Microscale characterisation of damage evolution in curling stones used in international competition

2020 ◽  
Author(s):  
Derek Leung ◽  
Florian Fusseis ◽  
Ian Butler
Keyword(s):  
Damage Evolution ◽  
Rock Physics ◽  
International Competition ◽  
Bottom Surface ◽  
Fracture Characteristics ◽  
Initiation And Propagation ◽  
Fracture Development ◽  
Macroscopic Fracture ◽  
Quantitative Characterisation ◽  
Synchrotron Microtomography

<p>The rocks used to produce curling stones for international competition are only sourced from two localities in the world: Ailsa Craig, Scotland and Trefor, Wales. Curling stones consist of two components: (1) the running band (the ring-shaped bottom surface of the stone which rests on the ice) and (2) the striking band (the convex band on the profile of stones which collides with those of other stones). With a focus on the striking bands, we aim to document the damage evolution of curling stones using synchrotron microtomography (3D characterisation of pristine samples and 4D damage evolution), optical and scanning electron microscopy (quantitative characterisation of pristine samples and microfracture characterisation of damaged striking bands), and petrophysical testing (fracture characteristics and comparative data). These data will be complemented by an on-ice experiment that will determine the mechanics (e.g., stress distribution, contact area, and velocity) of curling stone impacts. Out of four curling stone varieties (from Ailsa Craig and Trefor), we observe the striking bands of three varieties to show macroscopic, incipient to mature, curvilinear fractures. The curvature of these fractures is consistent and does not vary significantly between individual stones and between curling stone varieties. However, the degree of macroscopic fracture development differs between aged striking bands of curling stone types: Blue Trefor (macroscopic fractures not observed), Red Trefor (weakly incipient), Ailsa Craig Common Green (incipient to juvenile), and Ailsa Craig Blue Hone (juvenile to mature). Unfortunately, it is not possible to determine the degree of usage (age) of the selected samples and thus it is not possible to normalize these apparent differences in damage. Given that the striking band limits the lifetime of curling stones, understanding the damage evolution of curling stones can contribute valuable information to the maintenance of curling stones. The rock physics of curling stone impacts is linked to dynamic spalling and more broadly to rock failure, as these processes are ultimately related to the initiation and propagation of fractures.</p>

Damage Evolution of the Interphase on C/SiC Composites with CZM Method

2012 ◽  
Vol 166-169 ◽  
pp. 2847-2850
Author(s):  
Yan Jun Chang ◽  
Zhuo Li ◽  
Ke Shi Zhang
Keyword(s):  
Residual Stress ◽  
Damage Evolution ◽  
Fem Analysis ◽  
Matrix Crack ◽  
Thermal Residual Stress ◽  
Analysis Model ◽  
Initial Matrix ◽  
Thermal Residual Stresses ◽  
Initiation And Propagation ◽  
Sic Composites

Considering thermal residual stress and initial matrix crack, the cylinder FEM analysis model for C/SiC tow was established. The cohesive element and damage criterions were introduced to simulation the initiation and propagation of interphase crack processes of C/SiC composites. The thermal residual stresses release with the initial matrix crack and the cracking on interphase. The interphase crack length was dominated by the performance of interphase. Analysis demonstrated that the CZM model can simulate well the thermal residual stress and the delamination of the interphase.

scholarly journals The Effect of Microstructural Change on Fracture Behavior in Heat-Affected Zone of API 5L X65 Pipeline Steel

2000 ◽  
Author(s):  
Jang-Bog Ju ◽  
Jae-il Jang ◽  
Woo-sik Kim ◽  
Dongil Kwon
Keyword(s):  
Fracture Behavior ◽  
Impact Test ◽  
Pipeline Steel ◽  
Microstructural Change ◽  
Fracture Characteristics ◽  
Welded Structures ◽  
The World ◽  
Natural Gas Transmission ◽  
Macroscopic Fracture ◽  
Girth Welds

Reliability evaluation of welded structures by mechanical testing of weld heat-affected zones (HAZs) has become general practice throughout the world. HAZs of steel welded joints show a gradient of microstructure from the fusion line to the unaffected base metal. This study is concerned with a correlation between the microstructural change and the fracture characteristics in HAZs of both seam and girth welds of API 5L X65 pipeline steel, which is generally used for natural gas transmission pipelines in Korea. The focus in present study was the investigation of macroscopic fracture behavior of the various regions within HAZ. Changes in microstructure and impact toughness were observed using synthetic HAZ specimens as well as actual HAZ specimens. To evaluate the macroscopic toughness of actual HAZ, Charpy V-notch impact test was performed.

A Reseach of Fracture Mechanism in Micro Cutting of 45 Steel Based on Material Properties

2013 ◽  
Vol 675 ◽  
pp. 370-373 ◽  
Author(s):  
Hong Jun Ding ◽  
Xi Bin Wang
Keyword(s):  
Material Properties ◽  
Fracture Process ◽  
Dislocation Theory ◽  
Film Sample ◽  
Fracture Characteristics ◽  
Micro Cutting ◽  
Transmission Electron ◽  
Initiation And Propagation ◽  
Cutting Model ◽  
Ductile Fracture Process

Abstract: Though the observation in micro cutting of 45 steel, the deformation zone of fracture characteristics was studied, and the corresponding cutting model was established; on dynamic tensile and situ observation of 45 steel by transmission electron microscopy , micro cutting ductile fracture process is simulated by the experiment on the steel tensile of 45 film sample, and the mechanism on initiation and propagation of crack in micro cutting fracture was studied with dislocation theory.

Gross Crack Initiation and Propagation in Brittle Thin Solid and Annular Disks Subjected to Impact Loading

1984 ◽  
Vol 106 (2) ◽  
pp. 167-172 ◽  
Author(s):  
W. Johnson ◽  
Y. L. Bai ◽  
S. K. Ghosh
Keyword(s):  
Impact Fracture ◽  
Rigid Base ◽  
Grinding Wheel ◽  
Crack Initiation And Propagation ◽  
Fracture Characteristics ◽  
Fracture Patterns ◽  
Initiation And Propagation ◽  
The Impact ◽  
Annular Disks ◽  
Circular Disks

This paper derives from a study of grinding wheel break-up behavior due to impact. The impact fracture characteristics of circular disks of plaster of Paris with a concentric central hole were studied experimentally [1] for three types of loading: (a) when the disks were suspended freely and loaded intensely at one point on their circumference by an explosive detonator; (b) when the disks were allowed to fall under gravity from a certain height on to a rigid base; and (c) when a disk, resting on a rigid base, was struck by a flat ended rigid body which was dropped on to it from a certain height. Quasi-static flattening tests on the disks were also carried out. The paper describes a theoretical investigation into the stress analysis of disks under impact, classifies the relevant damage sustained by them and attempts to unify the “gross” impact fracture patterns which arise in different modes of dynamic loading. The extent of local flattening of the quasi-statically loaded disks before fracture, is also reported. Good correlation between the theory and experimental results is obtained, especially for rings of diameter ratio (Di/D0) of around 0.5.

Crack Investigation of the Multilayer TiN/Ti Coatings during the Nanoindentation Test

2012 ◽  
Vol 504-506 ◽  
pp. 1293-1298
Author(s):  
Konrad Perzynski ◽  
Łukasz Madej
Keyword(s):  
Mechanical Properties ◽  
Fracture Initiation ◽  
Element Model ◽  
Columnar Structure ◽  
Nanoindentation Test ◽  
Deposition Method ◽  
Extended Finite Element ◽  
Laboratory Equipment ◽  
Initiation And Propagation ◽  
Fracture Development

Nanoindentation test is one of the most commonly used methods for the strength investigation of the nanomaterials. Information provided from such test gives the possibility to obtain a knowledge about fracture development under the spot hitting tool. However, nano dimensions of the coatings obtained by the deposition method creates problems with exact investigation of this test. Costs of experimental study are very often excessive due to very specialized laboratory equipment. The numerical simulations can be a support for mentioned experimental research as they give possibility of fast and efficient investigation on behavior of different nanolayers dimensions and alignments. The main aim of this work is focused on taking into account real morphology of microstructure of ceramic TiN layers deposited on the metallic Ti layers during nanoindentation test. This combination of layers is widely used in medicine for improvement mechanical properties and biocompatibility behavior of bio elements. Particular attention during numerical simulation is put on influence of columnar structure of these layers on fracture development. Results obtained from the extended finite element model (XFEM) for various nanolayers alignments is discussed according to the fracture initiation and propagation.

Residual Life Assessment of Steam Generators With Alloy 600TT Tubing: Methods and Application

2009 ◽  
Author(s):  
Ian de Curieres ◽  
Marie-Christine Meunier ◽  
Pierre Joly
Keyword(s):  
Probabilistic Model ◽  
Damage Evolution ◽  
Residual Life ◽  
Tube Bundle ◽  
Life Assessment ◽  
Steam Generators ◽  
Initiation And Propagation ◽  
Residual Life Assessment ◽  
Inspection Data ◽  
Propagation Stage

The aim of the paper is to introduce methods to estimate the residual life of steam generators with alloy 600TT (thermally treated) tubing, taking into account PWSCC as the main contributor damage. The methods take into account both initiation and propagation of PWSCC cracks in the expansion transition zone of SG tubes, as well as the state of damage (cracking and plugging) of the tube bundle, at a given time, known from inspection results. A probabilistic model is used to treat initiation, while propagation stage is treated in a deterministic way based on inspection data. After introducing the methods used to assess the residual life, a brief parametric study will be shown, to illustrate the effects of initiation versus propagation. Eventually, the cases of a few actual steam generators with tubing made of alloy 600TT, showing different situations of present damage and damage evolution rates will be presented.

scholarly journals Fracture Characteristics and Damage Evolution of Coating Systems Under Four-Point Bending

2016 ◽  
Vol 13 (6) ◽  
pp. 1043-1052 ◽  
Author(s):  
Haiyan Liu ◽  
Lihong Liang ◽  
Yingbiao Wang ◽  
Yueguang Wei
Keyword(s):  
Damage Evolution ◽  
Fracture Characteristics ◽  
Four Point Bending

scholarly journals CO2-Driven Hydraulic Fracturing Trajectories across a Preexisting Fracture

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qi Zhang ◽  
Jiehao Wang ◽  
Yufeng Gao ◽  
Shengfei Cao ◽  
Jingli Xie ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Damage Evolution ◽  
Stress Ratio ◽  
Bedding Plane ◽  
Hydraulic Fractures ◽  
The Finite Element Method ◽  
Bedding Planes ◽  
Initiation And Propagation ◽  
Gas Seepage ◽  
Simulation Results

Defining the trajectory of hydraulic fractures crossing bedding planes and other fractures is a significant issue in determining the effectiveness of the stimulation. In this work, a damage evolution law is used to describe the initiation and propagation of the fracture. The model couples rock deformation and gas seepage using the finite element method and is validated against classical theoretical analysis. The simulation results define four basic intersection scenarios between the fluid-driven and preexisting fractures: (a) inserting—the hydraulic fracture inserts into a bedding plane and continues to propagate along it; (b) L-shaped crossing—the hydraulic fracture approaches the fracture/bedding plane then branches into the plane without crossing it; (c) T-shaped crossing—the hydraulic fracture approaches the fracture/bedding plane, branches into it, and crosses through it; (d) direct crossing—the hydraulic fracture crosses one or more bedding planes without branching into them. The intersection scenario changes from (a) → (b) → (c) → (d) in specimens with horizontal bedding planes when the stress ratio β ( β = σ y / σ x ) increases from 0.2 to 5. Similarly, the intersection type changes from (d) → (c) → (a) with an increase in the bedding plane angle α (0° → 90°). Stiffness of the bedding planes also exerts a significant influence on the propagation of hydraulic fractures. As the stiffness ratio E 1 ¯ / E 2 ¯ increases from 0.1 to 0.4 and 0.8, the seepage area decreases from 22.2% to 41.8%, and the intersection type changes from a T-shaped crossing to a direct crossing.

scholarly journals Influence of Three-Dimensional Stress Field Variation on Fracture Evolution Characteristics of a Roof

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xuyang Shi ◽  
Zhaolin Li ◽  
Qingxiang Cai ◽  
Wei Zhou ◽  
Wenshuai Li
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Principal Stress ◽  
Three Dimensional ◽  
Surrounding Rock ◽  
Fracture Characteristics ◽  
Principal Stress Direction ◽  
True Triaxial ◽  
Fracture Evolution ◽  
Macroscopic Fracture

Excavation disturbance on the dynamic variation of the three-dimensional stress field is the main cause for the dynamic disasters of the surrounding rock mass of the roof. The stress condition in the surrounding rock mass of the roof during entry excavation and its impact on entry stability are systemically studied in this study. It is found that the surrounding rock mass of the roof is mainly influenced by the combined effect of the stress unloading and stress transference induced by entry excavation. A servo-controlled true triaxial material testing system is used to conduct the true triaxial loading and unloading experiments of rocks under different stress paths. The influence of different stress paths, especially the variation of the principal stress direction, on the mechanical characteristics and fracture characteristics of rocks is investigated. The results indicate that the variation of the principal stress direction has a significant impact on the macroscopic fracture characteristics of the rock. The main macroscopic fracture plane of the rock highly depends on the intermediate principal stress. The fracture evolution of the roof rock mass during entry excavation is analyzed. The results show that the change of the three-dimensional stress field induces the formation of complex fracture networks in the surrounding rock mass of the roof. The roof is likely to dislocate horizontally and collapse. The corners of the entry are seriously damaged. Based on the above findings, a support scheme is proposed to maintain the stability of a gob-side entry. The field experience suggests that the support scheme can achieve good results.

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