New API RP2A Tubular Joint Strength Design Provisions

2007 ◽  
Vol 129 (3) ◽  
pp. 177-189 ◽  
Author(s):  
David Pecknold ◽  
Peter Marshall ◽  
Justin Bucknell
Keyword(s):  
Static Strength ◽  
Strength Prediction ◽  
Load Factor ◽  
Prediction Equations ◽  
Hollow Section ◽  
Out Of Plane ◽  
Bending Loads ◽  
Tubular Joint ◽  
Plane Bending ◽  
Circular Hollow Section

The development of the new API RP2A (22nd edition) parametric static strength prediction equations for planar circular hollow section tubular joints is described. Prediction equations are presented for brace axial, brace in-plane bending, and brace out-of-plane bending loads. The prediction equations are based on screened test databases, augmented, and extended by an extensive new series of validated nonlinear finite element simulations for nonoverlapping K joints, double tee (DT/X) joints, and T joints. The increased reliability (reduced scatter) provided by the new static strength formulation was used to justify a reduction of the load factor of safety to 1.6 from the previous value of 1.7.

Discussion on two methods for determining static strength of tubular T-joints at elevated temperature

2016 ◽  
Vol 20 (5) ◽  
pp. 704-721 ◽  
Author(s):  
Yongbo Shao ◽  
Haicheng Zhao ◽  
Dongping Yang
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Elevated Temperature ◽  
Critical Temperature ◽  
Mechanical Analysis ◽  
Static Strength ◽  
T Joints ◽  
Hollow Section ◽  
Tubular Joint ◽  
Circular Hollow Section

To predict the static strength of a welded tubular joint at elevated temperature using finite element simulation, two methods in the literature were reported. The first method aims to analyze the static strength of a tubular joint at a specified elevated temperature, and a routine mechanical analysis is carried out by defining the material properties at the specified elevated temperature according to some specifications. This method does not consider the heat transfer process of the tubular joint in a fire condition. The second method is used to determine the static strength of a tubular joint using a combination of transient state heat transfer analysis and mechanical analysis. The tubular joint subjected to a specified load is heated in accordance with ISO 834-1 standard fire curve to fail at a critical temperature, and the specified load is considered as the static strength of the joint at the critical temperature. In this study, a detailed parametric study on the failure process of circular hollow section tubular T-joints at elevated temperature is carried out using finite element method. The static strengths of the circular hollow section T-joint models obtained from the two methods are compared. The comparison shows that the first method produces a higher estimation on the static strength compared to the second method. Finally, the effect of some geometrical parameters, chord stress ratio, and elevated temperature on the difference of the two methods is also investigated.

scholarly journals Stress Distribution Analysis of DKDT Tubular Joint in a Minimum Offshore Structure

Rekayasa ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 191-199
Author(s):  
Irma Noviyanti ◽  
Rudi Walujo Prastianto ◽  
Murdjito Murdjito
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Axial Force ◽  
Oil And Gas ◽  
Bending Moment ◽  
Out Of Plane ◽  
Tubular Joint ◽  
Plane Bending ◽  
Intersection Line ◽  
Marginal Field

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.

scholarly journals Effects of Out-of-plane Brace-to-chord Angle on Multiplane CHS X-joints Behavior Under Brace Compression

2019 ◽  
Author(s):  
Bida Zhao ◽  
Ke Li ◽  
Chengqing Liu ◽  
Dengjia Fang ◽  
Jianguo Wu
Keyword(s):  
Load Transfer ◽  
Influence Factor ◽  
Experimental Tests ◽  
Hollow Section ◽  
Out Of Plane ◽  
Transfer Pattern ◽  
The Common ◽  
Circular Hollow Section ◽  
Numerical Parametric Study ◽  
Layered Lattice

Multiplanar CHS X-joints, different from the common uniplanar CHS X-joints, usually with a relative small out-of-plane brace-to-chord angle (OPBCA) for appealing architectural appearance in the single layered lattice structures. In order to study the effects of OPBCA on the static behavior of circular hollow section (CHS) X-joints under brace axial compression, experimental tests and numerical parametric study on the ultimate capacity and load transfer pattern of the CHS X-joints were carried out. The numerical analysis results had good consistent with experimental tests in terms of the capacity and fail mode of the X- joints. OPBCA changes the load transfer pattern to more load at the up saddle point from the same load at the up and bottom saddles in uniplanar X-joints, and more obvious for the X-joints with lager OPBCA. OPBCA is also unfavorable to the capacity, especially the X-joints with relative large brace-to-chord diameter ratio and in-plane brace-to-chord angle. Then an equation considering the OPBCA influence factor, extended the capacity prediction formulae of uniplanar X-joints in the current specifications to the multiplanar X-joints, is also established; and the equation has been validated favorably.

Static Strenght of Doubler Plate Reinforced Tubular K-Joints under Bending Load

2012 ◽  
Vol 166-169 ◽  
pp. 645-648
Author(s):  
Wei Ning Sui ◽  
Xin Long Zhang ◽  
Guo Chang Li ◽  
Xue Bai
Keyword(s):  
Ultimate Strength ◽  
Static Strength ◽  
Geometric Parameters ◽  
Hollow Section ◽  
Numerical Studies ◽  
Bending Load ◽  
Circular Hollow Section

Abstract: In order to study static strength of doubler plate reinforced circular hollow section (CHS) K-joints, experimental and numerical studies conducted by the authors. The effects of parameters Δ (the ratio between the length of doubler plate and the diameter of the brace) and α (the width of the doubler plate) on CHS K-joints subjected to bending load have been investigated and reported by the authors. It is found that the ultimate strength of a CHS K-joints reinforced with appropriately proportioned doubler plates can be up to 2 ratio to its un-reinforced counterpart. Reasonable geometric parameters of the doubler plate can make the chord, brace and doubler plate work together to bear the external bending load. The width and length parameter of the doubler plate, however, have no effect on the stiffness of the reinforced K-joints.

Ultimate strength of a double-tee tubular joint subjected to combined chord compression and brace out-of-plane bending

1998 ◽  
Vol 33 (5) ◽  
pp. 385-394 ◽  
Author(s):  
C T Kang ◽  
D G Moffat ◽  
J Mistry
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Experimental Tests ◽  
Design Rules ◽  
Linear Finite Element ◽  
Out Of Plane ◽  
Tubular Joint ◽  
Plane Bending ◽  
Different Levels

The effects of chord axial compression on the ultimate strength of a double-tee (DT) tubular joint subjected to brace out-of-plane bending have been studied both experimentally and numerically. The results from four experimental tests with different levels of chord compression are presented, together with the results of a parametric study using non-linear finite element procedures. The results are compared with the American Petroleum Institute's design rules for DT joints subjected to combined brace and chord loading.

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