Premature failure mechanism of the cemented carbide blade in drilling Wansheng-limestone with water jet

2015 ◽  
Vol 51 (4) ◽  
pp. 321
Author(s):  
Xiaofeng Yang ◽  
Hongwei Zhou ◽  
Yong Kang ◽  
Re Xia
Keyword(s):  
Failure Mechanism ◽  
Water Jet ◽  
Cemented Carbide ◽  
Premature Failure

Mechanism Analysis of Jet Drilling Rock by Numerical Simulation and Experiment

2012 ◽  
Vol 455-456 ◽  
pp. 400-405 ◽  
Author(s):  
Hua Lin Liao
Keyword(s):  
Failure Mechanism ◽  
Control Volume ◽  
Jet Impingement ◽  
Rock Failure ◽  
Water Jet ◽  
Rock Damage ◽  
Mechanism Analysis ◽  
Jet Impact ◽  
Breaking Mechanism ◽  
Pressure Water

Rock damage and breaking mechanism with water jet has been as yet a difficult problem due to jet high turbulence and complicacy of rock material. According to fluid-structure interaction (FSI) theory, the standard k-epsilon two equations and control volume method for water jet, and the elastic orthotropic continuum and finite element method for rocks, are employed respectively to establish a numerical analyzing model of high pressure water jet impinging on rock. A damage criterion, with non-dimensional coefficient to characterize rock damage, is also set up for analyzing rock failure mechanism with water jet. The process of jet impact on the rock is simulated, by using the FSI model, Micro failure mechanism test and analysis with scanning electron microscope (SEM) for rock failure surface by jets cutting were performed, whose results show that the micro-mechanism of rock failure due to water jet impingement is a brittle fracture in the condition of tensile and shearing stress. The test results also agree well with the numerical simulating analysis, which constructs a bridge between the micro-failure and macro-breaking mechanism of rock with water jets impact. The investigation affords a new method for studying the mechanism of rock failure underhigh pressure water jet impingement.

The effects of inclined particle water jet on rock failure mechanism: Experimental and numerical study

2020 ◽  
Vol 185 ◽  
pp. 106639 ◽  
Author(s):  
Lei Li ◽  
Fangxiang Wang ◽  
Tianyang Li ◽  
Xiaodong Dai ◽  
Xueyang Xing ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Numerical Study ◽  
Rock Failure ◽  
Water Jet

Analysis of Premature Rip-Off Failure Mechanism of Reinforced Concrete Beams Strengthened with FRPs

2006 ◽  
Vol 324-325 ◽  
pp. 1325-1328
Author(s):  
Cheol Woo Park ◽  
Jong Sung Sim ◽  
Sung Jae Park
Keyword(s):  
Reinforced Concrete ◽  
Failure Mechanism ◽  
Failure Load ◽  
Reinforced Concrete Beams ◽  
Shear Stresses ◽  
Strengthening Effect ◽  
Rc Beams ◽  
Premature Failure ◽  
Cfrp Plate ◽  
Proposed Model

Various types and forms of FRP materials have been applied for structural strengthening of reinforced concrete (RC) beams. When CFRP plates are used, however, a premature failure used to occur before strengthening effect appears adequately. This is primarily due to the rip-off of CFRP plate attached on RC beams. Despite of numerous studies on the rip-off failure of externally strengthened RC beams, the failure mechanism is not clearly explained yet. Investigations from the literatures have shown that the rip-off failure is dependant on vertical and shear stresses at the level of main reinforcements in RC beams. This study suggests an analytical model to investigate the ripoff failure load based on the stresses at the level of main reinforcements. The proposed model is relatively simple and produces very comparable results to the test data. Therefore, it is anticipated that the proposed model can be successfully used to provide further information on the rip-off failure mechanisms and its prevention.

Failure of Cemented Carbide Tools When Executing Intermittent Cuts

1979 ◽  
Vol 101 (4) ◽  
pp. 391-396 ◽  
Author(s):  
S. M. Bhatia ◽  
P. C. Pandey ◽  
H. S. Shan
Keyword(s):  
Experimental Results ◽  
Cemented Carbide ◽  
Operating Speed ◽  
Tool Failure ◽  
Premature Failure ◽  
Operating Range ◽  
Tool Edge ◽  
Cemented Carbide Tools ◽  
Safe Operating ◽  
Intermittent Cutting

Premature failure of the cutting edge is a major problem associated with the application of cemented carbide tools in intermittent cutting operations. In such cases, unlike in continuous cutting, the tool edge fails due to fracture, well before the permissible limit of wear is approached. This paper reports some of the findings pertaining to the behavior of cemented carbide tools when used in interrupted cuts on a lathe. Based on the type of tool failure observed, the operating speed and feed range has been divided into four regions and the mode of tool failure in each region has been discussed. From the experimental results obtained, it is possible to specify a safe operating range for cemented carbide tools when executing intermittent cuts.

scholarly journals Corrosion Behavior and Failure Mechanism of Prestressed Rock Bolts (Cables) in the Underground Coal Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qiong Wang ◽  
Fengnian Wang ◽  
Aiwu Ren ◽  
Rui Peng ◽  
Jian Li
Keyword(s):  
Failure Mechanism ◽  
Corrosion Behavior ◽  
Coal Mine ◽  
Pitting Corrosion ◽  
Service Time ◽  
Outer Diameter ◽  
Uniform Corrosion ◽  
Rock Bolts ◽  
Premature Failure ◽  
Underground Coal Mine

Premature failure of rock bolts (cables) due to stress corrosion cracking (SCC) is a phenomenon that has been reported to occur in the underground environment. In the 1990s, many failure accidents of bolts which occurred in the United Kingdom were caused by SCC [1]. In this study, the corrosion behavior and failure mechanism of rock bolt (cable) samples obtained from the underground coal mine were examined and discussed. Macroscopic observation and weight loss tests were carried out for the bolts’ corrosion characteristics without failure. The results show that the bolts with short service time (1.5–2 yrs) underwent uniform corrosion. However, bolts with longer service time (3–8 yrs) experienced different pitting corrosion degrees. The corroding degree of different parts of bolt samples shows the following decreasing trend: bolt head > bolt end > free section. The absolute corrosion degree increased with the service time, while the corrosion rate was the highest in the early stage and dropped down in the later stage. At the same time, the macro- and micromethods were used to analyse the failure mechanism in the broken cable sample. Failure of one cable sample with a medium service life (6 yrs) was found to be controlled by the SCC. It was induced by long-term action of O, Cl, and S in the surrounding rock environment and resulted in pitting corrosion. The pitting corrosion reduced the outer diameter of the rock cable and its bearing capacity, leading to the final fracture.

Sign in / Sign up

Export Citation Format

Share Document