Modified Low-Cycle Fatigue Estimation Using Machine Learning for Radius-Cut Coke-Shaped Metallic Damper Subjected to Cyclic Loading

2020 ◽  
Vol 20 (6) ◽  
pp. 1849-1858 ◽  
Author(s):  
Jaehoon Bae ◽  
Chang-Hwan Lee ◽  
Minjae Park ◽  
Robel Wondimu Alemayehu ◽  
Jaeho Ryu ◽  
...  
Keyword(s):  
Machine Learning ◽  
Cyclic Loading ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Fatigue Estimation ◽  
Metallic Damper

Cyclic Deformation and Buckling Behavior of Pipe With Local Metal Loss Subjected to Seismic Ground Motion

2011 ◽  
Author(s):  
Masaki Mitsuya ◽  
Hiroshi Yatabe
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Earthquake Resistance ◽  
Metal Loss ◽  
Cycle Fatigue ◽  
Longitudinal Length

Buried pipelines may be deformed due to earthquakes and also corrode despite corrosion control measures such as protective coatings and cathodic protection. In such cases, it is necessary to ensure the integrity of the corroded pipelines against earthquakes. This study developed a method to evaluate the earthquake resistance of corroded pipelines subjected to seismic ground motions. Axial cyclic loading experiments were carried out on line pipes subjected to seismic motion to clarify the cyclic deformation behavior until buckling occurs. The test pipes were machined so that each one would have a different degree of local metal loss. As the cyclic loading progressed, displacement shifted to the compression side due to the formation of a bulge. The pipe buckled after several cycles. To evaluate the earthquake resistance of different pipelines, with varying degrees of local metal loss, a finite-element analysis method was developed that simulates the cyclic deformation behavior. A combination of kinematic and isotropic hardening components was used to model the material properties. These components were obtained from small specimen tests that consisted of a monotonic tensile test and a low cycle fatigue test under a specific strain amplitude. This method enabled the successful prediction of the cyclic deformation behavior, including the number of cycles required for the buckling of pipes with varying degrees of metal loss. In addition, the effect of each dimension (depth, longitudinal length and circumferential width) of local metal loss on the cyclic buckling was studied. Furthermore, the kinematic hardening component was investigated for the different materials by the low cycle fatigue tests. The kinematic hardening components could be regarded as the same for all the materials when using this component as the material property for the finite-element analyses simulating the cyclic deformation behavior. This indicates that the cyclic deformation behavior of various line pipes can be evaluated only based on their respective tensile properties and common kinematic hardening component.

Pipe Elbows Under Strong Cyclic Loading

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
George E. Varelis ◽  
Spyros A. Karamanos ◽  
Arnold M. Gresnigt
Keyword(s):  
Cyclic Loading ◽  
Low Cycle Fatigue ◽  
Seismic Loading ◽  
Fatigue Curve ◽  
Design Codes ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Finite Element Analyses ◽  
Fatigue Design ◽  
Process Piping

Motivated by the response of industrial piping under seismic loading conditions, the present study examines the behavior of steel process piping elbows, subjected to strong cyclic loading conditions. A set of experiments is conducted on elbow specimens subjected to constant amplitude in-plane cyclic bending, resulting into failure in the low-cycle-fatigue range. The experimental results are used to develop a low-cycle-fatigue curve within the strain-based fatigue design framework. The experimental work is supported by finite element analyses, which account for geometrical and material nonlinearities. Using advanced plasticity models to describe the behavior of elbow material, the analysis focuses on localized deformations at the critical positions where cracking occurs. Finally, the relevant provisions of design codes (ASME B31.3 and EN 13480) for elbow design are discussed and assessed, with respect to the experimental and numerical findings.

scholarly journals Low Cycle Fatigue Life Evaluation of Notched Specimens Considering Strain Gradient

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1001
Author(s):  
Shenghuan Qin ◽  
Zaiyin Xiong ◽  
Yingsong Ma ◽  
Keshi Zhang
Keyword(s):  
Cyclic Loading ◽  
Constitutive Model ◽  
Strain Gradient ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Plastic Behavior ◽  
Cycle Fatigue ◽  
New Model ◽  
Hysteresis Behavior ◽  
Notched Specimens

An improved model based on the Chaboche constitutive model is proposed for cyclic plastic behavior of metal and low cycle fatigue of notched specimens under cyclic loading, considering the effect of strain gradient on nonlinear kinematic hardening and hysteresis behavior. The new model is imported into the user material subroutine (UMAT) of the finite element computing software ABAQUS, and the strain gradient parameters required for model calculation are obtained by calling the user element subroutine (UEL). The effectiveness of the new model is tested by the torsion test of thin copper wire. Furthermore, the calibration method of strain gradient influence parameters of constitutive model is discussed by taking the notch specimen of Q235 steel as an example. The hysteresis behavior, strain distribution and fatigue failure of notched specimens under cyclic loading were simulated and analyzed with the new model. The results prove the rationality of the new model.

Low-cycle fatigue life and plasticity mechanisms of a Fe−15Mn−10Cr−8Ni−4Si seismic damping alloy under cyclic loading at various temperatures

2021 ◽  
Vol 220 ◽  
pp. 117267
Author(s):  
Takahiro Sawaguchi ◽  
Ilya Nikulin ◽  
Kazuyuki Ogawa ◽  
Susumu Takamori ◽  
Fumiyoshi Yoshinaka ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Seismic Damping

Fatigue Characteristic of S355J2 Steel after Surface Frictional-Mechanical Treatment in Corrosive Environment

2014 ◽  
Vol 224 ◽  
pp. 21-26
Author(s):  
Dorota Kocańda ◽  
Andrzej Górka ◽  
Krzysztof Grzelak ◽  
Janusz Torzewski ◽  
Ellina Łunarska ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Mechanical Treatment ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Corrosive Environment ◽  
Cycle Fatigue ◽  
Constant Amplitude ◽  
Fatigue Characteristic ◽  
Low Alloyed Steel

In the paper low (LCF) and high cycle fatigue (HCF) behavior of the S355J2 low alloyed steel after surface frictional-mechanical treatment in a corrosive environment (3.5 % NaCl ) has been presented. The treatment was used in order to improve mechanical and fatigue properties of the steel. Obtained experimental results indicate an insignificant improvement of mechanical and fatigue properties of the strengthened steel under the conditions of corrosion at constant amplitude cyclic loading. It is particularly noticeable in the range of low-cycle fatigue.

Plastic Deformation Kinetics of Eutectic Pb-Sn Solder Joints in Monotonic Loading and Low-Cycle Fatigue

1992 ◽  
Vol 114 (2) ◽  
pp. 112-117 ◽  
Author(s):  
Z. Guo ◽  
A. F. Sprecher ◽  
H. Conrad
Keyword(s):  
Cyclic Loading ◽  
Value Function ◽  
Low Cycle Fatigue ◽  
True Stress ◽  
Cycle Fatigue ◽  
Dislocation Glide ◽  
Deformation Kinetics ◽  
Test Conditions ◽  
Controlling Mechanism ◽  
Kinetics Of

The deformation kinetics of near-eutectic Pb-Sn alloys in monotonic and cyclic loading in shear at 300K were investigated by determining the stress exponent n in the Dorn equation using several techniques including strain rate cycling. n was found to be a single-value function of the true stress for the present range of test conditions for both the monotonic and cyclic loading. It ranged from ~4 at the lowest stresses to ~30 at the highest stresses. The n-value of ~4 is concluded to represent dislocation glide and climb as the controlling mechanism, while values of n > 10 reflect power low breakdown.

Microstructure Evolution during LCF of a 10%Cr Steel at Room Temperature

2016 ◽  
Vol 879 ◽  
pp. 1311-1316 ◽  
Author(s):  
Roman Mishnev ◽  
Nadezhda Dudova ◽  
Rustam Kaibyshev
Keyword(s):  
Cyclic Loading ◽  
Dislocation Density ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Strain Softening ◽  
Low Cycle Fatigue ◽  
Lattice Dislocation ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Number Of Cycles

The influence of cyclic loading on microstructure and hardness of a 10%Cr steel with 3%Co and 0.008%B was examined at room temperature and total strain amplitudes of ±0.25% and ±0.6%. Low cycle fatigue (LCF) curves exhibit a stress peak after a few cycles. Hardening is attributed to an increase in dislocation density; no changes in lath size were observed. Then stress tends to decrease monotonically with number of cycles that is indicative for material softening. At εac =±0.25%, strain softening is attributed to decreasing dislocation density and lath coarsening under LCF, whereas at εac =±0.6%, the knitting reaction between dislocations comprising lath boundaries and trapped lattice dislocation leading to the transformation of lath boundaries to subboundaries is a reason for hardness decrease and strain-induced subgrain coarsening.

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