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.

scholarly journals Confining T-joints by adding two outer hollow ring flanges welded to additional hollow circular pipe

2017 ◽  
Vol 44 (10) ◽  
pp. 783-801 ◽  
Author(s):  
Peter Gerges Melek ◽  
Mohamed Hussein ◽  
Sameh Gaawan
Keyword(s):  
Parametric Study ◽  
Diameter Ratio ◽  
Outer Ring ◽  
Circular Pipe ◽  
Compression Force ◽  
T Joints ◽  
Hollow Section ◽  
Joint Location ◽  
Circular Hollow Section ◽  
Strengthening Technique

Increasing the capacity of circular hollow section (CHS) T-joints is a challenge for the designers due to its closed nature that makes strengthening difficult as the traditional strengthening techniques focus on adding ring stiffeners inside the chord, these techniques require splitting the chord at each joint location into more than one part and this is not applicable for stiffening prefabricated and erected T-joints. This paper presents a proposed strengthening technique that is based on confining the T-joint by two outer hollow ring flanges welded to additional hollow circular pipe. A parametric study is carried out to investigate the effect of the hollow ring flanges diameter, the added elements thickness, and the spacing between the hollow outer ring flanges on increasing the capacity of T-joints for different values of β (db/d0: brace diameter-to-chord diameter ratio) when the brace is either subjected to tension or compression force. Finally, it is observed that the compressive T-joints gain up to 267% of its original capacity and the tensile T-joints gain up to 65% of its original capacity.

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.

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.

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

scholarly journals A Finite Element Investigation into the Effect of Slope of Grain on Wood Baseball Bat Durability

2019 ◽  
Vol 9 (18) ◽  
pp. 3733 ◽  
Author(s):  
Joshua Fortin-Smith ◽  
James Sherwood ◽  
Patrick Drane ◽  
Eric Ruggiero ◽  
Blake Campshure ◽  
...  
Keyword(s):  
Finite Element ◽  
Wood Density ◽  
Wood Species ◽  
Parametric Study ◽  
Material Behavior ◽  
Finite Element Models ◽  
Ball Speed ◽  
Ball Impact ◽  
Fundamental Understanding ◽  
The Relationship

Bat durability is defined as the relative bat/ball speed that results in bat breakage, i.e., the higher the speed required to initiate bat cracking, the better the durability. In 2008, Major League Baseball added a regulation to the Wooden Baseball Bat Standards concerning Slope-of-Grain (SoG), defined to be the angle of the grain of the wood in the bat with respect to a line parallel to the longitudinal axis of the bat, as part of an overall strategy to reverse what was perceived to be an increasing rate of wood bats breaking into multiple pieces during games. The combination of a set of regulations concerning wood density, prescribed hitting surface, and SoG led to a 30% reduction in the rate of multi-piece failures. In an effort to develop a fundamental understanding of how changes in the SoG impact the resulting bat durability, a popular professional bat profile was examined using the finite element method in a parametric study to quantify the relationship between SoG and bat durability. The parametric study was completed for a span of combinations of wood SoGs, wood species (ash, maple, and yellow birch), inside-pitch and outside-pitch impact locations, and bat/ball impact speeds ranging from 90 to 180 mph (145 to 290 kph). The *MAT_WOOD (MAT_143) material model in LS-DYNA was used for implementing the wood material behavior in the finite element models. A strain-to-failure criterion was also used in the *MAT_ADD_EROSION option to capture the initiation point and subsequent crack propagation as the wood breaks. Differences among the durability responses of the three wood species are presented and discussed. Maple is concluded to be the most likely of the three wood species to result in a Multi-Piece Failure. The finite element models show that while a 0°-SoG bat is not necessarily the most durable configuration, it is the most versatile with respect to bat durability. This study is the first comprehensive numerical investigation as to the relationship between SoG and bat durability. Before this numerical study, only limited empirical data from bats broken during games were available to imply a qualitative relationship between SoG and bat durability. This novel study can serve as the basis for developing future parametric studies using finite element modeling to explore a large set of bat profiles and thereby to develop a deeper fundamental understanding of the relationship among bat profile, wood species, wood SoG, wood density, and on-field durability.

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