scholarly journals A Nonlinear Fatigue Damage Model Based on Equivalent Transformation of Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Lu Zhang ◽  
Jie Jin ◽  
Wei Zhou ◽  
Wen-Liang Li ◽  
Meng Qiao

It is rather difficult for engineers to apply many of the fatigue damage models for requiring a knee point, material-dependent coefficient, or extensive testing, and some of them are only validated by a fatigue test of two-stage loading rather than higher-stage loading. In this paper, we propose a new model of fatigue cumulative damage in variable amplitude loading, which just requires the information of the S-N curve determined from the fatigue experiment. Specifically, the proposed model defines a stress equivalent transformation way to translate the damage of one stress to another stress through simple calculation. Experimental data of fatigue including two-, three-, and four-block loading verify the superiority of the proposed model by comparing it with the Miner model and Manson model. The results show that the proposed model can be generalized to any type of loading and presents a better prediction. Therefore, the advantage of the proposed model can be easily used by an engineer.

2019 ◽  
Vol 29 (4) ◽  
pp. 610-625
Author(s):  
Jie Zhou ◽  
Hong-Zhong Huang ◽  
Miles V Barnhart ◽  
Guoliang Huang ◽  
Yan-Feng Li

Many fatigue damage models have been investigated based on the S– N curve or modified S– N curve; however, a number of them require additional efforts to determine the material parameters or do not consider the loading history (loading interactions, loading sequences, loading levels, etc.). These limitations can result in extreme deviations for estimating the fatigue life in real-world scenarios. To address these limitations, a new fatigue damage model is developed based on the material memory, which can be described as the degradation of mechanical properties under cyclic loadings. Comparisons with three models are used to demonstrate the validity of the proposed model. Furthermore, four sets of experimental data under two-stress and four-stress levels are carried out to verify the validation of the proposed model, which improves the residual life estimation over the three existing models used for comparison.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1768
Author(s):  
Lizhen Huang ◽  
Weilian Qu ◽  
Ernian Zhao

The multiaxial fatigue critical plane method can be used to evaluate the extremely-low-cycle fatigue (ELCF) damage of beam-to-column welded joints in steel frameworks subjected to strong seismic activity. In this paper, fatigue damage models using structural detail parameters are studied. Firstly, the fatigue properties obtained from experiments are adopted to assess ELCF life for steel frameworks. In these experiments, two types of welded specimens, namely, plate butt weld (PB) and cruciform load-carrying groove weld (CLG), are designed according to the structural details of steel beam and box column joints, in which both structural details and welded factors are taken into account. Secondly, experiments are performed on three full-scale steel welded beam-to-column joints to determine the contribution of stress and/or strain to damage parameters. Finally, we introduce a modification of the most popular fatigue damage model of Fatemi and Socie (FS), modified by us in a previous study, for damage evaluation, and compare this with Shang and Wang (SW) in order to examine the applicability of the fatigue properties of PB and CLG. This study shows that the modified FS model using the fatigue properties of CLG can predict the crack initiation life and evaluate the damage of beam-to-column welded joints, and can be subsequently used for further investigation of the damage evolution law.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yaoliang Zhu ◽  
Jin Yu ◽  
Yanyan Cai ◽  
Xin Tang ◽  
Wei Yao ◽  
...  

The deformation rules and failure types of rock fatigue damage at different temperatures are quite different, and existing constitutive theory cannot describe them quantitatively. A novel rock fatigue damage model considering the effects of temperature was presented based on phenomenology. In this model, the residual strain method was used to define the fatigue damage, and the Harris attenuation function was introduced to characterize the cyclic damage evolution. The proposed model has considered the influence of the initial damage and temperature, and the model parameters can be easily calculated. The accuracy of the model was verified by comparing the calculated values of cyclic upper strain and fatigue life with previous test results. The physical significance of the model parameters shows that parameter a is related to fatigue stress ratio and lithology, while parameter b is related to temperature. The study has some reference values for the fatigue damage model of rock considering the influence of temperature.


2012 ◽  
Vol 26 (11) ◽  
pp. 3439-3446 ◽  
Author(s):  
Hong Chen ◽  
De-Guang Shang ◽  
Yu-Jie Tian ◽  
Jian-Zhong Liu

Author(s):  
Chen Shen ◽  
Abderrahim Talha ◽  
Adel Hamdi ◽  
Noureddine Benseddiq

Criteria of fatigue damage play a key role in life prediction of structures subjected to random loadings. In previous works, a cumulative damage model called damage stress model was developed. This model takes into account not only the loading history but also the nonlinear evolution of damage. Damage stress model improved its predictive capability of fatigue life for several materials such as steels and aluminum alloys. In this paper, a new approach of cumulative damage, based upon the damage stress model parameter, is investigated for different loading paths under finite life regime. To build the new damage indicator, the damage stress model parameter is coupled with an equivalent stress formulated via Sines, Dang Van and Robert fatigue criteria, respectively. The relevance of the proposed model is examined using series of biaxial tests performed on cruciform specimens made of an aluminum alloy. Several types of loadings composed of constant amplitude fatigue, cumulative fatigue with two/three blocks and repeated blocks were set up. Good agreement is highlighted when the prediction, obtained with the proposed model, is compared to our experimental data.


2016 ◽  
Vol 853 ◽  
pp. 62-66 ◽  
Author(s):  
Peng Yue ◽  
Qiang Lei ◽  
Cheng Lin Zhang ◽  
Shun Peng Zhu ◽  
Hong Zhong Huang

To evaluate the fatigue damage accumulation and predict the residual life of components at different stress levels, this paper proposed a modified cumulative damage model based on the strain energy density parameter. Noting that mean stress and load interaction under uniaxial fatigue loading exhibit significant effects on fatigue damage accumulation and life prediction. According to this, a new model based on damaged stress model which considers the effects of mean stress and load interaction was presented in this paper. The proposed model was verified by using four experimental data sets of aluminium alloys and steels. The experimental results are compared with those of the Miner’s rule, damaged stress model (DSM) and damaged energy model (DEM). Results show that the proposed model agrees better with the experimental observations than others.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongsong Li ◽  
Yongbao Liu ◽  
Xing He ◽  
Wangtian Yin

The failure of many aircraft structures and materials is caused by the accumulation of fatigue damage under variable-amplitude cyclic loading wherein the damage evolution of materials is complicated. Therefore, to study the cumulative fatigue damage of materials under variable-amplitude cyclic loading, a new nonlinear fatigue damage accumulation model is proposed based on the ecological quality dissipation of materials by considering the effects of load interaction and sequence. The proposed new model is validated by the test data obtained for three kinds of material under multilevel fatigue loading. Compared with the Miner model and Kwofie model, the proposed model can more effectively analyse the accumulative damage and predict fatigue life of different materials under variable-amplitude cyclic loading than others. The study provides a basis for predicting fatigue life accurately and determining reasonable maintenance periods of aircraft structures.


Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 919 ◽  
Author(s):  
Huang ◽  
Ding ◽  
Li ◽  
Zhou ◽  
Huang

Fatigue damage accumulation theory is one of the core contents in structure fatigue strength design and life prediction. Among them, the nonlinear damage model can overcome the shortcomings of the linear damage model, which takes the loading sequence effect into account. Besides, the loading interaction cannot be ignored for its profound influence in damage accumulation behavior. In the paper, some commonly-used methods of the linear and nonlinear fatigue damage accumulation theory are investigated. In particular, a modified nonlinear fatigue damage accumulation model which considers the effects of loading sequences as well as loading interactions on fatigue life is developed, and a load interaction parameter is obtained by analyzing damage models which assumes that the load logarithm ratio between adjacent stress levels can characterize this phenomenon. Finally, the modified model is employed to predict the fatigue life of high pressure turbine disc. Moreover, comparison is made between the experimental data as well as the predicted lives using the Miner’s rule, the Ye’s model, and the modified model.


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