Peak-To-Peak Change in Magnetization Caused by Fracture

2013 ◽  
Vol 787 ◽  
pp. 755-758
Author(s):  
Jian Wei Li ◽  
Zhong Su ◽  
Gui Ping Lv ◽  
Li Jun Pang ◽  
Wei Jia
Keyword(s):  
Fatigue Fracture ◽  
Magnetic Dipole ◽  
Fracture Zone ◽  
Linear Increase ◽  
Tensile Fracture ◽  
Tensile Fatigue ◽  
Magnetization Change

To simulated the magnetization change at the instant of fracture, assume that the distribution of dislocation-magnetic dipole is consistent, the models of dislocation-magnetic dipole for tensile fracture and tensile-tensile fatigue fracture are established, respectively: The distribution of magnetic dipole for tensile fracture is linear increase from distant to the fracture zone, while the distribution of magnetic dipole for tensile-tensile fatigue fracture is converging only at the fracture zone. It is found that the established model can present the change of peak-to-peak in magnetization for tensile fracture and tensile-tensile fatigue fracture.

Small specimen techniques for estimation of tensile, fatigue, fracture and crack propagation material model parameters

2021 ◽  
pp. 030932472110252
Author(s):  
Julija Kazakeviciute ◽  
James Paul Rouse ◽  
Davide Focatiis ◽  
Christopher Hyde
Keyword(s):  
Fatigue Fracture ◽  
Structural Integrity ◽  
Standard Specimen ◽  
Creep Behaviour ◽  
Parameter Determination ◽  
Model Parameters ◽  
Small Specimen ◽  
Testing Methods ◽  
Advantages And Disadvantages ◽  
Tensile Fatigue

Small specimen mechanical testing is an exciting and rapidly developing field in which fundamental deformation behaviours can be observed from experiments performed on comparatively small amounts of material. These methods are particularly useful when there is limited source material to facilitate a sufficient number of standard specimen tests, if any at all. Such situations include the development of new materials or when performing routine maintenance/inspection studies of in-service components, requiring that material conditions are updated with service exposure. The potentially more challenging loading conditions and complex stress states experienced by small specimens, in comparison with standard specimen geometries, has led to a tendency for these methods to be used in ranking studies rather than for fundamental material parameter determination. Classifying a specimen as ‘small’ can be subjective, and in the present work the focus is to review testing methods that utilise specimens with characteristic dimensions of less than 50 mm. By doing this, observations made here will be relevant to industrial service monitoring problems, wherein small samples of material are extracted and tested from operational components in such a way that structural integrity is not compromised. Whilst recently the majority of small specimen test techniques development have focused on the determination of creep behaviour/properties as well as sub-size tensile testing, attention is given here to small specimen testing methods for determining specific tensile, fatigue, fracture and crack growth properties. These areas are currently underrepresented in published reviews. The suitability of specimens and methods is discussed here, along with associated advantages and disadvantages.

The Analysis of 16MnR Steel Compact Tensile Fatigue Fracture after High Temperature

2012 ◽  
Vol 253-255 ◽  
pp. 341-344
Author(s):  
An Zhong Liu ◽  
Tao Wang ◽  
Su Zhang
Keyword(s):  
Fractal Dimension ◽  
High Temperature ◽  
Crack Initiation ◽  
Fatigue Fracture ◽  
Heating Temperature ◽  
Steel Sample ◽  
Experimental Results ◽  
Tensile Fatigue

In this paper, the test of compact tensile fatigue fracture of 16MnR steel was done after high temperature, and the relation between the proof values Ji at crack initiation of fatigue fracture and fatigue fracture fractal dimension was studied. The experimental results show that the relation between the proof values Ji at crack initiation and the heating temperature. The compact tensile fatigue fracture fractal dimension was changed when 16MnR steel sample was heated to different temperature.

scholarly journals Effectiveness and petroleum geological significance of tectonic fractures in the ultra-deep zone of the Kuqa foreland thrust belt: a case study of the Cretaceous Bashijiqike Formation in the Keshen gas field

2021 ◽  
Author(s):  
Rong-Hu Zhang ◽  
Ke Wang ◽  
Qing-Lu Zeng ◽  
Chao-Feng Yu ◽  
Jun-Peng Wang
Keyword(s):  
Natural Gas ◽  
Fracture Zone ◽  
Vertical Direction ◽  
Gas Production ◽  
Vertical Shear ◽  
Tensile Fracture ◽  
Fracture Aperture ◽  
Thrust Belt ◽  
Geological Significance ◽  
High Production

AbstractThe buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m. The average matrix porosity of the reservoir is 5.5%, and the average matrix permeability is 0.128 × 10−3 μm2. In order to reveal the characteristics and effectiveness of ultra-deep fractures and their effects on reservoir properties and natural gas production, outcrops, cores, thin section, image logs and production testing data are used to investigate the effectiveness of tectonic fractures in ultra-deep reservoirs in the Kuqa foreland thrust zone, and the corresponding geological significance for oil and gas exploration and development are discussed. Tectonic fractures in the thrust belt include EW-trending high-angle tensile fractures and NS-trending vertical shear fractures. The former has a relatively high filling rate, while the latter is mostly unfilled. Micro-fractures are usually grain-piercing-through cracks with width of 10–100 microns. In the planar view, the effective fractures are concentrated in the high part and wing zones of the long axis of the anticline, and along the vertical direction, they are mainly found in the tensile fracture zone above the neutral plane. The adjustment fracture zone has the strongest vertical extension abilities and high effectiveness, followed by the nearly EW longitudinal tensile fracture zone, and the netted fracture zone with multiple dip angles. The effectiveness of fracture is mainly controlled by fracture aperture and filling degrees. Effective fractures can increase reservoir permeability by 1–2 orders of magnitude. The higher part of the anticline is associated with high tectonic fracture permeability, which control enrichment and high production of natural gas. The netted vertical open fractures effectively communicate with pores and throats of the reservoir matrix, which forms an apparent-homogenous to medium-heterogeneous body that is seen with high production of natural gas sustained for a long term.

scholarly journals Tensile Behavior of Sintered Stainless Steel Fiber Felts: Effect of Sintering Joints and Fiber Ligaments

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 768 ◽  
Author(s):  
Jun Ma ◽  
Qiancheng Zhang ◽  
Weidong Song ◽  
Jianzhong Wang ◽  
Huiping Tang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Tensile Properties ◽  
Bonding Strength ◽  
Steel Fiber ◽  
Tensile Elongation ◽  
Tensile Fracture ◽  
Practical Applications ◽  
Tensile Fatigue ◽  
Stainless Steel Fiber

To optimize the tensile properties of sintered 316L stainless steel fiber felts (SSFFs) which is important for their practical applications, the influence of sintering conditions on the microstructure (fiber ligament, sintering joint) and in turn, the tensile properties was investigated experimentally. It was shown that the tensile strength and tensile elongation of SSFFs were dominated by the tensile properties of the fiber ligaments and the bonding strength of the sintering joints. With the increase of sintering temperature versus holding time, the tensile strength of the fiber ligaments dropped significantly, while the sintering joints grew, producing a higher bonding strength between the fibers, resulting in more fibers being involved in the tensile process. These changes in sintering joints and fiber ligaments finally led to a relatively static ultimate strength of SSFFs with a significantly increased elongation, thus with a large increase in tensile fracture energy. The increase of size of the sintering joints also helped to considerably raise the tensile fatigue limit of 316L SSFFs. This research provides a basis to improve the mechanical properties of sintered 316L SSFFs in industrial production.

scholarly journals Fracture Characteristics and Zoning Model of Overburden during Longwall Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhengyi Ti ◽  
Jiazhen Li ◽  
Meng Wang ◽  
Xiaoyan Li ◽  
Zhupeng Jin ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Longwall Mining ◽  
Shear Fracture ◽  
Coal Pillar ◽  
Tensile Fracture ◽  
Fracture Mechanisms ◽  
Winkler Foundation ◽  
Fracture Characteristics ◽  
Fracture Evolution ◽  
Key Stratum

The fracture characteristics and zoning model of overburden during longwall mining are the basis of coal mine disaster prevention. However, the existing theoretical model is inconsistent with the field measurement. In order to further research into the strata’s fracture characteristics and optimize the overburden’s zoning model, we used the elasticity and Winkler foundation theory to establish first fracture and periodic fracture mechanics models of clamped boundary supported by an elastic foundation with a key stratum as the research object. We analyzed the stress distribution characteristics and fracture evolution pattern of the mining-induced key stratum. We analyzed the zoning characteristics of mining-induced overburden and established the zoning model according to different fracture mechanisms. The results show that the key stratum formed a double “O-X” shaped interconnected fracture zone after the first fracture. The key stratum formed a double “C-K” shaped interconnected fracture zone after the periodic fracture. We divided the mining-induced overburden into three zones along the horizontal direction: the original rock zone, the inverted triangular compression-shear fracture zone, and the trapezoidal tensile fracture zone. The study revealed the mechanism of inverted step fracture in the separation zone, explained the fracture mechanism of the coal pillar support zone, and has significant theoretical value for the prevention and control of water disasters, gas outbursts, and strata movement.

scholarly journals Meso-Experimental Study on Tensile Characteristics of Clay

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yi Zhou ◽  
Meng Cui ◽  
Dequan Zhou ◽  
Xiaojia Wang ◽  
Xiao Fu
Keyword(s):  
Experimental Study ◽  
Fracture Zone ◽  
Rapid Change ◽  
Tensile Failure ◽  
Tensile Fracture ◽  
Testing System ◽  
Adjacent Area ◽  
Test Results ◽  
Acquisition Device ◽  
Stretching Process

This paper presents an experimental study on the meso-structure change of clay using an innovative testing system. It aims to evaluate the tensile characteristics of clay. The testing system designed in this paper includes a tensile loading device, an image acquisition device, and an image processing program, which can collect and process the meso-structural images of the soil sample and predict the location of tensile fracture zone with a small preloading. The tests were conducted with three different observation zones, including the tensile fracture zone (Zone 1), the adjacent area of tensile fracture zone (Zone 2), and the areas away from the tensile fracture zone (Zone 3). The results show that the development of cracks is continuous but not linear until tensile failure in Zone 1, and the cracks emerge but stop developing in Zone 2 with the penetration of the cracks in Zone 1, while there is only an overall deviation without any cracks in Zone 3. The variety of mesostructural quantitative parameters in Zone 1 can be divided into three stages: stable stage, rapid change stage, and failure stage. The changes of parameters in Zone 2 show a similar law with those in Zone 1, but the variation is smaller due to the cessation of cracks. The parameters in Zone 3 essentially remain unchanged throughout the whole procedure. According to the test results, the whole stretching process of clay can be divided into the sprouting, the development, and the penetration of cracks.

Evaluating the Mechanical Properties of MEMS by Combining the Resonance Frequency and Microtensile Methods

2003 ◽  
Vol 782 ◽  
Author(s):  
Dongil Son ◽  
Jong-jin Kim ◽  
Dong Won Kim ◽  
Tae Won Lim ◽  
Dongil Kwon
Keyword(s):  
Fracture Toughness ◽  
Resonance Frequency ◽  
Sacrificial Layer ◽  
Fatigue Properties ◽  
Tensile Fracture ◽  
Notched Specimen ◽  
Tensile Fatigue ◽  
Microtensile Test ◽  
Fatigue Notch Factor ◽  
Tip Radius

ABSTRACTTensile, fracture and fatigue properties of single- and polycrystalline silicon and LIGA-Ni were evaluated by the resonance frequency and microtensile methods. A new method for evaluating the fracture toughness that combines these two methods was proposed. A pre-crack was generated in an electrostatically driven test specimen and a load was applied by piezoelectrically driven microtensile equipment. Before the microtensile test, a new surface micromachining technique including a two-step sacrificial layer removal was used. The pre-cracked specimen was attached to microtensile equipment by a UV-adhesive glass grip. The fatigue pre-crack was successfully introduced and the fracture toughness could be derived on the basis of fracture mechanics. The fracture toughness of the pre-cracked specimen was relatively low compared with that of the notched specimen, so that we were able to determine the effect of the notch tip radius. The fatigue properties of LIGA-Ni film were also evaluated. A tensile-tensile fatigue load was applied by a piezoelectric actuator, and real-time load-displacement curves were displayed via computer. The dependence of S-N curves, crack propagation rates and fatigue-notch factor on the applied load for 10 μm Ni film was analyzed.

Tensile and fatigue fracture mechanisms of a Zr-based bulk metallic glass

2003 ◽  
Vol 18 (2) ◽  
pp. 456-465 ◽  
Author(s):  
Z.F. Zhang ◽  
J. Eckert ◽  
L. Schultz
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Fatigue Fracture ◽  
Metallic Glasses ◽  
Shear Fracture ◽  
Fatigue Cracks ◽  
Stress Axis ◽  
Tensile Fracture ◽  
Fracture Plane ◽  
Shear Stresses

The tensile and fatigue fracture behavior of Zr59Cu20Al10Ni8Ti3 bulk metallic glass was investigated. It was found that under tensile load the metallic glass always displays brittle shear fracture and the shear fracture plane makes an angle of θT (=54°) with respect to the stress axis, which obviously deviates from the maximum shear stress plane (45°). Under cyclic tension-tension loading, fatigue cracks first initiate along the localized shear bands on the specimen surface, then propagate along a plane basically perpendicular to the stress axis. Tensile fracture surface observations reveal that fracture first originates from some cores, then propagates in a radiate mode, leading to the formation of a veinlike structure and final failure. The fatigue fracture processes of the specimens undergo a propagation stage of fatigue cracks followed by catastrophic failure. Based on these results, a tensile fracture criterion for bulk metallic glasses is proposed by taking the effect of normal stress into account. It is suggested that both normal and shear stresses affect the fracture process of metallic glasses and cause the deviation of the fracture angle away from 45°

The Cortisol Response to Normal and Nocturnal Awakening

2000 ◽  
Vol 14 (1) ◽  
pp. 24-28 ◽  
Author(s):  
F. Hucklebridge ◽  
A. Clow ◽  
H. Rahman ◽  
P. Evans
Keyword(s):  
Area Under The Curve ◽  
Secretory Activity ◽  
Linear Increase ◽  
Cortisol Response ◽  
The Awakening ◽  
Basal Cortisol ◽  
Free Cortisol ◽  
Main Effect ◽  
Nocturnal Awakening ◽  
Night Awakening

Abstract Free cortisol as measured in saliva increases markedly following awakening. It is not clear, however, whether this is truly a stress-neuroendocrine response to awakening or a manifestation of the hypothalamic-pituitary-adrenal (HPA) circadian cycle. We investigated whether the awakening cortisol response can be generated in the middle of nocturnal sleep, when secretory activity in the HPA axis is low. In a within subject design, salivary cortisol response was measured under three different awakening conditions: (1) awakening at the normal morning awakening time; (2) awakening four hours prior to normal awakening time, and (3) awakening the following morning after interrupted sleep. The overall main effect was a linear increase in free cortisol following awakening with no significant interaction with awakening condition. Cortisol levels, as determined by area under the cortisol curve calculated with reference to zero, did differ by awakening condition. The two morning awakening conditions were comparable but values were lower for night awakening. Area under the curve change (calculated with reference to the first awakening cortisol base value), however, did not distinguish the three awakening conditions. We conclude from these data that there is a clear free cortisol response to awakening for both nocturnal and morning awakening although the absolute levels produced are lower for nocturnal awakening when basal cortisol is low. Nocturnal interruption of sleep did not affect the subsequent morning response.

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