scholarly journals Research on Fatigue Properties of Typical Welded Joints of DH36 Steel at −60 °C

2020 ◽  
Vol 10 (11) ◽  
pp. 3742
Author(s):  
Weidong Zhao ◽  
Guoqing Feng ◽  
Wenchao Liu ◽  
Huilong Ren
Keyword(s):  
Stress Concentration ◽  
Welded Joints ◽  
Room Temperature ◽  
Polar Region ◽  
Hot Spot ◽  
Fatigue Properties ◽  
Test Results ◽  
Hot Spot Stress ◽  
Confidence Levels ◽  
Better Than

As the development of the polar region continues to increase, the fatigue properties of structures at low temperature are increasingly receiving researcher attention. This study aimed to investigate the fatigue properties of T-welded and cruciform welded joints at −60 °C. Logarithmic S–N curves based on the hot-spot stress of the T-welded and cruciform welded joints at 50% and 95% confidence levels were obtained at −60 °C. The test results showed that the fatigue properties of T-welded joints were almost 2–7% better than those of the cruciform welded joints at −60 °C. Factors that affected the fatigue properties of welded joints, such as the stress concentration factor, microstructure, Vickers hardness profiles, and fractography, were also studied and the test results showed that the fatigue properties of cruciform welded joints at −60 °C were 57.215% better than at room temperature.

scholarly journals Analysis of fatigue behavior of welded joints in orthotropic bridge deck using traction structural stress

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401989021 ◽  
Author(s):  
Haibo Yang ◽  
Hongliang Qian ◽  
Ping Wang ◽  
Pingsha Dong
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Welded Joints ◽  
Concentration Factor ◽  
Hot Spot ◽  
Fatigue Behavior ◽  
Steel Bridge ◽  
Structural Stress ◽  
Test Results ◽  
Hot Spot Stress

In this study, the fatigue behavior of welded joints in an orthotropic steel bridge is simulated and analyzed. The traction structural stress method is proven to be more accurate and effective, and the predicted results agree well with the test results compared to traditional assessment methods, including the nominal stress, hot-spot stress, and effective notch stress methods. The traction structural stress concentration factor curves of welded joints under cyclic tensile and bending moment loading are obtained. The accuracy and validity of finite-element simulation methods for welded joints in orthotropic steel bridge are verified by comparing simulation results with full-scale tests results. Equivalent nominal stresses predicted by the master S–N curve method based on traction structural stress results agree well with the fatigue test results with small standard deviation. The fatigue behavior of orthotropic steel bridge analysis specifications Eurocode3 and GB50017 is combined with the traction structural stress method using unified traction structural stress concentration factor curves. This approach provides practical guidance for the fatigue behavior design of orthotropic steel bridges.

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.

Stress concentration factors for non-90° X-connections made of square hollow sections

1998 ◽  
Vol 25 (2) ◽  
pp. 370-375 ◽  
Author(s):  
J A Packer ◽  
J Wardenier
Keyword(s):  
Stress Concentration ◽  
Strong Influence ◽  
Hot Spot ◽  
Steel Structures ◽  
Hot Spot Stress ◽  
Hollow Section ◽  
Measured Stress ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Hollow Structural Sections

A number of fatigue experiments and stress concentration factor measurements on non-90°, square hollow section X-connections have been carried out. Comparison of the measured stress concentration factors with those derived from existing parametric formulae for 90° T- and X-connections showed a strong influence of the brace angle. A tentative extension of the range of validity of the parametric formulae for 90° T- and X-connections for other brace angles has been derived.Key words: steel structures, connections, fatigue, hollow structural sections, hot spot stress, stress concentration factors.

Synthesis of Nano-MnO2/CNTs Composite and Electrochemical Properties as Electrode Material for Supercapacitor

2012 ◽  
Vol 512-515 ◽  
pp. 1005-1008 ◽  
Author(s):  
Jian Wang ◽  
Jin Hai Liu ◽  
Xue Bo Zhao ◽  
Guo Lu Li ◽  
Bing Qing Wei
Keyword(s):  
Carbon Nanotube ◽  
Specific Capacitance ◽  
Manganese Oxides ◽  
Room Temperature ◽  
Aqueous Alcohol ◽  
Test Results ◽  
Multiwalled Carbon ◽  
Scan Rate ◽  
Swnt Film ◽  
Better Than

The manganese oxides (MnO2) with nanostructures was fabricated with non-aqueous alcohol and aqueous solution of potassium permanganate (KMnO4) at room temperature. The test results show that the nano-MnO2 well coated on the surface of carbon nanotube (CNT), while the specific capacitance of the composites with MnO2 deposited on singlewall carbon nanotube (SWNT) was better than coated on multiwalled carbon nanotube (MWNT). The specific capacitance of MnO2 coated on SWNT film can reach 769F/g at scan rate of 5mv/s in the first cycle.

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.

Fatigue Strength Evaluation for Gas Welded Joint of Similar and Dissimilar Materials

2007 ◽  
Vol 345-346 ◽  
pp. 359-362
Author(s):  
Dong Ho Bae ◽  
Yeong Sin Kim ◽  
Gyu Young Lee ◽  
Kwang Jin Park
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
Hot Spot ◽  
Tensile Load ◽  
Dissimilar Materials ◽  
Fatigue Tests ◽  
Design Criterion ◽  
Hot Spot Stress ◽  
Fatigue Design ◽  
Fatigue Design Criterion

In order to establish a reasonable and integrated fatigue design criterion for the long life design of the gas welded body structure, stress distribution around the gas welded joints subjected to tensile load was numerically analyzed. And also, the P-Nf curves were obtained by fatigue tests. By using these results, P-Nf curves were rearranged in the σ-Nf relation with the hot spot stress at the welded joint. And a guideline for fatigue design of gas welded joints was proposed.

Qualification of the Notch Stress Approach for the Fatigue Assessment of Welded Pressure Equipment and Power Plant Components

2017 ◽  
Author(s):  
Jürgen Rudolph ◽  
Ralf Trieglaff ◽  
René Stößlein ◽  
Fabian Hauser
Keyword(s):  
Test Data ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Hot Spot ◽  
Pressure Vessels ◽  
Assessment Procedure ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Fatigue Assessment ◽  
Notch Stress

The fatigue assessment of welded joints in different engineering disciplines is usually based on nominal, structural or notch stresses on one hand (elastic concept using component fatigue curves of load controlled test data) and local strains on the other hand (elasto-plastic concept using material fatigue curves of strain-controlled push-pull test data of un-notched and polished standard specimens). The concepts of the first mentioned group are implemented in widespread standards and recommendations such as [1] to [3]. The fatigue assessment procedure of the European standard for unfired pressure vessels (EN 13445-3, Clause 17 & 18 and related annexes) [4] is currently under revision with one focus on the elaboration of user friendly fatigue assessment options for welded components [5]. The current state of the art focuses on the application of an adapted structural hot spot stress approach to the fatigue assessment of welded pressure equipment [5]. Although this is a significant step forward, the implementation of a notch stress approach can furtherly increase the fatigue assessment options by detailed weld seam analysis. The paper focuses on respective methodological proposals and application examples of typical welded joints. The finite element analysis as part of the procedure has to be harmonized with the requirements of the assessment procedure. Of course, the compatibility of the hot spot stress approach and a notch stress approach has to be guaranteed for individual examples. The direct comparison of the different approaches allows for a qualitative evaluation of methods. The application of an appropriate master fatigue curve FAT100 and the limitations with regard of stress/strain ranges in the low cycle fatigue (LCF) regime as well as the fatigue assessment of welded joints with mild weld toe notches is the subject of special considerations. The latest recommendations of German Welding Society (DVS) [6] constitute a reference for the last two subjects raised.

Sign in / Sign up

Export Citation Format

Share Document