Examination of Various Bending Moments on the Run Side and on the Branch Side for the Stress Index C2 of ASME NB-3600 Class 1 Branch Connections

2016 ◽  
Author(s):  
Umar Faraz ◽  
Robert Gurdal
Keyword(s):  
Cross Section ◽  
Branch Pipe ◽  
Bending Moment ◽  
Additional Stress ◽  
Main Question ◽  
Bending Moments ◽  
Technical Paper ◽  
Class 1 ◽  
The Impact ◽  
Stress Analyses

Previous stress analyses have shown that the requirement of exclusively using the branch pipe cross-section properties for the NB-3600 Class 1 branch connection stress analyses can be very severe (conservative), when compared with using the branch nozzle cross-section properties. In the analyses performed for a 2015 PVP technical paper (Ref. 2), one of the questions raised was the fact that only two specified bending moments were used in those previous stress analyses: 1,000,000 in-lbf as the run bending moment and 20,000 in-lbf as the branch bending moment. In fact, that was the main question that was raised. Therefore, the purpose of this technical paper is to perform additional stress analyses, based on various bending moments on the run side and on the branch side. The impact of using these various bending moments will be evaluated. The 2001 Edition of the ASME-Code removed a note at the bottom of the branch connection NB-3600 Figure. This note is required to be able to perform more accurate NB-3600 piping stress analyses of the branch connection. There is at this time a suggestion to restore that note.

Comparison Between the ASME Code NB-3600 Piping Design Branch Connection Stress Analyses and Finite Element Analyses

2015 ◽  
Author(s):  
Umar Faraz ◽  
Robert Gurdal
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Branch Pipe ◽  
Finite Element Analyses ◽  
Moment Stress ◽  
Design Rules ◽  
Pipe Cross Section ◽  
Class 1 ◽  
Asme Code ◽  
Stress Analyses

Stresses in Class 1 branch connections that consist of large bore run pipe with a reinforced branch nozzle should rarely be limited by the run–branch interface stresses. The end of the “branch nozzle – branch pipe” interface is the location on the branch nozzle one would expect to see the limiting stress. Therefore, it is important that reasonable Design Rules are maintained in the ASME Code Section III for the stress analyses of the Class 1 Piping branch connections to avoid over-predicting the “run pipe - branch nozzle” interface stresses. This will allow the analysts to concentrate on load reductions needed in a logical manner. In Class 1 Piping Design, the calculation of the branch total stress due to the moments is the result of the sum of the stresses from the run moment and of the stresses from the branch moment with these branch moment stresses being calculated using either the branch pipe cross-section or the branch nozzle cross-section. This in itself is already severe, when compared with other Piping Design Rules for branch connections. In addition, starting with the ASME Code year 2002, the branch-side moment stress is based exclusively on the branch pipe cross-section, which leads to a higher moment stress, and this higher moment stress is still absolutely added to the run-side moment stress. As indicated in that ASME Code year 2002 and beyond, this addition is independent of the length of the branch nozzle reinforcement. This leads to total moment stresses that are the sums of moment stresses that do not occur at all at the same location. The purpose of this technical paper is to compare a) the stresses calculated with the earlier more correct Class 1 Piping methodology from 2001 and before 2001; b) the stresses calculated with the more recent and more severe Class 1 Piping methodology; and c) the stresses from finite-element analyses. Conclusions are provided on what should be done for the future Class 1 Piping Design methodology of branch connections.

REGULATION OF GUYED MAST STRESSES

2009 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Donatas Jatulis ◽  
Algirdas Juozapaitis
Keyword(s):  
Numerical Experiment ◽  
Cross Section ◽  
Cross Sections ◽  
Mobile Communications ◽  
Bending Moment ◽  
Physical Parameters ◽  
Bending Moments ◽  
Rational Distribution ◽  
Guyed Mast ◽  
Prestressed Structures

Development of mobile communications and their networks in Lithuania produced an essential influence on high telecommunications structures design activities. In its turn it has stimulates their research and innovations of such structural systems. One of the most efficient systems of telecommunication structures is guyed mast. It should be indicated that the behaviour of prestressed structures systems has been thoroughly examined in many investigations. But recently the increase of economical efficiency of guyed masts becomes undoubtedly actual. The development of such structures in many cases is directed to the selection in the mast elements scheme and their cross-sections. It should be underlined that geometric and physical parameters have a decisive moment on prestressed structures. An exact parameters choice allows to obtain in the mast rational distribution of bending moments, predetermining a project solution closely connected with the mass criteria. The diagram of bending moment’s distribution in guyed mast is considered rational when negative and positive moment values are absolutely equal. In the present research, analytical expressions for rational bending moments determining are presented. Above mentioned non-linear expressions estimate an influence of axial force for the bending moments. When solving the task of rational bending moments in a guyed mast, it is necessary to select suitable (i.e. rational) guyed mast bending spans. In the article is described the calculations of the guys fastening altitudes when guy level number is known. It should be noted that it is necessary to use the way of gradual approximation. The sequence of calculations is interrupted, when the sum of guyed mast spans corresponds to the exactness selected. The decisive part in mast behaviour is played by guys. The main parameters of them are pretension and cross-section area. In the article the equations are presented for determining the above-mentioned parameters. It should be stressed that after making uniform stresses of the guys on the different level of each of them it is possible to minimise some steel quantities. In the article a numerical experiment is presented for determining the technical-economical effectiveness of stress regulation. For the analysis, a standard three edged lattice guyed mast with cross-section parameters was selected in a usual way. By the suggested beam composition methods the design of the shaft was performed, and the results obtained were compared to a standard guyed mast shaft. For determining the stresses of beam elements Robot Millennium software was used; its reliability was demonstrated by earlier investigations. The results of numerical experiment that the maximal bending moment of composed guyed mast is three times less than that of a standard maximal one. An applied regulation of stresses has allowed to lessen much of the cross-section of guy rope. By applying the suggested methods it was possible to diminish the steel expenditure of shaft by more than 30%.

Combined Bending and Compression of a Pressurized Circular Cylindrical Membrane Column

1965 ◽  
Vol 87 (3) ◽  
pp. 372-378
Author(s):  
W. E. Jahsman
Keyword(s):  
Compressive Strength ◽  
Cross Section ◽  
Compressive Load ◽  
Circular Cross Section ◽  
Bending Moment ◽  
Maximum Load ◽  
Bending Moments ◽  
Lateral Deflection ◽  
The Cross

Load-lateral deflection curves are developed for a pressurized tube of circular cross section under combined bending and compression. The tube walls are assumed to have negligible compressive strength so that wrinkling develops if the stress tends to become negative. It is found that for a given bending moment, the load increases monotonically with deflection until a maximum is reached beyond which the load decreases with increasing deflection. An interaction curve of the maximum load versus bending moment shows that the presence of only a small amount of bending significantly decreases the maximum compressive load below the classical Euler load. Conversely, for bending moments which produce almost complete wrinkling of the cross section, only very small amounts of compressive load can be supported.

Effect of Anti-Wear Tape on Behavior of Flexible Risers

2014 ◽  
Author(s):  
Chongyao Zhou ◽  
Naiquan Ye ◽  
Svein Sævik
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Cross Section ◽  
Bending Moment ◽  
Laboratory Measurements ◽  
Flexible Riser ◽  
Bending Loads ◽  
Flexible Risers ◽  
Bending Behavior ◽  
The Impact

The service life of a flexible riser is often dominated by the metallic layers under cyclic bending loads, particularly the tensile armor layers. The effect of the anti-wear tapes is normally omitted during cross section modelling, where a plane-remain-plane assumption is usually used for stick condition. Significant differences have been observed between numerical analysis assuming plane surfaces remain plane and laboratory measurements studying the bending moment versus curvature for a flexible riser which has anti-wear tapes between the two tensile armor layers. A new shear interaction algorithm has been developed in the numerical model to improve the modeling of the anti-wear tapes by taking the thickness and shear modulus of the anti-wear material into account. The impact of these parameters on the bending behavior of the flexible riser is demonstrated by comparing the numerical analysis results with the laboratory measurements.

scholarly journals Analysis of the effect of reinforcement of diaphragm spans on their spatial work

2021 ◽  
pp. 93-97
Author(s):  
Katerina Berezhna ◽  
Sergey Krasnov
Keyword(s):  
Cross Section ◽  
Bending Moment ◽  
Element Model ◽  
Optimal Number ◽  
Beam Deflection ◽  
Bending Moments ◽  
Technical Standards ◽  
Value Analysis ◽  
Bridge Structures ◽  
Different Dimensions

A large number of bridges in Ukraine have been built in the 60–70 s (about 54 % of the total number). In that regard, the number of cases of detecting various types of damage on the elements of bridge structures is increasing, which can cause emergencies in the future. It also suggests that most of the bridges and overpasses were built according to the old technical standards and now do not meet the modern standards of DBN V.2.3-14: 2006 and DBN V.2.3-22: 2009, both in terms of carrying capacity and dimensions of the roadway. Therefore, the issues of strengthening the existing spans are relevant. Goal. The work analyzes the effect of reinforcement of diaphragm spans on their spatial work in order to determine the effectiveness of reinforcement by gluing additional rigid reinforcement and installing transverse metal beams. The tasks that have been solved in the work are as follows: creating an adequate finite element model of the diaphragm span; limiting the number of options for design schemes to the optimal number; construction and analysis of the graphs of bending moments and deflections in the cross-section in the middle of the span of beams. Results. The graphs of the distribution of bending moments in the beams of the superstructure for different dimensions show that the presence of reinforcement does not affect the value of the bending moment, and the distribution of forces between the beams of the superstructure becomes less uniform with an increase in their number. The deflections for all load cases and dimensions are greater than the deflections of beams with reinforcement; however, the installation of an additional transverse metal beam does not affect the values and distribution of deflections. Beam deflection graphs become less uniform with an increase in their number. Practical value. Analysis of the effect of reinforcement on the spatial work of span structures has shown that only reinforcement of beams with longitudinal rigid reinforcement without installing transverse beams is expedient in practice.

A New Approach to Determining the Bending Moment in Tube Forming

2015 ◽  
Vol 1127 ◽  
pp. 31-37
Author(s):  
Eva Peterková ◽  
Radko Samek
Keyword(s):  
Cross Section ◽  
Bending Moment ◽  
Material Model ◽  
Bending Moments ◽  
Rigid Plastic ◽  
Hardening Material ◽  
New Approach ◽  
The Real ◽  
Tube Cross Section ◽  
Subsequent Integration

The article deals with more precise method of bending moment determination for rigid plastic work hardening material. Unlike earlier methods, a new methodology takes into account the real shape of the deformed tube cross-section after bending. The real centroid position of the tube cross-section, the change of wall thickness and the irregularly deformed tube cross-section are considered. The paper presents a possible way of determining the real bending moment, reflecting the geometrical changes of the “flattened” cross-section. This approach is based on the subsequent integration of elementary bending moments, which reflects successive changes of the bending stress and a material model as well.

scholarly journals Effects of the Mortar Matrix on the Flexural Capacity of Masonry Cross Sections Strengthened with FRCM Materials

2020 ◽  
Vol 10 (21) ◽  
pp. 7908
Author(s):  
Giovanni Crisci ◽  
Giancarlo Ramaglia ◽  
Gian Piero Lignola ◽  
Francesco Fabbrocino ◽  
Andrea Prota
Keyword(s):  
Epoxy Resin ◽  
Cross Section ◽  
Cross Sections ◽  
Structural Engineering ◽  
Bending Moment ◽  
Fiber Reinforced ◽  
Flexural Capacity ◽  
Flexural Response ◽  
The Impact ◽  
Mortar Matrix

The strengthening intervention strategies that exist for masonry buildings are based on the use of thin composites and are a recent activity used in structural engineering. Nowadays, mortar matrices are frequently found instead of epoxy resins, since the fiber reinforced cementitious matrix (FRCM) composites are more compatible with masonry than fiber reinforced plastic (FRP) ones. The mortar matrix in FRCM composites is not comparable to the epoxy resin, and therefore its contribution is different not only in traction but above all on the compression side. Due to its larger thickness, if compared to the epoxy resin, the impact of the mortar matrix on the flexural response of strengthened cross sections is not negligible. This paper aimed to investigate the influence of the contribution of the mortar matrix on the compression side on the flexural capacity of strengthened cross section. As such, p–m interaction domains and bending moment–curvature diagrams were evaluated to understand the influence of several mechanical properties of fiber and mortar matrices on FRCM efficiency, typical of real applications. Hence, the impact of several constitutive relationships of composites (linear and bilinear behavior) was considered for the structural analysis of the strengthened cross section. The presented results are all completely in a dimensionless form; therefore, independent of geometry and mechanical parameters can be the basis for developing standardized design and/or verification methodologies useful for the strengthening systems for masonry elements.

An experimental investigation of a right-angled single unreinforced mitred-bend subjected to various bending moments

1966 ◽  
Vol 1 (3) ◽  
pp. 248-263 ◽  
Author(s):  
N Jones ◽  
R Kitching
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Bending Moment ◽  
Straight Tube ◽  
Bending Moments ◽  
Curved Pipe ◽  
Design Procedures ◽  
Out Of Plane ◽  
Plane Bending ◽  
Comprehensive Study

It is well known that, upon the application of an in-plane bending moment, the initially circular cross-section of a curved pipe tends to flatten and become approximately elliptical in shape making it much more flexible than an equivalent straight tube. Mitred-bends exhibit similar properties though the behaviour is far more complex. A comprehensive study of a 90° single unreinforced mitred-bend having a radius/thickness ratio of 19 has been performed by means of a stress-probing method. In order to make the work more complete, results have been obtained for a similar bend when subjected to out-of-plane bending and twisting moments. Experimental measurements of stress and flexibility for each type of loading are discussed and certain modifications suggested to existing design procedures.

scholarly journals Optimization of the parameters of truss beams with two posts

2021 ◽  
Vol 48 (3) ◽  
pp. 117-132
Author(s):  
A. K. Yusupov ◽  
H. M. Musеlеmov, ◽  
T. O. Ustarhanov
Keyword(s):  
Cross Section ◽  
Optimal Parameter ◽  
Bending Moment ◽  
Internal Force ◽  
Numerical Calculations ◽  
Design Parameters ◽  
Bending Moments ◽  
The Cross ◽  
Theoretical Results

Based on the theoretical results obtained in the article [17], here the analysis of the influence of various design parameters on the own weight and cost of metal of truss beams with two posts is carried out. An optimal parameter has been obtained that makes it possible to reduce the calculated bending moment in the cross section of a truss beam with two struts.Method. By equalizing the bending moments in various design sections of the truss beam, the internal force factors are reduced. The corresponding equation for optimizing the parameters of the beam has been drawn up and a formula has been obtained to determine the optimal parameter of the structure as a whole.Result. Using the example of numerical calculations, a decrease in the calculated bending moment by 14% compared to truss beams without optimization is shown.Conclusion. The proposed method and algorithm testify to the efficiency and rationality of the obtained optimal parameter of the structure as a whole.

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