High Strain Low Cycle Fatigue and Anti-Seismic Behavior of HRB400 QST Reinforced Steel Bars

Based on the failure model of building structural steels under earthquake loading, High strain low cycle fatigue properties of HRB400QST (yield strength grade 400MPa, Quenched and Self Tempered) reinforced steel bars with diameters of 20mm and 16mm(unmachined) and HRB400V-N MA(microalloying)with diameters of 16mm (unmachined) were investigated. Based on the tests of total strain controlling, cycle strain response character of three kinds of steel bars and the relationship between cyclic stress and strain were researched. Hollomon and Coffin-Manson formulas were used to induce fatigue life formulas of three kinds of steel bars, and then the values of σa·Δεt were gained when Nf =100, calculated results show that the high strain low cycle fatigue properties of HRB400V-N MA rebars tested are much better than HRB400QST steel bars. Rupture surface scan reveals that surface hardened layer will reduce the cyclic toughness, and is bad for the anti-seismic performance.

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Low cycle fatigue properties of anti-seismic steel HRB400E reinforcing steel bars

Green Building, Materials and Civil Engineering ◽

10.1201/b17568-67 ◽

2014 ◽

pp. 337-340

Keyword(s):

Low Cycle Fatigue ◽

Fatigue Properties ◽

Reinforcing Steel ◽

Cycle Fatigue ◽

Steel Bars

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Evaluation of Low Cycle Fatigue Performance of Selective Laser Melted Titanium Alloy Ti–6Al–4V

Metals ◽

10.3390/met9101041 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1041 ◽

Cited By ~ 3

Author(s):

Peng Zhang ◽

Allen Naihui He ◽

Fei Liu ◽

Kaifei Zhang ◽

Junjie Jiang ◽

...

Keyword(s):

Low Cycle Fatigue ◽

Fatigue Cracks ◽

Cyclic Stress ◽

Fatigue Properties ◽

Cycle Fatigue ◽

Low Carbon ◽

Specific Strength ◽

Material Fatigue ◽

Lower Strain ◽

High Degree

The material of Ti–6Al–4V has been widely applied in various industries, such as automobile, aerospace, and medical due to its high specific strength, superior thermal stability and strong corrosion resistance. In the recent decades, selective laser melting (SLM) has become an attractive method to fabricate Ti–6Al–4V parts, thanks to its significant advantages in low material consumption, the high degree of freedom in design, low carbon footprint, etc. Predictability of SLM material fatigue properties is especially important for the safety-critical structures under dynamic load cases. The present research is aimed at evaluating the low cycle fatigue (LCF) performance of SLM Ti–6Al–4V under high loading states. LCF tests were performed for as-built and annealed SLM Ti–6Al–4V. Comparison between LCF properties of SLM Ti–6Al–4V and the wrought Ti–6Al–4V was also made. It was found that as-built SLM Ti–6Al–4V demonstrated a comparable LCF performance with the wrought material. The LCF life of as-built SLM Ti–6Al–4V was longer than that of wrought Ti–6Al–4V at lower strain amplitudes. However, the wrought Ti–6Al–4V had better LCF performance at higher strain amplitudes. The results revealed that the porosity in the as-built SLM material exerted much more impact on the degradation of the material at high strain amplitudes. Annealing deteriorated the LCF performance of SLM Ti–6Al–4V material due to the formation of coarser grains. The cyclic Ramberg–Osgood and the Basquin–Coffin–Manson models were fitted to depict the cyclic stress–strain and the strain–life curves for the SLM Ti–6Al–4V, based on which the LCF performance parameters were determined. In addition, the fatigue fracture surfaces were observed by using scanning electron microscopy (SEM), and the results indicated that fatigue cracks originated from the surface or subsurface defects.

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Low Cycle Fatigue of Cast γ-TiAl Based Alloys at High Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.452-453.421 ◽

2010 ◽

Vol 452-453 ◽

pp. 421-424 ◽

Cited By ~ 4

Author(s):

Martin Petrenec ◽

Miroslav Šmíd ◽

Tomáš Kruml ◽

Karel Obrtlík ◽

Jaroslav Polák

Keyword(s):

Fatigue Life ◽

Low Cycle Fatigue ◽

Fatigue Cracks ◽

Surface Region ◽

Cyclic Stress ◽

Cyclic Strength ◽

Fatigue Properties ◽

Cycle Fatigue ◽

Nb Content ◽

Cyclic Straining

The low-cycle fatigue properties of cast nearly lamellar TiAl alloys with diverse Nb content at room temperature and 750°C were compared. Monotonic tensile curves, cyclic stress-strain curves (CSSC) and combined fatigue life curves were obtained at both temperatures. After cyclic straining the surface relief and the fracture surfaces were observed using scanning electron microscopy. The increase in Nb content significantly improves tensile properties and CSSCs at both temperatures. The combined fatigue life curves especially at 750 °C are shifted to higher fatigue lives. The effect o Nb content on the tensile and cyclic strength is discussed in relation to the thickness of the lamellae. Persistent slip markings formed along interlamellar interfaces were predominant locations for fatigue cracks. At both temperatures and materials showed similar crack initiation and propagation behavior. The cracks initiated at surface or in sub-surface region creating smooth flat areas corresponding to the persistent slip bands.

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Effect of T6 Treatment on Low-Cycle Fatigue Properties of Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc Alloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.664.28 ◽

2014 ◽

Vol 664 ◽

pp. 28-33

Author(s):

Ying Lan ◽

Li Jia Chen ◽

Xin Che ◽

Feng Li

Keyword(s):

Strain Hardening ◽

Low Cycle Fatigue ◽

Aging Treatment ◽

Cyclic Strain ◽

Cyclic Stress ◽

Cyclic Strength ◽

Fatigue Properties ◽

Strain Hardening Exponent ◽

Cycle Fatigue ◽

Linear Behavior

The low-cycle fatigue behaviors of as-extruded and T6 treated Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloys at room temperature have been investigated under those total-strain amplitudes ranged from 0.3% to 1.0%, and the influence of T6 treatment on the low-cycle fatigue properties of Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloy was clarified. The experimental results show that during fatigue deformation, the significant cyclic strain hardening and stable cyclic stress response can be noted for both as-extruded and T6 treated Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloys. The fatigue life of as-extruded Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloy at all strain amplitudes is longer than that of the alloy subjected to T6 aging treatment. The relationship between both elastic and plastic strain amplitudes with reversals to failure shows a monotonic linear behavior, and can be described by the Basquin and Coffin-Manson equations, respectively. The T6 treatment can significantly increase the cyclic strain hardening exponent and cyclic strength coefficient of extruded Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloy.

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Low-cycle fatigue properties of bimetallic steel bars after exposure to elevated temperature

Journal of Constructional Steel Research ◽

10.1016/j.jcsr.2021.106959 ◽

2021 ◽

Vol 187 ◽

pp. 106959

Author(s):

Jianmin Hua ◽

Fei Wang ◽

Zhengtao Yang ◽

Xuanyi Xue ◽

Lepeng Huang ◽

...

Keyword(s):

Elevated Temperature ◽

Low Cycle Fatigue ◽

Fatigue Properties ◽

Cycle Fatigue ◽

Steel Bars

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Effect of Tensile Dwell on Low Cycle Fatigue of Cast Superalloy Inconel 792-5A at 800°C

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.488-489.735 ◽

2011 ◽

Vol 488-489 ◽

pp. 735-738

Author(s):

Miroslav Šmíd ◽

Karel Obrtlík ◽

Martin Petrenec ◽

Jaroslav Polák

Keyword(s):

High Strain ◽

Low Cycle Fatigue ◽

Cyclic Hardening ◽

Cyclic Stress ◽

Cycle Fatigue ◽

Lower Stress ◽

Secondary Cracks ◽

Continuous Cycling ◽

Cast Superalloy ◽

Strain Cycling

Effect of tensile dwell on low cycle fatigue of cast Inconel 792-5A is studied in symmetrical strain cycling at 800°C. Cyclic hardening/softening curves, cyclic stress-strain curves (CSSC) and fatigue life curves were obtained in continuous cycling and in cycling with tensile dwells. Dwells have slight effect on hardening/softening curves at high strain amplitudes. CSSC in cycling with dwells is shifted to lower stress amplitudes. No significant effect of dwells on Basquin curves is observed. Density of slip markings in continuous cycling is significantly higher in comparison with cycling with dwells. Samples cycled with dwells are typical of high density of secondary cracks, although sporadic slip markings were also found.

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