A Simple Calibrated Ductile Fracture Model and Its Application in Failure Analysis of Steel Connections
Abstract
:1. Introduction
2. Characterization of Material’s Ductility and Stress State
3. Theoretical Derivation of the New Ductile Fracture Model
3.1. Determination of Stress Triaxiality Dependence Function
3.2. Determination of the Lode Angle Dependence Function
3.3. Theoretical Formula of the New Fracture Model
4. Verification of the New Fracture Model via Structural Steel Notched Specimens
5. Application of New Fracture Model in Failure Analysis of Steel Connections
5.1. Fracture Prediction Analysis of a Welded Beam-To-Column Connection
5.2. Fracture Prediction Analysis of a CHS Branch to SHS Chord X-Joint
6. Discussion
6.1. The Correlation between Stress Triaxiality and Lode Angle Dependence
6.2. Validity of Stress Triaxiality Dependence Function for Other Stress States
6.3. Methods to Improve the Prediction Accuracy of the Proposed Fracture Model
7. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Young’s Modulus E(GPa) | Poisson’s Ratio μ | Hardening Parameter K(MPa) | Hardening Exponent n |
---|---|---|---|
222.8 | 0.3 | 969.14 | 0.2 |
Test No. | Test Specimen | ηav | χi,new-model | χi,Tresca | Δnew-model | ΔTresca | ||||
---|---|---|---|---|---|---|---|---|---|---|
1 | Smooth round bar | 0.566 | 1 | 1.599 | 1.452 | 1.599 | 0.092 | 0.000 | 17.3% | 56.8% |
2 | Notched round bar (Notch radius = 6.25 mm) | 0.835 | 1 | 0.951 | 0.999 | 1.599 | 0.051 | 0.681 | ||
3 | Notched round bar (Notch radius = 3.125 mm) | 1.029 | 1 | 0.739 | 0.776 | 1.599 | 0.050 | 1.165 | ||
4 | Notched round bar (Notch radius = 1.5 mm) | 1.330 | 1 | 0.542 | 0.536 | 1.599 | 0.011 | 1.951 | ||
5 | Pure-shear flat plate | 0.106 | 0.21 | 1.460 | 1.487 | 0.803 | 0.019 | 0.450 | ||
6 | Tensile-shear flat plate | 0.433 | 0.71 | 1.264 | 1.221 | 1.105 | 0.034 | 0.126 | ||
7 | Grooved plate (Notch radius = 10 mm) | 0.755 | 0 | 0.945 | 0.542 | 0.779 | 0.426 | 0.176 | ||
8 | Grooved plate (Notch radius = 3 mm) | 0.884 | 0 | 0.846 | 0.456 | 0.779 | 0.461 | 0.080 | ||
9 | Grooved plate (Notch radius = 1 mm) | 1.204 | 0 | 0.524 | 0.304 | 0.779 | 0.420 | 0.487 |
Specimen Region | Young’s Modulus E (MPa) | Yield Strength σy0 (MPa) | Ultimate Strength σu (MPa) | Hardening Exponent n | Fracture Strain under Tension |
---|---|---|---|---|---|
Straight part of the column | 2.06 × 105 | 440.8 | 533.3 | 0.085 | 1.07 |
Conner region of the column | 2.06 × 105 | 511.0 | 570.6 | 0.073 | 1.03 |
Beam flange plate | 2.06 × 105 | 380.5 | 544.1 | 0.22 | 1.02 |
Groove weld | 2.06 × 105 | 380.1 | 491.3 | 0.28 | 1.33 |
Specimen Region | Young’s Modulus E (MPa) | Yield Strength σy0 (MPa) | Ultimate Strength σu (MPa) | Hardening Exponent n | Fracture Strain under Tension |
---|---|---|---|---|---|
Branch | 2.06 × 105 | 375 | 563 | 0.16 | 1.00 |
Chord | 2.06 × 105 | 325 | 401 | 0.187 | 1.03 |
Weld | 2.06 × 105 | 416 | 500 | 0.156 | 1.39 |
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Li, W.; Jing, Y. A Simple Calibrated Ductile Fracture Model and Its Application in Failure Analysis of Steel Connections. Buildings 2022, 12, 1358. https://doi.org/10.3390/buildings12091358
Li W, Jing Y. A Simple Calibrated Ductile Fracture Model and Its Application in Failure Analysis of Steel Connections. Buildings. 2022; 12(9):1358. https://doi.org/10.3390/buildings12091358
Chicago/Turabian StyleLi, Wenchao, and Yuan Jing. 2022. "A Simple Calibrated Ductile Fracture Model and Its Application in Failure Analysis of Steel Connections" Buildings 12, no. 9: 1358. https://doi.org/10.3390/buildings12091358