We have recently reported on the mechanistic differences in ductile failure between stainless steel manufactured by hot isostatic pressing (HIP) and forging, from which it was established that the oxygen concentration must be properly controlled. As part of an ongoing investigation into the mechanics of ductile failure in novel HIP materials, X-ray CT has been employed as a tool to quantify and characterize the differences in ductile damage below the fracture surface of failed compact tension fracture toughness test specimens. Herein we report on some of the challenges associated with handling data relative to the fracture surface, which can extend far into the cores under investigation.
{"title":"Challenges Associated With the Quantitative Analysis of Ductile Damage Using X-Ray Computed Tomography","authors":"A. J. Cooper, T. Burnett, O. Tuck, A. Sherry","doi":"10.1115/PVP2018-84023","DOIUrl":"https://doi.org/10.1115/PVP2018-84023","url":null,"abstract":"We have recently reported on the mechanistic differences in ductile failure between stainless steel manufactured by hot isostatic pressing (HIP) and forging, from which it was established that the oxygen concentration must be properly controlled. As part of an ongoing investigation into the mechanics of ductile failure in novel HIP materials, X-ray CT has been employed as a tool to quantify and characterize the differences in ductile damage below the fracture surface of failed compact tension fracture toughness test specimens. Herein we report on some of the challenges associated with handling data relative to the fracture surface, which can extend far into the cores under investigation.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85945929","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}
The determinant of the Jacobian matrix is frequently used in the Finite Element Method as a measure of mesh quality. A new metric is defined, called the Standard Error, based on the distribution of the determinants of the Jacobian matrices of all elements of a finite element mesh. Where the Jacobian norm can be used to compare the quality of one element to another of the same type, the Standard Error compares the mesh quality of different versions of a finite element model where each version uses a different element type. To motivate this new Standard Error, we investigate the geometric meaning of the Jacobian norm on 3D Finite Elements. This mesh quality metric is applied to 8, 20, and 27 node hexahedra, 6 and 15 node prisms, 4 and 10 node tetrahedra, 5 and 13 node pyramid, and 3, 4, 6, 8, and 9 node shell elements. The shape functions for these 14 element types, or more precisely their first partial derivatives, are used to construct the Jacobian Matrix. The matrix is normalized to compensate for size. The determinant of the Jacobian is calculated at Gaussian points within each element. Statistics are gathered to form the Standard Error of the mesh. To illustrate the applicability of this a priori metric, we present two simple example problems having exact answers, and two industry-type problems, a pipe elbow with a crack and a magnetic resonance imaging (MRI) birdcage RF coil resonance, both having no analytical solution. Significance and limitations of using this a priori metric to assess the accuracy of finite element simulations of different mesh designs are presented and discussed.
{"title":"Application of an a priori Jacobian-Based Error Estimation Metric to the Accuracy Assessment of 3D Finite Element Simulations","authors":"R. Rainsberger, J. Fong, P. Marcal","doi":"10.1115/PVP2018-84784","DOIUrl":"https://doi.org/10.1115/PVP2018-84784","url":null,"abstract":"The determinant of the Jacobian matrix is frequently used in the Finite Element Method as a measure of mesh quality.\u0000 A new metric is defined, called the Standard Error, based on the distribution of the determinants of the Jacobian matrices of all elements of a finite element mesh. Where the Jacobian norm can be used to compare the quality of one element to another of the same type, the Standard Error compares the mesh quality of different versions of a finite element model where each version uses a different element type.\u0000 To motivate this new Standard Error, we investigate the geometric meaning of the Jacobian norm on 3D Finite Elements. This mesh quality metric is applied to 8, 20, and 27 node hexahedra, 6 and 15 node prisms, 4 and 10 node tetrahedra, 5 and 13 node pyramid, and 3, 4, 6, 8, and 9 node shell elements. The shape functions for these 14 element types, or more precisely their first partial derivatives, are used to construct the Jacobian Matrix. The matrix is normalized to compensate for size. The determinant of the Jacobian is calculated at Gaussian points within each element. Statistics are gathered to form the Standard Error of the mesh.\u0000 To illustrate the applicability of this a priori metric, we present two simple example problems having exact answers, and two industry-type problems, a pipe elbow with a crack and a magnetic resonance imaging (MRI) birdcage RF coil resonance, both having no analytical solution.\u0000 Significance and limitations of using this a priori metric to assess the accuracy of finite element simulations of different mesh designs are presented and discussed.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88896395","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}
S. Komazaki, Keisuke Obata, M. Tomobe, M. Yaguchi, A. Kumada
The small punch (SP) testing technique was applied to five heats of Gr.91 steel, which had been actually used for boiler pipings in different ultra-super critical (USC) power plants for long periods of time, to investigate the applicability of this testing technique to the assessment of heat-to-heat variation of creep property. The SP creep test was carried out at the temperature of 650°C and under the loads of 190, 230, 300 N using a small disk-type specimen (ϕ 8 × 0.5 mm). The experimental results revealed that the SP creep rupture strength (rupture life) and the deformation rate were different depending on the heat. These differences were qualitatively in good agreement with those observed in the uniaxial creep test. The results obtained in this study indicated that the SP creep testing technique could be a strong tool for the assessment of heat-to-heat variation of in-service boiler pipings.
{"title":"Assessment of Heat-to-Heat Variation of Gr.91 Boiler Pipings by Small Punch Creep Test","authors":"S. Komazaki, Keisuke Obata, M. Tomobe, M. Yaguchi, A. Kumada","doi":"10.1115/PVP2018-84153","DOIUrl":"https://doi.org/10.1115/PVP2018-84153","url":null,"abstract":"The small punch (SP) testing technique was applied to five heats of Gr.91 steel, which had been actually used for boiler pipings in different ultra-super critical (USC) power plants for long periods of time, to investigate the applicability of this testing technique to the assessment of heat-to-heat variation of creep property. The SP creep test was carried out at the temperature of 650°C and under the loads of 190, 230, 300 N using a small disk-type specimen (ϕ 8 × 0.5 mm). The experimental results revealed that the SP creep rupture strength (rupture life) and the deformation rate were different depending on the heat. These differences were qualitatively in good agreement with those observed in the uniaxial creep test. The results obtained in this study indicated that the SP creep testing technique could be a strong tool for the assessment of heat-to-heat variation of in-service boiler pipings.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90901686","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}
Kun Yu, Xianwu Shi, Zhijun Li, Chun Li, Shuangjian Chen, Xingtai Zhou
As one of the most promising Generation IV nuclear reactors, thorium molten salt reactor (TMSR) possesses inherent safety, simplified fuel cycle and high power generation efficiency. However, the structure material of TMSR must encounter challenges of high-temperature environment and serious molten fluoride salts corrosion. Although the UNS N10003 alloy has excellent performance in TMSR, the high cost of this alloy reduces the economy of TMSR. Although the austenitic stainless steel possesses excellent high temperature strength and lower cost, it exhibits poor corrosion resistance in molten fluoride salts. Therefore, the purpose of this work is using Ni cladding on austenitic stainless steel by gas tungsten arc welding (GTAW) for corrosion protection and investigating the effects of thermal ageing on microstructure and hardness of cladding. The elements distribution and segregation, the precipitates behavior and the microstructure evolution of interface and cladding layer under as-welded and thermal ageing conditions were studied by a series of characterization methods respectively. The hardness evolution of claddings under as-welded and thermal ageing conditions were tested and discussed.
{"title":"Effects of Thermal Ageing on Microstructure and Hardness of Ni Cladding on Austenitic Stainless Steel by GTAW","authors":"Kun Yu, Xianwu Shi, Zhijun Li, Chun Li, Shuangjian Chen, Xingtai Zhou","doi":"10.1115/PVP2018-84125","DOIUrl":"https://doi.org/10.1115/PVP2018-84125","url":null,"abstract":"As one of the most promising Generation IV nuclear reactors, thorium molten salt reactor (TMSR) possesses inherent safety, simplified fuel cycle and high power generation efficiency. However, the structure material of TMSR must encounter challenges of high-temperature environment and serious molten fluoride salts corrosion. Although the UNS N10003 alloy has excellent performance in TMSR, the high cost of this alloy reduces the economy of TMSR. Although the austenitic stainless steel possesses excellent high temperature strength and lower cost, it exhibits poor corrosion resistance in molten fluoride salts. Therefore, the purpose of this work is using Ni cladding on austenitic stainless steel by gas tungsten arc welding (GTAW) for corrosion protection and investigating the effects of thermal ageing on microstructure and hardness of cladding. The elements distribution and segregation, the precipitates behavior and the microstructure evolution of interface and cladding layer under as-welded and thermal ageing conditions were studied by a series of characterization methods respectively. The hardness evolution of claddings under as-welded and thermal ageing conditions were tested and discussed.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79632954","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}
Hisakazu Tajika, T. Sakimoto, T. Handa, S. Igi, R. Ikeda, J. Kondo
Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipe with size of 36” OD and 23mm WT was investigated with two types of experiments. One was a pipe bending test with whole pipe. The length of the specimen was approximately 8m and GW was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. The other test was curved wide plate (CWP) test. In both tests, test pipes were cut and welded using GTAW in the first two layers and GMAW for the subsequent passes. Welding wire of TG-S62 and MG-S58P were used for GTAW and GMAW respectively to achieve over-matching girth weld considering the pipe body strength. Elliptical EDM notch was installed in the GW HAZ as simulated weld defect. In pipe bending test, buckling occurred at the intrados at 300 mm apart from the GW. 2D average compressive strain at buckling was 3.59% and this high compressive strain was considered to derive from the high strain capacity of this pipes. After the buckling, deformation concentrated to the buckling wrinkle. Test pipe broke at 35.5 degrees of pipe end rotation and the location was in base metal at the extrados opposite to the buckling wrinkle. The HAZ notch opened and CTOD was 1.44 mm and the global strain in 2D length average strain was 7.8%. In CWP test, tensile strain simply got large and pipe finally broke at global strain of 9.6% and CTOD of 15 mm. The break location was the HAZ notch. There was a significant difference in CTOD growth in HAZ between two test types. Conditions and factors that effect to these differences are argued in this paper.
{"title":"Strain Capacity Investigation on Grade X70 High Strain Line Pipe With Girth Weld","authors":"Hisakazu Tajika, T. Sakimoto, T. Handa, S. Igi, R. Ikeda, J. Kondo","doi":"10.1115/PVP2018-85059","DOIUrl":"https://doi.org/10.1115/PVP2018-85059","url":null,"abstract":"Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important.\u0000 In this study strain capacity of Grade X70 high strain pipe with size of 36” OD and 23mm WT was investigated with two types of experiments. One was a pipe bending test with whole pipe. The length of the specimen was approximately 8m and GW was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test.\u0000 The other test was curved wide plate (CWP) test. In both tests, test pipes were cut and welded using GTAW in the first two layers and GMAW for the subsequent passes. Welding wire of TG-S62 and MG-S58P were used for GTAW and GMAW respectively to achieve over-matching girth weld considering the pipe body strength. Elliptical EDM notch was installed in the GW HAZ as simulated weld defect.\u0000 In pipe bending test, buckling occurred at the intrados at 300 mm apart from the GW. 2D average compressive strain at buckling was 3.59% and this high compressive strain was considered to derive from the high strain capacity of this pipes. After the buckling, deformation concentrated to the buckling wrinkle. Test pipe broke at 35.5 degrees of pipe end rotation and the location was in base metal at the extrados opposite to the buckling wrinkle. The HAZ notch opened and CTOD was 1.44 mm and the global strain in 2D length average strain was 7.8%.\u0000 In CWP test, tensile strain simply got large and pipe finally broke at global strain of 9.6% and CTOD of 15 mm. The break location was the HAZ notch. There was a significant difference in CTOD growth in HAZ between two test types. Conditions and factors that effect to these differences are argued in this paper.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77958580","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}
Effects of strain amplitude and loading path on cyclic deformation behavior and martensitic transformation of 304 stainless steel were experimentally investigated at room temperature. Series of symmetrical strain-control low cycle fatigue tests with strain amplitude ranging from 0.4% to 1.0% and various loading paths (uniaxial, torsional, proportional, rhombus, square and circular) with the same equivalent strain amplitude of 0.5% were carried out. Three-stage cyclic deformation behavior containing initial hardening, cyclic softening or saturation, and secondary hardening as well as near-linear relationship between α’-martensite content and number of cycles was observed during the whole life regime as for each test. Besides, a nearly linear relation between peak stress and α’-martensite content was found during secondary hardening stage. Furthermore, higher strain amplitude or non-proportionality of loading path resulted in higher cyclic stress response and α’-martensite content growth rate, defined by the slope of curves of α’-martensite content versus number of cycles.
{"title":"Effects of Strain Amplitude and Loading Path on Cyclic Behavior and Martensitic Transformation of 304 Stainless Steel","authors":"Yajing Li, Dunji Yu, Xu Chen","doi":"10.1115/PVP2018-84888","DOIUrl":"https://doi.org/10.1115/PVP2018-84888","url":null,"abstract":"Effects of strain amplitude and loading path on cyclic deformation behavior and martensitic transformation of 304 stainless steel were experimentally investigated at room temperature. Series of symmetrical strain-control low cycle fatigue tests with strain amplitude ranging from 0.4% to 1.0% and various loading paths (uniaxial, torsional, proportional, rhombus, square and circular) with the same equivalent strain amplitude of 0.5% were carried out. Three-stage cyclic deformation behavior containing initial hardening, cyclic softening or saturation, and secondary hardening as well as near-linear relationship between α’-martensite content and number of cycles was observed during the whole life regime as for each test. Besides, a nearly linear relation between peak stress and α’-martensite content was found during secondary hardening stage. Furthermore, higher strain amplitude or non-proportionality of loading path resulted in higher cyclic stress response and α’-martensite content growth rate, defined by the slope of curves of α’-martensite content versus number of cycles.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84484896","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}
C. S. Marchi, J. Yamabe, M. Schwarz, H. Matsunaga, S. Zickler, S. Matsuoka, Hideo Kobayashi
Methods to qualify materials for hydrogen service are needed in the global marketplace to enable sustainable, low-carbon energy technologies, such as hydrogen fuel cell electric vehicles. Existing requirements for qualifying materials are not adequate to support growth of hydrogen technology as well as being inconsistent with the growing literature on the effects of hydrogen on fracture and fatigue. This report documents an internationally coordinated effort to develop a test method for qualifying materials for high-pressure hydrogen fuel system onboard fuel cell electric vehicles. In particular, consistency of fatigue life testing strategies is discussed. Fatigue life tests were conducted at three different institutes in high-pressure gaseous hydrogen (90 MPa) at low temperature (233K) to confirm consistency across distinct testing platforms. The testing campaign includes testing of both smooth and notched axial fatigue specimens at various combinations of pressure and temperature. Collectively these testing results provide insight to the sensitivity of fatigue life testing to important testing parameters such as pressure, temperature and the presence of stress concentrations.
{"title":"Global Harmonization of Fatigue Life Testing in Gaseous Hydrogen","authors":"C. S. Marchi, J. Yamabe, M. Schwarz, H. Matsunaga, S. Zickler, S. Matsuoka, Hideo Kobayashi","doi":"10.1115/PVP2018-84898","DOIUrl":"https://doi.org/10.1115/PVP2018-84898","url":null,"abstract":"Methods to qualify materials for hydrogen service are needed in the global marketplace to enable sustainable, low-carbon energy technologies, such as hydrogen fuel cell electric vehicles. Existing requirements for qualifying materials are not adequate to support growth of hydrogen technology as well as being inconsistent with the growing literature on the effects of hydrogen on fracture and fatigue. This report documents an internationally coordinated effort to develop a test method for qualifying materials for high-pressure hydrogen fuel system onboard fuel cell electric vehicles. In particular, consistency of fatigue life testing strategies is discussed. Fatigue life tests were conducted at three different institutes in high-pressure gaseous hydrogen (90 MPa) at low temperature (233K) to confirm consistency across distinct testing platforms. The testing campaign includes testing of both smooth and notched axial fatigue specimens at various combinations of pressure and temperature. Collectively these testing results provide insight to the sensitivity of fatigue life testing to important testing parameters such as pressure, temperature and the presence of stress concentrations.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79176788","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}
A simple testing method to evaluate the influence of high pressure hydrogen gas up to 100 MPa on mechanical properties at the temperature between 20 K and up to 800 K had been developed. In this method, instead of using high-pressure gas vessels, high pressure gas was filled into a small hole in the hollow-type test piece from a hydrogen gas cylinder or a compressor for 10 MPa or 100 MPa test. A small inner diameter of the hole enables to evaluate also the reduction of area in the slow strain-rate tensile (SSRT) tests. The temperature of the test piece with the high pressure gas can be changed simply by surrounding coolant or heater between 20 K and 800 K. Lots of test results by this method proved that almost the same results were obtained between this method and the conventional method with high-pressure gas vessels where test piece is installed. The great advantages of this method are not only the less cost for the facilities of high-pressure vessels but also the ability of tests at lower or higher temperatures than those with the vessels. So, this method is proposed to be used world-widely to evaluate the mechanical properties of structural materials for extremely severe environments, such as high-pressure hydrogen applications and also to study the mechanism of the influence of high-pressure hydrogen for design and reliability of those facilities. In this paper, the details of testing procedure of this method and results of tensile and fatigue tests in up to 70 MPa hydrogen gas on several kinds of stainless steels obtained by this method are presented.
{"title":"Simple Mechanical Testing Method to Evaluate Influence of High Pressure Hydrogen Gas","authors":"T. Ogata","doi":"10.1115/PVP2018-84187","DOIUrl":"https://doi.org/10.1115/PVP2018-84187","url":null,"abstract":"A simple testing method to evaluate the influence of high pressure hydrogen gas up to 100 MPa on mechanical properties at the temperature between 20 K and up to 800 K had been developed. In this method, instead of using high-pressure gas vessels, high pressure gas was filled into a small hole in the hollow-type test piece from a hydrogen gas cylinder or a compressor for 10 MPa or 100 MPa test. A small inner diameter of the hole enables to evaluate also the reduction of area in the slow strain-rate tensile (SSRT) tests. The temperature of the test piece with the high pressure gas can be changed simply by surrounding coolant or heater between 20 K and 800 K. Lots of test results by this method proved that almost the same results were obtained between this method and the conventional method with high-pressure gas vessels where test piece is installed. The great advantages of this method are not only the less cost for the facilities of high-pressure vessels but also the ability of tests at lower or higher temperatures than those with the vessels. So, this method is proposed to be used world-widely to evaluate the mechanical properties of structural materials for extremely severe environments, such as high-pressure hydrogen applications and also to study the mechanism of the influence of high-pressure hydrogen for design and reliability of those facilities.\u0000 In this paper, the details of testing procedure of this method and results of tensile and fatigue tests in up to 70 MPa hydrogen gas on several kinds of stainless steels obtained by this method are presented.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85826308","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}
Sannmit Shinde, A. Gordon, Zachary Poust, Steve Pitolaj, J. Drago, Paul Nichols
Pressurized vessels that transfer media from one location to another often contain a bolted connection. Gaskets are essential for these systems since they confer high levels of leak mitigation across of range of operating environments (i.e., internal pressure and temperature). The balance of both sealability and compressibility must be displayed in candidate gasket materials to be subjected to aggressive operating conditions. Historically, thin gauge gasket (i.e., 1/16” thick) confer high sealability while thick gaskets offer superior compressibility (i.e., 1/8”). Fabricated with skive cut, ceramic particle-reinforced PTFE, these materials display linear viscoelastic behavior that allow consolidation to occur. For example, GYLON® 3504 is filled with Aluminosilicate Microspheres, GYLON®3510 is filled with barium sulfate, respectively, to efficiently fill crevices along the surfaces of the flange. Novel textured PTFE gasket (3504 EPX and 3510 EPX) have been developed to simultaneously confer sealability and compressibility compared to flat products. A design of experiments (DoE) approach is applied to characterize the factors that influence load relaxation responses of the both candidate textured PTFE (dual-face honeycomb) and existing (flat) gasket styles. Using an instrumented test platform analyzed. A new parameter is presented to quantify gasket efficiency. The collection of efficiency measurement methods and approach to re-torque optimization convey a novel framework that designers can invoke to facilitate improved flange performance.
{"title":"Combined Statistical-Mechanical Characterization of a Next Generation Textured PTFE for Extreme Environments","authors":"Sannmit Shinde, A. Gordon, Zachary Poust, Steve Pitolaj, J. Drago, Paul Nichols","doi":"10.1115/PVP2018-84039","DOIUrl":"https://doi.org/10.1115/PVP2018-84039","url":null,"abstract":"Pressurized vessels that transfer media from one location to another often contain a bolted connection. Gaskets are essential for these systems since they confer high levels of leak mitigation across of range of operating environments (i.e., internal pressure and temperature). The balance of both sealability and compressibility must be displayed in candidate gasket materials to be subjected to aggressive operating conditions. Historically, thin gauge gasket (i.e., 1/16” thick) confer high sealability while thick gaskets offer superior compressibility (i.e., 1/8”). Fabricated with skive cut, ceramic particle-reinforced PTFE, these materials display linear viscoelastic behavior that allow consolidation to occur. For example, GYLON® 3504 is filled with Aluminosilicate Microspheres, GYLON®3510 is filled with barium sulfate, respectively, to efficiently fill crevices along the surfaces of the flange. Novel textured PTFE gasket (3504 EPX and 3510 EPX) have been developed to simultaneously confer sealability and compressibility compared to flat products. A design of experiments (DoE) approach is applied to characterize the factors that influence load relaxation responses of the both candidate textured PTFE (dual-face honeycomb) and existing (flat) gasket styles. Using an instrumented test platform analyzed. A new parameter is presented to quantify gasket efficiency. The collection of efficiency measurement methods and approach to re-torque optimization convey a novel framework that designers can invoke to facilitate improved flange performance.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75516116","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}
Jae-Hee Kim, Min Kyu Kim, Ye-Rin Choi, D. Cho, Moon-Ki Kim, Jaeboong Choi
The present paper proposed the modified limit load solution related to code case N-513-4 which is currently actively researched. To apply to assessment method for an elbow in code case N-513-4, the crack should be postulated as the idealized circumferential through-wall crack (TWC). For this reason, it could be led to overestimate the results due to the assumption of real crack shape. Then, the many research which is related to an accurate solution for a straight pipe by considering realistic crack has been investigated. However, the accurate solution for the elbow with non-idealized TWC is still lacked. Therefore, based on three-dimensional finite element model, the effect of non-idealized circumferential TWC on plastic limit load was investigated under internal pressure. To do this, the finite element (FE) model and analysis procedure employed in the present numerical study were validated by comparing the present finite element analyses result with existing solutions for idealized TWC in the elbow. Then, the correction factor for calculating plastic limit load was newly proposed as a tabulated form by considering practical ranges of geometry.
{"title":"A Study on the Effect of Non-Idealized Crack on a 90° Elbow by Using Finite Element Analysis","authors":"Jae-Hee Kim, Min Kyu Kim, Ye-Rin Choi, D. Cho, Moon-Ki Kim, Jaeboong Choi","doi":"10.1115/PVP2018-84758","DOIUrl":"https://doi.org/10.1115/PVP2018-84758","url":null,"abstract":"The present paper proposed the modified limit load solution related to code case N-513-4 which is currently actively researched. To apply to assessment method for an elbow in code case N-513-4, the crack should be postulated as the idealized circumferential through-wall crack (TWC). For this reason, it could be led to overestimate the results due to the assumption of real crack shape. Then, the many research which is related to an accurate solution for a straight pipe by considering realistic crack has been investigated. However, the accurate solution for the elbow with non-idealized TWC is still lacked. Therefore, based on three-dimensional finite element model, the effect of non-idealized circumferential TWC on plastic limit load was investigated under internal pressure. To do this, the finite element (FE) model and analysis procedure employed in the present numerical study were validated by comparing the present finite element analyses result with existing solutions for idealized TWC in the elbow. Then, the correction factor for calculating plastic limit load was newly proposed as a tabulated form by considering practical ranges of geometry.","PeriodicalId":23651,"journal":{"name":"Volume 6B: Materials and Fabrication","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74691902","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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