A new distortion energy-based equivalent stress for multiaxial fatigue life prediction

Scott‐Emuakpor, Onome; George, Tommy; Cross, Charles; Wertz, John; Shen, M.-H. Herman

doi:10.1016/j.ijnonlinmec.2011.12.002

Cited by 24 publications

(10 citation statements)

References 26 publications

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“…Four of the 12 fatigue experiments conducted for each Vendor batch used the dwell testing application and the rest were fatigue using the step test method. Previous research on titanium and aluminium shows that although the step test has a lower life performance than dwell, the results are comparable with respect to normal fatigue data scatter . The prediction bounded comparisons between dwell and step test methods are provided in Figs and for Vendor I and II, respectively .…”

Section: Resultsmentioning

confidence: 66%

“…Previous research on titanium and aluminium shows that although the step test has a lower life performance than dwell, the results are comparable with respect to normal fatigue data scatter. 11,16,17 The prediction bounded comparisons between dwell and step test methods are provided in Figs 8 and 9 for Vendor I and II, respectively. 13 Observing the regression correlation of the experimental data, the comparison in Fig.…”

Section: Bending Fatigue Life Comparisonmentioning

confidence: 99%

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Bending fatigue life characterisation of direct metal laser sintering nickel alloy 718

Scott‐Emuakpor

Schwartz

George

et al. 2015

Fatigue Fract Eng Mat Struct

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Bending fatigue behaviour of direct metal laser sintering (DMLS), Nickel (Ni) Alloy 718 has been assessed as preliminary qualification to additively manufacture advanced gas turbine engine components. Motivation for this work comes from the possibility of using DMLS to improve functionality of hot‐section components. By using DMLS, turbine blades and heat exchangers cooling passages can be enhanced, leading to improved engine performance. This study focuses on vibratory high cycle fatigue (HCF) assessment of DMLS Ni Alloy 718 from two suppliers. Specimens were fatigued via vibration‐based bending and compared with published rotating bending cold‐rolled Ni Alloy 718. Tensile analysis and microscopy were also conducted to understand fatigue and fracture trends. HCF, tensile properties and microscopy comparisons show that fatigue and strength of DMLS Ni may be sensitive to post‐fusion treatments. Nonetheless, fatigue performance of DMLS Ni compares well with rotating bending fatigue of cold‐rolled Ni.

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Section: Resultsmentioning

confidence: 66%

Section: Bending Fatigue Life Comparisonmentioning

confidence: 99%

Bending fatigue life characterisation of direct metal laser sintering nickel alloy 718

Scott‐Emuakpor

Schwartz

George

et al. 2015

Fatigue Fract Eng Mat Struct

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“…However, fatigue life not only has relation with plastic strain range but also is affected by the strain rate, strain ratio, hold time, and many other loading parameters. Energy-based life prediction model can unify the damage caused by this different loading parameters and mean stress, [29] also multiaxial loads [30] can be included in the energy-based model. Kujawski and Ellyin [31] developed a preliminary damage model by using plastic strain energy as a parameter, as shown by Equation 11, which has the same form with Coffin-Manson law.…”

Section: Energy-based Modelmentioning

confidence: 99%

Characterization of Low Cycle Fatigue Performance of New Ferritic P92 Steel at High Temperature: Effect of Strain Amplitude

Wang

Gong

Zhao

et al. 2015

steel research int.

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Low cycle fatigue (LCF) tests were performed at various strain amplitudes ranging from 0.2 to 0.8% to investigate the effects of strain amplitude on cyclic softening behavior and LCF lifetime of new ferrtic P92 steel. LCF tests were conducted under strain controlled in fully reversed manner with strain rate of 1.0 Â 10 À3 s À1 at high temperature of 650 8C. A novel fatigue life end criterion was adopted in this analysis. The effects of strain amplitude on the cyclic softening behavior, the evolution of plastic strain amplitude, hysteresis loop area and the fatigue life were discussed. Similar softening curves were achieved except for the strain amplitude of 0.2%. The evolution of hysteresis loop areas at the smaller strain range amplitude (less than 0.4%) is contrary to the larger ones. A modified life prediction model was proposed based on Coffin-Manson model and energy-based model, comparison of predicted lifetime and experimental data shows that the model gives a good estimation. In order to better understand the basic stress-strain behavior, time-independent cyclic plasticity model was used to represent the cyclic mechanical behavior of this steel. Comparison of the simulated and experimental results shows that the proposed model can give a reasonable prediction of stress-strain hysteresis loop for P92 steel at high temperature.

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“…3 Fatigue failure assessment based on hysteresis energy and thermal response [21][22][23][24] has been under extensive study during past decades. Both plastic strain energy [25][26][27][28][29][30] and total strain energy [31][32][33][34] have been the focus of a number of studies. It was postulated by Feltner and Morrow 35 that total non-recoverable plastic work measured from the hysteresis loop would be constant at the point of failure.…”

mentioning

confidence: 99%

Thermodynamic entropy generation in the course of the fatigue crack initiation

Ontiveros

Amiri

Kahirdeh

et al. 2016

Fatigue Fract Eng Mat Struct

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Evolution of the thermodynamic entropy generation during fatigue crack initiation life of notched specimens is studied. A set of experimental results of AA7075‐T651 is examined to determine applicability of the thermodynamic entropy generation as an index of fatigue crack initiation. Entropy accumulation is calculated from hysteresis energy and temperature rise. An increasing trend of entropy accumulation with the number of cycle to failure is observed on macroscale measurements. Results also determine that the entropy generations from the samples under the same operating conditions are similar as the crack grows. Scanning electron microscope analysis is performed on the fractured surfaces to observe the fatigue striations, and persistent slip bands are observed employing an optical microscope. A discussion is presented regarding the length scales on which crack initiation occurs and entropy calculation is made.

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A new distortion energy-based equivalent stress for multiaxial fatigue life prediction

Cited by 24 publications

References 26 publications

Bending fatigue life characterisation of direct metal laser sintering nickel alloy 718

Bending fatigue life characterisation of direct metal laser sintering nickel alloy 718

Characterization of Low Cycle Fatigue Performance of New Ferritic P92 Steel at High Temperature: Effect of Strain Amplitude

Thermodynamic entropy generation in the course of the fatigue crack initiation

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