Linbo Zhu, Yilong Yang, Hongwei Huang, A. Bouzid, Jun Hong
The concentricity of the aero-engine rotor is an important parameter to evaluate the quality of final assembly and directly affects the vibration characteristics, especially for high-speed rotation. The use of a bolted flange joint is the basic type of connection in aero-engine rotors. During the initial tightening of the bolts, large deformation usually occurs in the flange because its thickness is small. The deformation in the flange has a major impact on the concentricity and consequently the dynamic behavior of the aero-engine rotor. This paper proposes a novel stack-build assembly method to predict the concentricity of multi-stage rotors considering the deformation of the flange. The Small Displacement Torsor (SDT) method is employed to construct the mathematical model of part errors. The homogeneous coordinate transformation method is used to analyze the deviation propagation in the bolted flange joint of each stage part. A finite element (FE) model is built to obtain the deformation of the bolted flange joints by simulating the assembly process. The deformation of the flange is involved in the stack-build assembly model as an error matrix. Furthermore, the influence of the assembly process such as interference and preload, tightening sequence on the concentricity is investigated. The results show that bolted flange joints have a significant effect on concentricity, especially for the complex geometry at the flange interface. The developed approach is validated by experimental tests conducted on a multi-stage rotor. This study can provide guidance and enhance the dynamic performance of bolted joints for aero-engine rotors.
{"title":"A Novel Method to Predict the Concentricity of Aero-Engine Rotor Considering the Assembly Process of Bolted Flange Joints","authors":"Linbo Zhu, Yilong Yang, Hongwei Huang, A. Bouzid, Jun Hong","doi":"10.1115/pvp2022-84924","DOIUrl":"https://doi.org/10.1115/pvp2022-84924","url":null,"abstract":"\u0000 The concentricity of the aero-engine rotor is an important parameter to evaluate the quality of final assembly and directly affects the vibration characteristics, especially for high-speed rotation. The use of a bolted flange joint is the basic type of connection in aero-engine rotors. During the initial tightening of the bolts, large deformation usually occurs in the flange because its thickness is small. The deformation in the flange has a major impact on the concentricity and consequently the dynamic behavior of the aero-engine rotor. This paper proposes a novel stack-build assembly method to predict the concentricity of multi-stage rotors considering the deformation of the flange. The Small Displacement Torsor (SDT) method is employed to construct the mathematical model of part errors. The homogeneous coordinate transformation method is used to analyze the deviation propagation in the bolted flange joint of each stage part. A finite element (FE) model is built to obtain the deformation of the bolted flange joints by simulating the assembly process. The deformation of the flange is involved in the stack-build assembly model as an error matrix. Furthermore, the influence of the assembly process such as interference and preload, tightening sequence on the concentricity is investigated. The results show that bolted flange joints have a significant effect on concentricity, especially for the complex geometry at the flange interface. The developed approach is validated by experimental tests conducted on a multi-stage rotor. This study can provide guidance and enhance the dynamic performance of bolted joints for aero-engine rotors.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74405759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the severe cyclic thermal and structural loading that coke drums experience during operation, thermo-mechanical low-cycle fatigue failure has become a prominent consideration in the design of coke drums. Fatigue failure is commonly observed at the skirt-to-shell attachment weld, due to thermal gradients that develop during heating and cooling cycles. To reduce temperature differences between the coke drum shell and skirt near the attachment weld, “hot-boxes” are often implemented in skirt designs. Hot-boxes are enclosed regions of space near the attachment weld that maintain the skirt at temperatures similar to the nearby shell through natural convection and radiation. The present study investigates the effect of hot-box emissivity and height on the fatigue life of the attachment weld for skirt designs with and without keyholes. The results presented herein indicate that, for the skirt height investigated, fatigue life has negligible sensitivity to the height of the hot-box when no keyholes are present on the skirt. In contrast, varying fatigue performance is observed as a function of hot-box height when keyholes are included as part of the skirt design. Although the functional relationship between hot-box height and fatigue life for the skirt design with keyholes is non-monotonic, the results provide directional insight into the optimization of hot-box size.
{"title":"On the Effect of Hot-Box Size on Coke Drum Skirt Fatigue Life","authors":"J. Fernando, Henry Kwok, L. Wong, L. Chan","doi":"10.1115/pvp2022-84068","DOIUrl":"https://doi.org/10.1115/pvp2022-84068","url":null,"abstract":"\u0000 Due to the severe cyclic thermal and structural loading that coke drums experience during operation, thermo-mechanical low-cycle fatigue failure has become a prominent consideration in the design of coke drums. Fatigue failure is commonly observed at the skirt-to-shell attachment weld, due to thermal gradients that develop during heating and cooling cycles. To reduce temperature differences between the coke drum shell and skirt near the attachment weld, “hot-boxes” are often implemented in skirt designs. Hot-boxes are enclosed regions of space near the attachment weld that maintain the skirt at temperatures similar to the nearby shell through natural convection and radiation. The present study investigates the effect of hot-box emissivity and height on the fatigue life of the attachment weld for skirt designs with and without keyholes. The results presented herein indicate that, for the skirt height investigated, fatigue life has negligible sensitivity to the height of the hot-box when no keyholes are present on the skirt. In contrast, varying fatigue performance is observed as a function of hot-box height when keyholes are included as part of the skirt design. Although the functional relationship between hot-box height and fatigue life for the skirt design with keyholes is non-monotonic, the results provide directional insight into the optimization of hot-box size.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72697696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heramb P. Mahajan, L. Maciel, G. Ngaile, T. Hassan
The printed circuit heat exchanger (PCHE) has small channels with high surface area, making them an efficient solution for next-generation nuclear plants (NGNPs). These PCHEs are fabricated through a diffusion bonding process. This fabrication step changes the microstructure of wrought metal plates. The current ASME design code does not support the PCHE design for NGNPs due to a lack of test data. Hence, there has been initiative towards elevated temperature mechanical property characterization of the diffusion bonded material. One of the most common channel shapes is a semicircular channel with sharp corners. These corners act as a stress riser at the diffusion bonding interface. Evaluating elevated temperature mechanical performance of diffusion bonded material in the presence of stress risers is an essential step towards the ASME code development of PCHE design. This study selected two specimen geometries: the first is a PCHE bar specimen for tensile loading with three rows and three columns of channels, and the second is a lab-scaled PCHE with six rows and eight columns of channels. A set of elevated temperature monotonic and cyclic tests were conducted on the PCHE bar specimen to evaluate the mechanical performance under axial tensile loadings to study the failure mechanism. The lab-scaled PCHE specimens were tested under overpressure loads at room temperature, and pressure creep and pressure creep-fatigue loadings to mimic the realistic loading conditions observed in typical NGNPs. The X-ray scans of channeled specimens show interesting observations. The test results and observations are presented in the paper.
{"title":"Mechanical Performance Evaluation of the Printed Circuit Heat Exchanger Core Experiments Under Tension and Pressure Loading","authors":"Heramb P. Mahajan, L. Maciel, G. Ngaile, T. Hassan","doi":"10.1115/pvp2022-81247","DOIUrl":"https://doi.org/10.1115/pvp2022-81247","url":null,"abstract":"\u0000 The printed circuit heat exchanger (PCHE) has small channels with high surface area, making them an efficient solution for next-generation nuclear plants (NGNPs). These PCHEs are fabricated through a diffusion bonding process. This fabrication step changes the microstructure of wrought metal plates. The current ASME design code does not support the PCHE design for NGNPs due to a lack of test data. Hence, there has been initiative towards elevated temperature mechanical property characterization of the diffusion bonded material. One of the most common channel shapes is a semicircular channel with sharp corners. These corners act as a stress riser at the diffusion bonding interface. Evaluating elevated temperature mechanical performance of diffusion bonded material in the presence of stress risers is an essential step towards the ASME code development of PCHE design. This study selected two specimen geometries: the first is a PCHE bar specimen for tensile loading with three rows and three columns of channels, and the second is a lab-scaled PCHE with six rows and eight columns of channels. A set of elevated temperature monotonic and cyclic tests were conducted on the PCHE bar specimen to evaluate the mechanical performance under axial tensile loadings to study the failure mechanism. The lab-scaled PCHE specimens were tested under overpressure loads at room temperature, and pressure creep and pressure creep-fatigue loadings to mimic the realistic loading conditions observed in typical NGNPs. The X-ray scans of channeled specimens show interesting observations. The test results and observations are presented in the paper.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84143713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In vibration service, small-bore piping connections, especially unsupported cantilever configurations, are associated with a high level of concern as potential fatigue crack initiation locations. Various international guidelines and procedures address the assessment of piping vibration in general and of small-bore connections in particular. In this work, a review of these guidelines as applied to a specific class of small-bore connection was performed by means of a finite element parametric study on a large number of branch connections. The small-bore configuration evaluated in this work is an unsupported cantilever connection made using an integrally reinforced forged branch fitting with butt-welded joints. At the end of the branch is a flanged connection with either a blind flange only, or a single or double valve with a blind flange. For the parametric study a random distribution of run pipe diameter and thickness and branch pipe diameter, thickness, and length was used to evaluate a few thousand different small-bore configurations. Modal analysis was used to determine the relationship between stress and velocity at two critical locations: the weld between the branch fitting and header and the weld between the branch pipe and branch fitting. Results of the parametric study were processed and compared to the evaluation criteria of a number of established and upcoming guidelines and standards.
{"title":"Parametric Study on the Vibration of Small-Bore Piping Branch Connections","authors":"G. van Zyl, R. Brodzinsky","doi":"10.1115/pvp2022-84119","DOIUrl":"https://doi.org/10.1115/pvp2022-84119","url":null,"abstract":"\u0000 In vibration service, small-bore piping connections, especially unsupported cantilever configurations, are associated with a high level of concern as potential fatigue crack initiation locations. Various international guidelines and procedures address the assessment of piping vibration in general and of small-bore connections in particular. In this work, a review of these guidelines as applied to a specific class of small-bore connection was performed by means of a finite element parametric study on a large number of branch connections. The small-bore configuration evaluated in this work is an unsupported cantilever connection made using an integrally reinforced forged branch fitting with butt-welded joints. At the end of the branch is a flanged connection with either a blind flange only, or a single or double valve with a blind flange. For the parametric study a random distribution of run pipe diameter and thickness and branch pipe diameter, thickness, and length was used to evaluate a few thousand different small-bore configurations. Modal analysis was used to determine the relationship between stress and velocity at two critical locations: the weld between the branch fitting and header and the weld between the branch pipe and branch fitting. Results of the parametric study were processed and compared to the evaluation criteria of a number of established and upcoming guidelines and standards.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90402816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined piping, a piping stress analysis is done using commercially available piping flexibility analysis software. In the stress analysis, the refractory weight and stiffnesses are included in the piping model. From the piping analysis, the calculated sustained and expansion stresses are compared with ASME B31.3 [1] allowable stresses and the forces and moments from the analysis are used in the design of attached equipment (vessel nozzle, valves, expansion joints etc.) piping restraints and supports. In this paper it will be shown that for a piping stress analysis, using the combined stiffness of the refractory and pipe material on the straight section of the pipe is satisfactory but when it is used on the bends, it will result in un-conservative resultant forces and moments from thermal expansion. To obtain satisfactory resultant forces and moments, the calculated refractory stiffnesses on the bends should be increased in the piping model. The piping stress analysis results were verified with finite element results and past experimental work.
{"title":"Modeling Refractory Stiffness for Piping Flexibility Analysis","authors":"C. Nadarajah","doi":"10.1115/pvp2022-83678","DOIUrl":"https://doi.org/10.1115/pvp2022-83678","url":null,"abstract":"\u0000 Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined piping, a piping stress analysis is done using commercially available piping flexibility analysis software. In the stress analysis, the refractory weight and stiffnesses are included in the piping model. From the piping analysis, the calculated sustained and expansion stresses are compared with ASME B31.3 [1] allowable stresses and the forces and moments from the analysis are used in the design of attached equipment (vessel nozzle, valves, expansion joints etc.) piping restraints and supports.\u0000 In this paper it will be shown that for a piping stress analysis, using the combined stiffness of the refractory and pipe material on the straight section of the pipe is satisfactory but when it is used on the bends, it will result in un-conservative resultant forces and moments from thermal expansion. To obtain satisfactory resultant forces and moments, the calculated refractory stiffnesses on the bends should be increased in the piping model. The piping stress analysis results were verified with finite element results and past experimental work.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83950600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jacob Hundl, B. Millet, Bryan Mosher, K. Kirkpatrick
A simplified method for analyzing pressure vessel response to blast overpressure incidents was developed in a previous study that demonstrated the ability to apply, evaluate and interpret the results of an overpressure incident on vertical pressure vessels without the use of advanced FEA software. The previous study was primarily focused on the development of the simplified method from existing literature and the step-by-step implementation of the method in an example case. The method itself was only applied to one example case and compared to a control case. This paper will verify the simplified method and determine its applicability by evaluating the response of several different vessels to different overpressure values and comparing the results to control cases performed using the CONWEP model in ABAQUS. The sampling of vessels will be determined by using common vessel diameters with different diameter to length ratios. The simplified method developed in the previous study will also be further refined by the application of Newmark’s Method, which allows for the evaluation of the dynamic response of a system to a time-history loading. Newmark’s Method is an average acceleration scheme that is primarily used in structural analysis to measure seismic response. The results from the analysis, along with a comparison between the data from the simplified method and the control case, will be discussed.
{"title":"Verification and Applicability of a Simplified Method for Analyzing Blast Overpressure in Vertical Pressure Vessels","authors":"Jacob Hundl, B. Millet, Bryan Mosher, K. Kirkpatrick","doi":"10.1115/pvp2022-84746","DOIUrl":"https://doi.org/10.1115/pvp2022-84746","url":null,"abstract":"\u0000 A simplified method for analyzing pressure vessel response to blast overpressure incidents was developed in a previous study that demonstrated the ability to apply, evaluate and interpret the results of an overpressure incident on vertical pressure vessels without the use of advanced FEA software. The previous study was primarily focused on the development of the simplified method from existing literature and the step-by-step implementation of the method in an example case. The method itself was only applied to one example case and compared to a control case. This paper will verify the simplified method and determine its applicability by evaluating the response of several different vessels to different overpressure values and comparing the results to control cases performed using the CONWEP model in ABAQUS. The sampling of vessels will be determined by using common vessel diameters with different diameter to length ratios. The simplified method developed in the previous study will also be further refined by the application of Newmark’s Method, which allows for the evaluation of the dynamic response of a system to a time-history loading. Newmark’s Method is an average acceleration scheme that is primarily used in structural analysis to measure seismic response. The results from the analysis, along with a comparison between the data from the simplified method and the control case, will be discussed.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79442289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study concentrates on the corrosion behavior of bolted flanged gasketed joint systems. A novel fixture is proposed to quantify the corrosion between gaskets and flanges under services conditions. According to the literature, due to the presence of crevices and potential differences between gaskets and flanges, corrosion widely occurs in such joints. Crevice corrosion and galvanic corrosion can create paths to leakage of the pressurized fluid and may cause catastrophic failure. Corrosion in bolted gasketed joints was investigated previously; however, the effects of the operating conditions were not reported. Operating conditions include fluid flow, pressure, pH, conductivity, temperature, and gasket contact pressure. The first step of this research study is to introduce a new experimental setup to examine the corrosion behavior of bolted flanged gasketed joints. The developed setup is a fixture that consists of a pressurized bolted gasketed joint that enables real-time monitoring and recording of the corrosion parameters under the influence of service conditions. In the second step, potentiodynamic polarization test is carried out (according to ASTM G5) to measure the corrosion rate and obtain more details on the corrosion behavior of a pair flange and gasket materials. These tests are conducted using the novel designed setup that reproduce the behavior of industrial bolted flanged gasketed joint systems. It consists of a working electrode (flange material), a reference electrode (Ag/AgCl), and an auxiliary electrode (a stainless-steel rod). Three types of graphite gaskets are considered for electrochemical tests. The 0.6 M NaCl solution is used for the corrosion tests. After each test, the corroded surfaces of the specimens are examined via confocal laser microscopy to visualize the morphology of the damaged zones on the surface and localize corrosion, respectively.
本研究集中于螺栓法兰垫圈连接系统的腐蚀行为。提出了一种新的夹具来量化在使用条件下垫片和法兰之间的腐蚀。根据文献，由于垫圈和法兰之间存在裂缝和潜在的差异，腐蚀广泛发生在这些接缝中。缝隙腐蚀和电偶腐蚀会造成加压流体泄漏，并可能导致灾难性的破坏。先前对螺栓密封接头的腐蚀进行了研究;然而，没有报告操作条件的影响。操作条件包括流体流量、压力、pH值、电导率、温度和垫片接触压力。本研究的第一步是引入一种新的实验装置来检测螺栓法兰垫圈连接的腐蚀行为。开发的装置是一个由加压螺栓垫圈连接组成的夹具，可以实时监控和记录在使用条件影响下的腐蚀参数。第二步，根据ASTM G5进行动电位极化试验，测量腐蚀速率，获得一对法兰和垫片材料腐蚀行为的更多细节。这些测试是使用新设计的装置进行的，该装置再现了工业螺栓法兰垫圈连接系统的行为。它由工作电极(法兰材料)、参比电极(Ag/AgCl)和辅助电极(不锈钢棒)组成。三种类型的石墨垫片被考虑用于电化学测试。腐蚀试验采用0.6 M NaCl溶液。每次测试后，通过共聚焦激光显微镜检查试样的腐蚀表面，分别观察表面上损伤区域的形态和局部腐蚀。
{"title":"An Improved Fixture to Quantify Corrosion in Bolted Flanged Gasketed Joints Subjected to Service Conditions","authors":"Soroosh Hakimian, L. Hof, H. Bouzid","doi":"10.1115/pvp2022-82668","DOIUrl":"https://doi.org/10.1115/pvp2022-82668","url":null,"abstract":"\u0000 This study concentrates on the corrosion behavior of bolted flanged gasketed joint systems. A novel fixture is proposed to quantify the corrosion between gaskets and flanges under services conditions. According to the literature, due to the presence of crevices and potential differences between gaskets and flanges, corrosion widely occurs in such joints. Crevice corrosion and galvanic corrosion can create paths to leakage of the pressurized fluid and may cause catastrophic failure. Corrosion in bolted gasketed joints was investigated previously; however, the effects of the operating conditions were not reported. Operating conditions include fluid flow, pressure, pH, conductivity, temperature, and gasket contact pressure. The first step of this research study is to introduce a new experimental setup to examine the corrosion behavior of bolted flanged gasketed joints. The developed setup is a fixture that consists of a pressurized bolted gasketed joint that enables real-time monitoring and recording of the corrosion parameters under the influence of service conditions. In the second step, potentiodynamic polarization test is carried out (according to ASTM G5) to measure the corrosion rate and obtain more details on the corrosion behavior of a pair flange and gasket materials. These tests are conducted using the novel designed setup that reproduce the behavior of industrial bolted flanged gasketed joint systems. It consists of a working electrode (flange material), a reference electrode (Ag/AgCl), and an auxiliary electrode (a stainless-steel rod). Three types of graphite gaskets are considered for electrochemical tests. The 0.6 M NaCl solution is used for the corrosion tests. After each test, the corroded surfaces of the specimens are examined via confocal laser microscopy to visualize the morphology of the damaged zones on the surface and localize corrosion, respectively.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80220264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leonardo de la Roca, Igor Meira, Carlos D. Girão, José Carlos Veiga
In most industrial plants, the maintenance of the piping system is a crucial part of the site’s health and integrity, as leakage can often lead to costly losses and even disastrous accidents with the loss of life. An incorrect assembly of a bolted flange joint will most likely form a leak path in the sealing surface and lead to joint failure. Standards such as the ASME PCC-1 Guidelines for Pressure Boundary Bolted Flange Joint Assembly, have the purpose of guiding towards safer procedures of gasket installation in bolted flange connections, where specific gasket assembly methods regarding recommended fastening torque and bolt sequence are described in detail. However, to this day, said guidelines are not strictly followed. The lack of training concerning the recommended methods leads to unqualified flanged joint assemblers and hence the most common cause of gasket failure, which is an improper installation. Therefore, there is a need to produce instructional tools, physical in nature or not, that help raise awareness to the recommended, standardized, gasket installation methods and good practices in bolted flanged joint assemblies, aiming to reduce the volume of industrial plants’ leakage caused by improper installation, preventing further health and environmental problems. The present work describes a set of mathematical methods designed for flange assembly training simulations, intended to be used as an educational tool to enhance the abilities and knowledge of assemblers. The work includes methods of calculating elastic interactions between bolts and other common phenomena characteristics of flange tightening.
{"title":"Numerical Approaches for Bolt Interactions in Flange Gasket Assemblies","authors":"Leonardo de la Roca, Igor Meira, Carlos D. Girão, José Carlos Veiga","doi":"10.1115/pvp2022-84816","DOIUrl":"https://doi.org/10.1115/pvp2022-84816","url":null,"abstract":"\u0000 In most industrial plants, the maintenance of the piping system is a crucial part of the site’s health and integrity, as leakage can often lead to costly losses and even disastrous accidents with the loss of life. An incorrect assembly of a bolted flange joint will most likely form a leak path in the sealing surface and lead to joint failure. Standards such as the ASME PCC-1 Guidelines for Pressure Boundary Bolted Flange Joint Assembly, have the purpose of guiding towards safer procedures of gasket installation in bolted flange connections, where specific gasket assembly methods regarding recommended fastening torque and bolt sequence are described in detail. However, to this day, said guidelines are not strictly followed. The lack of training concerning the recommended methods leads to unqualified flanged joint assemblers and hence the most common cause of gasket failure, which is an improper installation. Therefore, there is a need to produce instructional tools, physical in nature or not, that help raise awareness to the recommended, standardized, gasket installation methods and good practices in bolted flanged joint assemblies, aiming to reduce the volume of industrial plants’ leakage caused by improper installation, preventing further health and environmental problems. The present work describes a set of mathematical methods designed for flange assembly training simulations, intended to be used as an educational tool to enhance the abilities and knowledge of assemblers. The work includes methods of calculating elastic interactions between bolts and other common phenomena characteristics of flange tightening.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72768469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. De Agostinis, D. Croccolo, S. Fini, G. Olmi, F. Robusto, C. Scapecchi
Pre-applied threadlockers are widely adopted in industrial applications, due to their favorable features in terms of handling of the fastener and savings in terms of assembly-line dosing systems. In the practice, fasteners with the pre-applied adhesive may undergo storage and/or shipping in harsh environmental conditions, both in terms of temperature and humidity. Questions may arise as to whether such thermal-hygroscopic aging (prior to assembly): (i) affects the tribological properties of the fastener at tightening and/or (ii) the breakaway torque of the fastener after curing. By means of an experimental approach, this work primarily aims at answering the first question, indeed scarcely covered by the literature. As for the second question, measurement of the breakaway torque is carried out for the sake of comparison with the data provided by the adhesives datasheets, where available. Based on a common bolt and plate configuration, the study involves different pre-applied threadlockers in terms of strength grade, among several hygrothermal conditions, representative of frequent storage/shipping conditions. The experimental data have been analyzed by means of the ANOVA tools to assess the effectiveness of the input parameters (adhesive type and aging conditions) on the response in terms of both thread friction coefficient at tightening and breakaway torque of the fastener after tightening completion and complete polymerization. Guidelines useful to the design engineer are reported in the conclusions.
{"title":"An Investigation About the Ageing Behaviour of Pre-Applied Threadlockers","authors":"M. De Agostinis, D. Croccolo, S. Fini, G. Olmi, F. Robusto, C. Scapecchi","doi":"10.1115/pvp2022-84216","DOIUrl":"https://doi.org/10.1115/pvp2022-84216","url":null,"abstract":"\u0000 Pre-applied threadlockers are widely adopted in industrial applications, due to their favorable features in terms of handling of the fastener and savings in terms of assembly-line dosing systems. In the practice, fasteners with the pre-applied adhesive may undergo storage and/or shipping in harsh environmental conditions, both in terms of temperature and humidity. Questions may arise as to whether such thermal-hygroscopic aging (prior to assembly): (i) affects the tribological properties of the fastener at tightening and/or (ii) the breakaway torque of the fastener after curing. By means of an experimental approach, this work primarily aims at answering the first question, indeed scarcely covered by the literature. As for the second question, measurement of the breakaway torque is carried out for the sake of comparison with the data provided by the adhesives datasheets, where available. Based on a common bolt and plate configuration, the study involves different pre-applied threadlockers in terms of strength grade, among several hygrothermal conditions, representative of frequent storage/shipping conditions. The experimental data have been analyzed by means of the ANOVA tools to assess the effectiveness of the input parameters (adhesive type and aging conditions) on the response in terms of both thread friction coefficient at tightening and breakaway torque of the fastener after tightening completion and complete polymerization. Guidelines useful to the design engineer are reported in the conclusions.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"117 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78537612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After flange assembly and following a period of operation, some of the compressive stress on a gasket is lost due to factors such as temperature, pressure, flange movement, and material composition. Increased leakage (fugitive emissions) is often a result of gasket stress loss; however, the increased, operating leak rate is not necessarily directly proportional to the degree of gasket stress loss. A study was conducted using a previously published leak rate model based on an equation set derived from the Pressure Vessel Research Council to provide a demonstration of the impact of load loss (under operating conditions) on the predicted gasket leak rate. The model incorporates system pressure and gasket stress as input variables along with gasket specific factors determined from room temperature tightness test data. Model-derived leak rate data have been plotted as a function of gasket assembly stress for several material types including polytetrafluoroethylene, compressed fiber, and flexible graphite. Plot trends were found to vary noticeably by material type as well as by manufacturer. The derived model outputs are a confirmation that predicted leak rates are not linearly proportional to the degree of gasket stress loss. The results of this study may be instructive to the end user for comparing predicted leak rates of gasket materials over a gasket stress loss range associated with a given application.
在法兰组装完成并经过一段时间的操作后，由于温度、压力、法兰运动和材料成分等因素，垫片上的一些压应力会丢失。增加泄漏(逃逸排放)往往是由于垫片应力损失;然而，操作泄漏率的增加并不一定与垫片应力损失的程度成正比。一项研究使用了先前发布的泄漏率模型，该模型基于压力容器研究委员会(Pressure Vessel Research Council)导出的一组方程，以演示负载损失(在运行条件下)对预测垫片泄漏率的影响。该模型结合了系统压力和垫片应力作为输入变量，以及由室温密封性测试数据确定的垫片特定因素。模型导出的泄漏率数据已绘制为垫片组装应力的函数，用于几种材料类型，包括聚四氟乙烯，压缩纤维和柔性石墨。图的趋势因材料类型和制造商的不同而有显著差异。导出的模型输出证实了预测泄漏率不是与垫片应力损失程度成线性比例的。这项研究的结果可能对最终用户在与给定应用相关的垫片应力损失范围内比较垫片材料的预测泄漏率具有指导意义。
{"title":"Load Loss as a Factor Impacting Gasket Leakage","authors":"Dale A. Rice, J. Waterland","doi":"10.1115/pvp2022-84703","DOIUrl":"https://doi.org/10.1115/pvp2022-84703","url":null,"abstract":"\u0000 After flange assembly and following a period of operation, some of the compressive stress on a gasket is lost due to factors such as temperature, pressure, flange movement, and material composition. Increased leakage (fugitive emissions) is often a result of gasket stress loss; however, the increased, operating leak rate is not necessarily directly proportional to the degree of gasket stress loss. A study was conducted using a previously published leak rate model based on an equation set derived from the Pressure Vessel Research Council to provide a demonstration of the impact of load loss (under operating conditions) on the predicted gasket leak rate. The model incorporates system pressure and gasket stress as input variables along with gasket specific factors determined from room temperature tightness test data. Model-derived leak rate data have been plotted as a function of gasket assembly stress for several material types including polytetrafluoroethylene, compressed fiber, and flexible graphite. Plot trends were found to vary noticeably by material type as well as by manufacturer. The derived model outputs are a confirmation that predicted leak rates are not linearly proportional to the degree of gasket stress loss. The results of this study may be instructive to the end user for comparing predicted leak rates of gasket materials over a gasket stress loss range associated with a given application.","PeriodicalId":23700,"journal":{"name":"Volume 2: Computer Technology and Bolted Joints; Design and Analysis","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83140726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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