Study on the Piezomagnetic Response to Low-Cycle Fatigue of X80 Pipeline Steel

2016 ◽  
Author(s):  
Sheng Bao ◽  
Shengnan Hu ◽  
Meili Fu ◽  
Huangjie Lou
Keyword(s):  
Pipeline Steel ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Degradation Process ◽  
Fatigue Tests ◽  
Stable Phase ◽  
X80 Pipeline Steel ◽  
Steady Stage ◽  
Initial Stage ◽  
Microstructural Condition

The objective of this work is to explore the relationship between the progressive material degradation process of fatigue and the evolution of the piezomagnetic field surrounding a ferromagnetic sample. The continuous examination of changes in the magnetomechanical behavior during a series of strain-controlled fatigue tests was performed on X80 pipeline steel samples. Analysis of the data obtained allowed the division of the fatigue life of the investigated steel into three stages: incipient stage, steady stage and terminal stage. Furthermore, the piezomagnetic field evolution demonstrates conspicuous changes in the initial stage of fatigue loading, then reverts to a relatively stable phase, and finally, drastic variations appear again before terminal failure. The progressive degradation of the steel under cyclic loading can therefore be tracked by following the evolution of the piezomagnetic field. The characteristics of the evolution of the piezomagnetic responses are also discussed in terms of the mechanical and microstructural condition of the steel during the fatigue process.

Evolution of the Stress-Induced Magnetic Field of Pipeline Steel due to Fatigue Loading

2019 ◽  
Author(s):  
Sheng Bao ◽  
Zhengye Zhao ◽  
Qiang Luo ◽  
Yibin Gu
Keyword(s):  
Magnetic Field ◽  
Fatigue Life ◽  
Pipeline Steel ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
X80 Pipeline Steel ◽  
Three Stages ◽  
Loading And Unloading ◽  
Magnetic Field Variations ◽  
The Magnetic Field

Abstract The objective of this research is to explore the correlation between piezomagnetic fields and cyclic loading in X80 pipeline steel. A series of stress-controlled fatigue tests were carried out, and the magnetic field variations were recorded simultaneously during the whole loading process. The results demonstrate that the fatigue life of the investigated steel can be divided into three stages. The reversal points that appear during the loading and unloading processes can be used as new parameters to reflect the fatigue state and estimate the fatigue life.

SEM In Situ Investigation on Fatigue Cracking Behavior of X80 Pipeline Steel with Inclusions

2011 ◽  
Vol 284-286 ◽  
pp. 1096-1100 ◽  
Author(s):  
Ke Tong ◽  
Yan Ping Zeng ◽  
Xin Li Han ◽  
Yao Rong Feng ◽  
Xiao Dong He
Keyword(s):  
Crack Initiation ◽  
Pipeline Steel ◽  
Fatigue Cracking ◽  
Fatigue Loading ◽  
In Situ Observation ◽  
X80 Pipeline Steel ◽  
Cracking Behavior ◽  
The Matrix ◽  
Extension Period

The micro-mechanical behavior of inclusions in X80 pipeline steel under fatigue loading was investigated by means of SEM in situ observation. The influence of sizes and shapes of inclusion on crack initiation and propagation was analyzed. The result shows that for large-size single-particle inclusion, cracks initiate from the interior under the fatigue loading. When a certain circulation cycles are reached, cracks initiate at the matrix near the sharp corner of the inclusion. The cracks extend at the matrix during the stable extension period and unstable extension period following the crack initiation, until fracture occurred. For chain inclusion, cracks first initiate at the interface between inclusion and matrix within the chain area, and the circulation cycles needed for initiation are far less than single inclusion. Cracks steadily extend after the initiation, and then fracture after very short circulation cycles. A chain of inclusion with the shape corners is serious harmful to the fatigue properties.

Low-cycle fatigue loading of BDS 25G pipeline steel

1998 ◽  
Vol 30 (2) ◽  
pp. 133-137
Author(s):  
G.A. Papadopoulos ◽  
Y.A. Davidov ◽  
S.B. Vodenicharov
Keyword(s):  
Pipeline Steel ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Cycle Fatigue

Tension–tension fatigue performance and stiffness degradation of nanosilica-modified glass fiber-reinforced composites

2017 ◽  
Vol 52 (6) ◽  
pp. 823-834 ◽  
Author(s):  
Jitendra S Tate ◽  
Adekunle T Akinola ◽  
Sergio Espinoza ◽  
Swapnil Gaikwad ◽  
Dinesh Kumar Kannabiran Vasudevan ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Epoxy Composites ◽  
Stiffness Degradation ◽  
Glass Fiber Reinforced ◽  
R Ratio ◽  
Static Mechanical

The aim of this study is to investigate the influence of nanosilica on glass-reinforced epoxy composites under static mechanical and tension–tension fatigue loading. The glass-reinforced epoxy composites were manufactured with three different concentrations of nanosilica (6, 7, and 8 wt%). Static mechanical tests include tensile, flexure and short-beam strength. 6 wt% nanosilica composites showed the greatest enhancement in tensile strength, percentage elongation, and inter-laminar shear strength compared to the other concentrations and the control. Extensive tension–tension fatigue tests (R-ratio of 0.1 and frequency 2 Hz) were conducted on the control and 6 wt% nanosilica composites. In load-controlled and constant amplitude tests, a percentage of the ultimate tensile strength was applied to the specimens. Stress applied was from 80% of UTS, and reduced in steps of 10% until specimens survived 1 million cycles. In high-cycle and low-cycle fatigue tests, 6 wt% nanosilica composites showed 10 and 3 times improvement in fatigue life, respectively, compared to the control composites. Stiffness degradation curves were explained with three stages of damage mechanisms. The final failure occurred due to fiber breakage in the third stage. Both the control and 6 wt% nanosilica composites survived 1 million cycles at a maximum stress of 46.6 MPa, but at the end of 1 million cycles, control composites lost 65% modulus compared to 45% modulus loss in the 6 wt% nanosilica composites.

Low Cycle Fatigue Behaviors of TI-6AL-4V Alloy Controlled by Strain and Stress

2012 ◽  
Vol 525-526 ◽  
pp. 441-444
Author(s):  
Rui Feng Wang ◽  
You Tang Li ◽  
Hu Ping An
Keyword(s):  
Stress Ratio ◽  
Low Cycle Fatigue ◽  
Cyclic Strain ◽  
Cyclic Creep ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Compressive Stresses ◽  
Initial Stage ◽  
Main Factor

The low cycle fatigue behaviors of TI-6AL-4V alloy controlled by strain were investigated by experiment. The fatigue tests were performed at room temperature, and cyclic strain and stress ratio are 0.1 with triangle load wave. The results show that TI-6AL-4V alloy is soften rapidly under the cyclic tensile stresses and it is harden rapidly under the cyclic compressive stresses during the initial-stage of strain controlled fatigue, and the rates of cyclic soften and cyclic harden are decreased with the fatigue progress. The soften rate is related to the cyclic strain but little to the cyclic stress during the overall fatigue progress. The change of cyclic stress is related to the macro friction stresses. The results of experiment show that obvious cyclic creep occurs under the stress controlled low cycle fatigue conditions, and the magnitude of cyclic creep strain is related to the maximum cyclic stress. The softening of tensile friction stresses is the main factor of cyclic creep.

scholarly journals Testing and Evaluation of Anchor Channels under Fatigue Loading

CivilEng ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 1-13
Author(s):  
Thilo Fröhlich ◽  
Dieter Lotze
Keyword(s):  
Endurance Limit ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Alternative Approach ◽  
Current Assessment ◽  
General Existence ◽  
Repeated Load ◽  
Testing And Evaluation

Cast-in anchor channels are used to connect steel components to concrete structures e.g., for elevators, cranes or machines, where repeated load cycles require verification against fatigue failure. The fatigue resistance of anchor channels may be determined by tests according to the interactive method, which provides a complete description of the S/N curve from one to infinite load cycles according to the current assessment document. This procedure differs from conventional fatigue concepts, which do not consider loads that are part of low cycle fatigue, but also question the general existence of an endurance limit. An alternative approach presented in this paper is based on the assumption that the S/N curve can be approximated by a bilinear function. The procedure for the evaluation of fatigue tests on anchor channels embedded in concrete is described. A comparison with the current qualification criteria is given by a test example to discuss the applicability of the proposed method.

scholarly journals Changing Mechanisms of Surface Relief and the Damage Evaluation of Low Cycle Fatigued Austenitic Stainless Steel

2018 ◽  
Vol 165 ◽  
pp. 04007
Author(s):  
Nao Fujimura ◽  
Takashi Nakamura ◽  
Kosuke Takahashi
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Surface Relief ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Arithmetic Mean ◽  
Strongly Correlated ◽  
Persistent Slip Bands

To quantitatively investigate the cause of the changes in arithmetic mean roughness Ra and arithmetic mean waviness Wa of austenitic stainless steel under low-cycle fatigue loading, precise observation focusing on persistent slip bands (PSBs) and crystal grain deformations was conducted on SUS316NG. During the fatigue tests, the specimen’s surface topography was regularly measured using a laser microscope. The surface topographies were analysed by frequency analysis to separate the surface relief due to PSBs from that due to grain deformation. The height caused by PSBs and that by grain deformation were measured respectively. As a result, both of the heights rose with the increase of usage factor (UF). The amount of increase in the heights with respect to UF increased with strain range. The trend of development of both heights was similar with the trend of Ra and Wa. A comparison between Ra and the height caused by PSBs showed that these values strongly correlated with each other. A comparison between Wa and the height caused by grain deformation also showed that these values strongly correlated with each other. Consequently, the surface texture parameters Ra and Wa represent the changes in the heights of surface reliefs due to PSBs and grain deformation.

scholarly journals Low-Cycle Fatigue Crack Initiation Simulation and Life Prediction of Powder Superalloy Considering Inclusion-Matrix Interface Debonding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4018
Author(s):  
Shuming Zhang ◽  
Yuanming Xu ◽  
Hao Fu ◽  
Yaowei Wen ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Interface Debonding ◽  
Damage Evolution Equation ◽  
Finite Element Software

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

scholarly journals Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4070
Author(s):  
Andrea Karen Persons ◽  
John E. Ball ◽  
Charles Freeman ◽  
David M. Macias ◽  
Chartrisa LaShan Simpson ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Prediction Models ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Wearable Sensors ◽  
Fatigue Tests ◽  
Proof Of Concept ◽  
Cycle Fatigue ◽  
Wearable Sensing ◽  
Failure Data

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from “bench to bedside,” fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

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