Prediction of ductile fracture for circular hollow section bracing members under extremely low cycle fatigue

Xu, Fei; Chan, Tak Ming; Sheehan, Therese; Gardner, Leroy

doi:10.1016/j.engstruct.2020.110579

Cited by 28 publications

(11 citation statements)

References 45 publications

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“…These elements are quite effective in modeling the cyclic behavior of braces preventing the hourglass and shear locking effects and requiring less computational time with high accuracy similar to the threedimensional solid elements. 43 A finer mesh of 5 mm x5 mm in element size is used in the mid-region of the brace where the local buckling is expected. The end connections where the inelastic deformation is expected to occur are also modeled using a finer mesh size of 10 mm x 10 mm.…”

Section: Numerical Analysismentioning

confidence: 99%

Stability assessment and development of design criteria for SCBF systems with in‐plane buckling braces

Patra

Sahoo

2022

Earthq Engng Struct Dyn

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Special concentrically braced frames (SCBFs) with in‐plane buckling (IPB) braces are often designed using the provisions applicable for out‐of‐plane buckling (OOPB) brace systems. As a result, the IPB brace systems may fail in the undesirable modes as observed in past experimental studies. In this study, a novel simplified analytical formulation based on the rigid beam spring model (RBSM) has been proposed to prevent the out‐of‐plane buckling of IPB braces. A high‐fidelity finite element model (FEM) is generated and validated with the experimental studies incorporating the influence of the residual stress, imperfection, and strain hardening. The variability, sensitivity, and uncertainties involved in predicting the direction of buckling of braces are examined. A parametric study has been carried out to investigate the influence of thickness and clearance of the gusset and knife plates, geometric imperfections, slenderness ratios, compactness ratios, residual stresses, and frame actions considering the most destabilizing effect in the OOPB mode. The third mode of buckling, termed as the mixed‐mode of buckling, has been observed in this study. A design criterion is proposed to get the desired IPB mode of buckling of braces in SCBFs. Multivariate regression analysis is carried out to incorporate the impact of various parameters as well as uncertainties in the formulation of the design criteria. The validity of the proposed equation is verified by comparing the findings of past experimental studies for various loading scenarios. Finally, a resistance factor of 0.8 in the LRFD approach has been proposed for the IPB brace systems.

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Section: Numerical Analysismentioning

confidence: 99%

Stability assessment and development of design criteria for SCBF systems with in‐plane buckling braces

Patra

Sahoo

2022

Earthq Engng Struct Dyn

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“…Meanwhile, we modify the fracture equivalent plastic strain from the modified Mohr-Coulomb formula [37] in the initial model to the stress-modified critical strain model (SMCS) [44] expressed in Equation (6) to dismiss the effect of the Lode angle parameter on damage, due to the value of the corner points of steel piers base being close to −1 or 1, to further simplify the model parameters.…”

Section: Simplified Ductile Fracture Model For Ulcfmentioning

confidence: 99%

“…According to experimental results, Kuwamura et al [ 5 ] divided the ULCF failure process of steel structures into three stages, namely the initiation of ductile crack (fiber crack), the steady growth of ductile crack, and the sudden expansion of brittle crack (cleavage failure). The studies [ 6 ] found that the initiation of ductile crack accounts for a large part of the overall fatigue life, that is, when the crack appears, it will propagate rapidly under continuous ULCF loading. Therefore, accurate evaluation on the resistance of the structural steel to ULCF damage is of highly significant meaning for the seismic design of steel structures.…”

Section: Introductionmentioning

confidence: 99%

“…The ductile fracture model for ULCF proposed by Bai et al [ 15 ] based on the ductility capacity consumption method can consider the loading history process by introducing the nonlinear and historical effect functions under the complex loading history and has been shown to have good applicability at the material and component levels [ 6 , 30 ]. The simplified ductile fracture model proposed by Jia et al [ 31 ] adopted the conventional linear evolution hypothesis to calculate damage in the loading process, but it was proved to produce conservative life evaluation under cyclic constant-amplitude loading [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

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A Simplified Ductile Fracture Model for Predicting Ultra-Low Cycle Fatigue of Structural Steels

Xie

2022

Materials

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Under strong earthquakes, steel structures are prone to undergoing ultra-low cycle fatigue (ULCF) fracture after sustaining cyclic large-strain loading, leading to severe earthquake-induced damage. Thus, establishing a prediction method for ULCF plays a significant role in the seismic design of steel structures. However, a simple and feasible model for predicting the ULCF life of steel structures has not been recognized yet. Among existing models, the ductile fracture model based on ductility capacity consumption has the advantage of strong adaptability, while the loading history effect in the damage process can also be considered. Nevertheless, such models have too many parameters and are inconvenient for calibration and application. To this end, focusing on the prediction methods for ULCF damage in steel structures, with the fragile parts being in moderate and high stress triaxiality, this paper proposes a simplified uncoupled prediction model that considers the effect of stress triaxiality on damage and introduces a new historical-effect related variable function reducing the calibration work of model parameters. Finally, cyclic loading test results of circular notched specimens verify that the proposed model has the advantages of a small dispersion of parameters for calibration, being handy for application, and possessing reliable results, providing a prediction method for ULCF damage of structural steels.

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“…counting technique applied through fibre-based elements [12], (2) post-processing of FE simulation data [2] using the "rain flow" counting technique in conjunction with the Coffin-Mason strain-life relationship [13,14] and (3) finite element (FE) simulations with a fracture criterion [3,15,16]. The first approach is frequently employed in structure-level simulations, i.e.…”

Section: Introductionmentioning

confidence: 99%

Fracture prediction for square hollow section braces under extremely low cycle fatigue

Pan

Chan

et al. 2022

Thin-Walled Structures

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Prediction of ductile fracture for circular hollow section bracing members under extremely low cycle fatigue

Cited by 28 publications

References 45 publications

Stability assessment and development of design criteria for SCBF systems with in‐plane buckling braces

Stability assessment and development of design criteria for SCBF systems with in‐plane buckling braces

A Simplified Ductile Fracture Model for Predicting Ultra-Low Cycle Fatigue of Structural Steels

Fracture prediction for square hollow section braces under extremely low cycle fatigue

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