Local approaches applied to a seam-welded tubular joint

Author(s):  
D. Radaj ◽  
C.M. Sonsino ◽  
W. Fricke
Keyword(s):  
Author(s):  
P. Thibaux ◽  
J. Van Wittenberghe ◽  
E. Van Pottelberg ◽  
M. Van Poucke ◽  
P. De Baets ◽  
...  

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.


Author(s):  
Shaojun Wang ◽  
Xiaoying Tang ◽  
Houde Yu ◽  
Yaozhou Qian ◽  
Jun Cheng ◽  
...  

Responding to complexity and particularity welding on the geometry of TKY tubular node, this paper constructs mathematical model of tubular joint weld of arbitrary section by simplifying the geometry structure, and draws welded joints and ultrasonic sound beam lines based on the actual specifications in order to solve the problems of low efficiency, positioning difficulty, missing inspection and etc. The computeraided simulation technology can realize the visualization in the beam coverage model of welded joints, which can commendably guide the design of ultrasonic phased array inspection and overcome the blindness of the instrument detection parameters, thus improving the effectiveness and pertinence of the actual detection. Study shows that it is beneficial to enhance the effectiveness of the detection tubular joint weld by employment of Visual beam and ultrasonic phased array technology.


Author(s):  
Hideaki Murayama ◽  
Kazuro Kageyama ◽  
Kohei Ohara ◽  
Kiyoshi Uzawa ◽  
Makoto Kanai ◽  
...  

Defects and damage in a structural joint can trigger a critical degradation or collapse of the structure. Among joints, welded joints have many uncertainties, such as remaining stress, initial defects, and heat-affected zone. Such uncertainties in a welded joint can also induce a strain fluctuation, when they are subjected to a load. Conversely, the strain fluctuation along the weld line may represent the presence of uncertainties in the welded joint. This means that monitoring strain distribution along the weld line can be good way to assess their integrity and improve reliability of the structure. We have developed a novel distributed strain measurement technique which can measure strain distributions along fiber Bragg gratings (FBG) in an optical fiber and has the high spatial resolution and we applied it to strain monitoring of a welded tubular joint. The spatial resolution o is less than 1 mm and it was confirmed by measurement simulations and experiments. Then, we measured the strain distributions along the weld line of the tubular joint of a steel pipe subjected to a tensile load by the developed measurement system. We could successfully measure the development of the strain distribution along the weld line, where the sharply fluctuating strain distributions resulting from some defects were observed. In this paper, we describe the measurement principle and performance of the optical fiber sensor, and then show the results of strain monitoring in the welded joint.


2010 ◽  
pp. 491-497
Author(s):  
F Mashir ◽  
X Zhao ◽  
Z Xiao ◽  
P Dong ◽  
L Tong
Keyword(s):  

Rekayasa ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 191-199
Author(s):  
Irma Noviyanti ◽  
Rudi Walujo Prastianto ◽  
Murdjito Murdjito

A marginal field defines as an oil and/or gas field that has a short production period, low proven reservoir, and could not be exploited using existing technology. As the demand for oil and gas keeps increasing, one of the solutions to tackle the issues is to build the modified platform which came to be more minimalist to conduct the oil and gas production in the marginal field. Naturally, the minimum offshore structures are cost less but low in redundancy, therefore, pose more risks. Although the study on the minimum structures is still uncommon, there are opportunities to find innovative systems that need to have a further analysis toward such invention. Therefore, this study took the modified jacket platform as a minimum structure, and local stresses analysis by using finite element method is applied for the most critical tubular joint with multiplanarity of the joint is taking into account. The analysis was carried out using the finite element program of Salome Meca with three-dimensional solid elements are used to model the multiplanar joint. Various loading types of axial force, in-plane bending moment, and out-of-plane bending moment are applied respectively to investigate the stress distribution along the brace-chord intersection line of the tubular joint. The results show that the hotspot stress occurred at a different point along each brace-chord intersection line for each loading type. Finally, as compared to the in-plane bending moment or out-of-plane bending moment loading types, the axial force loading state is thought to generate greater hotspot stress.


2014 ◽  
Vol 501-504 ◽  
pp. 791-795
Author(s):  
Lan Chen ◽  
Bo Yin

As a new type of joint, the thick-walled steel tubular joint is applied in the single-layer latticed shell to solve the connectivity problem of rectangular tube. In combination with the design of practical project, the effect of the new joint stiffness on the overall stability of a single-layer latticed shell and the value of joint stiffness are studied by ANSYS. Some parameters as the rectangular tube section, the thickness of thick-walled steel tube and connecting plate are taken into account in the process of geometric nonlinear analysis. The results show that joint stiffness has great influence on the overall stability of a single-layer latticed shell and the range of effect gradually increases with the growth of rectangular tube section.


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