scholarly journals Effect of geometric parameters and combined loading on stress distribution of tubular T-joints

Mechanika ◽  
2019 ◽  
Vol 25 (5) ◽  
pp. 350-356
Author(s):  
Samira Belhour ◽  
Hafida Kahoul ◽  
Ahmed Bellaouar ◽  
Sébastien Murer
Keyword(s):  
Axial Loading ◽  
Computation Time ◽  
Geometric Parameters ◽  
Combined Loading ◽  
Offshore Platforms ◽  
Tubular Structures ◽  
Stress Concentrations ◽  
Standard Samples ◽  
T Joints ◽  
Modeling And Analysis

Steel tubular structures are widely used in the construction of offshore platforms and T-type junctions are extensively used in this domain. The tubular members are welded, which generates significant stress concentrations at the edges. The stress levels reached in these critical places are used to assess lifetimes based on fatigue curves from tests conducted on standard samples. This study is devoted to the modeling and analysis of T-type welded tubular structures for the determination of hot spots stresses (HSS) at the chord/brace intersection, A numerical analysis was carried out to study the effect of a combined loading composed of an axial loading and a continuation of rational bending, that best assimilate real conditions, as well as the effect of normalized geometric parameters α, β, g on the distribution of stress concentration (area and values) of T-joints. The mechanical behaviour has been modeled in 2D using quadrangular and triangular thin-shell elements by the finite element method (FEM). It is the most appropriate approach because it considers all geometric complexities and singularities of the structure, while the efforts as well as the computation time are considerably reduced compared to an experimental study or to complex FE models implementing solid elements. In this study, we use the COMSOL-MULTIPHYSICS® software...

STRUCTURAL STRESS METHOD FOR FATIGUE DESIGN OF CONCRETE FILLED STEEL TUBULAR T-JOINTS UNDER AXIAL LOADING

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Idris A. Musa
Keyword(s):  
Fatigue Life ◽  
Three Dimensional ◽  
Axial Loading ◽  
Fe Model ◽  
Structural Stress ◽  
Stress Concentrations ◽  
Engineering Structures ◽  
T Joints ◽  
Tubular Joints ◽  
Concrete Filling

Steel tubular structural members are being widely used in various engineering structures. The steel tubular joints will have fatigue problem when subjected to repetitive loading. Fatigue strength is one of the key factors that control the design of steel tubular joints in structures subjected to frequent loading. Research has shown that concrete filling of the steel tubes can effectively reduce stress concentrations at the joint. In this study, the structural stress method which involves the through-thickness stress distribution, has been employed to estimate the fatigue life of concrete filled steel tubular (CFST) T-joints under axial loading in the brace. A Finite Element (FE) model has been developed using ABAQUS. The three-dimensional 8-node hexahedral element has been employed in the FE model. The structural stresses have been extracted and the fatigue life of the joint has been estimated. The results have been verified using experimental results reported in the literature. The current study showed that the structural stress method can effectively predict reliable fatigue life in concrete filled steel tubular (CFST) T-joints.

The Parametrical Stress Analysis of Tubular T Joints

1985 ◽  
Vol 107 (4) ◽  
pp. 473-478
Author(s):  
T.-Y. Chen ◽  
B.-Z. Chen ◽  
Y.-Q. Wang
Keyword(s):  
Experimental Data ◽  
Stress Concentration ◽  
Stress Analysis ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Axial Loading ◽  
Geometric Parameters ◽  
T Joints ◽  
Data Tables ◽  
The Relationship

The relationship between the geometric parameters of α, β, γ and τ of tubular T joints and chord stress concentration factor, SCF, has been investigated. With the use of calculated values as well as experimental data tables were compiled for a wide variety of cases when axial loading on the branch is applied. Finally, a probability analysis is given as to the reliability of using a particular SCF value.

Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels

1981 ◽  
Vol 103 (2) ◽  
pp. 268-273
Author(s):  
My Dao Thien ◽  
M. Massoud
Keyword(s):  
Probabilistic Approach ◽  
Design Procedure ◽  
Axial Loading ◽  
Geometric Parameters ◽  
Computer Algorithms ◽  
Mean Values ◽  
Helical Springs ◽  
Reliability Level ◽  
Classical Design ◽  
Mission Success

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.

Stiffness of RHS "T" Joints under Combined Brace Bending and Axial Loading

2014 ◽  
Author(s):  
R.M.M.P. Matos ◽  
L.F. Costa Neves ◽  
L.R.O. de Lima ◽  
P.C.G. da S. Vellasco ◽  
J.G. Santos da Silva
Keyword(s):  
Axial Loading ◽  
T Joints

Mechanical Modeling of Multilayered Films on an Elastic Substrate—Part I: Analysis

1990 ◽  
Vol 112 (4) ◽  
pp. 309-316 ◽  
Author(s):  
F. Erdogan ◽  
P. F. Joseph
Keyword(s):  
Interfacial Crack ◽  
Strain Energy Release ◽  
Interfacial Zone ◽  
Stress Concentrations ◽  
Elastic Substrate ◽  
Multilayered Films ◽  
Elastic Continuum ◽  
Modeling And Analysis ◽  
Film Substrate ◽  
Homogeneous Temperature

In this paper the basic residual stress problem for multilayered or multiple films on an elastic substrate is considered. The stresses may be caused by a homogeneous temperature variation or slow thermal cycling and by far field mechanical loading. The films are approximated by orthotropic membranes and the substrate is assumed to be an elastic continuum. The interfacial zone is modeled by either an ideal interface or a homogeneous shear layer. The primary interest in the paper is in examining stress concentrations or singularities near the film ends. For the two interface conditions considered, this is done by varying the film/substrate contact angle. Also studied are strain energy release rate for the propagation of an interfacial crack and the direction and the magnitude of the maximum cleavage stress for a possible crack initiation in the substrate. The basic modeling and analysis are considered in Part I. Part II of the paper is devoted to the presentation and discussion of the results.

Fatigue Behavior of Welded T-Joints with a CHS Brace and CFCHS Chord under Axial Loading in the Brace

2013 ◽  
Vol 18 (2) ◽  
pp. 142-152 ◽  
Author(s):  
Ke Wang ◽  
Le-Wei Tong ◽  
Jun Zhu ◽  
Xiao-Ling Zhao ◽  
Fidelis R. Mashiri
Keyword(s):  
Fatigue Behavior ◽  
Axial Loading ◽  
T Joints

Determining the Limit Plastic Load in T-Joints of Pipelines Subjected to Compound Combined Loading

2015 ◽  
Vol 51 (5-6) ◽  
pp. 414-419
Author(s):  
V. N. Skopinskii ◽  
N. A. Berkov ◽  
R. A. Vozhov
Keyword(s):  
Combined Loading ◽  
T Joints

Elastic stresses due to axial loading of a two-brace tubular k joint with and without overlap

1981 ◽  
Vol 16 (1) ◽  
pp. 67-77 ◽  
Author(s):  
H Fessler ◽  
W J G Little
Keyword(s):  
Finite Element ◽  
Axial Loading ◽  
Stress Concentrations ◽  
Elastic Stresses ◽  
Full Penetration

The elastic stresses in non-overlapped and overlapped K joints under axial loading have been obtained by frozen stress photoelastic techniques. The models are representative of joints with stress-relieved, full penetration, ground welds and have brace angles of 45° and 135°. Results are compared with those of similarly shaped models analysed by other techniques (finite element and strain-gauged steel models) and with stress concentrations in joints with the same tube parameters but having different brace arrangements.

Nonlinear Analysis of Offshore Platforms Subjected to Earthquake Loading Considering the Effects of Joint Flexibility

2009 ◽  
Author(s):  
S. Samadani ◽  
A. A. Aghakouchak ◽  
J. Mirzadeh Niasar
Keyword(s):  
Structural Analysis ◽  
Nonlinear Analysis ◽  
Offshore Structures ◽  
Offshore Platforms ◽  
Joint Flexibility ◽  
Modeling And Analysis ◽  
Shell Elements ◽  
Tubular Joints ◽  
Two Samples ◽  
Non Linear

In a conventional method of structural analysis, for modeling and analysis of jacket type offshore platforms, member connections are assumed to be rigid. In this method, members are rigidly connected which means there is no axial or rotational deformation at the end of brace member relative to chord axis. However in reality local deformations occur at chord surface due to applied loads from braces, which mean tubular joints are considerably flexible especially in non linear range of deformations. Therefore results of analysis based on rigid connections assumption differ from real behavior of the structure. Various research works have been carried out in the past on tubular joints and different methods have been presented in order to include the effect of joint flexibility in structural analysis. Most of these methods are just valid in elastic range but some non-linear methods have also been developed for simple tubular joints. In order to carry out a nonlinear analysis on a 3-D model of an offshore platform with multi-brace / multi-planar tubular joints, none of these simplified methods is applicable. In this case a complete model of tubular joints by non-linear shell elements is the most accurate one which is not only valid for non-linear analyses but also covers all type of tubular joints. In this paper two samples of offshore platforms are studied. These platforms are modeled using the following approaches: 1. No modeling of joints as structural elements (rigid connections). 2. Modeling of joint can with nonlinear shell elements (flexible connection). Different types of static non-linear analysis (Push over) are carried out and results are compared. In order to evaluate the results and compare this type of modeling with simplified methods included in professional software for the analysis of offshore structures, aforementioned platforms are also analyzed using the Fessler and MSL models to include effects of joint flexibility. The results of these types of modeling are also compared with the previous ones.

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