Study on the Hot Spot Stress Distribution at Multi-Planar Tubular KK Joints Under Axial Loads

2011 ◽  
Author(s):  
Jingxia Yue ◽  
Jin Gan ◽  
Weiguo Wu ◽  
Shihong Zhai ◽  
Yanhua Yang
Keyword(s):  
Finite Element ◽  
Hot Spot ◽  
Fe Analysis ◽  
Axial Loads ◽  
T Joints ◽  
Hot Spot Stress ◽  
Essential Information ◽  
Tubular Joints ◽  
Jack Up ◽  
Initial Prediction

The Hot Spot Stress (HSS) distribution around welded tubular joints in truss legs is essential information for the fatigue assessment of jack-up platforms. Both Finite Element (FE) analysis and model test were carried out on a multi-planar tubular KK joints under asymmetric axial loads in our research. The study shows that the HSS distribution around welded joints is different from common K or T joints, and the maximum HSS appears between crown and saddle on the chord surface at the chord-brace intersection. Moreover, some sensitive factors which influence the locations of the maximum HSS were investigated by FEA in this paper. The analysis results are useful for the optimal structure designing and crack initial prediction of the offshore jack-up platforms legs.

Fatigue of Tubular Joints: Hot Spot Stress Method Revisited

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Pingsha Dong ◽  
Jeong K. Hong
Keyword(s):  
Hot Spot ◽  
Life Assessment ◽  
Structural Stress ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Fatigue Design ◽  
Fatigue Data ◽  
Section Viii ◽  
Remaining Life Assessment

A series of well-known tubular joints tested in UKSORP II have been re-evaluated using the mesh-insensitive structural stress method as a part of the on-going Battelle Structural Stress JIP efforts. In this report, the structural stress based analysis procedure is first presented for applications in tubular joints varying from simple T joints, double T Joints, YT joints with overlap, and K joints with various internal stiffening configurations. The structural stress based SCFs are then compared with those obtained using traditional surface extrapolation based hot spot stress methods. Their abilities in effectively correlating the fatigue data collected from these tubular joints are demonstrated. These tests are also compared with the T curve typically used for fatigue design of tubular joints as well as the structural stress based master S-N curve adopted by ASME Section VIII Div 2. Finally, some of the implications on fracture mechanics based remaining life assessment for tubular joints are discussed in light of the results obtained in this investigation.

scholarly journals SIZE EFFECT OF WELDED THIN-WALLED TUBULAR JOINTS

2007 ◽  
Vol 07 (01) ◽  
pp. 101-127 ◽  
Author(s):  
FIDELIS RUTENDO MASHIRI ◽  
XIAO-LING ZHAO ◽  
MANFRED A. HIRT ◽  
ALAIN NUSSBAUMER
Keyword(s):  
Size Effect ◽  
Wall Thickness ◽  
Hot Spot ◽  
Fatigue Behavior ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Thin Walled Tube ◽  
Simple Extrapolation ◽  
Thin Walled

This paper clarifies the terminologies used to describe the size effect on fatigue behavior of welded joints. It summarizes the existing research on size effect in the perspective of newly defined terminologies. It identifies knowledge gaps in designing tubular joints using the hot spot stress method, i.e. thin-walled tubular joints with wall thickness less than 4 mm and thick-walled tubular joints with wall thickness larger than 50 mm, or diameter to thickness ratio less than 24. It is the thin-walled tubular joints that are addressed in this paper. It is found that thin-walled tube-plate T-joints do not follow the conventional trend: the thinner the section is, the higher the fatigue life. It is also found that simple extrapolation of existing fatigue design curves may result in unsafe design of thin-walled tube–tube T-joints. The effect of chord stiffness on fatigue behavior of thin-walled tubular T-joints is also discussed.

Fatigue of Tubular Joints: Hot Spot Stress Method Revisited

2008 ◽  
Author(s):  
Pingsha Dong ◽  
Jeong K. Hong
Keyword(s):  
Hot Spot ◽  
Life Assessment ◽  
Structural Stress ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Fatigue Design ◽  
Fatigue Data ◽  
Section Viii ◽  
Remaining Life Assessment

A series of well-known tubular joints tested in UKSORP II have been re-evaluated using the mesh-insensitive structural stress method as a part of the on-going Battelle Structural Stress JIP efforts. In this report, the structural stress based analysis procedure is first presented for applications in tubular joints varying from simple T joints, double T Joints, YT joints with overlap and K joints with various internal stiffening configurations. The structural stress based SCFs are then compared with those obtained using traditional surface extrapolation based hot spot stress methods. Their abilities in effectively correlating the fatigue data collected from these tubular joints are demonstrated. These tests are also compared with the T curve typically used for fatigue design of tubular joints as well as the structural stress based master S-N curve adopted by ASME Section VIII Div 2. Finally, some of the implications on fracture mechanics based remaining life assessment for tubular joints are discussed in light of the results obtained in this investigation.

Experimental, numerical and parametric studies on stress concentration factors of T-joints under tension

2021 ◽  
pp. 136943322110499
Author(s):  
Feleb Matti ◽  
Fidelis Mashiri
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Study ◽  
Hot Spot ◽  
Joint Models ◽  
Element Analysis ◽  
T Joints ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Good Agreement

This paper investigates the behaviour of square hollow section (SHS) T-joints under static axial tension for the determination of stress concentration factors (SCFs) at the hot spot locations. Five empty and corresponding concrete-filled SHS-SHS T-joint connections were tested experimentally and numerically. The experimental investigation was carried out by attaching strain gauges onto the SHS-SHS T-joint specimens. The numerical study was then conducted by developing three-dimensional finite element (FE) T-joint models using ABAQUS finite element analysis software for capturing the distribution of the SCFs at the hot spot locations. The results showed that there is a good agreement between the experimental and numerical SCFs. A series of formulae for the prediction of SCF in concrete-filled SHS T-joints under tension were proposed, and good agreement was achieved between the maximum SCFs in SHS T-joints calculated from FE T-joint models and those from the predicted formulae.

scholarly journals Use of 3D Scan of Weld Joint in Finite Element Analysis and Stochastic Analysis of Hot-Spot Stresses in Tubular Joint for Fatigue Life Estimation

2019 ◽  
Author(s):  
Mikkel L. Larsen ◽  
Vikas Arora ◽  
Marie Lützen ◽  
Ronnie R. Pedersen ◽  
Eric Putnam
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Welded Joints ◽  
Hot Spot ◽  
Strain Range ◽  
Fe Model ◽  
Design Codes ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Weld Toe

Abstract Several methods for modelling and finite element analysis of tubular welded joints are described in various design codes. These codes provide specific recommendations for modelling of the welded joints, using simple weld geometries. In this paper, experimental hot-spot strain range results from a full-scale automatically welded K-node test are compared to corresponding finite element models. As part of investigating the automatically welded K-joint, 3D scans of the weld surfaces have been made. These scans are included in the FE models to determine the accuracy of the FE models. The results are compared to an FE model with a simple weld geometry based on common offshore design codes and a model without any modelled weld. The results show that the FE model with 3D scanned welds is more accurate than the two simple FE models. As the weld toe location of the 3D scanned weld is difficult to locate precisely in the FE model and as misplacement of strain gauges are possible, stochastic finite element modelling is performed to analyse the resulting probabilistic hot-spot stresses. The results show large standard deviations, showing the necessity to evaluate the hot-spot stress method when using 3D scanned welds.

Finite Element Analysis of Elliptical Chord

2013 ◽  
Vol 3 (4) ◽  
pp. 44-61
Author(s):  
K. S. Narayana ◽  
R. T. Naik ◽  
R. C. Mouli ◽  
L. V. V. Gopala Rao ◽  
R. T. Babu Naik
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Compressive Load ◽  
Dynamic Strength ◽  
Element Analysis ◽  
T Joints ◽  
Shell Elements ◽  
Tubular Joints ◽  
Plane Bending

The work presents the Finite element study of the effect of elliptical chords on the static and dynamic strength of tubular T-joints using ANSYS. Two different geometry configurations of the T-joints have been used, namely Type-1 and Type-2. An elastic analysis has been considered. The Static loading conditions used are: axial load, compressive load, In-plane bending (IPB) and Out-plane bending (OPB). The natural frequencies analysis (dynamic loading condition) has also been carried out. The geometry configurations of the T-joints have been used, vertical tubes are called brace and horizontal tubes are called chords. The joint consists of brace joined perpendicular to the circular chord. In this case the ends of the chord are held fixed. The material used is mild steel. Using ANSYS, finite element modeling and analysis of T-joint has been done under the aforementioned loading cases. It is one of the most powerful methods in use but in many cases it is an expensive analysis especially due to elastic–plastic and creep problems. Usually, three dimensional solid elements or shell elements or the combination of two types of elements are used for generating the tubular joints mesh. In tubular joints, usually the fluid induced vibrations cause the joint to fail under resonance. Therefore the natural frequencies analysis is also an important issue here. Generally the empirical results are required as guide or comparison tool for finite element investigation. It is an effective way to obtain confidence in the results derived. Shell elements have been used to model the assembled geometry. Finite element ANSYS results have been validated with the LUSAS FEA and experimental results, that is within the experimentation error limit of ten percentage.

Experimental Investigation and FE Stress Analysis of Adhesive T-Joint with and without Crack in Fluidization Bed

2014 ◽  
Vol 695 ◽  
pp. 609-612 ◽  
Author(s):  
A. Nor ◽  
Mohd Afendi ◽  
Mohd Shukry Abdul Majid ◽  
B. Izzawati ◽  
S. Nurhashima ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Tensile Testing ◽  
Perforated Plate ◽  
Fe Analysis ◽  
Mode I ◽  
Adhesively Bonded ◽  
T Joints ◽  
Actual Structure ◽  
Actual Size

In this study, investigation on adhesive T-joint with and without crack in urea granulator fluidization bed was carried out by experiment and finite element (FE) analysis. Specimens with and without crack were made from actual size of 1.25 mm perforated plate to duplicate actual structure of granulator fluidization bed and verified using commercial finite element. The existence of crack will affect the strength of adhesive T-joint. The objectives of this project were to examine a series of adhesively bonded T-joints with and without crack under mode I loading, to identify the effective bond thickness by tensile testing and FE analysis. It was found that result pattern from experiment was in agreement with FE analysis.

Theoretical Analysis and Experimental Verification of the Stress Concentration Factor at the Steel Tube-Welded Hollow Sphere Connection Node

2016 ◽  
Vol 851 ◽  
pp. 739-744
Author(s):  
Bo Li ◽  
Hong Gang Lei ◽  
Xu Yang
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Theoretical Analysis ◽  
Hollow Sphere ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Hot Spot ◽  
Steel Tube ◽  
Element Analysis ◽  
Hot Spot Stress

In this paper, the author uses ANSYS, the software of finite element analysis, to establish the finite element model, the hot spot stress value of different connection structures of steel tube-welded hollow sphere under uniaxial elongation has been analyzed, the theoretical stress concentration factor of this joint has been obtained. Through the static test on the four typical test-piece, 26 steel tube-welded hollow spherical nodes in total, the actually measured stress concentration factor of the joints has been obtained. The theoretical analysis basically coincides with the law of stress concentration factor obtained from the test results.

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