Study on Load Capacity Limits of Flanged Pressure Vessel Nozzles

2021 ◽  
pp. 86-93
Author(s):  
Walther Stikvoort
Author(s):  
Michael Martin ◽  
Chris Watson ◽  
Keith Wright

The use of finite element based limit load analysis for the assessment of the primary load capacity of a pressure vessel is well established and numerous papers on the subject, including experimental results, have been published in the last decade. Finite element based limit load analysis is often used in the context of NB-3228.1 Limit Analysis to demonstrate a margin against ductile burst as an alternative to satisfaction of the NB-3200 limits on general, local and primary membrane plus bending stress intensity. However, although NB-3200 permits the use of ‘limit analysis’, no specific guidance on the use of finite element methods for this purpose is provided. Other pressure vessel codes, including ASME VIII Division 2 and EN13445 contain explicit guidance on the use of finite element methods for limit load analysis. To address this, a Code Case is currently under development to provide technical guidance on the use of finite element based limit load analysis within the context of NB-3200 assessments. The Code Case provides a step-by-step procedure which guides the analyst in the application of limit load analysis and ensures that a valid analysis has been undertaken. The topics of geometric weakening, yield surface selection, tentative wall thickness, element selection and selection of Sm are accounted for in the Code Case and discussed. This paper provides a detailed review of the Code Case and shows how it can be used in practice.


1988 ◽  
Vol 20 (1) ◽  
pp. 287-290
Author(s):  
R. Huster ◽  
C. H. Möbius

The directives issued by the German Waste Water Association (ABWASSERTECHNISCHE VEREINIGUNG (ATV)) and by the British WATER RESEARCH CENTRE (WRC) in respect of the rating and control of activated sludge circuits and of the loading of secondary settling tanks of biological waste water treatment plants were studied for their applicability to papermill effluents. To this end, several years' testing was carried out on an activated sludge pilot plant and on various industrial plants. These tests revealed that secondary settling tanks of papermill effluent treatment plants may safely be rated in accordance with ATV up to a sludge volume index (SVI) of 300 ml/g and a sludge return rate of 3. If SVI values are low, the WRC process permits excessive surface loadings and is thus only practicable for high SVI levels. If sedimentation properties of the activated sludge are poor, load capacity limits are indicated more correctly by the WRC method. A simplified settling velocity method derived from the WRC process gives reliable information on the load capacity of secondary settling tanks and may readily be used for sludge circulation control.


1986 ◽  
Vol 84 ◽  
Author(s):  
M.D. Merz ◽  
F. Gerber ◽  
R. Wang

AbstractThe Materials Characterization Center (MCC) at Pacific Northwest Lab- oratory is performing three kinds of corrosion tests for the Basalt Waste Isolation Project (BWIP) to establish the interlaboratory reproducibility and uncertainty of corrosion rates of container materials for high-level nuclear waste. The three types of corrosion tests were selected to address two distinct conditions that are expected in a repository constructed in basalt. An air/steam test is designed to address corrosion during the operational period and static pressure vessel and flowby tests are designed to address corrosion under conditions that bound the condi ring the post-closure period of the repository.The results of tests at reference testing conditions, which were defined to facilitate interlaboratory comparison of data, are presented. Data are reported for the BWIP/MCC-105.5 Air/Steam Test, BWIP/MCC-105.1 Static Pressure Vessel, and BWIP/MC-105.4 Flowby Test. In those cases where data are available from a second laboratory, a statistical analysis of interlaboratory results is reported and expected confidence intervals for mean corrosion rates are given. Other statistical treatment of data include analyses of the effects of vessel-to-vessel variations, test capsule variations for the flowby test, and oven-to-oven variations for air/steam tests.


Author(s):  
Dennis Flanagan ◽  
Alessandro Fisher BS ◽  
Carmen Ciardiello ◽  
Vito Moreno ◽  
Alen Uvalic ◽  
...  

When planning an implant supported restoration the dentist is faced with the surgical and prosthetic technical issues as well as the patient’s expectations. Many patients wish an immediate solution to an edentulous condition. This is especially may be true in the esthetic zone. The extent of the zone is determined by the patient. The dentist may consider when it is feasible to load the supporting implants with definitive or provisional prosthetics. For the work herein, consideration of many parameters were theoretically assessed for inclusion: bone density, cortical thickness, seating torque, parafunction, bite load capacity, number of implants under load, implant/crown ratio, implant diameter and length. After assessment, the most influential parameters were selected. An iteration, using patient age, implant diameter, bite load capacity and cortical thickness, is now presented to aid the implant dentist in determining the feasibility for immediate functional loading of a just placed dental implant in a healed site. Extensive testing is required to develop this concept. According to this iteration, most immediate functional loaded implants would fail. A future refined and definitive formula may enable the clinician to safely immediately functional load an implant with a definitive prosthesis.


2018 ◽  
Vol 9 (5) ◽  
pp. 174
Author(s):  
Agus Maryoto ◽  
Han Ay Lie ◽  
Nanang Gunawan Wariyatno

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