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.

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.

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.

Multiaxial fatigue assessment for outer cylinder of landing gear by critical plane method

2021 ◽  
pp. 095441002110260
Author(s):  
Yingyu Wang ◽  
Xiaofan Zhang ◽  
Xingliang Dong ◽  
Weixing Yao
Keyword(s):  
Outer Cylinder ◽  
Fatigue Loading ◽  
Landing Gear ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Proportional Loading ◽  
Fatigue Lifetime ◽  
Plane Method ◽  
Multiaxial Stress State ◽  
Maximum Variance

The in-service loadings on the landing gear are usually complex and from different directions, which lead to the fatigue critical locations in the landing gear structure mostly in multiaxial stress state. A methodology based on the critical plane method was proposed for estimating the fatigue lifetime of outer cylinder of the main landing gear undergoing variable amplitude (VA) multiaxial proportional loading. The orientation of the critical plane was determined by the so-called maximum variance method. The Bannantine–Socie’s cycle counting method and Miner’s linear rule were applied with Zhang–Yao’s criterion in this research. The calculated results on the fatigue lifetime of the outer cylinder were compared with the experimental data. The results indicate that the methodology proposed in this article is a sound method for fatigue life prediction of engineering components bearing complex VA multiaxial fatigue loading.

Evaluation of Multiaxial Fatigue Life Prediction Methodologies for Ti-6Al-4V

2002 ◽  
Vol 124 (2) ◽  
pp. 229-237 ◽  
Author(s):  
Alan R. Kallmeyer ◽  
Ahmo Krgo ◽  
Peter Kurath
Keyword(s):  
Fatigue Damage ◽  
Life Prediction ◽  
Equivalent Stress ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Proportional Loading ◽  
Biaxial Fatigue ◽  
Fatigue Data ◽  
Stress States ◽  
Mean Stresses

Many critical engineering components are routinely subjected to cyclic multiaxial stress states, which may include non-proportional loading and multidimensional mean stresses. Existing multiaxial fatigue models are examined to determine their suitability at estimating fatigue damage in Ti-6Al-4V under complex, multiaxial loading, with an emphasis on long-life conditions. Both proportional and non-proportional strain-controlled tension/torsion experiments were conducted on solid specimens. Several multiaxial fatigue damage parameters are evaluated based on their ability to correlate the biaxial fatigue data and uniaxial fatigue data with tensile mean stresses (R>−1) to a fully-reversed (R=−1) uniaxial baseline. Both equivalent stress-based models and critical plane approaches are evaluated. Only one equivalent stress model and two critical plane models showed promise for the range of loadings and material considered.

A Simple and Efficient Reformulation of the Classical Manson–Coffin Curve to Predict Lifetime Under Multiaxial Fatigue Loading—Part I: Plain Materials

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Luca Susmel ◽  
Giovanni Meneghetti ◽  
Bruno Atzori
Keyword(s):  
Fatigue Loading ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Maximum Shear Strain ◽  
Technical Literature ◽  
Fatigue Life Estimation ◽  
Starting Point ◽  
Nonzero Mean ◽  
Phase Angles ◽  
Mean Stresses

This paper summarizes an attempt to devise an engineering method suitable for predicting fatigue lifetime of metallic materials subjected to both proportional and nonproportional multiaxial cyclic loadings. The proposed approach takes as a starting point the assumption that the plane experiencing the maximum shear strain amplitude (the so-called “critical plane”) is coincident with the micro-/mesocrack initiation plane. In order to correctly account for the presence of both nonzero mean stresses and nonzero out-of-phase angles, the degree of multiaxiality/nonproportionality of the stress state damaging crack initiation sites is suggested here to be evaluated in terms of the ratio between maximum normal stress and shear stress amplitude relative to the critical plane. Such a ratio is used then to define nonconventional Manson–Coffin curves, whose calibration is done through two strain-life curves generated under fully reversed uniaxial and fully reversed torsional fatigue loadings, respectively. The accuracy and reliability of our approach were systematically checked by using approximately 350 experimental data taken from the technical literature and generated by testing 13 different materials under both in-phase and out-of-phase loadings. Moreover, the accuracy of our criterion in estimating lifetime in the presence of nonzero mean stresses was also investigated. Such an extensive validation exercise allowed us to prove that the fatigue life estimation technique formalized in the present paper is a reliable tool capable of correctly evaluating fatigue damage in engineering materials subjected to multiaxial cyclic loading paths.

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.

Life Prediction Method of CC and DS Ni Base Superalloys Under High Temperature Biaxial Fatigue Loading

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Takashi Ogata
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Life Prediction ◽  
Compressive Strain ◽  
Prediction Method ◽  
Strain Range ◽  
Fatigue Loading ◽  
Normal Strain ◽  
Biaxial Fatigue

Polycrystalline conventional casting (CC) and directionally solidified (DS) Ni base superalloys are widely used as gas turbine blade materials. It was reported that the surface of a gas turbine blade is subjected to a biaxial tensile-compressive fatigue loading during a start-stop operation, based on finite element stress analysis results. It is necessary to establish the life prediction method of these superalloys under biaxial fatigue loading for reliable operations. In this study, the in-plane biaxial fatigue tests with different phases of x and y directional strain cycles were conducted on both CC and DS Ni base superalloys (IN738LC and GTD111DS) at high temperatures. The strain ratio ϕ was defined as the ratio between the x and y directional strains at 1/4 cycle and was varied from 1 to −1. In ϕ=1 and −1. The main cracks propagated in both the x and y directions in the CC superalloy. On the other hand, the main cracks of the DS superalloy propagated only in the x direction, indicating that the failure resistance in the solidified direction is weaker than that in the direction normal to the solidified direction. Although the biaxial fatigue life of the CC superalloy was correlated with the conventional Mises equivalent strain range, that of the DS superalloy depended on ϕ. The new biaxial fatigue life criterion, equivalent normal strain range for the DS superalloy was derived from the iso-fatigue life curve on a principal strain plane defined in this study. Fatigue life of the DS superalloy was correlated with the equivalent normal strain range. Fatigue life of the DS superalloy under equibiaxial fatigue loading was significantly reduced by introducing compressive strain hold dwell. Life prediction under equibiaxial fatigue loading with the compressive strain hold was successfully made by the nonlinear damage accumulation model. This suggests that the proposed method can be applied to life prediction of the gas turbine DS blades, which are subjected to biaxial fatigue loading during operation.

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