@inproceedings{LaunertRhodePasternaketal., author = {Launert, Benjamin and Rhode, Michael and Pasternak, Hartmut and Kannengießer, Thomas}, title = {Welding residual stresses in high-strength steel. Experimental results}, series = {The International Colloquium on Stability and Ductility of Steel Structures}, booktitle = {The International Colloquium on Stability and Ductility of Steel Structures}, editor = {Dubina, Dan and Ungureanu, Viorel}, edition = {2016 edition}, publisher = {Ernst \& Sohn}, isbn = {978-92-9147-133-1}, pages = {517 -- 524}, abstract = {This article presents the latest results of an ongoing national research project on improved models for the prediction of welding residual stresses of thick-plated welded I-girders. The experimental program is presented and the importance of different influencing factors on the residual stresses is discussed in detail. All results are compared for mild (S355J2+N) and high strength (S690QL) steel. Finally, conclusions for further works are drawn.}, language = {en} } @misc{LaunertRhodeKrommetal., author = {Launert, Benjamin and Rhode, Michael and Kromm, Arne and Pasternak, Hartmut and Kannengießer, Thomas}, title = {Measurement and numerical modeling of residual stresses in welded HSLA component-like I-girders}, series = {Welding in the World}, volume = {61}, journal = {Welding in the World}, number = {2}, issn = {0043-2288}, doi = {10.1007/s40194-016-0413-x}, pages = {223 -- 229}, abstract = {The present contribution shows the residual stress results obtained from experiments with the sectioning method in comparison to global (structural) welding simulation models on component-like (i.e., large scale) I-girders made of structural steel grades S355 and S690QL. Plates were welded by conventional gas metal arc welding using two different heat inputs. In addition, the base material was assumed to be approximately stress-free. Based on these results, conclusions and recommendations for the design of welded I-girders are drawn.}, language = {en} } @misc{LaunertSzczerbaGajewskietal., author = {Launert, Benjamin and Szczerba, Radosław and Gajewski, Marcin and Rhode, Michael and Pasternak, Hartmut and Giżejowski, Marian}, title = {The buckling resistance of welded plate girders taking into account the influence of post-welding imperfections - Part 1: Parameter study}, series = {Materials Testing}, volume = {59}, journal = {Materials Testing}, number = {1}, issn = {0025-5300}, doi = {10.3139/120.110964}, pages = {47 -- 56}, abstract = {Welding is the most important joining technique and offers the advantage of customizable plate thicknesses. On the other hand, welding causes residual stresses and deformations influencing the load carrying capacity. Their consideration in the design requires simple and fast models. Though welding simulation has contributed to accurately access to these values nowadays, their application to large components remains still in a less practicable range. Nevertheless, many studies emphasized the need to make corrections in recently available simplified models. Especially the influence of residual stresses seems somewhat overestimated in many cases if comparing conventional structural steel S355 and high-strength steel S690. In times of computer-aided design, an improved procedure to implement weld-inducted imperfections appears overdue. This will be presented in two parts. The first part illustrates the potential influence of post-welding imperfections exemplified for weak axis buckling in comparison with the general method in accordance with Eurocode 3. Residual stresses and initial crookedness were varied systematically in order to produce a scatter band of capacities. An approach to characterize the borders of these imperfections was undertaken before that. The excessive scattering of reduction factors for the load bearing capacity demonstrates the importance of these variables. Results were finally evaluated against advanced simulation models which will be further detailed in part two of this contribution.}, language = {en} } @misc{PasternakLaunertKannengiesseretal., author = {Pasternak, Hartmut and Launert, Benjamin and Kannengießer, Thomas and Rhode, Michael}, title = {Advanced Residual Stress Assessment of Plate Girders Through Welding Simulation}, series = {Procedia Engineering}, volume = {172}, journal = {Procedia Engineering}, issn = {1877-7058}, doi = {10.1016/j.proeng.2017.02.013}, pages = {23 -- 30}, abstract = {This article provides an impression on potentials in applying nowadays welding simulation tools in construction design. This is carried out exemplary on plate girders from two structural steel grades. The calculated residual stresses are compared with measurements by sectioning method. It has been repeatedly stated that present Eurocode models fail to approximate the residual stresses. Especially for high strength steel (HSS) only limited information is available on realistic occurring residual stresses in typical I-girders. The investigations are aimed to give further guidance on these values. A few proposals on advanced models are discussed.}, language = {en} } @techreport{LaunertPasternakRhodeetal., author = {Launert, Benjamin and Pasternak, Hartmut and Rhode, Michael and Kromm, Arne and Kannengießer, Thomas}, title = {Erh{\"o}hung der Tragf{\"a}higkeit geschweißter I-Tr{\"a}ger aus hochfestem Baustahl durch verbesserte Ans{\"a}tze zur Ber{\"u}cksichtigung von Eigenspannungen}, pages = {4}, language = {de} } @inproceedings{KrommRhodeLaunertetal., author = {Kromm, Arne and Rhode, Michael and Launert, Benjamin and Dixneit, Jonny and Kannengießer, Thomas and Pasternak, Hartmut}, title = {Combining Sectioning Method and X-Ray Diffraction for Evaluation of Residual Stresses in Welded High Strength Steel Components}, series = {Residual Stresses 2016 - ICRS-10}, booktitle = {Residual Stresses 2016 - ICRS-10}, editor = {Holden, Thomas M. and Mur{\´a}nsky, Ondrej and Edwards, Lyndon}, publisher = {Materials Research Forum LLC}, address = {Millersville, PA}, isbn = {978-1-94529116-6}, doi = {10.21741/9781945291173-28}, pages = {163 -- 168}, abstract = {Residual stresses and distortions in welded I-girders for steel construction are relevant when evaluating the stability of steel beams and column members. The application of high strength steels allows smaller wall thicknesses compared to conventional steels. Therefore, the risk of buckling has to be considered carefully. Due to the lack of knowledge concerning the residual stresses present after welding in high strength steel components conservative assumptions of their level and distribution is typically applied. In this study I-girders made of steels showing strengths of 355 MPa and 690 MPa were welded with varying heat input. Due to the dimension of the I-girders and the complex geometry the accessibility for residual stress measurement using X-ray diffraction was limited. Therefore, saw cutting accompanied by strain gauge measurement has been used to produce smaller sections appropriate to apply X-ray diffraction. The stress relaxation measured by strain gauges has been added to residual stresses determined by X-ray diffraction to obtain the original stress level and distribution before sectioning. The combination of both techniques can produce robust residual stress values. From practical point of view afford for strain gauge application can be limited to a number of measuring positions solely to record the global amount of stress relaxation. X-ray diffraction can be applied after sectioning to determine the residual stresses with sufficient spatial resolution.}, language = {en} } @inproceedings{LaunertRhodeKrommetal., author = {Launert, Benjamin and Rhode, Michael and Kromm, Arne and Pasternak, Hartmut and Kannengießer, Thomas}, title = {Residual Stress Influence on the Flexural Buckling of Welded I-Girders}, series = {Residual Stresses 2016 - ICRS-10}, booktitle = {Residual Stresses 2016 - ICRS-10}, editor = {Holden, Thomas M. and Mur{\´a}nsky, Ondrej and Edwards, Lyndon}, publisher = {Materials Research Forum LLC}, address = {Millersville, PA}, isbn = {978-1-94529116-6}, doi = {10.21741/9781945291173-19}, pages = {109 -- 114}, abstract = {The nonlinear analysis became a common tool to precisely assess the load-bearing behavior of steel beam and column members. The failure level is significantly influenced by different types of imperfections, among geometric also structural imperfections (residual stresses). Here are still gaps in the knowledge. Nowadays, 3-D welding simulation developed to a level where it could provide reliable estimation of weld-induced distortion and residual stresses. Nevertheless, modelling and computational effort are still in a less practicable range. In this study a simplified procedure to implement residual welding stresses in continuous large scale members is proposed and the influence on the ultimate limit state of slender members in compression is evaluated for two common structural steel grades. The results showed significant improvements in the utilization of load bearing capacity compared with simplified design methods. The comparatively general approach in this study offers potential for future optimization.}, language = {en} } @inproceedings{PasternakLaunertKannengiesseretal., author = {Pasternak, Hartmut and Launert, Benjamin and Kannengießer, Thomas and Rhode, Michael}, title = {Residual stresses and imperfections in welded high-strength I-shape members}, series = {Insights and Innovations in Structural Engineering, Mechanics and Computation, Proceedings of the Sixth International Conference on Structural Engineering, Mechanics and Computation, Cape Town, South Africa, 5-7 September 2016}, booktitle = {Insights and Innovations in Structural Engineering, Mechanics and Computation, Proceedings of the Sixth International Conference on Structural Engineering, Mechanics and Computation, Cape Town, South Africa, 5-7 September 2016}, editor = {Zingoni, Alphose}, publisher = {Taylor \& Francis}, address = {London}, isbn = {978-1-138-02927-9}, pages = {403 -- 404}, abstract = {This article addresses the imperfections caused by the weld assembly in I-shape sections made of two structural steel grades. Load influencing imperfections are assumed as deviations from the ideal shape (e.g. bending distortion) and longitudinal residual stresses. The quality of a numerically aided design of components exposed to either compression and/or bending is significantly affected, depending on these parameters [1]. The Eurocode provides robust simplified models. As a result, the Ultimate Limit State (ULS) is approached on a conservative basis. The following investigations are aimed at providing further guidance on these values in component-like specimens. The long term goal is an improved understanding of the load-bearing capacity of such sections. As a first step in this process, the experimental and corresponding numerical studies are presented.}, language = {en} }