Entrances, Branches, and Bends

2019 ◽  
pp. 85-110
Author(s):  
Troy Shinbrot
Keyword(s):  
Couette Flow ◽  
Model Building ◽  
Rotating Cylinders ◽  
Chaotic Flows ◽  
Static Mixers ◽  
Out Of Plane ◽  
Plane Bending ◽  
Volume Preserving

Effects of boundaries are described, including those associated with entrances, branches, and bends in tubes. Couette flow between rotating cylinders, modelling of volume-preserving flows, and chaotic flows are described. Model building is considered, and the effects of out of plane bending are discussed in the context of static mixers.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane, and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Stresses in Curved, Circular Thin-Wall Tubes

1963 ◽  
Vol 30 (1) ◽  
pp. 134-135
Author(s):  
E. A. Utecht
Keyword(s):  
Thin Wall ◽  
Bending Moments ◽  
Circular Tubes ◽  
Out Of Plane ◽  
Thin Walled ◽  
Plane Bending

Curves are presented which give stress intensification factors for curved, thin-walled circular tubes under various combinations of in-plane and out-of-plane bending moments.

Out-of-Plane Bending (Opb) Test of Large Diameter Mooring Chains

2021 ◽  
Author(s):  
m.r. Karimi ◽  
J. Braun ◽  
E. Gooijer ◽  
P. Barros ◽  
E. Carlberg ◽  
...  
Keyword(s):  
Large Diameter ◽  
Out Of Plane ◽  
Plane Bending

Chain Out of Plane Bending (OPB) Fatigue Joint Industry Project (JIP) Static Test Program and OPB Interlink Stiffness

2016 ◽  
Author(s):  
Lucile Rampi ◽  
Fata Dewi ◽  
Michel Francois ◽  
Arnaud Gerthoffert ◽  
Pedro Vargas
Keyword(s):  
Fatigue Loading ◽  
Time Frame ◽  
Small Time ◽  
Static Test ◽  
Fatigue Design ◽  
Out Of Plane ◽  
Bending Stresses ◽  
Plane Bending ◽  
Mooring Chain ◽  
Fatigue Mechanism

In 2002, several mooring chains of a deepwater offloading buoy failed prematurely within a very small time frame. These chains were designed according to conventional offshore fatigue assessment using API recommendations. With this first deepwater buoy application, a new mooring chain fatigue mechanism was discovered. High pretension levels combined with significant mooring chain motions caused interlink rotations that generated significant Out of Plane Bending (OPB) fatigue loading. Traditionally, interlink rotations are relatively harmless and generate low bending stresses in the chain links. The intimate mating contact that occurs due to the plastic deformation during the proof loading and the high pretension of the more contemporary mooring designs have been identified as aggravating factors for this phenomenon. A Joint Industry Project (JIP), gathering 26 different companies, was started in 2007 to better understand the Out of Plane Bending (OPB) mooring chain fatigue mechanism and to propose mooring chain fatigue design recommendations. This paper summarizes the quasi static OPB stiffness measurement campaign and the post processing work to derive the OPB interlink stiffness.

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