scholarly journals Finite Element Analyses on Local Buckling Strength of Polygonal-Section Shell Towers

2012 ◽  
Vol 13 (4) ◽  
pp. 1900-1907 ◽  
Author(s):  
Seong-Mi Park ◽  
Byung-Ho Choi
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Finite Element Analyses ◽  
Buckling Strength

Failure Analysis of Thinned Wall Elbows Under Excessive Seismic Loading

2002 ◽  
Author(s):  
Masaki Shiratori ◽  
Yoji Ochi ◽  
Izumi Nakamura ◽  
Akihito Otani
Keyword(s):  
Finite Element ◽  
Fatigue Damage ◽  
Failure Modes ◽  
Low Cycle Fatigue ◽  
Local Buckling ◽  
Seismic Loading ◽  
Cycle Fatigue ◽  
Finite Element Analyses ◽  
Residual Thickness ◽  
Limited Period

A series of finite element analyses has been carried out in order to investigate the failure behaviors of degraded bent pipes with local thinning against seismic loading. The sensitivity of such parameters as the residual thickness, locations and width of the local thinning to the failure modes such as ovaling and local buckling and to the low cycle fatigue damage has been studied. It has been found that this approach is useful to make a reasonable experimental plan, which has to be carried out under the condition of limited cost and limited period.

Local Buckling Assessments for the Medgaz Pipeline

2007 ◽  
Author(s):  
D. DeGeer ◽  
C. Timms ◽  
J. Wolodko ◽  
M. Yarmuch ◽  
R. Preston ◽  
...  
Keyword(s):  
Finite Element ◽  
Gas Flow ◽  
Local Buckling ◽  
External Pressure ◽  
Full Scale ◽  
Regression Equations ◽  
Finite Element Analyses ◽  
Bending Strain ◽  
Primary Focus ◽  
Full Scale Tests

Medgaz is a consortium of leading international energy companies, with the aim of designing, building and operating an Algerian-European gas pipeline via Spain. The offshore section of this pipeline will be 210 km long, traversing the Mediterranean Sea floor at a maximum depth of 2160 metres. The 24-inch diameter, grade X70 line will provide up to 8 billion cubic metres of natural gas per year, with first gas flow expected in 2009. To support the technical issues surrounding such an ultra-deepwater pipelay, a number of full scale local buckling tests and detailed finite element analyses were undertaken at the C-FER facility in Edmonton, Canada. Local buckling conditions of concern included buckling of the pipe section at the pipe-buckle arrestor interface and collapse of the plain pipe under high external pressure. These conditions may arise during various phases of pipeline installation and operation, but the primary focus was to evaluate the local buckling integrity of the pipe during installation using the S-lay method. These conditions were assessed for both as-fabricated pipe and pipe that was heat treated to simulate a pipe coating process. This paper describes the Medgaz pipeline, its current state of development, the installation challenges that necessitated the buckling assessments, and some of the work performed throughout the study, including full scale tests, finite element analyses, and regression analyses. Collapse and critical bending strain predictive equations were developed and are also presented, and are compared to other well known collapse and critical bending strain equations. The results of these assessments have suggested that, for the local buckling conditions presented herein, the S-lay method can be successfully employed for ultra-deep water pipelay. The results demonstrated that the proposed pipe-buckle arrestor connection design will not cause premature buckling as the pipe traverses along the stinger during installation. In addition, potentially high bending strains in the overbend will not significantly influence the collapse strength of the pipe. The regression equations presented in this paper have also been shown to provide an accurate means of predicting pipe local buckling and collapse.

Local Buckling Behavior of X100 Linepipes

2003 ◽  
Author(s):  
Nobuhisa Suzuki ◽  
Ryuji Muraoka ◽  
Alan Glover ◽  
Joe Zhou ◽  
Masao Toyoda
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
Critical Strain ◽  
Axial Stress ◽  
Local Buckling ◽  
Bending Moment ◽  
Finite Element Analyses ◽  
Design Factor ◽  
Shell Elements ◽  
Buckling Behavior

Local buckling behavior of API 5L X100 grade linepipes subjected to axial compression and/or bending moment is discussed in this paper based on results obtained by finite element analyses. Yield-to-tensile strength (Y/T) ratio and design factor were taken into account in the finite element analyses in order to discuss their effects on the local buckling behavior. The local bucking behavior of such lower strength linepipes as X60 and X80 grade linepipes is also discussed for comparison. Two-dimensional solid elements and four-node shell elements were used for the finite element modeling of the linepipes subjected to axial compression and bending moment, respectively. The study has improved the understanding of local buckling behavior of the X100 grade linepipes and observed the following trends. When a linepipe is subjected to axial compression, the critical axial stress decreases with increasing design factor and Y/T ratio. However, the nominal critical strain increases with increasing design factor and decreasing Y/T ratio. When a linepipe is subjected to bending moment, the critical bending moment decreases with increasing design factor and Y/T ratio. Similarly, the nominal critical strain increases with increasing design factor. However, the nominal critical strain increases with decreasing Y/T ratio when the design factor is less than and equal to 0.6 and decreases with decreasing Y/T ratio when the design factor is equal to 0.8.

Design of flexure revolute joint based on compliance and stiffness ellipsoids

2021 ◽  
pp. 095441002110169
Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson
Keyword(s):  
Finite Element ◽  
Single Point ◽  
Synthesis Method ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Rotational Stiffness ◽  
Rotational Angle ◽  
Parameterized Model ◽  
Flexure Joints ◽  
Translational Stiffness

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.

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