Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleDai R, Gardner L, Wadee MA, 2025, , Structures, Vol: 82, ISSN: 2352-0124
The stability and design of fixed-ended stainless steel unequal-leg angle section members subjected to axial compression are studied herein. The critical buckling behaviour is first described; existing experimental data on stainless steel and aluminium alloy unequal-leg angle section columns collected from the literature are then employed to validate nonlinear finite element models developed within the commercial package ABAQUS. A comprehensive numerical parametric study is subsequently conducted considering members made from the three main families of stainless steel (austenitic, ferritic and duplex) with a broad spectrum of geometric configurations and slenderness values. The behaviour and load-carrying capacity of the studied columns are shown to depend not only on the global slenderness, but also on the ratio of the elastic torsional-flexural to minor-axis flexural buckling loads. The collected experimental data and generated numerical results are employed to evaluate the ultimate resistance predictions given by the current Eurocode 3 design provisions, revealing an excessive level of conservatism, particularly for cases where torsional-flexural buckling is dominant. A new design approach for fixed-ended stainless steel unequal-leg angle section columns, suitable for incorporation into future revisions of Eurocode 3, is subsequently proposed, reflecting the aforementioned observations. The proposed approach significantly improves the accuracy and consistency of the resistance predictions compared to the current design provisions. Finally, a reliability analysis is conducted following the EN 1990 procedure, resulting in a recommended partial safety factor of 1.1.
-
Journal articleZhang R, Amraei M, Piili H, et al., 2025, , Engineering Structures, Vol: 341, ISSN: 0141-0296
A comprehensive experimental investigation into the mechanical properties and structural performance of square hollow section (SHS) stub columns manufactured by laser beam powder bed fusion (PBF-LB/M) from AlSi10Mg aluminium alloy, has been conducted and is presented herein. A series of tensile and compressive coupons with different build directions, together with six SHS stub columns, were additively manufactured and tested. The PBF-LB/M AlSi10Mg material exhibited good mechanical performance and mild anisotropy, with yield and ultimate strengths of around 280烘Pa and 420烘Pa, respectively, and fracture strains of between about 4% and 7%. SHS profiles were examined to isolate the influence of the manufacturing process, enabling direct comparisons with the performance and design of conventionally produced cross-sections. The PBF-LB/M aluminium SHS stub columns failed by inelastic local buckling and exhibited similar performance to conventionally manufactured aluminium SHS in the slender range, while showing higher normalised load-carrying capacities in the stocky range. Comparisons with the existing design methods indicated that both Eurocode 9 (EC9) and the continuous strength method (CSM) can provide safe-sided resistance predictions, with the CSM yielding more accurate and consistent results.
-
Journal articleHuang C, Liang Z, Li G-Q, et al., 2025, , International Journal of Mechanical Sciences, Vol: 304, ISSN: 0020-7403
Utilising robotic welding technology, wire arc additive manufacturing (WAAM) is developing into a viable method for the production of structural steel elements. However, there remains a lack of knowledge on the fracture ductility of WAAM steels, which is of particular importance under extreme loading conditions, such as severe earthquakes. An experimental and numerical study into the ductile fracture behaviour of WAAM ER70S-6 carbon steel plates has therefore been undertaken and is reported herein. ER70S-6 steel was selected for this study for its widespread use in WAAM and its well-characterised and desirable mechanical properties, facilitating comparisons of fracture ductility with conventionally-produced steels. Following mechanical and microstructural characterisation, a series of WAAM fracture specimens of two thicknesses and various shapes (corresponding to various stress states) was tested under quasi-static tensile loading. Digital image correlation (DIC) was employed to monitor the evolution of the deformations and strains of the specimens during testing. The WAAM steel exhibited superior fracture ductility compared to equivalent, conventionally-produced steels, with the thicker material showing higher ductility than the thinner material. Finite element (FE) models of the fracture specimens were developed and validated, with good agreement between the simulated and measured load-displacement curves and strain fields demonstrated. Through the experiments and simulations, the equivalent plastic strain at fracture and the corresponding stress triaxiality and Lode angle parameter were determined for each specimen. The obtained fracture data were used to calibrate three typical ductile fracture models – the Modified Mohr-Coulomb (MMC), Hosford-Coulomb (H-C) and Lou-Huh (L-H) models. All the models were shown to provide accurate predictions of fracture initiation for the WAAM ER70S-6 steel. The calibrated fracture loci represent a step forward for the predi
-
Journal articleFang Q, Grosman S, Pullen A, et al., 2025, , Construction and Building Materials, Vol: 494, ISSN: 0950-0618
Masonry arch bridges with observed or suspected defects require effective structural health monitoring to ensure their safety under increasing traffic loads. Traditional methods, such as visual inspections, provide only qualitative assessments and do not capture the variations in key local and global response characteristics under traffic loading. More advanced structural health monitoring techniques can measure the variations in displacements and strain fields under traffic; however, they typically require contact sensors and partial or complete occupation of the monitored spans. This study examines, for the first time, the application of 3D Digital Image Correlation (DIC) as a non-invasive method for monitoring masonry arch bridges in the field. It offers a refined 3D DIC monitoring technique specifically designed for such structures under traffic loading, providing improved accuracy through various error mitigation strategies. Using a case study of the Mill Road Viaduct, a multi-span railway bridge in Lewisham (London, UK), 3D DIC effectively captured full-field displacements and crack openings caused by live traffic loads. The results revealed significant 3D effects, particularly in the arch barrel, and confirmed crack development in different directions, highlighting the superiority of 3D DIC monitoring over the conventional 2D DIC counterpart. The accuracy of the 3D DIC measurements was validated against 3D scanning data, demonstrating its reliability for bridge monitoring applications. Despite its advantages, factors such as camera stability, environmental noise and calibration complexities are identified in this paper as critical challenges that should be addressed for successful deployment in the field. This study highlights 3D DIC as a real-time, high-resolution structural monitoring tool, offering valuable insights for proactive maintenance strategies.
-
Journal articlePichler N, Li L, Huang C, et al., 2025, , Structures, Vol: 80, ISSN: 2352-0124
This paper addresses the modelling of the static and fatigue behaviour of as-built and machined wire arc additively manufactured (WAAM) steel, with particular focus on the effects of surface undulations, which arise due to process-induced irregularities in heat input, material deposition, and melt pool dynamics. Based on 3D laser scans of WAAM coupons, finite element (FE) models are developed and validated against experimental results obtained using digital image correlation (DIC). The FE method, though accurate, is computationally expensive, since very fine meshes are required to model the as-built undulating surfaces of the WAAM coupons. Therefore, two simplified analytical models, one based on bending and the other on surface curvature, are proposed for the local stress analysis of the WAAM coupons, allowing for the influence of undulating surface and material thickness. The proposed methods are shown to predict the local stresses in the WAAM steel with reasonable accuracy, achieving errors as low as approximately 8–9%, while maintaining high computational efficiency. The obtained local stresses are further used for the prediction of the fatigue crack initiation location and fatigue life of WAAM steel, achieving good agreement with the experimental results. Two fatigue design classes of FAT 145 and FAT 135 with endurance limits of 270烘Pa and 250烘Pa, respectively, are derived for WAAM ER70S-6 steel using the proposed models.
-
Journal articleYang J, Wadee MA, Gardner L, 2025, , Thin-Walled Structures, Vol: 215, ISSN: 0263-8231
An experimental investigation to assess the major-axis flexural behaviour of 12 hot-rolled S355 steel I-section beams strengthened by the addition of high strength steel (HSS) through wire arc additive manufacturing (WAAM) is presented. The geometry of the beam specimens was obtained by means of 3D laser scanning. The mechanical properties of both the hot-rolled and the WAAM steel were determined through monotonic tensile testing. Physical testing of the strengthened beam specimens was conducted. The results showed that the WAAM strengthening led to dramatic increases in bending resistances of between 35% and 80% under four-point bending, and of between 30% and 85% under three-point bending, for increases in mass of between just 5% and 15% respectively. At the same time, the specimens exhibited good ductility, despite the high strength of the WAAM additions. The presented experimental results, which are the first of their kind, successfully demonstrate the applicability of the proposed strengthening approach for both new and retrofitted steel beams, and the game-changing potential for enhancements in structural efficiency and reductions in embodied carbon in the construction industry.
-
Journal articleDai R, Gardner L, Wadee MA, 2025, , Thin-Walled Structures, Vol: 215, ISSN: 0263-8231
Formulae for determining the elastic buckling loads of structural steel rectangular hollow sections subjectedto concentrated transverse forces are presented herein. The predicted elastic buckling load is bounded by atheoretical lower bound, where only the material within the bearing length is mobilised, and a practical upperbound, where the adjacent material is mobilised to its maximum extent. The lower bound is the elastic bucklingload of a wide plate with a width equal to the bearing length and a length equal to the web depth, whilethe upper bound is determined from finite element (FE) analyses of various representative loading scenarios.The level of mobilisation of adjacent material (i.e., where a specific case lies between the lower and upperbounds) is quantified by introducing a coefficient that is calibrated through FE analyses in the commercialpackage ABAQUS. The rotational stiffness afforded to the webs by the flanges is also captured. The four loadingscenarios defined in the North American Specification and Australian/New Zealand Standard for the designof cold-formed steel structures, namely the Interior-Two-Flange (ITF), End-Two-Flange (ETF), Interior-One Flange (IOF) and End-One-Flange (EOF) loading conditions, alongside their transitional cases, are considered.Rectangular hollow sections with a broad spectrum of cross-sectional geometric proportions and bearing lengthsencompassing the aforementioned loading conditions are considered. It is found that the developed formulaefor predicting the elastic buckling loads under concentrated transverse forces provide accurate results that aretypically within 5% of the numerical values. Hence, the developed formulae can be employed as a convenientalternative to numerical methods in advanced structural design methodologies, such as the Direct StrengthMethod (DSM) and the Continuous Strength Method (CSM).
-
Journal articleTovar J, Bedrinana LA, Malaga-Chuquitaype C, 2025, , STRUCTURES, Vol: 80, ISSN: 2352-0124
-
Journal articleLi Z, Lin X, Vu-Quoc L, et al., 2025, , INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Vol: 126, ISSN: 0029-5981
-
Journal articleYang J, Wadee MA, Gardner L, 2025, , Journal of Constructional Steel Research, Vol: 232, ISSN: 0143-974X
The residual stress and residual distortion of three WAAM-strengthened steel I-section beams have been measured experimentally and simulated numerically in the present study. The widely used sectioning method was employed for the measurement of residual stresses, with the results revealing that the original underlying residual stress distribution in the studied hot-rolled steel I-section was significantly altered after the addition of the WAAM material, primarily owing to the heat input from the manufacturing process. Different residual stress patterns were observed for specimens with varying WAAM material arrangements. The overall bending distortion at the member level, also referred to as the pre-camber, and the local distortion at the cross-sectional level, were measured by means of 3D laser scanning. A lumped-layer sequential thermal–mechanical finite element (FE) modelling approach was then used to simulate the residual stresses and distortion within the examined specimens numerically. Good agreement was found between the FE results and the experimental observations. The measured residual stresses and the validated numerical approach can be employed in the design of WAAM-strengthened steel I-section beams and in the development of corresponding design provisions.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.