This study analyzes the effect of changes in groove angle on the fatigue strength of the V-groove butt weld joint made of SM490A steel used in excavators. Butt-type specimens with different groove angles of 40° and 30° were manufactured by CO2 welding at a speed of 300 mm/min on a 13.5 mm thick steel plate. Four-point bending fatigue tests were conducted at room temperature with a frequency of 5 Hz and stress ratio of R = 0.1, and fatigue limits were set to 2 × 106 cycles. The high-cycle fatigue life of VG40 was approximately 7% higher than that of VG30. The stress concentration coefficient calculated using the effective notch stress method was 1.62 for the VG40, and 1.78 for the VG30, with an approximate difference of 9%. This decrease in fatigue life was caused by stress concentration due to the notch effect at the weld root, which was attributed to the adjacent backplate. Although the fatigue life decreased slightly owing to the improvement angle of the welded part, no difference was observed in microstructure and hardness. Therefore, it was confirmed that a sound weld was formed. The results of this study can be used as important basic data for determining the V-groove angle.
BarsoumZJonssonB. Influence of weld quality on the fatigue strength in seam welds. Eng Fail Anal2011; 18: 971–979.
2.
SchorkBKucharczykPMadiaM, et al. The effect of the local and global weld geometry as well as material defects on crack initiation and fatigue strength. Eng Fract Mech2018; 198: 103–122.
3.
ÅstrandEStenbergTJonssonB, et al. Welding procedures for fatigue life improvement of the weld toe. Weld World2016; 60: 573–580.
4.
BraunMMüllerAMMilakovićAS, et al. Requirements for stress gradient-based fatigue assessment of notched structures according to theory of critical distance. Fatigue Fract Eng Mater Struct2020; 43: 1541–1554.
5.
BraunMKellnerL. Comparison of machine learning and stress concentration factors-based fatigue failure prediction in small-scale butt-welded joints. Fatigue Fract Eng Mater Struct2022; 45(11): 3403–3417.
6.
HolmstrandTMrdjanovNBarsoumZ, et al. Fatigue life assessment of improved joints welded with alternative welding techniques. Eng Fail Anal2014; 42: 10–21.
7.
DabiriMGhafouriMRaftarHR, et al. Neural network-based assessment of the stress concentration factor in a T-welded joint. J Constr Steel Res2017; 128: 567–578.
8.
LeeY-SGangY-TKimJ-S, et al. The study on the accidents analysis and preventive measures from a excavator. In: Proceedings of the safety management and science conference, Korea Safety Management & Science, Osan University, Republic of Korea, 2010, pp. 283–297.
9.
ZhangGJYuan-XiaoCQing-Tan, et al. Finite element analysis of working device for hydraulic excavator. J Chem Pharm Res2013; 5: 123–128.
10.
HanK-G. A basic study on the evaluation of reliability of the construction equipments in Korea (focused on the damage cases of excavators). Master’s Thesis. Seoul National University of Science and Technology, Seoul, South Korea, 2015.
11.
ParkS-C. Design of excavator boom structure based on fatigue strength of Weldment (II). J Weld Join2011; 29: 61–66.
12.
SunYHamelinCFlintT, et al. Prediction of dilution and its impact on the metallurgical and mechanical behavior of a multipass steel weldment. J Pressure Vessel Technol2019; 141: 061405.
13.
JonssonBSamuelssonJMarquisGB. Development of weld quality criteria based on fatigue performance. Weld World2011; 55: 79–88.
14.
JonssonBBarsoumZSperleJ-O. Weight optimization and fatigue design of a welded bogie beam structure in a construction equipment. Eng Fail Anal2012; 19: 63–76.
15.
MalikAMeroufelAAl-FozanS. Boiler tubes failures: a compendium of case studies. J Fail Anal Prev2015; 15: 246–250.
16.
ChoiCDLimIS. Comparative reliability of nondestructive testing for weld: water wall tube in thermal power plant boiler case study. J Appl Reliab2018; 18: 240–249.
17.
ChoiYMKangDKimYL, et al. Reliability assessment of PAUT technique in lieu of RT for tube welds in thermal power plant facilities. Appl Sci2022; 12: 5867.
18.
KimH-JRyuH. Characteristics of high heat input welding. In: Proceedings of the KWS conference, The Korean Welding and Joining Society, Seoul National University of Technology, 2010, pp. 13–17.
19.
ErikssonÅLignellA-MOlssonC, et al. Weld evaluation using FEM: a guide to fatigue-loaded structures. Stockholm: Industrilitteratur, 2003.
20.
FrickeW. Guideline for the fatigue assessment by notch stress analysis for welded structures. Int Inst Weld2008; 13: 2240–2308.
21.
RadajDSonsinoCFrickeW. Recent developments in local concepts of fatigue assessment of welded joints. Int J Fatigue2009; 31: 2–11.
22.
PradanaMQianXSwaddiwudhipongS, et al. An extrapolation method to determine the effective notch stress in circular hollow section X-joints. Fatigue Fract Eng Mater Struct2017; 40: 160–175.
23.
PradanaMRQianXSwaddiwudhipongS. Simplified effective notch stress calculation for non-overlapping circular hollow section K-joints. Mar Struct2017; 55: 1–16.
24.
BertiniLFrendoFMaruloG. Fatigue life assessment of welded joints by two local stress approaches: the notch stress approach and the peak stress method. Int J Fatigue2018; 110: 246–253.
25.
Al ZamzamiISusmelL. On the use of hot-spot stresses, effective notch stresses and the point method to estimate lifetime of inclined welds subjected to uniaxial fatigue loading. Int J Fatigue2018; 117: 432–449.
26.
ShenWYanRHeF, et al. Multiaxial fatigue analysis of complex welded joints in notch stress approach. Eng Fract Mech2018; 204: 344–360.
27.
RaftarHRDabiriMAholaA, et al. Re-evaluation of weld root fatigue strength for load-carrying fillet welded joints using the notch stress concept. Int J Fatigue2021; 144: 106076.
28.
AygülMAl-EmraniMUrushadzeS. Modelling and fatigue life assessment of orthotropic bridge deck details using FEM. Int J Fatigue2012; 40: 129–142.
29.
ShahriMMSandströmR. Effective notch stress and critical distance method to estimate the fatigue life of T and overlap friction stir welded joints. Eng Fail Anal2012; 25: 250–260.
30.
SimH-B. Effective notch stress method for fatigue evaluation of welded joints in a steel bridge deck. Int J Railway2012; 5: 89–92.
31.
NeuberH. Theory of notch stresses: Principles for exact stress calculation. Ann Arbor, MI: J. W. Edwards, 1946.
32.
RadajDSonsinoCMFrickeW. Fatigue assessment of welded joints by local approaches. Cambridge, England: Woodhead Publishing, 2006.
33.
RadajD. Generalised Neuber concept of fictitious notch rounding. Advanced methods of fatigue assessment. Berlin, Heidelberg: Springer, 2013, pp. 1–100.
34.
AbsonD. Acicular ferrite and bainite in C–Mn and low-alloy steel arc weld metals. Sci Technol Weld Joining2018; 23: 635–648.
35.
SongFShiMWangP, et al. Effect of Mn content on microstructure and mechanical properties of weld metal during high heat input welding processes. J Mater Eng Perform2017; 26: 2947–2953.
36.
HobbacherA. Recommendations for fatigue design of welded joints and components. Switzerland: Springer, 2016.
