scholarly journals An Experimental Study on Low-Cycle Fatigue Crack Initiation Life Prediction of Powder Superalloy FGH96 Based on the Manson-Coffin and Damage Mechanics Methods

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 489
Author(s):  
Yuanming Xu ◽  
Hao Chen ◽  
Shuming Zhang ◽  
Tianpeng He ◽  
Xuerong Liu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Prediction Models ◽  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Life Cycles ◽  
Cycle Fatigue ◽  
Element Analysis

The applicability of both prediction methods for low-cycle fatigue life of powder superalloy based on the Manson-Coffin equation and damage mechanics were addressed. Both fatigue life prediction models were evaluated by low-cycle fatigue experimental data of powder superalloy FGH96 with non-destructive standard parts and those with inclusions. Due to the characteristics of high strength and low plasticity of powder superalloy FGH96, errors in calculating the plastic strain amplitude deviate severely the prediction outcomes when using Manson-Coffin method. Meanwhile, by introducing the damage variable which characterizes the material damage, the damage evolution equation can be built by fitting the experimental data of standard parts and also applied to powder superalloy specimens containing inclusion. It is indispensable to accurately calculate the damage characterization parameter through finite element analysis in local stress concentration around the inclusion. The applicability of the prediction model was verified by the test life cycles of experimental specimens with different types and sizes of inclusions subsequently. Testing and simulation work showed much better prediction accuracies globally for the damage mechanics approach.

scholarly journals Research on low cycle fatigue life prediction considering average strain

2022 ◽  
Author(s):  
Yan Peng ◽  
Yang Liu ◽  
Haoran Li ◽  
Jiankang Xing
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Prediction Models ◽  
Low Cycle Fatigue ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Model Parameters ◽  
Cycle Fatigue ◽  
Average Strain

Abstract To address the difficult problems in the study of the effect of average strain on fatigue life under low-cycle fatigue loads, the effect of average strain on the low-cycle fatigue life of materials under different strain cycle ratios was discussed based on the framework of damage mechanics and its irreversible thermodynamics. By introducing the Ramberg-Osgood cyclic constitutive equation, a new low-cycle fatigue life prediction method based on the intrinsic damage dissipation theory considering average strain was proposed, which revealed the correlation between low-cycle fatigue strain life , material properties, and average strain. Through the analysis of the low-cycle fatigue test data of five different metal materials, the model parameters of the corresponding materials were obtained. The calculation results indicate that the proposed life prediction method is in good agreement with the test, and a reasonable characterization of the low-cycle fatigue life under the influence of average strain is realized. Comparing calculations with three typical low-cycle fatigue life prediction models, the new method is within two times the error band, and the prediction effect is significantly better than the existing models, which is more suitable for low-cycle fatigue life prediction. The low-cycle fatigue life prediction of different cyclic strain ratios based on the critical region intrinsic damage dissipation power method provides a new idea for the research of low-cycle fatigue life prediction of metallic materials.

LOW CYCLE FATIGUE BEHAVIOR AND LIFE PREDICTION OF A CAST COBALT-BASED SUPERALLOY

2012 ◽  
Vol 06 ◽  
pp. 251-256
Author(s):  
HO-YOUNG YANG ◽  
JAE-HOON KIM ◽  
KEUN-BONG YOO
Keyword(s):  
Fatigue Life ◽  
Strain Energy ◽  
Life Prediction ◽  
Prediction Models ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Total Strain Range ◽  
Different Temperatures

Co -base superalloys have been applied in the stationary components of gas turbine owing to their excellent high temperature properties. Low cycle fatigue data on ECY-768 reported in a companion paper were used to evaluate fatigue life prediction models. In this study, low cycle fatigue tests are performed as the variables of total strain range and temperatures. The relations between plastic and total strain energy densities and number of cycles to failure are examined in order to predict the low cycle fatigue life of Cobalt-based super alloy at different temperatures. The fatigue lives is evaluated using predicted by Coffin-Manson method and strain energy methods is compared with the measured fatigue lives at different temperatures. The microstructure observing was performed for how affect able to low-cycle fatigue life by increasing the temperature.

Study on Low-Cycle Fatigue Life of Base Metal of the Shock Absorber

2014 ◽  
Vol 936 ◽  
pp. 1361-1365
Author(s):  
Ai Li Li ◽  
Ri Gao ◽  
Ming De Sun ◽  
Xi Meng
Keyword(s):  
Fatigue Life ◽  
Base Metal ◽  
Life Prediction ◽  
Shock Absorber ◽  
Prediction Models ◽  
Low Cycle Fatigue ◽  
Engineering Application ◽  
Fatigue Life Prediction ◽  
Strain Effect ◽  
Cycle Fatigue

In this paper, by experiments on the low-cycle fatigue life of groups of base metal test specimens under constant total strain control, the number of cycles to fracture failure are obtained. The measured S-N curve of base metal is established and the fitted formulas based on three low cycle fatigue life prediction models are caculated according to the test data. The relationship between the low-cycle fatigue life and strain amplitude are concluded. The results of observation show that the elastic strain effect can be negligible in the range of strain amplitudes used for the study of low-cycle fatigue (0.01-0.08). In addition, the calculation suggests that the three-parameter power function is suitable for the low-cycle fatigue life prediction of the base metal because its prediction accuracy is higher than other methods. The research provides technology supports for life prediction and engineering application of the shock absorber.

Energy-Based Fatigue Life Prediction for Combined Low Cycle and High Cycle Fatigue

2013 ◽  
Author(s):  
Casey M. Holycross ◽  
M.-H. Herman Shen ◽  
Onome E. Scott-Emuakpor ◽  
Tommy J. George
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Life Prediction ◽  
High Cycle Fatigue ◽  
Prediction Models ◽  
Low Cycle Fatigue ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Data Set ◽  
Vibrational Loading

Gas turbine engine components are subjected to both low and high cycle fatigue as a result of mechanical and vibrational loading. Mechanical loading is generally within the low cycle fatigue regime and attributed to throttle up/throttle down cycles of various flight maneuvers or engine start-up/shut-down cycles over the course of a component’s lifetime. Vibrational loading causes high cycle fatigue of a multiaxial stress state, and is attributed to various forced and free vibration sources manifested as high order bending or torsion modes. Understanding the interaction of these two fatigue regimes is necessary to develop robust design techniques for gas turbine engines and turbomachinery in general. Furthermore, applying a method to accurately predict fatigue performance from a reduced data set can greatly reduce time and material costs. This study investigates commonly used fatigue life prediction models and techniques in their ability to accurately model fatigue lives of Al 6061-T651 cylindrical test specimens subjected to various stress ratios, mean stresses, and high cycle/low cycle interaction. Comparisons between these models are made and modifications are proposed than can account for these complex loading effects where appropriate.

Probabilistic Life Prediction for High Temperature Low Cycle Fatigue Using Energy-Based Damage Parameter and Accounting for Model Uncertainty

2011 ◽  
Author(s):  
Shun-Peng Zhu ◽  
Hong-Zhong Huang ◽  
Victor Ontiveros ◽  
Li-Ping He ◽  
Mohammad Modarres
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Fatigue Life ◽  
Model Uncertainty ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Probabilistic Method ◽  
Damage Parameter ◽  
Probabilistic Methods ◽  
Cycle Fatigue

Probabilistic methods have been widely used to account for uncertainty from various sources to predict fatigue life for components or materials. The Bayesian approach can potentially give more accurate estimates by combining test data with technical knowledge available from theoretical analyses and/or previous experimental results. The aim of the present paper is to develop a probabilistic methodology for high temperature low cycle fatigue life prediction using an energy-based damage parameter and to demonstrate the use of an efficient probabilistic method. Accordingly, a Black-box approach is used to quantify model uncertainty for three damage parameters (the generalized damage parameter, SWT and plastic strain energy density (PSED)) using measured differences between experimental data and model predictions. The proposed model was verified using experimental data for nickel-base Superalloy GH4133 under different temperatures from literature. The results show that the uncertainty bounds using the generalized damage parameter for life prediction are tighter than that of SWT and PSED methods, which leads to better decision making based on the same available knowledge.

A Continuum Damage Mechanics Approach for Fatigue Life Prediction of Open-Hole Metallic Plate

2014 ◽  
Vol 670-671 ◽  
pp. 1060-1067
Author(s):  
Xian Min Chen ◽  
Qin Sun ◽  
Di Guan ◽  
Feng Ping Yang
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Damage Evolution ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Damage Initiation ◽  
Open Hole

A damage evolution model is presented for fatigue life prediction of metallic structures. This model is formulated based on damage mechanics and the irreversible thermodynamics framework developed by LEMAITRE and CHABOCHE. Using this model, the fatigue lifetime can be predicted both in the high cycle fatigue (HCF) regime and the low cycle fatigue (LCF) regime. Based on the energy theory and material fatigue test data, the plastic strain threshold for damage initiation was modified for HCF and LCF respectively. The damage evolution parameters were determined according to the fatigue test results of standard specimens. A damage mechanics-finite element full-couple method was adopted to simulate the process of fatigue damage evolution. The numerical simulation of fatigue lives were compared with the fatigue tests of 2A12-T4 open-hole plates and good agreement was obtained.

scholarly journals Low-Cycle Fatigue Crack Initiation Simulation and Life Prediction of Powder Superalloy Considering Inclusion-Matrix Interface Debonding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4018
Author(s):  
Shuming Zhang ◽  
Yuanming Xu ◽  
Hao Fu ◽  
Yaowei Wen ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Interface Debonding ◽  
Damage Evolution Equation ◽  
Finite Element Software

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

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