Prediction of Cyclic Plastic Strain Energy Density and Fatigue Life of Non-Masing Behavior Materials Without Master Curve

2021 ◽  
Author(s):  
Sanjeev Singh Yadav ◽  
Samir Chandra Roy ◽  
J. Veerababu ◽  
Sunil Goyal
Keyword(s):  
Fatigue Life ◽  
Energy Density ◽  
Plastic Strain ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Master Curve ◽  
Cyclic Plastic ◽  
Plastic Strain Energy ◽  
Cyclic Plastic Strain

scholarly journals Low Cycle Fatigue Life Assessment Based on the Accumulated Plastic Strain Energy Density

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2372
Author(s):  
Yifeng Hu ◽  
Junping Shi ◽  
Xiaoshan Cao ◽  
Jinju Zhi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Energy Density ◽  
Plastic Strain ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Fatigue Initiation ◽  
Plastic Strain Energy

The accumulated plastic strain energy density at a dangerous point is studied to estimate the low cycle fatigue life that is composed of fatigue initiation life and fatigue crack propagation life. The modified Ramberg–Osgood constitutive relation is applied to characterize the stress–strain relationship of the strain-hardening material. The plastic strain energy density under uni-axial tension and cyclic load are derived, which are used as threshold and reference values, respectively. Then, a framework to assess the lives of fatigue initiation and fatigue crack propagation by accumulated plastic strain energy density is proposed. Finally, this method is applied to two types of aluminum alloy, LC9 and LY12 for low-cycle fatigue, and agreed well with the experiments.

scholarly journals Microstructure-sensitive critical plastic strain energy density criterion for fatigue life prediction across various loading regimes

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190766 ◽  
Author(s):  
Ritwik Bandyopadhyay ◽  
Veerappan Prithivirajan ◽  
Alonso D. Peralta ◽  
Michael D. Sangid
Keyword(s):  
Fatigue Life ◽  
Energy Density ◽  
Plastic Strain ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Hysteresis Loops ◽  
Strain Range ◽  
Strain Ratio ◽  
Material Point ◽  
Plastic Strain Energy

In the present work, we postulate that a critical value of the stored plastic strain energy density (SPSED) is associated with fatigue failure in metals and is independent of the applied load. Unlike the classical approach of estimating the (homogenized) SPSED as the cumulative area enclosed within the macroscopic stress–strain hysteresis loops, we use crystal plasticity finite element simulations to compute the (local) SPSED at each material point within polycrystalline aggregates of a nickel-based superalloy. A Bayesian inference method is used to calibrate the critical SPSED, which is subsequently used to predict fatigue lives at nine different strain ranges, including strain ratios of 0.05 and −1, using nine statistically equivalent microstructures. For each strain range, the predicted lives from all simulated microstructures follow a lognormal distribution. Moreover, for a given strain ratio, the predicted scatter is seen to be increasing with decreasing strain amplitude; this is indicative of the scatter observed in the fatigue experiments. Finally, the lognormal mean lives at each strain range are in good agreement with the experimental evidence. Since the critical SPSED captures the experimental data with reasonable accuracy across various loading regimes, it is hypothesized to be a material property and sufficient to predict the fatigue life.

Effect of plastic strain energy density on polymer optical fiber power losses

2006 ◽  
Vol 31 (7) ◽  
pp. 879 ◽  
Author(s):  
Yung-Chuan Chen ◽  
Jao-Hwa Kuang ◽  
Li-Wen Chen ◽  
Hua-Chun Chuang
Keyword(s):  
Energy Density ◽  
Plastic Strain ◽  
Optical Fiber ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Power Losses ◽  
Polymer Optical Fiber ◽  
Plastic Strain Energy

A unified damage model for fibrous composite laminae subject to in-plane stress-state and having multi material-nonlinearity

2020 ◽  
Vol 29 (9) ◽  
pp. 1329-1344
Author(s):  
GA Abu-Farsakh ◽  
AM Asfa
Keyword(s):  
Energy Density ◽  
Plastic Strain ◽  
Strain Energy Density ◽  
Damage Evolution ◽  
Strain Energy ◽  
Fibrous Composite ◽  
Damage Model ◽  
Damage Propagation ◽  
Damage Response ◽  
Plastic Strain Energy

In the present study, a novel methodology of damage modeling is introduced to predict damage propagation in fibrous composite materials according to the plastic strain energy density induced in the lamina only. The importance of the new damage-model is the ability to assess damage-evolution in fibrous composite laminae irrespective of stress-state and fiber-orientation angle. An energy-based model called as a unified damage model, is proposed to evaluate damage in unidirectional fibrous composite laminae. The aforementioned damage model represents a unique relationship between damage-evolution and the resulting plastic strain energy density induced in the composite lamina, as verified through this study. Damage propagation under a state of in-plane-stress is investigated for three composite laminas; boron/epoxy, graphite/epoxy, and carbon/epoxy. The unified damage model represents a simplified mathematical relation of quantum-damage (or modified-damage) variables in terms of the induced plastic-strain-energy density induced in a composite lamina. The developed unified damage model confirms the results of Ghazi-Ahmad macro-mechanical damage model in which graphite/epoxy has the lowest damage response, whereas boron/epoxy has the highest possible damage response amongst the three composite materials. Also, it is noticed that quantum-damage propagates nonlinearly with the evolved plastic strain energy density in fibrous composite laminae.

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