Volume 3: Design and Analysis最新文献

{"title":"Estimation of Bending Stresses in Piping Systems Subjected to Transient Pressure","authors":"Maral Taghva, L. Damkilde","doi":"10.1115/pvp2020-21556","DOIUrl":"https://doi.org/10.1115/pvp2020-21556","url":null,"abstract":"\u0000 Modifications in aged process plants may subject piping systems to fluid transient scenarios, which are not considered in the primary design calculations. Due to lack of strict requirements in ASME B31.3 the effect of this phenomenon is often excluded from piping structural integrity reassessments.\u0000 Therefore, the consequences, such as severe pipe motion or even rupture failure, are discovered after modifications are completed and the system starts to function under new operational conditions. The motivation for this study emanated from several observations in offshore oil and gas piping systems, yet the results could be utilized in structural integrity assessments of any piping system subjected to pressure waves.\u0000 This paper describes how to provide an approximate solution to determine maximum bending stresses in piping structures subjected to wave impulse loads without using rigorous approaches to calculate the dynamic response. This paper proposes to consider the effect of load duration in quasi-static analysis to achieve more credible results. The proposed method recommends application of lower dynamic load factors than commonly practiced values advised by design codes, for short duration loads such as shock waves. By presenting a real-life example, the results of improved and commonly practiced quasi-static analysis are compared with the site observations as well as dynamic analysis results. It is illustrated that modified quasi-static solution shows agreement with both dynamic analysis and physical behavior of the system.\u0000 The contents of this study are particularly useful in structural strength re-assessments where the practicing engineer is interested in an approximated solution indicating if the design criteria is satisfied.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128833788","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}

{"title":"Development of Stress Intensification Factors for Collared Type Piping Joints","authors":"C. Ewing","doi":"10.1115/pvp2020-21255","DOIUrl":"https://doi.org/10.1115/pvp2020-21255","url":null,"abstract":"\u0000 Stress Intensification Factors or SIFs allow piping to be analyzed using beam theory, with a SIF representing local effects of specific piping geometry. However, the current piping codes do not explicitly provide SIFs for collared type piping joints for use in pipe stress calculations.\u0000 The objective of this paper is to describe the methodology on how a finite element analysis (FEA) was to model the behavior of collared joints, and to ultimately develop appropriate SIFs that can be used in pipe stress analyses.\u0000 This paper describes a real-life analysis example on collared joints installed on a set of existing fuel transfer lines. The lines, which ranged in size from DN200 to DN350, were concrete lined carbon steel with the collars fillet welded to the carbon steel section of the piping.\u0000 Test coupons cut from existing pipe-collar sections were tested in a laboratory to determine the forces required to break the collar welds. Using FEA, the same test coupons were modelled to replicate the failure tests.\u0000 Multiple iterations were undertaken to determine an appropriate bi-linear stress-strain curve fit for the weld material. The curves of different weld electrode materials were considered. The curve which lead to results similar to those observed in physical testing was selected. From this, a failure stress across the weld could be determined. This stress, 435MPa was then used in subsequent models to determine the point at which the weld fails under bending loads. Multiple tests were analyzed to allow for possible effects of inclusions and voids.\u0000 Finite element models of the collar geometries were constructed and non-linear analyses were undertaken using the weld strengths determined from the coupon testing data. A simple cantilever type arrangement with a point load at one end was analyzed, inducing a bending moment across the collar.\u0000 The peak stress resulting from the bending moment across the collar weld at the center of the cantilevered pipe arrangement, was investigated across various pipe diameters, wall thicknesses, weld sizes and collar geometries.\u0000 Based on the results, a relationship between the pipe geometry and SIF was developed. Hence a pipe stress model of the transfer lines could ultimately be developed using these SIFs to predict the behavior of the piping.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121766413","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}

{"title":"Study on Buckling Strength Reduction Factor for Vertical Vessel Skirts With Access Opening by Elastic-Plastic Analysis","authors":"Takuma Takahashi, S. Kataoka, Yoshiaki Uno, Toshikazu Miyashita","doi":"10.1115/pvp2019-93517","DOIUrl":"https://doi.org/10.1115/pvp2019-93517","url":null,"abstract":"\u0000 Access opening is a key geometric feature of vertical vessel skirts. To ensure the structural stability of skirts, buckling strength reduction caused by openings shall be numerically evaluated.\u0000 In the previous study, Buckling Strength Reduction Factor (BSRF) was introduced as a design factor representing the effects of openings. However BSRF is based on the elastic bifurcation buckling under axial compressive load. The relations between BSRF and practical design conditions, such as bending moment, material plasticity, and local deformation, are not yet evaluated.\u0000 The purpose of this paper is to develop the buckling design method for vertical vessel skirts with access opening by investigating the relation between BSRF in consideration of practical design conditions and conventional design concepts for straight cylinder. The finite element analyses of buckling strength were conducted for cylindrical shells with and without openings under bending moments. In addition, nonlinear buckling behaviors of skirts with opening were studied by elastic-plastic analyses and limit-load analyses. These studies revealed the relation between BSRF and conventional buckling design concepts. Based on these results, a new buckling design approach which includes the application BSRF was proposed. This proposed approach provides a practical guide for buckling design of vertical vessel skirts with access opening.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124272413","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}

{"title":"Coke Drum Bottom Head Flange Design Optimisation","authors":"A. Berry, W. Brown, A. Seijas, Sarah Cook","doi":"10.1115/pvp2019-93136","DOIUrl":"https://doi.org/10.1115/pvp2019-93136","url":null,"abstract":"\u0000 Bottom head flange leaks on coke drums are a too common occurrence for coke drum operators. This paper discusses why these complex joints leak, exploring phenomena such as bolt relaxation, flange rotation, bolt hole cracking, plastic deformation of a flange face due to cyclic thermal transients, as well as investigating the effects of gasket stress variation which can lead to gasket movement and distortion during successive drum cycles. The industry trend is to install automatic bottom un-heading devices (BUDs) to facilitate safe, reliable coke removal and to increase production through shortening un-heading operations. A case study is reviewed which shows how a new drum flange, coupled to a BUD, has been optimized using Finite Element Analysis (FEA). The findings show adequate flange thickness and optimized hub dimensions are required to combat plastic deformation of the flange ring and reduce gasket stress variation. Five designs are modelled, varying the flange thickness, outside diameter and hub geometry. Due to the close proximity of a new side nozzle, the full lower section of the drum has been modelled using quarter and half symmetry FEA with applied temperature distributions from each phase of a typical coke drum cycle; heating, coking and quench. This has allowed for nozzle loadings to be evaluated and the location of the flange weld to be optimized to give the greatest fatigue life. An explanation into why periodic re-tightening is required to keep these joints tight is provided along with recommendations on suitable joint assembly techniques using a combination of bolt load verification and alternative bolting patterns from ASME PCC-1.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116959009","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}

{"title":"Development of New Design Fatigue Curves in Japan: Discussion of Effect of Surface Finish on Fatigue Strength of Nuclear Component Materials","authors":"M. Nakane, Yun Wang, Hisamitsu Hatoh, Masato Yamamoto, A. Hirano, Kentaro Hayashi","doi":"10.1115/pvp2019-93167","DOIUrl":"https://doi.org/10.1115/pvp2019-93167","url":null,"abstract":"\u0000 Based on the world wide fatigue test database, The Design Fatigue Curve (DFC) Phase 1 and 2 subcommittees established in The Japan Welding Engineering Society (JWES) have been developed new design fatigue curves which are applied for the nuclear component materials, in air environment. The effects of the design factor, such as mean stress, size effect and surface finish, etc. on the fatigue curves are also discussed with the fatigue database in order to construct fatigue evaluation method for the new design fatigue curves. The subcommittees also have studied the applicability of newly developed fatigue evaluation method to the nuclear component materials.\u0000 This paper reports the fatigue test results of machined finished small-scale test specimens which are used for the verification of proposed fatigue evaluation method. The materials subjected to the fatigue tests are austenitic stainless steel SUS316LTP, low-alloy steels SQV2A and SCM435H, and carbon steel STPT370. Specimens finished with lathe machining are subjected to the tests. The planed maximum height roughness of the specimen are 25 and 100 μm. The fatigue test results show that the surface finish effect on the fatigue strength in the high cycle region of the austenitic stainless steel can be negligible. On the other hand, fatigue strength of the carbon steel and low alloy steel is decreased as increasing the surface roughness of the specimen. Especially, decrease of fatigue strength for the specimens with more than 100 μm maximum height roughness is larger than that of conventional estimation. It is presumed that severe roughness introduced by lathe machining tends to behave as notches and increase the stress concentration at the specimen surface, and resulted in unexpected decrease of fatigue strength.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125065539","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}

{"title":"Experimental and Analytical Study on Local Failure of Structure Subjected to High Temperature and Pressure","authors":"Yoshiki Tsunemoto, T. Sakaguchi, Takuya Sato, N. Kasahara","doi":"10.1115/pvp2019-93166","DOIUrl":"https://doi.org/10.1115/pvp2019-93166","url":null,"abstract":"\u0000 In our past paper, the new fracture surface was proposed considering the effects of hydrostatic stress in an elastic-plastic region and in a creep region. In this paper, the mechanism the dominant factors of local failure were studied in an elastic-plastic region. Experimental and analytical study were made using circular plate specimens with a nozzle. The material was a lead alloy (99% Pb-1% Sb). The fracture test was performed in an elastic-plastic region at room temperature. Both ductile fracture and local failure were observed at structural discontinuities, based on the stiffness differences between attached nozzles and plates. In this study, the proposed fracture surface in an elastic-plastic region showed the fracture location accurately, for the both failure modes. It was concluded that the proposed fracture surface is available and useful in order to predict the failure mode and the failure location.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126115961","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}

{"title":"Measuring the Effectiveness of Metal Weld Overlay Repairs Through Bulge Depth and Bulge Sharpness Analysis","authors":"Egler D. Araque, Darren Love, Stephen Park, Daryl K. Rutt, Rick D. Clark","doi":"10.1115/pvp2019-93661","DOIUrl":"https://doi.org/10.1115/pvp2019-93661","url":null,"abstract":"\u0000 Weld overlay is a repair method that has been used over the last 10 years to limit the growth of bulges and to extend the remaining life of delayed coking drums. Different refinery operators have used varied approaches, ranging from localized patches on specific regions of concern, to bands along circumferential welds, to large sections of structural repair that completely cover a bulged area. The authors have observed the evolution of regions repaired with internal weld overlay on 18 drums over periods of 5 and 8 years. A comparison of bulge sharpness and bulge depth on a year-over-year basis is presented to measure the effectiveness of metal weld overlay and how the overlay impacts continued distortion of the vessel. Furthermore, factors such as the taper ratio in the transition zones, and the distance between the peak of a bulged area and the edges of the weld overlay, are presented as key parameters that affect the likelihood of cracks developing along the transition zones at the upper and lower edges of the repair.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122620516","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}

{"title":"Decay of Excitation Load From Heat Recovery Steam Generators (HRSG) to Attached Piping System As a Function of Pipe Supports Locations","authors":"E. Appiah, Kshitij P. Gawande","doi":"10.1115/pvp2019-93157","DOIUrl":"https://doi.org/10.1115/pvp2019-93157","url":null,"abstract":"\u0000 Construction of combined cycle gas turbine (CCGT) plants, which are combination of a simple cycle gas turbine (Brayton cycle) and a steam power cycle (Rankine cycle), have increased in recent years due to their high efficiency, low emissions, relative compact size, and minimal delivery time, among other advantages. One key component of CCGT is a heat recovery steam generator (HRSG). The HRSG is basically a heat exchanger composed of a series of preheaters (economizers), evaporator, reheaters, and superheaters. Combustion gas from gas turbine is used as an energy source for steam generation in the HRSG. Due to high mass flowrate of combustion turbine exhausts gas and injection of water to reduce NOx contents, high vibration and severe noise are created. The noise induces acoustic resonance in the HRSG duct cavities. The high vibration together with the acoustic resonance creates large forces. These forces have been attributed to excitation mechanisms including fluid elastic instability, random turbulence excitation, and periodic wake shedding. Some of the forces are transmitted to the attached pipes. Integrity of the piping system to withstand the forces depends on rigid and variable pipe supports. It is therefore paramount to determine the load induced into the supports to design them adequately. The purpose of this paper is to provide relative magnitude of loads experienced at various pipe supports as a function of distance from the HRSG (load decay). This knowledge is expected to help support designers to optimize material allocation to ensure pipe system integrity at optimum cost.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122932984","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}

{"title":"A Proposal of Inelastic Constitutive Equations of Lead Alloys Used for Structural Tests Simulating Severe Accident Conditions","authors":"Ryuta Hashidate, T. Onizawa, T. Wakai, N. Kasahara","doi":"10.1115/pvp2019-93820","DOIUrl":"https://doi.org/10.1115/pvp2019-93820","url":null,"abstract":"\u0000 This paper studies inelastic stress-strain relationship equation and creep rupture equation and creep strain equation of 99%lead-1% antimony alloy. Under the severe accident conditions, structural materials of nuclear power plants are subjected to excessive high temperature. Although it is very essential to clarify how the structure collapses under the severe accident conditions, there’re no experimental evidences of failure modes and the failure mechanisms in such high temperatures are not clarified. However, it is very difficult and expensive to perform structural tests using actual structural materials, such as austenitic stainless steels. Therefore, the authors propose to use lead alloys instead of actual structural materials. Because the strength of such alloys is much poorer than that of the actual structural materials, failure can be observed at much low temperature and by much small load.\u0000 For demonstration of analogy between the failure mechanisms of lead alloy structure at low temperature and those of the actual structures at extremely elevated temperature, numerical analyses are required. The authors proposes inelastic constitutive equations of lead alloy based on a series of material tests. Nonlinear numerical analyses, e.g. finite element analyses, can be performed using the proposed equations.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133831006","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}

{"title":"Suppression of Low Energy Natural Modes of Pipe for Mitigation of Turbulence Induced Vibration","authors":"A. Seena, Donghyung Lee, Juyoul Kim","doi":"10.1115/pvp2019-93696","DOIUrl":"https://doi.org/10.1115/pvp2019-93696","url":null,"abstract":"\u0000 Turbulence induced vibrations are most commonly encountered in industrial piping’s. Several guidelines are available for knowhow and its mitigation in piping designs and acceptable limits of vibration beyond which fatigue failure may occur in pipes. In present paper, it has been emphasized to predict potential turbulence induced vibrations at Design Stage rather than to have the expensive trouble-shooting solutions after the fabrication of system. The detailed review of currently available methods for assessing flow-induced vibrations in piping systems, including current limitations in existing codes and guidelines are discussed. These limitations are centered on the empirical approach currently taken in codes and guidelines. In present paper, a rational approach has been proposed in which the turbulent kinetic energy of the fluid flow is compared against the kinetic energy required to vibrate the pipe beyond its allowable level of vibration. The proposed method has been accessed using a documented case study. The parameters needed to evaluate the relative energies of vibration to turbulent kinetic energy of the fluid flow can be determined from FEA software, which make the present approach practically feasible for the mitigation at design stage.","PeriodicalId":150804,"journal":{"name":"Volume 3: Design and Analysis","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132446701","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}