipped with variable clearance flat bar supports at two different locations to investigate a variety of tube and flat-bar support configurations. The primary purpose of the overall project was to study the occurrence of In Plane (or streamwise) fluidelastic instability in a U-tube bundle with flat-bar tube supports with clearances or preloads. Initially, the test rig was configured for tests in airflow using an industrial air blower. Then tests with two-phase Refrigerant (R-134a) were performed. Part I of this two-part series describes the test rig, experimental setup and some of the challenges encountered, and the results of experiments with air flows. Part II will present results of tests using refrigerant two-phase flows.
{"title":"Investigations of In-Plane Fluidelastic Instability in a Multi-span U-bend Tube Array – Part I: Tests in Air Flow","authors":"P. Feenstra, T. Sawadogo, Bruce A. W. Smith, Victor Janzen, Helen Cothron","doi":"10.1115/1.4056466","DOIUrl":"https://doi.org/10.1115/1.4056466","url":null,"abstract":"\u0000 The tubes in the U-bend region of a recirculating type of nuclear steam generator are subjected to cross-flow of a two-phase mixture of steam and water. There is a concern that these tubes may experience flow-induced vibration, including the damaging effects of fluidelastic instability. This two-part series of papers presents the results of flow-induced vibration experiments performed by Canadian Nuclear Laboratories for the Electric Power Research Institute (EPRI) using the Multi-Span U-Bend test rig. The tube bundle is made of 22 U-bend tubes of 12.7 mm (0.5 in) diameter, arranged in a rotated triangular configuration with a pitch-to-diameter ratio of 1.5. The test rig was equipped with variable clearance flat bar supports at two different locations to investigate a variety of tube and flat-bar support configurations. The primary purpose of the overall project was to study the occurrence of In Plane (or streamwise) fluidelastic instability in a U-tube bundle with flat-bar tube supports with clearances or preloads. Initially, the test rig was configured for tests in airflow using an industrial air blower. Then tests with two-phase Refrigerant (R-134a) were performed. Part I of this two-part series describes the test rig, experimental setup and some of the challenges encountered, and the results of experiments with air flows. Part II will present results of tests using refrigerant two-phase flows.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42911787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Feenstra, T. Sawadogo, Bruce A. W. Smith, Victor Janzen, A. McLellan, Helen Cothron, Sean Kil
Tests to study Fluidelastic Instability in an array of U-bend tubes were recently completed in the Multi-Span U-Bend test rig at Canadian Nuclear Laboratories. These tests were sponsored by the Electric Power Research Institute and were designed to study In-Plane Fluid elastic instability of steam generator tubes in two-phase cross flow. This instability mechanism was first observed in previous experiments by Atomic Energy of Canada Limited. This mechanism was not thought to be a serious practical concern until 2012 when it caused severe damage to tubes in a new replacement steam generator in a nuclear power plant in the United States. In this study, tests were conducted both with flows of air and two-phase liquid/vapour Refrigerant 134a. The tube bundle consisted of 22 flexible U-bend tubes supported by a configurable flat-bar arrangement. Testing focused on the effects of support geometry and tube-to-support interaction. Data was recorded from 33 dynamic signals from accelerometers, displacement probes, force transducers, and void-fraction probes. Part I of this two-part series presented results of air tests. Part II presents results of tests using two-phase Freon refrigerant (R-134a) as the working fluid.
{"title":"Investigations of In-Plane Fluidelastic Instability in a Multi-Span Tube Array – Part II: Tests in Two-Phase Flow","authors":"P. Feenstra, T. Sawadogo, Bruce A. W. Smith, Victor Janzen, A. McLellan, Helen Cothron, Sean Kil","doi":"10.1115/1.4056467","DOIUrl":"https://doi.org/10.1115/1.4056467","url":null,"abstract":"\u0000 Tests to study Fluidelastic Instability in an array of U-bend tubes were recently completed in the Multi-Span U-Bend test rig at Canadian Nuclear Laboratories. These tests were sponsored by the Electric Power Research Institute and were designed to study In-Plane Fluid elastic instability of steam generator tubes in two-phase cross flow. This instability mechanism was first observed in previous experiments by Atomic Energy of Canada Limited. This mechanism was not thought to be a serious practical concern until 2012 when it caused severe damage to tubes in a new replacement steam generator in a nuclear power plant in the United States. In this study, tests were conducted both with flows of air and two-phase liquid/vapour Refrigerant 134a. The tube bundle consisted of 22 flexible U-bend tubes supported by a configurable flat-bar arrangement. Testing focused on the effects of support geometry and tube-to-support interaction. Data was recorded from 33 dynamic signals from accelerometers, displacement probes, force transducers, and void-fraction probes. Part I of this two-part series presented results of air tests. Part II presents results of tests using two-phase Freon refrigerant (R-134a) as the working fluid.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49461625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fluid-structure interaction (FSI) problems are important because they may induce serious damage to structures. In some FSI problems, the interaction mechanism is strongly dependent on the wave propagation across the solid-fluid interface. In this study, we attempted a quantitative evaluation of the effect of the solid surface wettability on the wave propagation across the solid-fluid interface with FSI in the case of longitudinal wave propagation vertically towards the interface. During the experiments, while the water was continuously compressed by the solid buffer motion, cavitation bubbles appeared being originated from the buffer-water interface as a result of the transmitted tensile wave propagating across the interface in a cycle. It was confirmed that interfacial boundary condition as wettability could change the wave transmission behavior owing to changes in the cavitation occurrence. It was also confirmed that the worse the wettability, the severer the cavitation intensity, and the greater the difference between the energy lost by the buffer and the energy stored in the water. Consequently, the effect of the cavitation inception on the wave propagation at the solid-fluid interface with FSI could be quantitatively evaluated by considering the energy transferred from the solid to the water.
{"title":"Dynamic Cavitation Inception by Wave Propagation Across Solid-Fluid Interface with Varying Solid Surface Wettability","authors":"Tomohisa Kojima, K. Inaba","doi":"10.1115/1.4056438","DOIUrl":"https://doi.org/10.1115/1.4056438","url":null,"abstract":"\u0000 Fluid-structure interaction (FSI) problems are important because they may induce serious damage to structures. In some FSI problems, the interaction mechanism is strongly dependent on the wave propagation across the solid-fluid interface. In this study, we attempted a quantitative evaluation of the effect of the solid surface wettability on the wave propagation across the solid-fluid interface with FSI in the case of longitudinal wave propagation vertically towards the interface. During the experiments, while the water was continuously compressed by the solid buffer motion, cavitation bubbles appeared being originated from the buffer-water interface as a result of the transmitted tensile wave propagating across the interface in a cycle. It was confirmed that interfacial boundary condition as wettability could change the wave transmission behavior owing to changes in the cavitation occurrence. It was also confirmed that the worse the wettability, the severer the cavitation intensity, and the greater the difference between the energy lost by the buffer and the energy stored in the water. Consequently, the effect of the cavitation inception on the wave propagation at the solid-fluid interface with FSI could be quantitatively evaluated by considering the energy transferred from the solid to the water.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41627847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Internal arcing in oil-immersed electrical equipment is inevitable and of great danger. Transient overpressure should be released by protectors quickly and controllably. Currently available pressure relief valves cannot fully protect the electrical equipment due to mismatch between insufficient relief capacity with correspondingly weak valve structure and increasing arcing energy in upgrading electrical systems. Additionally, flaming possibility of ejected high-temperature oil-gas mixture is distinct, and retained oil in an oil tank without any isolation may be ignited by the flame. Unfortunately, re-sealing of some existing single-outlet valves is out of control due to asymmetrical hydraulic pressure distribution on the valve plate which causes unstable valve plate movement. Therefore, a new pressure relief valve characterised by symmetrical outlets was developed. The novel structure and function of the new valve was firstly introduced, and comprehensive analysis regarding dynamic performances, strength and fluid development during the relief process were conducted. Finally, a prototype was manufactured and tested on a specific test system. The developed valve can well release the overpressure generated by a 6 MJ equivalent arcing fault without any flame during the entire relief process. Furthermore, the valve structure can withstand the pressure load, and valve plate can precisely re-seal the oil tank due to optimized fluid pressure distribution. This research provides an optimized pressure relief valve and a design guide for improved pressure relief valve.
{"title":"Design and Analysis of a New Pressure Relief Valve for Oil-Immersed Electrical Equipment","authors":"Liang Luo, Jinzhong Li, Nong Zhang, Ke Wang, Shuqi Zhang, Ningchuan Liang","doi":"10.1115/1.4056382","DOIUrl":"https://doi.org/10.1115/1.4056382","url":null,"abstract":"\u0000 Internal arcing in oil-immersed electrical equipment is inevitable and of great danger. Transient overpressure should be released by protectors quickly and controllably. Currently available pressure relief valves cannot fully protect the electrical equipment due to mismatch between insufficient relief capacity with correspondingly weak valve structure and increasing arcing energy in upgrading electrical systems. Additionally, flaming possibility of ejected high-temperature oil-gas mixture is distinct, and retained oil in an oil tank without any isolation may be ignited by the flame. Unfortunately, re-sealing of some existing single-outlet valves is out of control due to asymmetrical hydraulic pressure distribution on the valve plate which causes unstable valve plate movement. Therefore, a new pressure relief valve characterised by symmetrical outlets was developed. The novel structure and function of the new valve was firstly introduced, and comprehensive analysis regarding dynamic performances, strength and fluid development during the relief process were conducted. Finally, a prototype was manufactured and tested on a specific test system. The developed valve can well release the overpressure generated by a 6 MJ equivalent arcing fault without any flame during the entire relief process. Furthermore, the valve structure can withstand the pressure load, and valve plate can precisely re-seal the oil tank due to optimized fluid pressure distribution. This research provides an optimized pressure relief valve and a design guide for improved pressure relief valve.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45400373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The challenge of using existing ASME Section III, Division 5, Class A metallic materials for the construction of structural components of advanced reactors with corrosive coolants could be mitigated by allowing designers to use cladding to protect the base materials from corrosion. However, the existing Section III, Division 5 rules provide no guidance on the evaluation of strain accumulation and creep-fatigue damage in cladded components. The availability of design rules for cladded components that do not require long-term clad materials testing could promote the application of the cladding approach to accelerate the deployment schedule of these advanced reactor systems. To avoid long-term properties for the clad materials Part 1 of this work proposes two approximate design analysis methods for two types of clad materials - soft clads that creep much faster and have lower yield stress than the Class A base material, and hard clads that creep much slower and have higher yield stress than the Class A base material. The proposed analysis methods approximate the response of a soft clad by treating it as perfectly compliant and of a hard clad by treating it as linear elastic. Based on these approximate design analysis strategies this Part 2 develops a complete set of design rules for Class A components cladded with either soft or hard clad materials. Part 2 discusses the reasoning behind the proposed design rules and uses example finite element analyses of representative reactor components to illustrate the use of these design methods.
使用现有的ASME第III节，第5部分，A类金属材料来建造具有腐蚀性冷却剂的先进反应堆的结构部件的挑战可以通过允许设计师使用包层来保护基础材料免受腐蚀来缓解。然而，现有的Section III, Division 5规则没有对包覆构件的应变积累和蠕变疲劳损伤的评估提供指导。不需要长期包层材料测试的包层组件设计规则的可用性可以促进包层方法的应用，从而加快这些先进反应堆系统的部署进度。为了避免复合材料的长期性能，本工作的第1部分提出了两种近似设计分析方法，用于两种类型的复合材料-软包层，其蠕变速度快得多，屈服应力比A类基材低，硬包层，蠕变速度慢得多，屈服应力比A类基材高。所提出的分析方法将软包层的响应近似为完全柔顺，将硬包层的响应近似为线弹性。基于这些近似的设计分析策略，本部分开发了一套完整的a类组件的设计规则，无论是软包覆材料还是硬包覆材料。第2部分讨论了所建议的设计规则背后的原因，并使用代表性反应堆部件的示例有限元分析来说明这些设计方法的使用。
{"title":"Designing Cladded Components for High Temperature Nuclear Service. Part-2: Design Rules","authors":"B. Barua, M. Messner, R. Jetter, T. Sham","doi":"10.1115/1.4056151","DOIUrl":"https://doi.org/10.1115/1.4056151","url":null,"abstract":"\u0000 The challenge of using existing ASME Section III, Division 5, Class A metallic materials for the construction of structural components of advanced reactors with corrosive coolants could be mitigated by allowing designers to use cladding to protect the base materials from corrosion. However, the existing Section III, Division 5 rules provide no guidance on the evaluation of strain accumulation and creep-fatigue damage in cladded components. The availability of design rules for cladded components that do not require long-term clad materials testing could promote the application of the cladding approach to accelerate the deployment schedule of these advanced reactor systems. To avoid long-term properties for the clad materials Part 1 of this work proposes two approximate design analysis methods for two types of clad materials - soft clads that creep much faster and have lower yield stress than the Class A base material, and hard clads that creep much slower and have higher yield stress than the Class A base material. The proposed analysis methods approximate the response of a soft clad by treating it as perfectly compliant and of a hard clad by treating it as linear elastic. Based on these approximate design analysis strategies this Part 2 develops a complete set of design rules for Class A components cladded with either soft or hard clad materials. Part 2 discusses the reasoning behind the proposed design rules and uses example finite element analyses of representative reactor components to illustrate the use of these design methods.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46894006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abubakr E. S. Musa, Osamah H.A. Dehwah, Madyan A. Al-Shugaa, H. Al-Gahtani
Due to their thin-walled characteristics, axially loaded circular cylindrical shells (CCSs) commonly undergo buckling failure. The limiting buckling stress of such shells has not yet been fully developed due to a wide range of influencing parameters such as sensitivity to imperfections, nonlinearity, and buckling mode. It has been proved early, and in this study, that the non-axisymmetric buckling stress can be one of the remedies that casts into eliminating the overestimation caused by the classical axisymmetric buckling formula. However, the complex non-linear constrained optimization required to obtain the non-axisymmetric buckling stress and mode remains to be the main obstacle for practicing engineers to approach the non-axisymmetric buckling. In this study, the non-axisymmetric buckling formula has been cast in a compact form and possible approaches to utilize it have been discussed considering the degree of user knowledge and availability of computational tools. Moreover, it has been used to derive a closed-form buckling stress formula that considers the effect of all geometric and material properties. The proposed closed-form formula predicts buckling stress that is always less than that of the classical formula for L/R greater than 0.91 and the amount of reduction increases with the increase of L/R ratio. In comparison with the exact non-axisymmetric buckling formula, the proposed closed-form formula yields buckling stress within ± 4%. Thus, it shares the simplicity of the classical axisymmetric buckling formula and the accuracy of the non-axisymmetric buckling formula.
{"title":"Non-Axisymmetric Buckling Stress of Axially Compressed Circular Cylindrical Shells: Closed-Form and Simplified Formulae","authors":"Abubakr E. S. Musa, Osamah H.A. Dehwah, Madyan A. Al-Shugaa, H. Al-Gahtani","doi":"10.1115/1.4056152","DOIUrl":"https://doi.org/10.1115/1.4056152","url":null,"abstract":"\u0000 Due to their thin-walled characteristics, axially loaded circular cylindrical shells (CCSs) commonly undergo buckling failure. The limiting buckling stress of such shells has not yet been fully developed due to a wide range of influencing parameters such as sensitivity to imperfections, nonlinearity, and buckling mode. It has been proved early, and in this study, that the non-axisymmetric buckling stress can be one of the remedies that casts into eliminating the overestimation caused by the classical axisymmetric buckling formula. However, the complex non-linear constrained optimization required to obtain the non-axisymmetric buckling stress and mode remains to be the main obstacle for practicing engineers to approach the non-axisymmetric buckling. In this study, the non-axisymmetric buckling formula has been cast in a compact form and possible approaches to utilize it have been discussed considering the degree of user knowledge and availability of computational tools. Moreover, it has been used to derive a closed-form buckling stress formula that considers the effect of all geometric and material properties. The proposed closed-form formula predicts buckling stress that is always less than that of the classical formula for L/R greater than 0.91 and the amount of reduction increases with the increase of L/R ratio. In comparison with the exact non-axisymmetric buckling formula, the proposed closed-form formula yields buckling stress within ± 4%. Thus, it shares the simplicity of the classical axisymmetric buckling formula and the accuracy of the non-axisymmetric buckling formula.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46756630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hydrogen energy is a kind of clean secondary energy sources. Mixed hydrogen natural gas transportation technology is a new scheme of hydrogen transportation put forward in recent years. Using natural gas pipe to transport hydrogen is expected to further promote its application. In order to study the mechanical properties of buried steel pipe under the action of seismic waves, a numerical model of buried pipe is established. The time history and distribution of pipe section's stress under seismic wave are analyzed. Effects of seismic intensity, surrounding soil, buried depth and seismic wave type on pipe's mechanical properties are discussed. The results show that the pipe section stress fluctuates under the action of seismic wave, and the stress shifting effect occurs. The maximum stress is located in the directions of 45°, 135°, 225° and 315°. Stress increases with the increasing of seismic intensity, and the stress distribution of the pipe section is also changed. Stress responses of the pipe in different soil are different, and the stress distribution of pipe section at the maximum stress time is similar. The deeper the buried depth is, the greater the pipe stress is. Pipe stress is related to the maximum acceleration of the seismic wave and the spectrum characteristics. Those results can provide a basis for the design and safety evaluation of mixed hydrogen natural gas pipes.
{"title":"Stress Shifting Effect of Hydrogen Mixed Natural Gas Pipe Under Seismic Wave","authors":"Huohai Yang, Jie Zhang, Yang Chen","doi":"10.1115/1.4056083","DOIUrl":"https://doi.org/10.1115/1.4056083","url":null,"abstract":"\u0000 Hydrogen energy is a kind of clean secondary energy sources. Mixed hydrogen natural gas transportation technology is a new scheme of hydrogen transportation put forward in recent years. Using natural gas pipe to transport hydrogen is expected to further promote its application. In order to study the mechanical properties of buried steel pipe under the action of seismic waves, a numerical model of buried pipe is established. The time history and distribution of pipe section's stress under seismic wave are analyzed. Effects of seismic intensity, surrounding soil, buried depth and seismic wave type on pipe's mechanical properties are discussed. The results show that the pipe section stress fluctuates under the action of seismic wave, and the stress shifting effect occurs. The maximum stress is located in the directions of 45°, 135°, 225° and 315°. Stress increases with the increasing of seismic intensity, and the stress distribution of the pipe section is also changed. Stress responses of the pipe in different soil are different, and the stress distribution of pipe section at the maximum stress time is similar. The deeper the buried depth is, the greater the pipe stress is. Pipe stress is related to the maximum acceleration of the seismic wave and the spectrum characteristics. Those results can provide a basis for the design and safety evaluation of mixed hydrogen natural gas pipes.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42507244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The impact of a weaker heat of the wrought form of Haynes 282 nickel superalloy on predicted 100,000 hours creep rupture strength (CRS) and hence Maximum Allowable Working Stress (MAWS) was determined by correlating the creep rupture data of the two stronger heats of material that were used (along with the third weaker heat) to develop the ASME Code Case for this alloy. In comparison with the established MAWS values, estimated MAWS values were 3 to 7% higher in the temperature range of 700 to 800°C and up to 30% higher above 800°C when the weaker heat was removed from the data analysis. These results show the importance of minimizing heat to heat variability of properties that most affect creep strength, especially in developing Code case data for an alloy intended for use in high temperature and stress applications.
{"title":"Effect of Heat-to-Heat Variability On Long-Term Creep Rupture Lifetime Predictions of Single Step Aged Wrought Haynes 282 Alloy","authors":"V. Cedro, M. Render, Kelechi Chukwunenye","doi":"10.1115/1.4056084","DOIUrl":"https://doi.org/10.1115/1.4056084","url":null,"abstract":"\u0000 The impact of a weaker heat of the wrought form of Haynes 282 nickel superalloy on predicted 100,000 hours creep rupture strength (CRS) and hence Maximum Allowable Working Stress (MAWS) was determined by correlating the creep rupture data of the two stronger heats of material that were used (along with the third weaker heat) to develop the ASME Code Case for this alloy. In comparison with the established MAWS values, estimated MAWS values were 3 to 7% higher in the temperature range of 700 to 800°C and up to 30% higher above 800°C when the weaker heat was removed from the data analysis. These results show the importance of minimizing heat to heat variability of properties that most affect creep strength, especially in developing Code case data for an alloy intended for use in high temperature and stress applications.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63503401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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