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.

Axial strength of steel circular hollow section (CHS) X-joints strengthened by flanged larger pipe

2020 ◽  
Vol 47 (3) ◽  
pp. 301-316
Author(s):  
Peter Gerges ◽  
Sameh Gaawan ◽  
Ashraf Osman
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Thickness Ratio ◽  
Finite Element Models ◽  
T Joints ◽  
Hollow Section ◽  
Axial Strength ◽  
Structural Joints ◽  
Circular Hollow Section ◽  
Steel Design

In steel design, enhancing the structural joints’ capacity is considered a challenge that faces the designer. This challenge becomes more difficult when it comes to enhancing the capacities of circular hollow section (CHS) joints due to their closed nature that complicates the strengthening process. Recent research related to strengthening T-joints by utilizing two outer hollow ring flanges welded to additional pipe showed that this technique can significantly improve the joints’ strength. In this study, the utilization of this technique is extended for enhancing the axial strength of CHS X-joints. In this regard, a parametric study using finite element models was carried out to investigate the different design aspects that might affect the behavior of strengthened X-joints. The examined parameters included, the ring flange diameter, the stiffening pipe thickness and length for different brace diameter-to-chord diameter ratios and chord diameter to double chord thickness ratio. The results demonstrated that these strengthened X-joints gained significant axial strength that reached up to three times the axial strength of the unstrengthened joints. Guidelines for proper detailing of such strengthening scheme were provided. Finally, an equation that estimates the axial strength of strengthened joints was established based on the achieved results.

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.

Finite Element Validation Studies of BS7910 FAD Method Applied to Welded SHS Joints

2007 ◽  
Author(s):  
Zhengmao Yang ◽  
Seng Tjhen Lie ◽  
Wie Min Gho
Keyword(s):  
Finite Element ◽  
Offshore Structures ◽  
Reduction Factor ◽  
Plastic Collapse ◽  
Surface Cracks ◽  
Collapse Load ◽  
T Joints ◽  
Hollow Section ◽  
Wide Range ◽  
Circular Hollow Section

The failure assessment diagram (FAD) has now been widely accepted and used for the assessment of defects found in metallic structures. In BS7910 (2005), the use of this method for offshore structures has been validated for a range of joint geometries. But these validations are only applicable for circular hollow section (CHS) welded joints. For rectangular or square hollow section (RHS or SHS) joints, there are very few references available in the literature. In this paper, systematic investigations have been carried out for the validation and verification of the FAD curves for SHS T-joints. FAD curves for a wide range of welded SHS T-joints containing surface cracks have been established using the fracture mechanics data generated from the finite element analyses. The range of β ratio of these joints is from 0.3 to 0.8. Therefore, the failure mode is constrained in the chord face yielding. The influence of residual stresses on the plastic collapse load and the FAD curves has also been analyzed. The reduction factor used to calculate the plastic collapse load of the SHS T-joints containing cracks have been quantitatively examined, and the use of the BS7910 (2005) Level 2A FAD for SHS joints containing surface cracks has been validated accordingly.

Static Strength of RHS T-Joints with Reinforced Chord under In-Plane Bending Load

2014 ◽  
Vol 488-489 ◽  
pp. 790-794
Author(s):  
Dong Ping Yang ◽  
Yong Bo Shao ◽  
Feng Le Long ◽  
Geng Qi Niu ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Static Strength ◽  
Offshore Platforms ◽  
Joint Models ◽  
Element Analysis ◽  
T Joints ◽  
Hollow Section ◽  
Bending Load ◽  
Plane Bending

Welded tubular structures are widely used in many constructions, such as offshore platforms, which are all consisted of welded tubular members. There is a stress concentration at the intersection between chord and brace. When subjected to loads, a crack exists in the weld toe at the intersection. Then the propagation of the crack leads to failure of the joint. So the static strength of rectangular hollow section (RHS) T-joints with local chord reinforcement under in-plane bending load is investigated by using finite element method. To study the effect of the chord reinforcement of a RHS T-joint, overall 18 T-joint models with different chord reinforcements have been analyzed numerically. This paper presents the results of a detailed parametric study of the static strength of in-plane bending loaded tubular T-joints with reinforced chord. The study, carried out using non-linear finite elements, demonstrated the accuracy of the finite element analysis to investigate the effects of different geometric parameters which influence the static strength of the stiffened joints. It is found that the effect of the chord thickness near the intersection is significant in improving the ultimate capacity of T-joint models. The ultimate strength enhances as the length of the chord reinforcement becomes longer and the chord wall thickness becomes larger. The effect of the chord wall thickness on the static strength of T-joints are remarkable. However, increasing the length of the reinforced chord to improve the static strength of Tubular T-joint is relatively ineffective.

Study on Static Strength of Circular Hollow Section (CHS) T-Joint Reinforced with FRP

2011 ◽  
Vol 99-100 ◽  
pp. 72-75 ◽  
Author(s):  
Cheng Chen ◽  
Yong Bo Shao ◽  
Jie Yang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Parametric Analysis ◽  
Static Strength ◽  
Geometrical Parameters ◽  
Hollow Section ◽  
Tubular Joints ◽  
Element Simulation ◽  
Simulation Based ◽  
Circular Hollow Section

The static strength of circular hollow section (CHS) T-joint reinforced with FRP (Fiber Reinforced Polymer) is studied through the experimental test and finite element simulation. Based on the reliability of the finite element simulation which is verified from experimental data, the parametric analysis is conducted by using finite element (FE) software ABAQUS. In the parametric analysis, the improvement of FRP with different bonding lengths, directions and layers on the static strength of tubular T-joints is considered. Simultaneously, the effect of two key geometrical parameters  and  of the tubular joints on the reinforced efficiency is also included. Based on the results of the parametric study, the effect of FRP on increasing the static strength of tubular joints is finally generalized.

Modelling of double chord rectangular hollow section T-joints by finite element method

1982 ◽  
Vol 15 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Farooque A. Mirza ◽  
Atif A. Shehata ◽  
Robert M. Korol
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
T Joints ◽  
Hollow Section ◽  
Element Method

Elasto-plastic finite element analysis of double chord rectangular hollow section T-joints

1984 ◽  
Vol 19 (5-6) ◽  
pp. 829-838 ◽  
Author(s):  
Farooque A. Mkza ◽  
Atif A. Shehata ◽  
Robert M. Korol
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
T Joints ◽  
Hollow Section

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.

Sign in / Sign up

Export Citation Format

Share Document