The Fracture Characteristic of Mode III Rock Crack under Different Temperature

2014 ◽  
Vol 891-892 ◽  
pp. 884-888
Author(s):  
Li Yun Li ◽  
Tie Wu Tang ◽  
Zhi Qiang Xu ◽  
Wen Bin Liu ◽  
Guo Yane Zhou
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Disaster Prevention ◽  
Mode Iii ◽  
Underground Engineering ◽  
Different Temperatures ◽  
Deep Underground ◽  
Rock Specimens ◽  
Initiation Stress

A series of torsion tests under different temperature were carried out with circumferential notched cylindrical rock specimens. By this kind of specimens, mode III rock crack propagation in real meaning was realized. The initiation torsion M of the mode III rock crack was measured under different temperature. The variation law of M v.s. temperature T was obtained. The initiation stress near crack tip under different temperatures was calculated by finite element method, and then, the mode III fracture toughness KIIIC of the rock was obtained by further calculation. The experiment and numerical results show that the mode III fracture toughness of the rock decreases with the temperature increase. The results of the paper can be used in the design of deep underground engineering ,disaster prevention and mitigation engineering.

A Study of Rock Crack Fracture under Different Temperatures

2013 ◽  
Vol 577-578 ◽  
pp. 185-188
Author(s):  
Li Yun Li ◽  
Ming Xiu Li ◽  
Zhi Qiang Xu ◽  
Chen Fan ◽  
Da An Liu
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Mixed Mode Fracture ◽  
Underground Engineering ◽  
Mode Fracture ◽  
Three Point Bending ◽  
Critical Fracture ◽  
Relative Stress ◽  
Different Temperatures ◽  
Deep Underground

A series of critical fracture toughness of two kinds of rock materials under different temperature which varied from-50°C to 240°C are measured by I-II-III mixed mode fracture experiments adopting atypical three point bending specimens. Relative stress intensity factors of crack initiation are calculated by finite element method. Combining with calculated values, the experiment results show that, the mixed mode fracture toughness of the rocks decreases with the increase of temperature. The experimental and calculated results can be used in the design of deep underground engineering or disaster prevention and mitigation engineering.

Finite Element Analysis of the Stress on Cylinder of the Fluidized Bed Reactor for Fast Pyrolysis

2011 ◽  
Vol 201-203 ◽  
pp. 660-663
Author(s):  
Qing Ruo Xie ◽  
Yi Sun ◽  
Li Wen Zheng ◽  
Hu Qi Wang ◽  
Zhang Fa Tong
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fluidized Bed ◽  
Safety Assessment ◽  
Scale Up ◽  
Fast Pyrolysis ◽  
Fluidized Bed Reactor ◽  
Element Analysis ◽  
Ansys Analysis ◽  
Different Temperatures

A new experimental fluidized bed reactor was investigated and designed which has been widely utilized for fast pyrolysis under different temperatures (T=727–973 K).The stresses of the reactor cylinder are analyzed using finite element method(FEM, ANSYS Inc., U.S.A ) based on the safety assessment, and the cylinder is designed for installing scheme. The result of ANSYS analysis shows that the stress unstable positions are nearby both ends of the cylinder. The results of analysis are shown that the designing stresses are not beyond the allow able ones. So the designing parameters can possess sufficient reliability, and the design scheme can completely satisfy the strength requirement. Certainty of the stress could offered the valuable instruction for the application of the equipment on industrial scale-up.

scholarly journals Prediction of Characteristic Length and Fracture Toughness in Ductile-Brittle Transition

2008 ◽  
Author(s):  
Z. X. Wang ◽  
H. M. Li ◽  
Y. J. Chao ◽  
P. S. Lam
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Characteristic Length ◽  
Crack Tip ◽  
Critical Distance ◽  
Transition Regime ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Element Method

Finite element method was used to analyze the three-point bend experimental data of A533B-1 pressure vessel steel obtained by Sherry, Lidbury, and Beardsmore [1] from −160 to −45 °C within the ductile-brittle transition regime. As many researchers have shown, the failure stress (σf) of the material could be approximated as a constant. The characteristic length, or the critical distance (rc) from the crack tip, at which σf is reached, is shown to be temperature dependent based on the crack tip stress field calculated by the finite element method. With the J-A2 two-parameter constraint theory in fracture mechanics, the fracture toughness (JC or KJC) can be expressed as a function of the constraint level (A2) and the critical distance rc. This relationship is used to predict the fracture toughness of A533B-1 in the ductile-brittle transition regime with a constant σf and a set of temperature-dependent rc. It can be shown that the prediction agrees well with the test data for wide range of constraint levels from shallow cracks (a/W = 0.075) to deep cracks (a/W = 0.5), where a is the crack length and W is the specimen width.

Modification of Pre-Cracked Charpy Specimens for Surveillance Specimen Programs

2009 ◽  
Author(s):  
Boris Margolin ◽  
Vladimir Nikolaev ◽  
Valentin Fomenko ◽  
Lev Ryadkov
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Brittle Fracture ◽  
Stress And Strain ◽  
Test Results ◽  
Deep Side ◽  
Strain Fields ◽  
Calculation Analysis

Application of pre-cracked Charpy specimens with various depth of side-grooves is considered for fracture toughness prediction. Recommendations for prediction of temperature dependence of fracture toughness are given when using small-sized specimens with deep side-grooves. Test results of about 500 specimens, cut from materials with various degrees of embrittlement are presented. On the basis of 3D calculations by finite element method the procedure used in standard ASTM E 1921 for calculation of Ke and J, is developed for bending specimens with deep side-grooves. An attempt is undertaken to explain the obtained experimental data from the standpoints of the available criteria of brittle fracture based on calculation analysis of stress and strain fields (SSF) of SE(B)-10 specimens with various depths of side-grooves.

Analysis of Mode III Elastodynamic Cracked Plane using the Fractal Two-Level Finite Element Method

2010 ◽  
Author(s):  
J. Fan ◽  
Y. Y. Lee ◽  
A. Y. T. Leung ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mode Iii ◽  
Element Method

scholarly journals ANALYSIS OF CRACKS AT THE TORSION VALLARS CAUSED WITHOUT LOADING

2021 ◽  
Vol 07 (03) ◽  
pp. 72-79
Author(s):  
Tehran Mammadli Tehran Mammadli
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fracture Criterion ◽  
Fatigue Cracks ◽  
Tracked Vehicles ◽  
Element Method

Nowadays, the hull suspension systems that use torsion shafts as elastic suspension elements are fitted to the majority of modern tracked vehicles. The main type of failure in such systems is the fracture of the torsion shafts due to the formation of fatigue cracks, which leads to failure of the suspension assemblies. This work presents an analysis of fracture toughness of torsion shafts of a standard tracked chassis used to develop a family of multipurpose transport vehicles GT-TM, GT-TMS, etc. The analysis is carried out under an operating load level for a crack located on the cylindrical part of the torsion shaft, the plane of which is at an angle to the torsion shaft axis and coincides with the position of the main areas of the stress state. The calculation of fracture toughness is based on Irwin fracture criterion. The calculations of the maximum stress intensity factor along the crack front are performed using the finite element method in the ANSYS software package. The results of the analysis of fracture toughness are presented in the form of dependences of the critical depth of the crack on the ratio of the fracture half-length to its depth. The data obtained can be used to determine the residual life of torsion shafts of the tracked vehicles based on the chassis under consideration. Keywords: suspension system, fracture toughness of torsion shafts, edge crack, stress intensity factor, finite element method, Irwin fracture criterion.

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