A Procedure for Fast Evaluation of High-Cycle Fatigue Under Multiaxial Random Loading

2002 ◽  
Vol 124 (3) ◽  
pp. 558-563 ◽  
Author(s):  
Bin Li ◽  
Manuel de Freitas
Keyword(s):  
Shear Stress ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Hydrostatic Stress ◽  
Evaluation Procedure ◽  
Cycle Fatigue ◽  
Computationally Efficient ◽  
Random Loading ◽  
Fast Evaluation

This paper presents a fast evaluation procedure for high-cycle fatigue (HCF) under multiaxial random loading. The recent multiaxial cycle counting method of Wang and Brown is used to identify the loading reversals. For each identified reversal, the effective shear stress amplitude is directly calculated from the component stress ranges by an equation derived from the MCE approach, which is a newly developed method to account for nonproportional loading effect. This shear stress amplitude and the maximum hydrostatic stress during the time period of an identified reversal are used to evaluate the fatigue damage for that reversal by Crossland’s criterion. The fatigue damage of the loading block is then calculated by summing the damages of all the identified reversals by Miner’s rule. Comparisons with other multiaxial HCF approaches show that the procedure is a computationally efficient and conservative engineering approach.

A Procedure for Fast Evaluation of High-Cycle Fatigue Under Multiaxial Random Loading

2001 ◽  
Author(s):  
Bin Li ◽  
Manuel de Freitas
Keyword(s):  
Shear Stress ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Hydrostatic Stress ◽  
Evaluation Procedure ◽  
Cycle Fatigue ◽  
Random Loading ◽  
Proportional Loading ◽  
Fast Evaluation

Abstract This paper presents a fast evaluation procedure for high-cycle fatigue (HCF) under multiaxial random loading. The recent multiaxial cycle counting method of Wang and Brown is used to identify the loading reversals. For each identified reversal, the effective shear stress amplitude is directly calculated from the component stress ranges by an equation derived from the MCE approach, which is a newly developed method to account for non-proportional loading effect. This shear stress amplitude and the maximum hydrostatic stress during the time period of an identified reversal are used to evaluate the fatigue damage for that reversal by Crossland’s criterion. The fatigue damage of the loading block is then calculated by summing the damages of all the identified reversals by Miner’s rule. Comparisons with other multiaxial HCF approaches show that the procedure is a computationally efficient and conservative engineering approach.

Multiaxial high-cycle fatigue life prediction model based on the critical plane approach considering mean stress effects

2016 ◽  
Vol 27 (1) ◽  
pp. 32-46 ◽  
Author(s):  
Jia-Liang Zhang ◽  
De-Guang Shang ◽  
Yu-Juan Sun ◽  
Xiao-Wei Wang
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
Critical Plane ◽  
Stress Effects ◽  
Critical Plane Approach ◽  
Fatigue Criterion

The aim of this paper is to propose a modified multiaxial high-cycle fatigue criterion based on the critical plane approach. The proposed criterion contains three parameters, that is, shear stress amplitude, normal stress amplitude and mean normal stress. In order to take into account the mean shear stress effects, the critical plane is determined by the maximum shear stress. In the proposed multiaxial fatigue criterion, the influence of mean normal stress on fatigue damage is also considered. Based on the proposed criterion, the multiaxial fatigue life is predicted, and the results showed a good agreement with experimental data obtained from some literatures.

High Cycle Fatigue Damage Evaluation of Steel Pipelines Based on Microhardness Changes During Cyclic Loads: Part II

2018 ◽  
Author(s):  
Geovana Drumond ◽  
Bianca Pinheiro ◽  
Ilson Pasqualino ◽  
Francine Roudet ◽  
Didier Chicot
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Steel Structures ◽  
New Method ◽  
Microplastic Deformation ◽  
Surface Phenomenon ◽  
Cyclic Loads ◽  
Cycle Fatigue ◽  
Indentation Tests

The hardness of a material shows its ability to resist to microplastic deformation caused by indentation or penetration and is closely related to the plastic slip capacity of the material. Therefore, it could be significant to study the resistance to microplastic deformations based on microhardness changes on the surface, and the associated accumulation of fatigue damage. The present work is part of a research study being carried out with the aim of proposing a new method based on microstructural changes, represented by a fatigue damage indicator, to predict fatigue life of steel structures submitted to cyclic loads, before macroscopic cracking. Here, Berkovich indentation tests were carried out in the samples previously submitted to high cycle fatigue (HCF) tests. It was observed that the major changes in the microhardness values occurred at the surface of the material below 3 μm of indentation depth, and around 20% of the fatigue life of the material, proving that microcracking is a surface phenomenon. So, the results obtained for the surface of the specimen and at the beginning of the fatigue life of the material will be considered in the proposal of a new method to estimate the fatigue life of metal structures.

scholarly journals High Cycle Fatigue Appearance of 10wt% cr steel and Dissimilar Metal Weld

2021 ◽  
Vol 9 (VI) ◽  
pp. 2185-2202
Author(s):  
Hilal Ahmad Shah
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Cycle Fatigue ◽  
Crack Initiation And Propagation ◽  
R Ratio ◽  
Initiation And Propagation ◽  
Different Temperatures ◽  
Fracture Surface Analysis ◽  
Metal Weld

The present study deals with the high cycle fatigue (HCF) behavior of a ten wt% Cr steel at ambient also as high temperatures (300–853 K). S–N curves were created at unlike temperatures using an R-ratio of −1. Outcome of mean stress was established over and done with Haigh diagram at 853 K using different R-values. Fatigue life was found to decrease with upsurge in test temperature and stress amplitude. Fatigue life was attempted using Basquin equation. Detailed fracture surface analysis was performed to study the crack initiation and propagation modes towards empathetic the mechanisms of failure at different temperatures.

Safety Factor in Fatigue Under Fluctuating Stresses

1987 ◽  
Vol 109 (4) ◽  
pp. 397-401 ◽  
Author(s):  
V. A. Avakov
Keyword(s):  
Safety Factor ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Static Strength ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Safety Factors ◽  
Generalize Expression ◽  
Allowable Stresses ◽  
Number Of Cycles

It is common to assume identical allowable safety factors in static strength [m], defined by mean stress (Sm), and in fatigue [a], defined by stress amplitude (Sa), in order to find the full safety factor (F) under asymmetrical cycles, or to plot any type of the Sm–Sa diagram of allowable stresses. Here additional modification is considered to generalize expression of the full factor of safety in fatigue under asymmetrical stresses, utilizing unequal allowable safety factors in static strength (by mean stress) and in fatigue (by stress amplitude): ([a] ≠ [m]). We assume that loading is stationary, and cumulated number of cycles is large enough to consider high cycle fatigue.

The Influence of Microstructure Heterogeneities on the Very High Cycle Fatigue Behavior of Duplex Stainless Steel

2016 ◽  
Vol 258 ◽  
pp. 255-258
Author(s):  
Ulrich Krupp ◽  
Marcus Söker ◽  
Tina Waurischk ◽  
Alexander Giertler ◽  
Benjamin Dönges ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Ion Beam ◽  
Cyclic Plasticity ◽  
Cycle Fatigue ◽  
Heterogeneous Distribution ◽  
Very High Cycle Fatigue ◽  
Structural Applications ◽  
Very High

As being used for structural applications, where a high corrosion resistance is required, the fatigue behavior of duplex stainless steels (DSS) is governed by the partition of cyclic plasticity to the two phases, ferrite and austenite, respectively. Under very high cycle fatigue (VHCF) loading conditions, the heterogeneous distribution of crystallographic misorientations between neighboring grains and phases yields to a pronounced scatter in fatigue life, ranging from 1 million to 1 billion cycles for nearly the same stress amplitude. In addition, the relevant damage mechanisms depend strongly on the atmosphere. Stress corrosion cracking in NaCl-containing atmosphere causes a pronounced decrease in the VHCF life. By means of ultrasonic fatigue testing at 20kHz in combination with high resolution scanning electron microscopy, electron back-scattered diffraction (EBSD), focused ion beam milling (FIB) and synchrotron tomography, the microstructure heterogeneities were quantified and correlated with local fatigue damage. It has been shown that the fatigue process is rather complex, involving redistribution of residual stresses and three-dimensional barrier effects of the various interfaces. The application of a 2D/3D finite element model allows a qualitative prediction of the fatigue-damage process in DSS that is controlled by stochastic local microstructure arrangements.

scholarly journals Topology optimization for transversely isotropic materials with high-cycle fatigue as a constraint

2020 ◽  
Vol 63 (1) ◽  
pp. 161-172
Author(s):  
Shyam Suresh ◽  
Stefan B. Lindström ◽  
Carl-Johan Thore ◽  
Anders Klarbring
Keyword(s):  
Topology Optimization ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Transverse Isotropy ◽  
Transversely Isotropic ◽  
Back Stress ◽  
Optimization Method ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Time Model

AbstractWe propose a topology optimization method for design of transversely isotropic elastic continua subject to high-cycle fatigue. The method is applicable to design of additive manufactured components, where transverse isotropy is often manifested in the form of a lower Young’s modulus but a higher fatigue strength in the build direction. The fatigue constraint is based on a continuous-time model in the form of ordinary differential equations governing the time evolution of fatigue damage at each point in the design domain. Such evolution occurs when the stress state lies outside a so-called endurance surface that moves in stress space depending on the current stress and a back-stress tensor. Pointwise bounds on the fatigue damage are approximated using a smooth aggregation function, and the fatigue sensitivities are determined by the adjoint method. Several problems where the objective is to minimize mass are solved numerically. The problems involve non-periodic proportional and non-proportional load histories. Two alloy steels, AISI-SAE 4340 and 34CrMo6, are treated and the respective as well as the combined impact of transversely isotropic elastic and fatigue properties on the design are compared.

Sign in / Sign up

Export Citation Format

Share Document