New Model for Ductile Fracture of Metal Alloys. I: Monotonic Loading

Wen, Huajie; Mahmoud, Hussam

doi:10.1061/(asce)em.1943-7889.0001009

Cited by 57 publications

(24 citation statements)

References 38 publications

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“…This approach allows continuum modelling with reasonable finite element meshes and no assumed flaws to predict fracture in steel. Calibration [68], extension to cyclic loading [69], and application to structural steel connections, Fig. 9, [70] have recently been completed by Wen and Mahmoud and fracture-driven connection failure modes such as block shear may now be reliably predicted in finite element models.…”

Section: Explicit Modeling Of Steel Fracturementioning

confidence: 99%

00.02: Developments in research and assessment of steel structures: Highlights from the perspective of an American researcher

Schafer

2017

ce papers

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The objective of this paper is to provide a summary of recent developments in the research and assessment of steel building structures. The task is too broad to accomplish in a general sense, as such the perspective and biases of the author as an American research professor who primarily focuses on thin-walled steel building applications is explicitly recognized. The discussed research is separated into three areas: cold-formed steel structures, hot-rolled steel structures, and earthquake engineering for steel structures. The focus of the presentation is on research conducted within each of these three areas, in the last 5 years, primarily in the United States, with particular emphasis on projects that the author was directly involved in or lead. In addition, each area concludes with a brief discussion of developments in American steel codes and standards that are related to the research. Cold-formed steel structures have enjoyed a large body of recent research, advancements in: modelling, imperfection measurement, stiffness characterization, coupled instabilities, design under multiple actions, and system reliability are all highlighted. The author has had less direct involvement in much of the recent hot-rolled steel structural research, but serves on the committees where this research is brought into the American standards. Work that has had a specific impact on the American hot-rolled steel standards in beams, slender columns, composite columns, bracing, fire, and progressive collapse are all highlighted. In addition, recent research advancing modelling for fracture in steel is summarized due to the authors belief in the large long term impact of those efforts. Earthquake engineering for steel structures spans a broad space, highlighted research includes: benchmark tests and building models for cold-formed steel framing; new tests, modelling, and design guidance on structural steel seismic force-resisting systems; and new research in steel diaphragm systems. Taken as a whole, the paper aims to demonstrate the vibrancy in American steel building research, now more than 125 years since the first steel-framed skyscraper.Activity in cold-formed steel research is broad and it is impossible to provide a complete summary, recent efforts by Hancock [1] provide a more comprehensive treatment than that provided here. In this paper, a subset of key developments that the author believes have significant potential to transform the analysis or design of cold-formed steel structures is highlighted. Without a doubt, this paper leaves out significant advances that the author was either unaware of, or did not properly contemplate when preparing this summary. Computational Advances: GBT, cFSM, cFEMCold-formed steel members primarily utilize open singly-point-or un-symmetric thin-walled sections. As a result, global buckling modes are nearly always coupled (in flexure and torsion) and must include warping torsion. Due to the thin nature of the sheet used to form the sections, local plate deformations are engaged even at service ...

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Section: Explicit Modeling Of Steel Fracturementioning

confidence: 99%

00.02: Developments in research and assessment of steel structures: Highlights from the perspective of an American researcher

Schafer

2017

ce papers

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“…Therefore, phenomenological damage models are more practical in structural failure simulation especially under static loads. Two major mechanisms cause steel to fracture, which are ductile fracture due to the nucleation, growth, and coalescence of voids; and shear fracture due to shear band localization [6,7]. Steel damage in ABAQUS are defined by damage initiation criteria and damage evolution laws [8].…”

Section: Introductionmentioning

confidence: 99%

Damage Model Calibration for S275 and S690 Steels

Yang

Veljković

2019

ce papers

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A calibration procedure for material damage models of S275 and S690 structural steels is proposed based on their full range engineering stress‐strain curves. Combined linear and power stress‐strain laws with a weighting factor are used to describe damaged stress‐strain relations after necking. Material damage models are proposed based on the estimation of undamaged stress. Tensile coupon tests on S275 and S690 steels are modelled in ABAQUS with the explicit solver. Results show that the numerical engineering stress‐strain curves based on the proposed damage models are very close to the experimental results. An investigation is made to establish the damage susceptibility for S275 and S690 steels.

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“…The key factor differentiating ULCF and traditional fatigue is the significant plastic deformations prior to the final occurrence of fracture. The large plastic deformations simply invalidate the foundations of traditional fatigue, which is based on linear elastic fracture mechanics (Kanvinde, 2004;Wen and Mahmoud, 2016b). ULCF belongs to the category of ductile fracture, where the fracture profile can be described using monotonic loading failure phenomenon (Kanvinde and Deierlein, 2007;Wen and Mahmoud, 2016a).…”

Section: Introductionmentioning

confidence: 99%

“…Among these is the recent criterion developed by Wen and Mahmoud (2016a) under monotonic loading, which has been extensively validated through comparison with experimental results of coupons (Wen and Mahmoud, 2016a) and applied to practical structural connections under monotonic loading conditions (Wen and Mahmoud, 2017). The Wen-Mahmoud model (Wen and Mahmoud, 2016a) was further extended on the coupon level to the case of cyclic loading to include the effect of loading history and non-linear damage accumulation (Wen and Mahmoud, 2016b) and is being assessed in this study to evaluate its appropriateness for simulating ductile fracture under cyclic loading on the member level (shear links), as will be discussed in detail.…”

Section: Introductionmentioning

confidence: 99%

A New Approach to Predict Cyclic Response and Fracture of Shear Links and Eccentrically Braced Frames

Wen

Mahmoud

2018

Front. Built Environ.

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In eccentrically braced frames (EBFs) subjected to large lateral demands, inelastic actions are mostly concentrated in shear links. The links vary in size and, when employed in frames, are known to be subjected to combined tension/compression and shear stress states that influence their strength, low-cycle fatigue behavior, and fracture characteristics. Despite their significance as the main energy dissipation elements in a structure subjected to seismic demand, simulating their full response, including the number of cycles to failure, of these links as individual components, or when employed in full frames, is lacking. This is primarily because until recently, most low-cycle fatigue models did not allow link failures under complex stress states to be captured. In this study, by means of a well-established ultra-low cycle fatigue (ULCF) criterion, the behavior of these links is fully assessed. The focus is on short shear links since they are widely used in comparison to intermediate or long links. Results of the simulations are compared with their experimental equivalents and excellent comparisons are achieved, confirming the validity of the simulation methodology and providing, for the first time, a framework for simulating the ULCF behavior of shear links. The verified response prediction methodology is then applied at the structural level, and non-linear pushover analysis on EBFs is conducted. Unlike the existing numerical approaches where failure is indicated through a prescriptive target performance, such as 5% interstory drift for collapse prevention, the pushover analysis is conducted until complete fracture of the links and failure of the system. Seismic design parameters, such as deign and elastic base shears as well as force reduction factors, are also determined based on the pushover curves. The results demonstrate that the proposed approach can reliably predict the performance of EBFs and can potentially be used in future design and analysis of such frames.

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New Model for Ductile Fracture of Metal Alloys. I: Monotonic Loading

Cited by 57 publications

References 38 publications

00.02: Developments in research and assessment of steel structures: Highlights from the perspective of an American researcher

00.02: Developments in research and assessment of steel structures: Highlights from the perspective of an American researcher

Damage Model Calibration for S275 and S690 Steels

A New Approach to Predict Cyclic Response and Fracture of Shear Links and Eccentrically Braced Frames

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