Numerical investigation of inhomogeneous stress state and fracture of ceramic materials under Brazilian test

2020 ◽  
Author(s):  
Valentina A. Mikushina
Keyword(s):  
Stress State ◽  
Numerical Investigation ◽  
Ceramic Materials ◽  
Brazilian Test

scholarly journals Performance Investigation of Tunnel Lining with Cavities around Surrounding Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-5 ◽  
Author(s):  
Jiajia Li ◽  
Yong Fang ◽  
Cheng Liu ◽  
Yongxing Zhang ◽  
Weihua Lu
Keyword(s):  
Stress State ◽  
Numerical Investigation ◽  
Tunnel Lining ◽  
Cavity Size ◽  
Cavity Depth ◽  
Tunnel Stability ◽  
Severe Effect ◽  
Single Cavity ◽  
Cavity Width

This paper presents a systematical numerical investigation into the lining performance of a tunnel with cavities around surrounding rocks, focusing on the influences of cavity size and multicavity distribution. The study demonstrates that the cavities around surrounding rocks have much influence on tunnel stability and may induce damages in tunnel structures, in which cavity width has a more severe effect on the stress state of tunnel structures than cavity depth. Moreover, the numerical investigation also illustrates that the nonadjacent distribution of multicavities has more serious influence on tunnel structures than that from adjacent distribution of multicavities as well as that from a single cavity.

Numerical investigation of the WC re-precipitation impact on the residual stress state in WC20 wt.-%Co hardmetal

2019 ◽  
Vol 84 ◽  
pp. 105003
Author(s):  
Wolfgang Kayser ◽  
Stanley van Kempen ◽  
Alexander Bezold ◽  
Mirko Boin ◽  
Robert Wimpory ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Numerical Investigation ◽  
Residual Stress State

Two-Parameter Parabolic Mohr Strength Criterion Applied to Analyze the Results of the Brazilian Test

2014 ◽  
Vol 624 ◽  
pp. 630-634 ◽  
Author(s):  
Qi Fan ◽  
Shuan Cheng Gu ◽  
Bo Nan Wang ◽  
Rong Bin Huang
Keyword(s):  
Tensile Strength ◽  
Stress State ◽  
Tensile Stress ◽  
Failure Modes ◽  
Strength Criterion ◽  
Complex Stress State ◽  
Brazilian Test ◽  
Practical Significance ◽  
Uniaxial Tensile ◽  
Two Parameter

Geotechnical engineering in tension damage is one of the major failure modes. For a long time, Brazil test has practical significance and wide application value that has been used to determine the tensile strength of rock. When the specimen center destroyed tensile stress play a major role that is the theoretical basis of Brazil test. This is uniaxial tensile stress state, but the reality is complex stress state. Theoretical analysis shows that the Brazilian test does not truly reflect the tensile strength of rock, its test results to error. In this paper, two-parameter parabolic Mohr strength criterion for this error analysis, and propose amendments to the formula.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

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