Study of the Multiaxial Fatigue Life Influencing Factors Based on the Critical Plane Approach

2011 ◽  
Vol 295-297 ◽  
pp. 2314-2320
Author(s):  
Peng Min Lv ◽  
Chun Juan Shi
Keyword(s):  
Fatigue Life ◽  
Strain Amplitude ◽  
Phase Difference ◽  
Amplitude Ratio ◽  
Uniaxial Stress ◽  
Multiaxial Fatigue ◽  
Normal Strain ◽  
Critical Plane ◽  
Proportional Loading ◽  
Maximum Shear Strain

The tension-torsion thin walled tube specimens were used as the researching object in this paper. The method of determination to the critical plane which has the maximum normal strain and maximum shear strain was expounded. The strain state on the critical plane under non-proportional loading was analyzed, and the unified prediction model was used to calculate the fatigue life. In order to research the influence of phase difference on fatigue life under the non-proportional loading, the relation of the equivalent strain and the phase difference in different positive strain amplitude and different strain amplitude ratio were analyzed. It’s found that the dangerous phase difference which has the shortest fatigue life is in direct relation with the strain amplitude ratio. The general formula of dangerous phase difference is presented. Through the material mechanics performance and fatigue parameters of uniaxial stress state, the coefficients in the formula can be obtained and the coefficients of 15 kinds of common materials are given for practical application.

Life Prediction and Verification under Multiaxial Fatigue Loading

2013 ◽  
Vol 365-366 ◽  
pp. 991-994
Author(s):  
Lei Wang ◽  
Tian Zhong Sui ◽  
Qiu Cheng Tian
Keyword(s):  
Strain Amplitude ◽  
Life Prediction ◽  
Fatigue Loading ◽  
Multiaxial Fatigue ◽  
Normal Strain ◽  
Critical Plane ◽  
Proportional Loading ◽  
Maximum Shear Strain ◽  
Change Characteristics ◽  
Strain Change

The strain change characteristics of multiaxial fatigue are analyzed under the condition of the combined tension and torsion loading for thin-tube specimen. Based on the principle of multiaxial critical plane approach, a multiaxial fatigue damage parameter is established, which takes account of the effect of not only the maximum shear strain amplitude and normal strain amplitude on the critical plane but also the parameter of non-proportionality. The non-proportionality is the function of loading parameters which is closely contact with the strain change characteristics of multiaxial fatigue and it can indicate the whole material damage. The experiments under the tension-torsion proportional and non-proportional loading were conducted to verify the multiaxial fatigue life model proposed in this paper. The life prediction has a good correlation with the experimental results.

Multiaxial Fatigue Damage Models

2006 ◽  
Vol 324-325 ◽  
pp. 747-750 ◽  
Author(s):  
De Guang Shang ◽  
Guo Qin Sun ◽  
Jing Deng ◽  
Chu Liang Yan
Keyword(s):  
Shear Strain ◽  
Fatigue Damage ◽  
Multiaxial Fatigue ◽  
Normal Strain ◽  
Critical Plane ◽  
Proportional Loading ◽  
Maximum Shear Strain ◽  
Damage Models ◽  
Thin Tube ◽  
Critical Plane Approach

Two multiaxial damage parameters are proposed in this paper. The proposed fatigue damage parameters do not include any weight constants, which can be used under either multiaxial proportional loading or non-proportional loading. On the basis of the research on the critical plane approach for the tension-torsion thin tubular multiaxial fatigue specimens, two multiaxial fatigue damage models are proposed by combining the maximum shear strain and the normal strain excursion between adjacent turning points of the maximum shear strain on the critical plane. The proposed multiaxial fatigue damage models are used to predict the fatigue lives of the tension-torsion thin tube, and the results show that a good agreement is demonstrated with experimental data.

An Experimental Evaluation for Four Multiaxial Fatigue Approaches

2014 ◽  
Vol 627 ◽  
pp. 425-428
Author(s):  
Dan Jin ◽  
Da Jiang Tian ◽  
Qi Zhou Wu ◽  
Wei Lin
Keyword(s):  
Low Cycle Fatigue ◽  
Multiaxial Fatigue ◽  
304 Stainless Steel ◽  
Normal Strain ◽  
Cycle Fatigue ◽  
Critical Plane ◽  
Maximum Shear Strain ◽  
Rainflow Cycle Counting ◽  
Tubular Specimens ◽  
Damage Rule

A series of tests for low cycle fatigue were conducted on the tubular specimens for 304 stainless steel under variable amplitude and irregular axial-torsional loading. Rainflow cycle counting and linear damage rule are used to calculate fatigue damage and four approaches, e.g. SWT(Smith-Watson-Topper), KBM(Kandil-Brown-Miller), FS(Fatemi-Socie), and LKN(Lee-Kim-Nam) approach are employed to predict the fatigue life. The maximum shear strain plane, the maximum normal strain plane, and the maximum damage plane are considered as the critical plane, respectively. The effects of the choice of the critical plane on previous approaches are discussed. It is shown that comparing with the maximum shear/normal strain approach, the predictions are improved by using the maximum damage plane approach, part nonproportional paths for SWT, AV and part nonproportional paths for KBM, TV paths for FS. But for LKN, the prediction results are nonconservative for some paths than that of the maximum shear/normal strain approach.

A New Multiaxial Fatigue Life Prediction Model Under Proportional and Nonproportional Loading

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Jing Li ◽  
Qiang Sun ◽  
Zhong-Ping Zhang ◽  
Chun-Wang Li ◽  
Dong-Wei Zhang
Keyword(s):  
Fatigue Life ◽  
Damage Model ◽  
Cyclic Hardening ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Life Assessment ◽  
Normal Strain ◽  
Critical Plane ◽  
Nonproportional Loading ◽  
Fatigue Life Assessment

Based on the critical plane approach, the drawbacks of the Wang–Brown (WB) model are analyzed. It is discovered that the normal strain excursion in the WB model cannot account for the additional cyclic hardening well. In order to solve this problem, a new damage parameter for multiaxial fatigue is proposed. In the meantime, the procedure for multiaxial fatigue life assessment incorporating critical plane damage model is presented as well. In the new damage parameter, both strain and stress components are considered, and the effect of the additional cyclic hardening on the fatigue life during nonproportional loading is taken into account as well. In addition, the proposed model is modified when the mean stress is existence. It is convenient for engineering application because of no material constants in this parameter. The capability of fatigue life assessment for the proposed fatigue damage model is checked against the experimental data found in literature for tubular specimens of 1045HR steel, hot-rolled 45 steel, S460N steel, GH4169 alloy at elevated temperature, and the notched shaft of SAE 1045 steel, which is under cyclic bending and torsion loading. It is demonstrated that the proposed criterion gives satisfactory results for all the five checked materials.

scholarly journals Cyclic Deformation and Low-Cycle Fatigue for 316LN Stainless Steel under Non-proportional Loading

2019 ◽  
Vol 300 ◽  
pp. 08002
Author(s):  
Yajing Li ◽  
Bin Ren ◽  
Xu Chen
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Amplitude Ratio ◽  
Cyclic Behavior ◽  
Loading Path ◽  
Proportional Loading ◽  
Loading Paths ◽  
Shear Strain Amplitude

The effects of loading path and strain amplitude ratio on the cyclic behavior and fatigue life were investigated on a 316LN nuclear grade stainless steel employing a series of symmetrically strain-controlled fatigue tests at room temperature. The loading paths of Uniaxial, Torsional, Proportional, Rhombic, Rectangular, and Circular were employed with the constant equivalent strain amplitude of 0.5%. The strain amplitude ratio of 2.35, 1.73 and 1.27, defined by the ratio of shear strain amplitude to the axial strain amplitude, was realized by changing the shear strain amplitude under Proportional, Rhombic, Rectangular and Elliptical loading paths. As expected, the significant non-proportional additional hardening was observed. It’s interesting to note that the axial cyclic stress response varied with the strain amplitude ratio, and the law was different under different loading paths. The fatigue life of all the tests were evaluated by three critical plane criteria proposed by Smith-Watson-Topper (SWT), Fatemi-Socie (FS) and Chen-Xu-Huang (CXH). Results show that the SWT criterion significantly overestimated the fatigue life of non-proportional loading because the effect of shear damage was not considered. The CXH criterion for tensile-type failure yielded good prediction results except for two torsional data points. The FS criterion provided better predictions than other models.

scholarly journals Multiaxial Fatigue Life Prediction of GH4169 Alloy Based on the Critical Plane Method

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 255 ◽  
Author(s):  
Jianhui Liu ◽  
Zhen Zhang ◽  
Bin Li ◽  
Shanshan Lang
Keyword(s):  
Fatigue Life ◽  
Shear Strain ◽  
Yield Stress ◽  
Control Parameter ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Maximum Shear Strain ◽  
Plane Method ◽  
Gh4169 Alloy ◽  
Additional Hardening

The multiaxial fatigue life of GH4169 alloy was predicted based on the critical plane method. In this paper, a new critical plane-damage multiaxial fatigue parameter is proposed, in which the maximum shear strain is considered to be the main damage control parameter, and the correction parameter, including the normal stress and strain of the maximum shear strain plane, is defined as the second control parameter. The axis of principle strain rotates under non-proportional loading. Meanwhile, the mechanism of the variation of material microstructure and slip systems leads to an additional hardening phenomenon. The ratio of cyclic yield stress to static yield stress is used to represent cyclic strengthening capacity, and the influence of the phase difference and loading condition on the non-proportional reinforcement effect is considered. It is also proposed that different materials have different influences on the additional hardening phenomenon. Meanwhile, the model revision results in stress under asymmetrical loading. Experimental data of GH4169 alloy show that the proposed model can provide better prediction than the Smith–Watson–Topper (SWT) and Fatemi–Socie (FS) models.

Multiaxial Fatigue Life Prediction of Metallic Materials Based on Critical Plane Method under Non-Proportional Loading

2017 ◽  
Vol 730 ◽  
pp. 516-520 ◽  
Author(s):  
Er Nian Zhao ◽  
Wei Lian Qu
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Multiaxial Fatigue ◽  
Fatigue Life Prediction ◽  
Metallic Materials ◽  
Loading Conditions ◽  
Critical Plane ◽  
Proportional Loading ◽  
Plane Method ◽  
Strain Paths

The critical plane method is widely discussed because of its effectiveness for predicting the multiaxial fatigue life prediction of metallic materials under the non-proportional loading conditions. The aim of the present paper is to give a comparison of the applicability of the critical plane methods on multiaxial fatigue life prediction. A total of 205 multiaxial fatigue test data of nine kinds of metallic materials under various strain paths are adopted for the experimental verification. Results shows that the von Mises effective strain parameter and KBM critical plane parameter can give well predicted fatigue lives for multiaxial proportional loading conditions, but give poor prediction lives evaluation for multiaxial non-proportional loading conditions. However, FS parameter shows better accuracy than the KBM parameter for multiaxial fatigue prediction for both proportional and non-proportional loading conditions.

Analysis of Multiaxial Fatigue Evaluation in Engine Components Using an Improved Multiaxial Fatigue Life Model

2016 ◽  
Author(s):  
Cheng-cheng Zhang ◽  
Yuan Ren ◽  
Jing-yun Gao ◽  
Ying Li ◽  
Kun Yang
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Uniaxial Stress ◽  
Multiaxial Fatigue ◽  
Maintenance Cost ◽  
Multiaxial Loading ◽  
Proportional Loading ◽  
Life Model ◽  
Fatigue Evaluation ◽  
Engine Components

Current design methodologies for LCF/HCF of aero engine components are based on traditional uniaxial stress/strain methods like strain-life (ε-N), stress-life (S-N) and Goodman / Haigh diagram approaches, often applied with a wide safe factors to account for uncertainties in the understanding of multiaxial loading and other effects. With constantly striving to improve the performance and life of gas turbine engines, there is a need to increase accuracy of life prediction and reduce maintenance cost. Some multiaxial fatigue methods like Manson-McKnight, Sines, Smith-Watson-Topper etc. were developed to convert the multiaxial stresses into an equivalent uniaxial stress. This conversion simply provides the treatment of both the mean stress, the stress amplitude and directions. However, critical locations in engine components often experience significant multiaxial non-proportional loading conditions, such as blades and LP/HP shafts are subjected to HCF loading associated with mixed bending and torsional vibration modes. In this paper, the use of a new multiaxial fatigue life model was explored in the prediction of multiaxial fatigue behavior in aeronautic materials and structural steel. This new life model is based on the multiaxial S-N curve and an improved multiaxial high-cycle fatigue criterion which validated before by authors. The applied range of this new multiaxial fatigue life model were also compared with other models. Several groups of solid and hollow specimens with different ductile materials were conducted and evaluated under multiaxial loading cases. The predictions based on the proposed model give a better statistical result than other models.

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