A numerical investigation of static resistance of welded planar steel tubular joints under in-plane and out-of-plane bending at elevated temperatures

2019 ◽  
Vol 199 ◽  
pp. 109622 ◽  
Author(s):  
E. Ozyurt ◽  
Y.C. Wang
Keyword(s):  
Numerical Investigation ◽  
Elevated Temperatures ◽  
Tubular Joints ◽  
Out Of Plane ◽  
Plane Bending ◽  
Static Resistance

Stress Concentrations in DT/X Square-to-Square and Square-to-Round Tubular Joints

1994 ◽  
Vol 116 (2) ◽  
pp. 49-55 ◽  
Author(s):  
A. K. Soh ◽  
C. K. Soh
Keyword(s):  
Stress Concentration ◽  
Bending Moment ◽  
Bending Moments ◽  
Axial Loads ◽  
Stress Concentrations ◽  
Tubular Joints ◽  
Out Of Plane ◽  
Concentration Factors ◽  
Plane Bending ◽  
Stress Concentration Factors

A parametric stress analysis of DT/X square-to-square and square-to-round tubular joints subjected to axial loads, in-plane, and out-of-plane bending moments has been performed using the finite element technique in order to provide a sound basis for using such sections in the design of complex structures. The results of this analysis are presented as a set of equations expressing the stress concentration factor as a function of the relevant geometric parameters for various loading conditions. A comparison is made between the results obtained for square-to-square and square-to-round tubular joints and those obtained for round-to-round tubular joints by other researchers. In general, the stress concentration factors for square-to-square tubular joints are the highest, followed by those of the corresponding round-to-round joints, with those of the corresponding square-to-round joints the lowest when the joints are subject to axial loads. In the case of in-plane bending moment, the stress concentration factors for square-to-square joints are generally still the highest, but followed by those of the corresponding square-to-round joints, with those of the corresponding round-to-round joints the lowest. However, the stress concentration factors for the three types of joint are comparable when they are subject to out-of-plane bending moments.

Calculation of the stress concentration factor in the welded tube junction subjected to combined loadings

2014 ◽  
Vol 11 (4) ◽  
pp. 339-348 ◽  
Author(s):  
A. Fouathia ◽  
A. Mekroud ◽  
K. Bellagh
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Hot Spots ◽  
Combined Loading ◽  
Stress Concentrations ◽  
Tubular Joints ◽  
Out Of Plane ◽  
Welded Tube ◽  
Plane Bending ◽  
Shore Platforms

Fatigue failure caused by stress concentrations in tubular welded joints is observed in off shore platforms subjected to cyclic loading in corrosive marine environments. In some junctions, the stress concentration can induce a stress thirty times the nominal stress, and increase the risk of fatigue failure in tubular joints. Therefore, it is necessary to accurately assess the intensity of the stress concentrations to effectively deal with the problem of fatigue damage and lead to reliable tubular joints. This work aims to study the stress distribution and location of the "hot" spots in a Twelded tubular structure subjected to a combined loading of tension and bending (in-plane bending, out of plane bending and traction) to better simulate the actual loading.

Low Cycle Fatigue of T-Tubular Joints With Out-of-Plane Bending Loading

2007 ◽  
Author(s):  
Fro̸ydis Boge ◽  
Torgeir K. Helland ◽  
Stig Berge
Keyword(s):  
Low Cycle Fatigue ◽  
Hot Spot ◽  
Fatigue Loading ◽  
Published Data ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
R Ratio ◽  
Out Of Plane ◽  
Plane Bending ◽  
Bending Loading

Tubular T-joints were fatigue tested with out-of-plane bending loading. Six models were tested, three models with R-ratio of 0 and three with R = −1. Hot spot stress was measured for the brace and for the chord using the ECSC linear extrapolation procedure. Fatigue loading was applied in load control, to obtain through thickness cracking at a number of cycles in the range 4 000–200 000 cycles. The data were analysed and compared with published data and with current fatigue design criteria for tubular joints.

Stress Concentrations in T/Y and K Square-to-Square and Square-to-Round Tubular Joints

1992 ◽  
Vol 114 (3) ◽  
pp. 220-230 ◽  
Author(s):  
A. K. Soh ◽  
C. K. Soh
Keyword(s):  
Stress Concentration ◽  
Bending Moments ◽  
Axial Loads ◽  
Stress Concentrations ◽  
Tubular Joints ◽  
Out Of Plane ◽  
Concentration Factors ◽  
Plane Bending ◽  
Stress Concentration Factors ◽  
Element Technique

A parametric stress analysis of T/Y and K square-to-square and square-to-round tubular joints subjected to axial loads, in-plane and out-of-plane bending moments has been performed using the finite element technique in order to provide a sound basis for using such sections in the design of complex structures. The results of this analysis are presented as a set of 42 equations expressing the stress concentration factor as a function of the relevant geometric parameters for various loading conditions. A comparison is made between the results obtained for square-to-square and square-to-round tubular joints and those obtained for round-to-round tubular joints by other researchers. In general, the stress concentration factors obtained from round-to-round and square-to-round tubular joints are closer as compared with those of the corresponding square-to-square tubular joints. Moreover, the stress concentration factors for square-to-square tubular joints are generally lower than those of the corresponding round-to-round and square-to-round tubular joints when the joints are subject to axial loads; but the reverse is true when the joints are subject to in-plane bending moments. However, the stress concentration factors for the three types of joint are comparable when they are subject to out-of-plane bending moments.

A model technique for bending strength of tubular joints

1992 ◽  
Vol 27 (4) ◽  
pp. 197-210 ◽  
Author(s):  
H Fessler ◽  
W Hassell ◽  
T H Hyde
Keyword(s):  
Bending Strength ◽  
Strength Reduction ◽  
Lead Alloy ◽  
Bending Moments ◽  
Tubular Joints ◽  
Die Cast ◽  
Out Of Plane ◽  
Plane Bending ◽  
Bending Loading ◽  
Model Technique

One shape of ‘Y—T’ joint has been die-cast in a tin-lead alloy. Twenty-one models have been tested in in-plane or out-of-plane bending, loading one or both braces. The results are presented non-dimensionally as Ultimate Strength Reduction Ratios (USRR) i.e., as fractions of (simply calculated) bending moments which would have ensured failure of the brace remote from the joint. The results from the tin-lead models agreed with relevant results from steel models. Parametric equations derived mainly from ‘T’ joint data predict the failure of 90 degree braces well, but underestimate the strength of 45 degree braces in in-plane and out-of-plane bending. Plastic collapse occurs on the compressed side of the braces before tearing on the tension side.

Efficient Fatigue Testing of Tubular Joints

2015 ◽  
Author(s):  
P. Thibaux ◽  
J. Van Wittenberghe ◽  
E. Van Pottelberg ◽  
M. Van Poucke ◽  
P. De Baets ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Tubular Joints ◽  
Testing Method ◽  
Out Of Plane ◽  
Resonance Principle ◽  
Tubular Joint ◽  
The Cost ◽  
Good Agreement

Tubular joints are intensively used in off-shore structures for shallow waters. Depending on the sea conditions and the type of structure, the design can be fatigue driven. This is particularly the case for off-shore wind turbines, where turbulences are generating a fatigue loading. Any improvement of the fatigue performance of the tubular joint would be beneficial to reduce the weight and the cost of the structure. To assess efficiently the fatigue resistance of the tubular joint, a testing method has been developed based on the resonance principle. The complete circumference of the welded joint can be loaded, successively in the in-plane and out-of-plane modes at a frequency close to 20Hz. Finite element computations were used to investigate the feasibility of the concept. Then, an X-node was made and successfully tested to investigate the stress distribution along the weld. The experimental results were compared with finite element computations, giving a good agreement.

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.

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