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Baumgartner, J., Yıldırım, H. C. & Barsoum, Z. (2019). Fatigue strength assessment of TIG-dressed welded steel joints by local approaches. International Journal of Fatigue, 126, 72-78
Open this publication in new window or tab >>Fatigue strength assessment of TIG-dressed welded steel joints by local approaches
2019 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 126, p. 72-78Article in journal (Refereed) Published
Abstract [en]

Fatigue strength assessment methods by local approaches are widely used in the literature. This paper provides a comprehensive evaluation of published data for welded steel joints improved by TIG dressing methods. Fatigue classes for the local assessment methods with the available fatigue data are recommended. The available fatigue data extracted for transverse non-load carrying welds, cruciform joints as well as butt joints. In total, 17 published test series of weld details with various yield strengths and stress ratios are presented. Fatigue strength assessment is performed by considering the weld profile geometry within Finite Element models and taking the resulting stress gradients as basis for the evaluation. In addition, the influence of the steel grade is included. The most reliable results are derived by using the critical distance approach. Fatigue classes and critical distances are recommended as a result of the evaluations.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Fatigue design, Finite elements, Size effects, TIG-dressing, Welded joints, Finite element method, Microalloyed steel, Welding, Welds, Yield stress, Comprehensive evaluation, Cruciform joints, Fatigue strength assessment, Local approaches, Reliable results, TIG dressings, Fatigue of materials
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-252449 (URN)10.1016/j.ijfatigue.2019.04.038 (DOI)000472688800008 ()2-s2.0-85064954298 (Scopus ID)
Note

QC 20190715

Available from: 2019-07-15 Created: 2019-07-15 Last updated: 2019-07-29Bibliographically approved
Afshari, D., Mirzaahamdi, S. & Barsoum, Z. (2019). Residual Stresses in Resistance Spot Welded AZ61 Mg Alloy. CMES - Computer Modeling in Engineering & Sciences, 118(2), 275-290
Open this publication in new window or tab >>Residual Stresses in Resistance Spot Welded AZ61 Mg Alloy
2019 (English)In: CMES - Computer Modeling in Engineering & Sciences, ISSN 1526-1492, E-ISSN 1526-1506, Vol. 118, no 2, p. 275-290Article in journal (Refereed) Published
Abstract [en]

The use of magnesium alloys has been rapidly increased due to their ability to maintain high strengths at light weights. However weldability of steels and aluminum alloys by using resistance spot weld (RSW) process is a major issue, because it cannot be directly utilized for magnesium alloys. In this study, a structural-thermal-electrical finite element (FE) model has been developed to predict the distribution of residual stresses in RSW AZ61 magnesium alloy. Thermophysical and thermomechanical properties of AZ61 magnesium alloy have been experimentally determined, and have been used in FE model to increase the accuracy of the model. X-ray diffraction (XRD) technique has been utilized to measure the residual stresses in welded samples, and its results have been used to validate the FE model. Comparison study shows that the results obtained by using FE model have a good agreement with the experimental XRD data. In specific, the results show that the maximum tensile residual stress occurs at the weld center while decreases towards the nugget edge. In addition, the effects of welding parameters such as electrical current, welding time, and electrode force have been investigated on the maximum tensile residual stress. The results show that the tensile residual stress in welded joints rises by increasing the electrical current; however, it declines by prolonging the welding time as well as increasing the electrode force.

Place, publisher, year, edition, pages
TECH SCIENCE PRESS, 2019
Keywords
Resistance spot weld, AZ61 mg alloy, residual stresses, finite element model, x-ray diffraction
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-246293 (URN)10.31614/cmes.2019.03880 (DOI)000459391600002 ()2-s2.0-85063015035 (Scopus ID)
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-05-13Bibliographically approved
Umer, R., Barsoum, Z., Jishi, H. Z., Ushijima, K. & Cantwell, W. J. (2018). Analysis of the compression behaviour of different composite lattice designs. Journal of composite materials, 52(6), 715-729
Open this publication in new window or tab >>Analysis of the compression behaviour of different composite lattice designs
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2018 (English)In: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793X, Vol. 52, no 6, p. 715-729Article in journal (Refereed) Published
Abstract [en]

Four all-composite lattice designs were produced using a lost-mould procedure that involved inserting carbon fibre tows through holes in a core. Following resin infusion and curing, samples were heated to melt the core, leaving well-defined lattice structures based on what are termed BCC, BCCz, FCC and F2BCC designs. Analytical and numerical models for predicting the mechanical properties of the four designs are presented and these results are compared with the experimental data from the quasi-static compression tests. Compression tests on the four lattice structures indicated that the F2BCC lattice offered the highest compression strength, although when normalized by relative density, the BCCz lattice structure out-performed other structures. Similarly, the specific compression strengths were found to be superior to those of more traditional core materials. A number of failure mechanisms were also highlighted, including strut buckling, fracture at the strut-skin joints and debonding of reinforcing members at the central nodes. Finally, it is believed that the properties of these lattices can be further increased using higher fibre volume fractions.

Place, publisher, year, edition, pages
Sage Publications, 2018
Keywords
Lattice structures, sandwich cores, compression, lightweight structures
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-226806 (URN)10.1177/0021998317714531 (DOI)000429865700001 ()2-s2.0-85042867817 (Scopus ID)
Note

QC 20180508

Available from: 2018-05-08 Created: 2018-05-08 Last updated: 2018-06-04Bibliographically approved
Shams-Hakimi, P., Zamiri, F., Al-Emrani, M. & Barsoum, Z. (2018). Experimental study of transverse attachment joints with 40 and 60 mm thick main plates, improved by high-frequency mechanical impact treatment (HFMI). Engineering structures, 155, 251-266
Open this publication in new window or tab >>Experimental study of transverse attachment joints with 40 and 60 mm thick main plates, improved by high-frequency mechanical impact treatment (HFMI)
2018 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 155, p. 251-266Article in journal (Refereed) Published
Abstract [en]

In recent years, high-frequency mechanical impact (HFMI) treatment has grown in popularity due to its efficiency in improving the fatigue strength of welded joints. The fatigue performance of HFMI-treated welded steel joints has, however, not been thoroughly studied for plate thicknesses above 30 mm. In this study, 40 and 60 mm thick main plates with non-load-carrying transverse attachments have been fatigue tested under constant amplitude four-point bending, both in as-welded and HFMI-treated condition to investigate the fatigue performance for large plate thicknesses, typical for weldments in bridges. Axial fatigue strengths were estimated by a modification of the experimental results with fracture mechanics calculations. The main conclusions are that HFMI treatment can result in significant fatigue strength improvement even for large main plate thicknesses and that the difference in fatigue strength between bending and axial loading is negligible for the specimen geometries used in this study.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2018
Keywords
Fatigue, Thickness, HFMI, LEFM, Steel
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-221931 (URN)10.1016/j.engstruct.2017.11.035 (DOI)000419409800020 ()2-s2.0-85034604870 (Scopus ID)
Note

QC 20180131

Available from: 2018-01-31 Created: 2018-01-31 Last updated: 2018-01-31Bibliographically approved
Barsoum, Z., Stenberg, T. & Lindgren, E. (2018). Fatigue properties of cut and welded high strength steels-Quality aspects in design and production. In: Procedia Engineering: . Paper presented at 7th International Conference on Fatigue Design, Fatigue Design 2017, Senlis, France, 29 November 2017 through 30 November 2017 (pp. 470-476). Elsevier, 213
Open this publication in new window or tab >>Fatigue properties of cut and welded high strength steels-Quality aspects in design and production
2018 (English)In: Procedia Engineering, Elsevier, 2018, Vol. 213, p. 470-476Conference paper, Published paper (Refereed)
Abstract [en]

In this study, several aspects regarding effect of quality on the fatigue strength in welded cut HSS have been investigated and are discussed. A novel numerical algorithm has been developed which assesses the welded surface and calculates and quantifies weld quality parameters and the presence of defects which are critical in fatigue applications. The algorithm is designed for implementation in serial production. It will provide robust and reliable feedback on the quality being produced, which is essential if high strength steels are utilized and high quality welds are necessary for the structural integrity of the welded component. Two welding procedures which can increase the weld quality in as welded conditions have been assessed. It was found that by using these methods, the fatigue strength can be increased with 20% compared to normal weld quality. Furthermore, two fatigue assessment methods ability to account for increased weld quality in low cycle and high cycle fatigue applications has been studied. One of these methods showed sufficient accuracy in predicting the fatigue strength with small scatter and also account for increased weld quality. The influence of surface quality on cut edges was studied and the fatigue strength was estimated using international standards and a fatigue strength model for cut edges. It was found that the fatigue strength in testing was 15-70% higher compared to the estimation, thus proving a weak link between the international standard and fatigue strength.

Place, publisher, year, edition, pages
Elsevier, 2018
Series
Procedia Engineering, ISSN 1877-7058 ; 213
Keywords
Fatigue, high strength steel, quality, welded joints
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-228579 (URN)10.1016/j.proeng.2018.02.046 (DOI)2-s2.0-85047097393 (Scopus ID)
Conference
7th International Conference on Fatigue Design, Fatigue Design 2017, Senlis, France, 29 November 2017 through 30 November 2017
Note

QC 20180528

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-05-28Bibliographically approved
Yalchiner, F. B. & Barsoum, Z. (2017). Life Extension of Welded Structures Using HFMI Techniques - Potential Application to Offshore Structures. In: Iacoviello, F Moreira, PMGP Tavares, PJS (Ed.), 2nd International Conference on Structural Integrity, ICSI 2017: . Paper presented at 2nd International Conference on Structural Integrity (ICSI), SEP 04-07, 2017, Funchal, Portugal (pp. 377-384). Elsevier, 5
Open this publication in new window or tab >>Life Extension of Welded Structures Using HFMI Techniques - Potential Application to Offshore Structures
2017 (English)In: 2nd International Conference on Structural Integrity, ICSI 2017 / [ed] Iacoviello, F Moreira, PMGP Tavares, PJS, Elsevier, 2017, Vol. 5, p. 377-384Conference paper, Published paper (Refereed)
Abstract [en]

Fatigue damage development in welded structures is a local phenomenon and if one need to achieve an extension of the life for the structure local post weld improvements need to be use in order to reduce/remove local features which contribute to the fatigue damage. In order to enhance the life time of load carrying welded structures without large amount of cost investments, e.g. redesign and replacement of existing structures, post weld improvement techniques need to be more applied. New High Frequency Mechanical Impact (HFMI) technologies have been developed in the last 10 years which enables cost-effective life extension and reparation of welded structures. The use improvement techniques for technical life enhancement upgrade and repair of welded structures within various industries, e.g. oil and gas, have been an accepted practice. HFMI treatment techniques are based on localized peening process of the welded joints and the devices are portable. The impacting results in a local cold plastic deformation which remove weld defects reduce stress concentration and induce compressive residual stresses which eventually will enhance the fatigue life of the welded structure. An overview of existing improvement techniques for welded structures is given followed by description of new technologies (HFMI). A brief description of the new international guideline and design recommendations within the International Institute of Welding (IIW) is given. Several validation studies on the fatigue performance of HFMI techniques are presented and onsite potential applications of the techniques for joints in fixed offshore structures are outlined.

Place, publisher, year, edition, pages
Elsevier, 2017
Series
Procedia Structural Integrity, ISSN 2452-3216 ; 5
Keywords
Life extension, HFMI (High Frequency Mechanical Impact), Welded Structure, Fatigue
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-221406 (URN)10.1016/j.prostr.2017.07.185 (DOI)000419177800050 ()
Conference
2nd International Conference on Structural Integrity (ICSI), SEP 04-07, 2017, Funchal, Portugal
Note

QC 20180117

Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2018-01-29Bibliographically approved
Stenberg, T., Barsoum, Z., Astrand, E., Oberg, A. E., Schneider, C. & Hedegard, J. (2017). Quality control and assurance in fabrication of welded structures subjected to fatigue loading. Welding in the World, 61(5), 1003-1015
Open this publication in new window or tab >>Quality control and assurance in fabrication of welded structures subjected to fatigue loading
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2017 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 61, no 5, p. 1003-1015Article in journal (Refereed) Published
Abstract [en]

The current paper presents a comprehensive overview of weld quality control and assurance of welded structures where the major failure prevention is due to fatigue loading. It gives the drawbacks and limitation of quality control systems, international weld quality standards, and guidelines used in today's weld production. Furthermore, in recent development in quality control and assurance of welded structures, a new online method is presented. The main target is to enable a complete, online evaluation of large quantities of welds in an accurate and repeatable fashion. Information gathered will not only be used for determining the weld quality level with respect to the fatigue strength but also to be evaluated for use in improved process control, in welding power sources, and robot control systems. It is verified that the new online method, a new laser scanning technology, and algorithms can successfully be used as modern tools for automated unbiased geometrical weld quality assurance and implemented in weld production environment.

Place, publisher, year, edition, pages
SPRINGER HEIDELBERG, 2017
Keywords
Welded joints, Imperfections, Fatigue, Quality, Surface measurements, Inspection
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-215470 (URN)10.1007/s40194-017-0490-5 (DOI)000411060800015 ()2-s2.0-85027727366 (Scopus ID)
Note

QC 20171016

Available from: 2017-10-16 Created: 2017-10-16 Last updated: 2017-10-20Bibliographically approved
Khurshid, M., Leitnerb, M., Barsoum, Z. & Schneider, C. (2017). Residual stress state induced by High Frequency Mechanical Impact Treatment in different steel grades -numerical and experimental study. International Journal of Mechanical Sciences, 123, 34-42
Open this publication in new window or tab >>Residual stress state induced by High Frequency Mechanical Impact Treatment in different steel grades -numerical and experimental study
2017 (English)In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 123, p. 34-42Article in journal (Refereed) Published
Abstract [en]

High frequency mechanical impact treatment is observed to increase the fatigue strength of welded joints. This technique induces compressive residual stresses, increases the local hardness, and reduces the stress concentration by modifying the weld toe radius. The goal of this study was to investigate residual stresses induced by ultrasonic impact treatment in S355, S700MC, and S960 grades steel experimentally and numerically. Plate specimens were manufactured and treated with different treatment intensities i.e. vibration amplitudes of the Sonotrode. The indentation depths were measured by the aid of a laser scanner and residual stresses using X-ray diffraction technique. The effect of steel grade and treatment intensity on the induced compressive residual stress state was firstly studied experimentally. In addition, displacement controlled simulations were carried out to estimate the local residual stress condition considering the effect of different material models. Both the numerically estimated and experimentally measured residual stresses were qualitatively in good agreement. Residual stress state in S355 and S700MC can be estimated well using combined strain rate dependent material model. No significant effect of the treatment intensity is observed on the indentation depth and residual stress state for S355 grade steel. The indentation depth decreases with the increase in the yield strength of the steel.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Residual stress state; HFMI; Steel; X-ray diffraction; Finite element analysis; Fatigue strength
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-200920 (URN)10.1016/j.ijmecsci.2017.01.027 (DOI)000397695700003 ()2-s2.0-85011102713 (Scopus ID)
Note

QC 20170206

Available from: 2017-02-05 Created: 2017-02-05 Last updated: 2017-04-28Bibliographically approved
Khurshid, M., Barsoum, Z., Daeuwel, T. & Barsoum, I. (2017). Root fatigue strength assessment of fillet welded tube-to-plate joints subjected to multi-axial stress state using stress based local methods. International Journal of Fatigue, 101, 209-223
Open this publication in new window or tab >>Root fatigue strength assessment of fillet welded tube-to-plate joints subjected to multi-axial stress state using stress based local methods
2017 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 101, p. 209-223Article in journal (Refereed) Published
Abstract [en]

In this study the fatigue strength of fillet welded tube-to-plate joints failing at the weld root and subjected to multi-axial stress states is investigated. The fatigue test data is collected from the literature and it is assessed together with the experimental data generated in this study. Finite element analysis is used to analyze the stress state at the weld root. The fatigue strength estimation capabilities of local stress based methods such as the Principal Stress Hypothesis (PSH), von Mises Stress Hypothesis (vMH), Modified Wohler Curve Method (MWCM), and Effective Equivalent Stress Hypothesis (EESH) are compared. The applicability of modified Gough Pollard Equation (GPE) in local stress system is also assessed. It is observed that most of the proposed local stress assessment methods can estimate the fatigue strength of fillet welds subjected to multiaxial stress states with constant principal stress direction, e.g. proportional loading. In case of load histories which produce varying principal stress directions with respect to time, e.g. non-proportional loading, better estimation capability is shown by MWCM and EESH. In most of the cases of varying principal stress direction load histories, vMH and PSH fail to estimate the fatigue strength. The fatigue strength of specimens tested with combined loading is reduced in comparison to the fatigue strength of specimens tested with only internal pressure and only bending loading. Out-of-phase loading does not affect the fatigue strength significantly for the specimens in this study. However; a decrease in fatigue strength is observed for the test data for out-of-phase loading collected from the literature.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2017
Keywords
Fatigue strength, Tube-to-plate joint, Welded joints, Local stress based approaches, Multi-axial stress state
National Category
Aerospace Engineering
Identifiers
urn:nbn:se:kth:diva-210336 (URN)10.1016/j.ijfatigue.2017.02.007 (DOI)000403134000009 ()2-s2.0-85012237559 (Scopus ID)
Note

QC 20170704

Available from: 2017-07-04 Created: 2017-07-04 Last updated: 2017-07-04Bibliographically approved
Leitner, M., Khurshid, M. & Barsoum, Z. (2017). Stability of high frequency mechanical impact (HFMI) post-treatment induced residual stress states under cyclic loading of welded steel joints. Engineering structures, 143, 589-602
Open this publication in new window or tab >>Stability of high frequency mechanical impact (HFMI) post-treatment induced residual stress states under cyclic loading of welded steel joints
2017 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 143, p. 589-602Article in journal (Refereed) Published
Abstract [en]

This paper investigates the effect of cyclic loading on the stability of compressive residual stress fields induced by high frequency mechanical impact (HFMI) post-weld treatment. First, the effectiveness of the post-treatment technique is shown by fatigue tests incorporating mild steel S355 and high strength steel S960 longitudinal stiffener specimens. Extensive X-ray residual stress measurements support the beneficial impact on the compressive residual stress state for mild and high-strength steel structures. They also illustrate that cyclic loading leads to a significant local relaxation of this condition. Second, a numerical simulation chain incorporating a structural weld simulation, numerical analysis of the HFMI-treatment, and a final cyclic loading step for the investigated mild steel specimen is set-up. The results show that the residual stresses at the surface of the weld toe are in agreement to the X-ray measurements for both the as-welded and HFMI-treated condition, which basically proofs the applicability of the manufacturing simulation. The numerical computation including the first five load-cycles demonstrates that the simulated residual stress relaxation again exhibits consistent results with the measurements. An additional utilization of an analytical relaxation model from literature reveals that the estimation of the residual stress state in the high-cycle fatigue region is well employable. Therefore, the scientific results in this paper proof the applicability of the presented consecutive numerical-analytical procedure to assess the local compressive residual stress stability of HFMI-treated welded steel joints in both the low- and high-cycle fatigue region.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2017
Keywords
Welded joints, HFMI-treatment, Cyclic residual stress stability, X-ray measurement, Numerical simulation, Analytical residual stress relaxation models
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-208713 (URN)10.1016/j.engstruct.2017.04.046 (DOI)000401880300044 ()2-s2.0-85018959428 (Scopus ID)
Note

QC 2017-06-12

Available from: 2017-06-12 Created: 2017-06-12 Last updated: 2017-06-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-4180-4710

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