Cyclic Deformation Behavior and Buckling of Pipeline With Local Metal Loss in Response to Axial Seismic Loading

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Masaki Mitsuya ◽  
Hiroyuki Motohashi
Keyword(s):  
Cyclic Loading ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Protective Coatings ◽  
Low Cycle Fatigue ◽  
Control Measures ◽  
Earthquake Resistance ◽  
Isotropic Hardening ◽  
Metal Loss ◽  
Buried Pipelines

Buried pipelines may be corroded, despite the use of corrosion control measures such as protective coatings and cathodic protection, and buried pipelines may be deformed due to earthquakes. Therefore, it is necessary to ensure the integrity of such corroded pipelines against earthquakes. This study has developed a method to evaluate earthquake resistance of corroded pipelines subjected to seismic motions. Pipes were subjected to artificial local metal loss and axial cyclic loading tests to clarify their cyclic deformation behavior until buckling occurred under seismic motion. 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 cyclic deformation behavior. A combination of kinematic and isotropic hardening was used to model the material properties. The associated material parameters were obtained by 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 cyclic deformation behavior, including the number of cycles required for the buckling of pipes with varying degrees of metal loss.

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.

Mechanical properties and deformation behavior of a refractory multiprincipal element alloy under cycle loading

2021 ◽  
pp. 2050014
Author(s):  
Jing Peng ◽  
Fang Li ◽  
Bin Liu ◽  
Yong Liu ◽  
Qihong Fang ◽  
...  
Keyword(s):  
Grain Size ◽  
Cyclic Loading ◽  
Grain Growth ◽  
Work Hardening ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Low Cycle Fatigue ◽  
Damage Mechanism ◽  
Atomic Scale ◽  
Cycle Loading

In comparison with the state-of-the-art Ni-based superalloys, refractory multiprincipal element alloys (MPEAs) exhibit considerably higher strengths at temperatures above 1600[Formula: see text]C, which can be a significant potential required in the high demand for aerospace applications. However, the atomic-scale work-hardening behavior of such important materials during low-cycle loading remain unknown. Here, using molecular dynamics simulations, we study the low-cycle fatigue of nanocrystalline refractory multiprincipal element alloy with different grain sizes, to reveal the cyclic deformation, work hardening and damage mechanism. As a result, an extensive grain growth is observed during the cyclic deformation, thus driving the dynamic Hall–Petch strengthening mechanism. For the model with large grain size, the glide of partial dislocations with screw structure can be responsible for the deformation behavior under cyclic loading, and at small grain size the grain growth-coordinated deformation twinning can control the plastic process. The deformation twin boundaries generated during the cyclic loading show high stability, while the remaining high-angle grain boundaries are highly unstable. The initial softening followed by hardening depends upon the dislocation density and grain size. In particular, atomic-scale element segregation occurs after cyclic loading. This study gives a cyclic deformation micromechanism, and thus accelerates the design and development of superior fatigue-resistant refractory multiprincipal element alloy over a wide temperature range.

Modeling Cyclic Deformation of HSLA Steels Using Crystal Plasticity

2004 ◽  
Vol 126 (4) ◽  
pp. 339-352 ◽  
Author(s):  
C. L. Xie ◽  
S. Ghosh ◽  
M. Groeber
Keyword(s):  
Cyclic Loading ◽  
Crystal Plasticity ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Kinematic Hardening ◽  
Orientation Imaging Microscopy ◽  
Plasticity Model ◽  
Hsla Steels ◽  
Crystal Plasticity Model ◽  
Orientation Distributions

High strength low alloy (HSLA) steels, used in a wide variety of applications as structural components are subjected to cyclic loading during their service lives. Understanding the cyclic deformation behavior of HSLA steels is of importance, since it affects the fatigue life of components. This paper combines experiments with finite element based simulations to develop a crystal plasticity model for prediction of the cyclic deformation behavior of HSLA-50 steels. The experiments involve orientation imaging microscopy (OIM) for microstructural characterization and mechanical testing under uniaxial and stress–strain controlled cyclic loading. The computational models incorporate crystallographic orientation distributions from the OIM data. The crystal plasticity model for bcc materials uses a thermally activated energy theory for plastic flow, self and latent hardening, kinematic hardening, as well as yield point phenomena. Material parameters are calibrated from experiments using a genetic algorithm based minimization process. The computational model is validated with experiments on stress and strain controlled cyclic loading. The effect of grain orientation distributions and overall loading conditions on the evolution of microstructural stresses and strains are investigated.

Cyclic deformation behavior of HAYNES® HR-120® superalloy under low-cycle fatigue loading

2004 ◽  
Vol 36 (1-2) ◽  
pp. 85-98 ◽  
Author(s):  
L.J. Chen ◽  
P.K. Liaw ◽  
H. Wang ◽  
Y.H. He ◽  
R.L. McDaniels ◽  
...  
Keyword(s):  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Cycle Fatigue

scholarly journals A Comparison of Amplitude-and Time-Dependent Cyclic Deformation Behavior for Fully-Austenite Stainless Steel 316L and Duplex Stainless Steel 2205

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5594
Author(s):  
Shaohua Li ◽  
Wenchun Jiang ◽  
Xuefang Xie ◽  
Zhilong Dong
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Structural Integrity ◽  
Low Cycle Fatigue ◽  
Cyclic Softening ◽  
Plastic Strain Amplitude ◽  
Cyclic Plasticity ◽  
Stainless Steel 316L

Austenite and duplex stainless steels are widely used in engineering, and the latter exhibits a more excellent combination of mechanical properties and corrosion resistance due to the coexistence of austenite and ferrite and higher nitrogen. However, fatigue failure still threatens their structural integrity. A comprehensive comparison of their cyclic deformation behavior is a major foundation to understand the role of duplex-phase microstructure and nitrogen in the safety assessment of engineering components. Thus, in this paper, the cyclic deformation behavior of fully-austenitic stainless steel 316L and duplex stainless steel 2205 was studied by a series of low cycle fatigue tests with various strain amplitudes, loading rates and tensile holding. A theoretical mechanism diagram of the interaction between nitrogen and dislocation movements during cyclic loads was proposed. Results show that the cyclic stress response of 2205 was the primary cyclic hardening, followed by a long-term cyclic softening regardless of strain amplitudes and rates, while an additional secondary hardening was observed for 316L at greater strain amplitudes. Cyclic softening of 2205 was restrained under slower strain rates or tensile holding due to the interaction between nitrogen and dislocations. The cyclic plasticity of 2205 started within the austenite, and gradually translated into the ferrite with the elevation of the cyclic amplitude, which lead to a decreased hardening ratio with the increase in amplitude and a shorter fatigue life for a given smaller plastic strain amplitude.

Low Cycle Fatigue of FeAl (42 at. % Al) at Room Temperature

1996 ◽  
Vol 460 ◽  
Author(s):  
D. B. Hanes ◽  
R. Gibala
Keyword(s):  
Fatigue Life ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Surface Coatings ◽  
Protective Film ◽  
Cycle Fatigue ◽  
Environmental Embrittlement ◽  
Tension And Compression

ABSTRACTThe monotonie mechanical behavior in tension and compression of FeAl has been well documented. However, very little work has been done on the cyclic deformation behavior of this material. In this work, the behavior of FeAl (42 at. % Al) under low cycle fatigue was studied, including the effects of test environments and surface coatings. It was found that the fatigue life of this alloy is limited by environmental embrittlement. This embrittlement process can be equally well prevented by deformation in an oxygen environment or by coating the alloy with a protective film. The type of film applied appears to have little effect. Similar results were seen in monotonie testing.

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