Publications related to Welding

Strain-based analysis on the influence of local undercut geometry on fatigue crack initiation life

Alain Nussbaumer, Heikki Tapani Remes, Abinab Niraula

The local undercut defects at the weld toe provide a potential initiation site for fatigue cracks and significantly impact the structure's fatigue strength. The influence of continuous undercut depth on fatigue performance is widely studied, but the resear ...

2024

Dataset for "Complexity of crack front geometry enhances toughness of brittle solids"

John Martin Kolinski, Chenzhuo Li, Xinyue Wei

This data package supports the publication 'Complexity of crack front geometry enhances toughness of brittle solids' by Xinyue Wei, Chenzhuo Li, Cían McCarthy, and John M. Kolinski Nature physics (2024) - https://doi.org/10.1038/s41567-024-02435-x DOI: 1 ...

Zenodo2024

Experimental Investigation of Instability-Free Welded Moment Connections With Simplified Weld Details

Dimitrios Lignos, Andronikos Skiadopoulos

In capacity designed steel moment resisting frames, inelastic deformations are mostly concentrated in the steel beams and the column fixed ends of the first story. This design concept limits the participation of the column web’s panel zone in the energy di ...

2023

Hysteretic behaviour of welded connections with highly inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos

The current practice in capacity-designed steel moment resisting frames (MRFs) worldwide allows for limitedshear yielding in the column web panel zone. As such, inelastic deformations concentrate near the beam ends, thereby leading to flexural stre ...

Ernst & Sohn2023

Control of intermetallics in the interface in directed energy deposition of titanium on stainless steel 316L

Di Cui

Application of a single metal or alloy is often restricted by its properties from optimal combination of performance and cost. Therefore, there is a vast need of joining dissimilar metals for various applications in biomedical, aerospace, automobile and ma ...

EPFL2023

Geometric tolerances of welded connections with inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos, Ce Wen

Prequalified beam-to-column connections in steel moment resisting frames usually concentrate inelastic deformations in the steel beam ends. As such, nonlinear geo-metric instabilities (i.e., local buckling) may occur in these regions at modest lateral drif ...

Ernst & Sohn2023

Full-Scale Experiments of Cyclically Loaded Welded Moment Connections with Highly Dissipative Panel Zones and Simplified Weld Details

Dimitrios Lignos, Andronikos Skiadopoulos

This paper presents the experimental results of two welded unreinforced flange-welded web (WUF-W) beam-to-column connections that defy the current design paradigm of prequalified welded connections. The proposed WUF-W connections feature customized beveled ...

2023

Experimental Investigation of the Inelastic Cyclic Behavior of Concrete-Filled Double-Skin Tubular Beam-Columns with Corrugated Inner Skins and Ultrahigh-Strength Corner Tubes

Dimitrios Lignos, Mojtaba Farahi

This paper presents the experimental results from nine full-scale concrete-filled double-skin tubular (CFDST) beam-columns. The test specimens exploited two fabrication strategies, featuring either hollow steel inner skins with corrugated geometry or ultra ...

ASCE-AMER SOC CIVIL ENGINEERS2022

Full-scale testing of European steel beams with reduced beam section under reversed cyclic loading

Dimitrios Lignos, Hiroyuki Inamasu

Steel beams with reduced beam section (RBS) are often used as part of prequalified connections in seismic regions. However, RBS connections are not as common in Europe. Reasons relate to easiness in fabrication, which requires on-site welding, and the seis ...

Springer Nature2022

Welded moment connections with highly dissipative panel zones for enhanced seismic performance of steel moment frames

Andronikos Skiadopoulos

Research conducted after the 1994 Northridge earthquake in the U.S. and the 1995 Kobe earthquake in Japan led to the development of today's pre-qualified beam-to-column connections for capacity-designed steel moment resisting frames (MRFs). Welded moment c ...

EPFL2022

Seismic stability of steel moment resisting frames with inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos

This paper summarizes preliminary findings of nonlinear simulations aiming to quantify the seismic demands of codecompliant steel MRFs with variable panel zone targeted shear distortions, 𝛾!. The probability of beam fractures is explicitly considered in th ...

Earthquake Engineering Research Institute2022

Reliability analysis of welded stud shear connectors on simply-supported bridge girders

Scott Walbridge, Matthew James Sjaarda

This paper examines the reliability of welded stud shear connectors for steel-concrete composite bridge girders. A finite element model of a simply-supported bridge was created featuring link connector elements representing the shear studs between beam and ...

CANADIAN SCIENCE PUBLISHING2021

Post-tensioning of glass beams: Analytical determination of the allowable pre-load

Alain Nussbaumer, Pieter Christian Louter, Jagoda Cupac

The effectiveness of post-tensioning in enhancing the fracture resistance of glass beams depends on the level of compressive pre-stress introduced at the glass edge surface that will in service be exposed to tensile stresses induced by bending. Maximum pre ...

2021

Experimental Evaluation of Steel Columns under Seismic Hazard-Consistent Collapse Loading Protocols

Dimitrios Lignos

This paper presents results from 21 large-scale experiments on steel columns that examined their collapse behavior as related to steel moment resisting frames (MRFs). The test specimens included wide-flange and square hollow structural shapes (HSS) and wer ...

2021

Progress on Tests on Splices Between Nb3Sn Rutherford Cables for Graded High-Field Accelerator Magnets

Pierluigi Bruzzone, Mithlesh Kumar, Vincenzo D'Auria

Future high-field accelerator magnets foresee the extensive use of Nb3Sn, more expensive than the Nb-Ti of LHC. For projects involving the series production of magnets, conductor grading is mandatory in order to reduce the cost. To allow grading ...

IEEE Institute of Electrical and Electronics Engineers2021

Laser powder-bed fusion of metallic alloys with enhanced microstructures and properties

Navid Sohrabi

Laser powder-bed fusion (LPBF) is an additive manufacturing (AM) process that uses a laser to selectively melt a powder bed. This process can build dense samples with complicated geometries from a wide variety of metallic alloys. In this thesis, LPBF of al ...

EPFL2021

Adaptive Laser Welding Control: A Reinforcement Learning Approach

Silvio Zanoli, Giulio Masinelli

Despite extensive research efforts in the field of laser welding, the imperfect repeatability of the weld quality still represents an open topic. Indeed, the inherent complexity of the underlying physical phenomena prevents the implementation of an effecti ...

2020

Performance of Embedded Bolt Shear Connectors

Scott Walbridge, Matthew James Sjaarda

A laboratory research program carried out at the University of Waterloo featured the testing of three large-scale steel-concrete composite beam specimens with embedded bolt shear connectors. A detailed assessment of the connector performance was made, faci ...

TAYLOR & FRANCIS LTD2020

Enhanced strength and toughness of bulk ultrafine grained Cu by nacre-inspired lamellar structure

Roland Logé, Jun Wang, Chenguang Li

An ultrafine grained (UFG) bulk Cu with a novel nacre-inspired lamellar structure containing nano-bridges and aligned nanopores at inter-lamellar interfaces was fabricated by consolidation of a nanocrystal-attached ultrathin Cu flake powder by spark plasma ...

2020

Fatigue properties of as-welded and post-weld-treated high-strength steel joints: The influence of constant and variable amplitude loads

Alain Nussbaumer, Halid Can Yildirim, Heikki Tapani Remes

In HSS welded structures, HFMI allows fatigue strength improvement factors by inducing compressive residual stresses, cold-worked surface region and modifying the weld toe shape. According to the literature, the factors are proposed based on failures at CA ...

2020