Multiaxial Fatigue Damage Models

1987 ◽  
Vol 109 (4) ◽  
pp. 293-298 ◽  
Author(s):  
D. Socie

Two multiaxial fatigue damage models are proposed: a shear strain model for failures that are primarily mode II crack growth and a tensile strain model for failures that are primarily mode I crack growth. The failure mode is shown to be dependent on material, strain range and hydrostatic stress state. Tests to support these models were conducted with Inconel 718, SAE 1045, and AISI Type 304 stainless steel tubular specimens in strain control. Both proportional and non-proportional loading histories were considered. It is shown that the additional cyclic hardening that accompanies out of phase loading cannot be neglected in the fatigue damage model.

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.


2006 ◽  
Vol 324-325 ◽  
pp. 747-750 ◽  
Author(s):  
De Guang Shang ◽  
Guo Qin Sun ◽  
Jing Deng ◽  
Chu Liang Yan

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.


Author(s):  
De Guang Shang ◽  
Guo Qin Sun ◽  
Jing Deng ◽  
Chu Liang Yan

2019 ◽  
Vol 300 ◽  
pp. 08003
Author(s):  
Anghel Cernescu ◽  
Rhys Pullin

One of the challenges regarding multiaxial fatigue damage predictions is non-proportional loading. Relevant studies have shown that these multiaxial loadings cause significant additional hardening and reduction in durability due to non-proportionality. Fatigue life predictions due to non-proportional loadings are based on an equivalent non-proportional strain range that considers a material constant related to additional hardening and a non-proportionality factor. In this paper an analysis of the non-proportional factor for three multiaxial loadings forming a square in γ/√3 – ε coordinates is carried out. One of the observations revealed by this analysis is the sensitivity of the non-proportional factor to variable shear strain rate.


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

Author(s):  
N. H. Yang ◽  
H. Nayeb-Hashemi ◽  
A. Vaziri

Fiberglass reinforced composites are extensively used in various structural components. In order to insure their structural integrity, their monotonic and fatigue properties under multiaxial stress fields must be understood. Combined in-phase tension/torsion loading is applied to [±45°]4 E-glass/epoxy composite tubes under monotonic and fatigue conditions to determine the effects of multiaxial loading on its failure. Various monotonic and fatigue damage criteria are proposed. These models considered failure mode (failure plane), the energy method and the effective stress-strain method. It is observed for the majority of experiments, the failure initiated at the outer lamina layer at 45° to the tube axis. A damage criterion for multiaxial monotonic loading is proposed considering both normal and shear stress contributions on the plane of failure. The experimental data show an excellent agreement with this proposed model for various loading conditions. Other failure models are currently under investigation utilizing the stresses and strains at the composite laminate as well as stress and strain at the outer lamina layer. Multiaxial fatigue failure models are proposed considering again the plane of failure. Since the plane of the failure is subjected to mean and cyclic stresses (shear and normal) and mean and cyclic strains (shear and normal), the fatigue damage models consider the contributions of these stresses and strains to the fatigue life of the composite tube. In addition to the fatigue damage model based on the plane of failure, a multi-axial fatigue failure model is proposed considering the mean and cyclic energy during fatigue experiments. The experimental data show a good correlation between the proposed damage parameters and fatigue life of specimens with some scatter of the data. Other fatigue failure models are currently under investigation considering the loading frequency and visco-elastic properties of the composite.


Author(s):  
Dileep Sivaramaiyer ◽  
Esakki Muthu Shanmugam ◽  
Palani Udayanan ◽  
Girish K. Degaonkar

Complex stress strain response of a turbine rotor used in a gas turbine engine was studied. Simple and comprehensive approximation techniques developed by Muralidharan–Manson, Bäumel-Seeger (from data obtained from tension tests) and Roessle–Fatemi (from data obtained from hardness tests) were used to predict the fatigue constants of the rotor material. Multiaxial Fatigue damage models like von Mises equivalent strain model, Smith Watson Topper model, Fatemi–Socie Model, Kandil Brown and Miller model were used to predict the fatigue life of the rotor. Predictions were then compared with the life obtained from the same damage models using the experimental fatigue constants and the life obtained from Low Cycle Fatigue (LCF) testing of the turbine rotor. Acceptable life predictions were obtained with SWT model and FS model using the fatigue constants obtained from the experiment as well as from the approximation techniques. von-Mises equivalent strain model failed to give reasonable life predictions with fatigue constants obtained from the experiment and approximation techniques. The life predicted by KBM model using fatigue constants obtained from approximation techniques (Bäumel-Seeger and Roessle-Fatemi) was found unsatisfactory. The approximation technique proposed by Muralidharan-Manson in combination with all the damage models fitted the failure data within a factor of 5. Finite Element tools were used to determine the stress/strain response of the component under the mutiaxial loading condition.


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