Residual stress/strain evolution due to low‐cycle fatigue by removing local material volume and optical interferometric data

2019 ◽  
Vol 42 (9) ◽  
pp. 2061-2078
Author(s):  
Yury Matvienko ◽  
Vladimir Pisarev ◽  
Svyatoslav Eleonsky ◽  
Andrey Chernov
Keyword(s):  
Residual Stress ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Strain Evolution ◽  
Local Material ◽  
Material Volume

scholarly journals Stress-strain response in gears tooth root due to low cycle fatigue

2019 ◽  
Vol 287 ◽  
pp. 02002
Author(s):  
Marina Franulovic ◽  
Kristina Markovic ◽  
Zdravko Herceg
Keyword(s):  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Material Model ◽  
Strain Response ◽  
Tooth Root ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Main Research ◽  
Damage Initiation

Gears are mechanical components which experience high dynamic loading during their exploitation period. Therefore, their load carrying capacity together with life expectancy are often the main research interest in various studies. The research presented in this paper is focused on the materials response in spur gears tooth root, with the attention given to the repeated overloads during gears operation. In order to simulate low cycle fatigue by using numerical modeling of stress - strain relationship within material, the material model which takes into account isotropic and kinematic hardening is used here. Material response of specimens produced out of steel 42CrMo4 in different loading conditions is used for the calibration of material model, which is then applied to simulate damage initiation and materials stress - strain response in gears tooth root. The results show that materials response to the given loading conditions non-linearly change through the loading cycles.

Comparisons of Monotonic, Low-Cycle and Ultra-Low-Cycle Fatigue Behaviours of X52, X60 and X65 Piping Steel Grades

2014 ◽  
Author(s):  
J. C. R. Pereira ◽  
A. M. P. de Jesus ◽  
A. A. Fernandes ◽  
J. Xavier ◽  
B. Martins
Keyword(s):  
Low Cycle Fatigue ◽  
High Amplitude ◽  
Optical Methods ◽  
Experimental Program ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Deformation Localization ◽  
Damage Models ◽  
Steel Grades ◽  
Cyclic Plastic Strain

Seismic actions, settlements and landslides, accidental loads, fluctuations in the layers of permafrost and pipelines reeling induce large plastic deformations, with widespread yielding in the pipelines which may lead to failure, either due to monotonic loading or due to cyclic plastic strain fluctuations with high amplitude and short duration (Nf<∼100 cycles). The damage mechanisms from the high intensity cyclic loading show distinct mechanisms from the monotonic and low-cycle fatigue (LCF) (∼100<Nf<∼10000cycles). This fatigue domain is often called ultra-low-cycle fatigue (ULCF) or extreme-low-cycle fatigue (ELCF), in order to distinguish it from LCF. Despite of monotonic ductile fracture and LCF have been subjected to significant research efforts and a satisfactory understanding of these damaging phenomena has been already established, ULCF regime is not sufficiently investigated nor understood. Consequently, further advances should be done since the data available in literature is scarce for this fatigue regime. In addition, the performance of ULCF tests is very challenging and there is no specific help from standards available in literature. In this work, the performance of X52, X60 and X65 API steel grades under monotonic, LCF and ULCF loading conditions are investigated. An experimental program was carried out to derive monotonic, LCF and ULCF data for three piping steel grades. Typical smooth geometries are susceptive to instability under ULCF tests. To overcome or minimize this shortcoming anti-buckling devices may be used in the ULCF tests. The use of notched specimens facilitates the deformation localization and therefore contributes to overcome the instability problems. However, the non-uniform stress/strain states raise difficulties concerning the analysis of the experimental data, requiring the use of multiaxial stress/strain parameters. Optical methods and non-linear finite element models were used to assess the strain and stress histories at critical locations, which are used to assess some damage models.

Verification of Specimens for Low-Cycle Fatigue and Cyclic Plasticity Testing

1979 ◽  
Vol 101 (4) ◽  
pp. 321-327
Author(s):  
C. C. Schultz ◽  
H. M. Zien
Keyword(s):  
Finite Element ◽  
Low Cycle Fatigue ◽  
Cyclic Plasticity ◽  
Cycle Fatigue ◽  
Finite Element Analyses ◽  
Stress Strain ◽  
Inelastic Analysis ◽  
Analysis Methods ◽  
Strain Data

The results of inelastic finite element analyses of several uniaxial specimens used for low-cycle fatigue and cyclic plasticity testing are presented. The test specimens studied include both hourglass and uniform gage-type geometries. These results indicate that normally used hourglass specimens may significantly underestimate the strain for a given stress. Uniform gage specimens with commonly used length-to-diameter ratios are shown to provide adequate stress-strain data. Two extensively strain-gaged uniform gage specimens were tested to provide data to confirm the acceptability of the inelastic analysis methods.

Analysis on Low Cycle Fatigue Life and Fatigue Fracture Surface Morphology of TC25 Titanium Alloy

2016 ◽  
Vol 697 ◽  
pp. 652-657
Author(s):  
Rong Guo Zhao ◽  
Yi Yan ◽  
Yong Zhou Jiang ◽  
Xi Yan Luo ◽  
Qi Bang Li ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Fracture Surface ◽  
Crack Growth ◽  
Fatigue Fracture ◽  
Low Cycle Fatigue ◽  
Observation System ◽  
Cycle Fatigue ◽  
Stress Strain

At room temperature, the low cycle fatigue tests for smooth specimens of TC25 titanium alloy under various stress ranges are operated at a CSS280I-20w Electro Hydraulic Servo Universal Testing Machine with a microscopic observation system, and the low cycle fatigue lifetimes are measured. Based upon the analysis of stress-strain hysteresis loop of low cycle fatigue of TC25 titanium alloy, a simplified Manson-Coffin formula is derived according to both the experimental characteristics and the stress-strain constitutive model, the fatigue lifetimes are plotted against stress ranges, and a stress-fatigue life curve for TC25 titanium alloy is obtained by the linear regression analysis method. Finally, the fracture surface morphologies of TC25 specimens are investigated using a JSM-6360 Scanning Electron Microscopy, and the fatigue fracture mechanisms of low cycle fatigue are studied. It shows that the plastic deformations are mainly formed at the accelerated fracture stage, and various shear lips can be observed on the fracture surfaces, which demonstrates that the shear stress results in the final rupture of TC25 titanium alloy. During the fracture of low cycle fatigue, the cleavage nucleation leads to the formation of fatigue crack initiation region, the fatigue crack growth exhibits a mixed transgranular and intergranular crack growth mode, and in the final rupture region, the fracture surface of low cycle fatigue of TC25 titanium alloy appears as a typical semi-brittle fracture mode.

High Temperature, Low Cycle Fatigue Characterization of P91 Weld and Heat Affected Zone Material

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
T. P. Farragher ◽  
S. Scully ◽  
N. P. O'Dowd ◽  
C. J. Hyde ◽  
S. B. Leen
Keyword(s):  
High Temperature ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
Low Cycle Fatigue ◽  
Base Material ◽  
Strain Response ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Weld Material ◽  
The Cross

The high temperature low cycle fatigue behavior of P91 weld metal (WM) and weld joints (cross-weld) is presented. Strain-controlled tests have been carried out at 400 °C and 500 °C. The cyclic behavior of the weld material (WM) and cross-weld (CW) specimens are compared with previously published base material (BM) tests. The weld material is shown to give a significantly harder and stiffer stress–strain response than both the base material and the cross-weld material. The cross-weld tests exhibited a cyclic stress–strain response, which was similar to that of the base material. All specimen types exhibited cyclic softening but the degree of softening exhibited by the cross-weld specimens was lower than that of the base material and all-weld tests. Finite element models of the base metal, weld metal and cross-weld test specimens are developed and employed for identification of the cyclic viscoplasticity material parameters. Heat affected zone (HAZ) cracking was observed for the cross-weld tests.

Piping Stress-Strain Correlation for Seismic Loading

1988 ◽  
Vol 110 (4) ◽  
pp. 444-450
Author(s):  
G. Stawniczy ◽  
W. R. Bak ◽  
G. Hau
Keyword(s):  
Pressure Vessel ◽  
Failure Modes ◽  
Low Cycle Fatigue ◽  
Seismic Loading ◽  
Evaluation Procedure ◽  
Test Results ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Safety Margins ◽  
Fatigue Evaluation

This paper establishes limits on piping material strains for ASME Boiler and Pressure Vessel Code Level D loadings that ensure a limitation of deformation and provide suitable safety margins. In establishing the strain limits, potential piping failure modes due to compressive wrinkling and low-cycle fatigue are considered. A stress-strain correlation methodology to convert linear, elastically calculated Code Class 2 and 3 equation (9)-Level D stresses to strains is established. This correlation is based on the fatigue evaluation procedure of the Code and is verified by comparison with test results. A detailed discussion of test results compared with the stress-strain correlation methodology is also presented.

Sign in / Sign up

Export Citation Format

Share Document