Prediction of multiaxial fatigue life for complex three‐dimensional stress state considering effect of additional hardening

2019 ◽  
Vol 42 (11) ◽  
pp. 2558-2578
Author(s):  
Bingfeng Zhao ◽  
Liyang Xie ◽  
Jiaxin Song ◽  
Zhiqiang Zhao ◽  
Fuyou Fan ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Stress State ◽  
Three Dimensional ◽  
Multiaxial Fatigue ◽  
Additional Hardening

Fatigue Life Properties of Stainless Steels in Wide Ranged Biaxial Stress State

2019 ◽  
Vol 795 ◽  
pp. 60-65
Author(s):  
Shunsuke Saito ◽  
Fumio Ogawa ◽  
Takamoto Itoh
Keyword(s):  
Fatigue Life ◽  
Stress State ◽  
Stainless Steels ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Biaxial Stress ◽  
Loading Path ◽  
Inner Pressure ◽  
Biaxial Stress State

Multiaxial fatigue tests consisting of push-pull loading and cyclic inner pressure were carried out using hollow cylinder specimens of type 430 stainless and type 316 stainless steels at room temperature. 7 types of cyclic loading paths were employed by combining axial and hoop stresses: a Pull, an Inner-pressure, a Push-pull, an Equi-biaxial, a Square-shape, a LT-shape and a LC-shape. Fatigue lives vary depending on the loading path when those were evaluated by the maximum Mises’ equivalent stress on inner surface of the specimen. The fatigue lives of both the steels showed a similar tendency although some Pull tests take longer fatigue life when cracks initiated from inside surface of the specimen. This study investigated the crack initiation and propagation behaviors as well as the initiation of oil leakage to prove the behavior and discusses life evaluation for two steels under wide ranged biaxial stress state, too.

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.

scholarly journals A new multiaxial fatigue life prediction model considering additional hardening effect

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093533
Author(s):  
Li Bin ◽  
Liu Jianhui ◽  
Wang Xiuli
Keyword(s):  
Fatigue Life ◽  
Prediction Model ◽  
Life Prediction ◽  
Multiaxial Fatigue ◽  
Fatigue Life Prediction ◽  
Proportional Loading ◽  
Hardening Effect ◽  
Proposed Model ◽  
Additional Hardening ◽  
Life Prediction Model

The established linear fatigue life prediction model based on the Miner rule has been widely applied to fatigue life prediction under constant amplitude uniaxial and multiaxial loading. Considering the physical significance of crack formation and propagation, a multiaxial equivalent linear fatigue life prediction model is put forward based on Miner rule and critical plane method under constant amplitude loading. The essence of this approach is that the equivalent strain, which consists of the shear strain and normal strain on the critical plane, replaces the relevant parameter of uniaxial nonlinear fatigue damage model. The principal axes of stress/strain rotate under non-proportional loading. Meanwhile, the microstructure of material and slip systems change, which lead to additional hardening effect. The ratio of cyclic yield stress to static yield stress is used to represent the cyclic hardening capacity of material, and the influence of phase difference and loading condition on the non-proportional hardening effect is considered. The multiaxial fatigue life is predicted using equivalent stain approach, maximum shear stain amplitude model, CXH model, and equivalent multiaxial liner model under proportional and/or non-proportional loading. The smooth and notched fatigue specimens of four kinds of materials (Q235B steel, titanium alloy TC4, Haynes 188, and Mod.9Cr-1Mo steel) are used in the multiaxial fatigue experiments to verify the proposed model. The predicted results of these materials are compared with the test results, and the results show that these four models can achieve good effect under proportional loading, but the proposed model performs better than the other three models under non-proportional loading. Meanwhile, it also verifies that the proposed enhancement factor can reflect the influence of phase difference and material properties on additional hardening.

scholarly journals Multiaxial fatigue life evaluation using strain energy-based critical plane approach

2019 ◽  
Vol 22 ◽  
pp. 78-83
Author(s):  
Meng-Fei Hao ◽  
Shun-Peng Zhu ◽  
Fu-Long Xia
Keyword(s):  
Fatigue Life ◽  
Strain Energy ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Life Evaluation ◽  
Critical Plane Approach ◽  
Fatigue Life Evaluation

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Modified Stress Severity Factor Method Based on 3D-FEM

2014 ◽  
Vol 945-949 ◽  
pp. 1150-1154
Author(s):  
Xiao Hua Yang ◽  
Xue Jun Liu ◽  
Zhao Hu
Keyword(s):  
Fatigue Life ◽  
Stress State ◽  
Experimental Result ◽  
3D Fem ◽  
Severity Factor ◽  
Factor Method ◽  
D Model

The traditional stress severity factor (SSF) approach was applied to analyze the life of aircraft multi-fastener joint. 3-D model was established under simulated state of practical assembling using CATIA, and then the model was imported into ABAQUS to analyze the detail stress state of aircraft multi-fastener joint. The life of aircraft multi-fastener joint was estimated by amending the SSF method. The example shows that the fatigue life by the approach is closer to the experimental result.

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