Study of Typical Welded Joint Hot Spot Stress Concentration Factor

2010 ◽  
Vol 160-162 ◽  
pp. 1482-1487
Author(s):  
Bin Jie Wang ◽  
Qiang Li ◽  
Zhi Ming Liu
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
High Speed ◽  
Welded Joint ◽  
Hot Spot ◽  
Nominal Stress ◽  
Hot Spot Stress ◽  
The Difference ◽  
Fatigue Evaluation

Hot spot stress (HSS) approach is more applicable for fatigue evaluation, because it is more closer to the real stress at the welded notch than nominal stress.This paper studies a typical welded joint, fillet welded joint, which is used widely in high-speed car. Hot spot stress concentration factor is calculated under different nominal stress and loading methods. The S-N curves belong to nominal stress and hot spot stress were analysized. The result show that the difference between the S-N curves under different load style can be reduced greatly by hot spot stress. The hot spot stress characteristic variable was put forward, which is used to describe the influence from the welding size of the joint.

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.

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.

Research on the Stress Fatigue Assessment about the Hot Spot Stress on the Bogie Frame

2011 ◽  
Vol 328-330 ◽  
pp. 1281-1286
Author(s):  
Bin Jie Wang ◽  
Qiang Li ◽  
Zhi Ming Liu
Keyword(s):  
Fatigue Strength ◽  
High Speed ◽  
Hot Spot ◽  
Nominal Stress ◽  
Bottom Flange ◽  
Bogie Frame ◽  
Hot Spot Stress ◽  
Shell Elements ◽  
Joint Section ◽  
Fatigue Evaluation

As the loading conditions for the railway vehicles are becoming more and more complex, nominal stress has been unable to fully satisfy the requirements for assessing fatigue strength for weld structures. Hot spots stress is much more closer to the actual stress of a weld structure, it can suit the demand of high speed trains’ fatigue evaluation better. In this paper, on the basis of UIC615-4 standard, the nominal stress of the welded bogie frame was calculated and its fatigue strength was assessed using FEA method. Also, set the joint section between drawbar seat and the transom bottom flange as the object of the study, succeeded in evaluating the hot spot stress of the welded bogie frame. Compared the hot spot stress calculation result with the nominal stress from shell elements, the result shows that hot spot stress is higher than the nominal stress. Using the hot spot stress to assess fatigue has the higher reliability

Elastic Stress Concentration Factors (Kt) by Stress Gradient Method Using FEA

1996 ◽  
Author(s):  
Ajay Garg ◽  
Ravi Tetambe
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Maximum Stress ◽  
Elastic Stress ◽  
Stress Gradient ◽  
Nominal Stress ◽  
Element Analysis

Abstract The elastic stress concentration factor, Kt, is critical in determining the life of machines, especially in the case of notched components experiencing high cycle fatigue. This Kt is defined as the ratio of the maximum stress (σmax) at the notch to the nominal stress (σnom) in the region away from the notch effect. For simple geometries such as, plate with a hole, calculation of Kt from either closed form solution or from making simple but valid assumptions is possible [1,2]. However, for complex machine components such data is usually not available in the literature. Using Kt values from the simple geometries may lead to either over or under estimation of the real Kt for such complex geometries. Such error can then further lead to a substandard product or a product which is overdesigned and expensive. Present paper outlines a methodology for computing reasonably accurate elastic stress concentration factor, Kt, using finite element analysis (FEA) tool. The maximum stress (σmax) is readily available from the finite element analysis. The nominal stress (σnom) near the stress concentration is however can not be directly extracted from the FEA results. A novel approach of estimating reasonably accurate σnom is presented in this paper. This approach is based on selecting the correct path at the stress concentration region, post processing the stress and the stress gradient results along that path and identifying the cut of point where stress concentration effect begins to take place. This methodology is first validated using two examples with known Kt and later applied to a real world problem.

Giga-Cycle Fatigue Behavior of Notched Specimens for High Speed Steel

2010 ◽  
Vol 452-453 ◽  
pp. 749-752 ◽  
Author(s):  
Ryuichiro Ebara ◽  
K. Nakamoto ◽  
A. Ogura ◽  
Y. Ishihara ◽  
S. Hamaya
Keyword(s):  
Stress Concentration ◽  
Crack Initiation ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
High Speed ◽  
Fatigue Behavior ◽  
High Speed Steel ◽  
Carbon Matrix ◽  
Cycle Fatigue ◽  
Notched Specimens

Giga-cycle fatigue behavior of notched specimens with stress concentration factor, Kt of 1.5, 2.0 and 2.5 for 0.65 mass% carbon matrix high speed steel, YXR3 with Rockwell C scale hardness number of 60.7 is investigated. The higher the stress concentration factor the lower the giga-cycle fatigue strength is. The emphasis is placed upon the subsurface crack initiation observed on all notched specimens. Crack initiation mode of high speed steel is discussed with respect to fracture surface morphology.

Experimental Study of the Principal Stresses Separation Using a Combination of Photoelasticity and Thermoelastic Stress Analysis

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1427-1433 ◽  
Author(s):  
Akira Shimamoto ◽  
Hiroshi Ohkawara ◽  
Fumio Nogata ◽  
Sung Mo Yang
Keyword(s):  
Stress Concentration ◽  
Stress Analysis ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Test Specimen ◽  
Thermoelastic Stress ◽  
Thermoelastic Stress Analysis ◽  
Principal Stresses ◽  
Thermoelastic Stresses ◽  
The Difference

In this paper, we report the experimental results of the principal stresses separation using a combination stress analysis of photoelasticity and thermoelasticity. Experimental investigation was carried out on specimens made of epoxy resin with a center hole under constant tensile loads. In case of photoelasticity test, only the difference of the stress is obtained, and in case of thermoelastic stress analysis, only the sum of the stress is measured. However, it is difficult to separate principal stress by only either of them. Then, Mohr's stresses circle was employed as the most easy and convenient method to separate of principal stresses. Moreover, by using different shape of center hole at the specimens, the change of the stress concentration factor at the vicinity of center hole of the test specimen by data of photoelasticity and thermoelastic stress analysis was obtained. The effectiveness of the principal stresses separation from the photoelastic and thermoelastic stresses measured values was verified. We also confirmed the capacity of application of the thermoelastic stress analysis to evaluate stress concentration factor.

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