Effect of test method and crack size on the fracture toughness of a chain-silicate glass-ceramic

1986 ◽  
Vol 21 (7) ◽  
pp. 2365-2372 ◽  
Author(s):  
G. H. Beall ◽  
K. Chyung ◽  
R. L. Stewart ◽  
K. Y. Donaldson ◽  
H. L. Lee ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicate Glass ◽  
Glass Ceramic ◽  
Crack Size ◽  
Test Method ◽  
Chain Silicate ◽  
A Chain

Effect of Crystallization on Thermal Shock Behavior of a Chain-Silicate Canasite Glass-Ceramic

1987 ◽  
Vol 70 (1) ◽  
pp. C-2-C-3 ◽  
Author(s):  
Masaomi Oguma ◽  
Kenneth Chyung ◽  
Kimberly Yates Donaldson ◽  
D. P. H. Hasselman
Keyword(s):  
Thermal Shock ◽  
Glass Ceramic ◽  
Chain Silicate ◽  
A Chain ◽  
Thermal Shock Behavior

scholarly journals Dynamic Fracture Toughness and Dynamic Tensile Strength of the Rock from Different Depths of Beijing Datai Well

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ke Man ◽  
Xiaoli Liu
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Dynamic Fracture ◽  
Empirical Relation ◽  
Dynamic Fracture Toughness ◽  
Rock Failure ◽  
Test Method ◽  
Strength Increase ◽  
Dynamic Tensile Strength ◽  
Different Depths

From the standard test method suggested by ISRM and GB/T50266-2013, the uniaxial static tensile strength, dynamic tensile strength, and dynamic fracture toughness of the same basalt at different depths have been measured, respectively. It is observed that there may be an empirical relation between dynamic fracture toughness and dynamic tensile strength. The testing data show that both the dynamic fracture toughness and dynamic tensile strength increase with the loading rate and the dynamic tensile strength increases a little bit more quickly than the dynamic fracture toughness. With an increasing depth, the dynamic tensile strength has much more influence on the dynamic fracture toughness, as which it is much liable to bring out the unexpected catastrophes in the engineering projects, especially during the excavation at deep mining. From the rock failure mechanisms, it is pointed out that the essential reason of the rock failure is the microcrack unstable propagation. The crack processes growth, propagation, and coalescence are induced by tensile stress, not shear stress or compressive stress. The paper provides estimation of the dynamic fracture toughness from the dynamic tensile strength value, which can be measured more easily.

A Weibull Stress Approach Incorporating the Coupling Effect of Constraint and Plastic Strain in Cleavage Fracture Toughness Predictions

2014 ◽  
Author(s):  
Claudio Ruggieri ◽  
Robert H. Dodds
Keyword(s):  
Fracture Toughness ◽  
Plastic Strain ◽  
Cleavage Fracture ◽  
Coupling Effect ◽  
Crack Size ◽  
Parameter Analysis ◽  
Pressure Vessel Steel ◽  
Fracture Parameter ◽  
Vessel Steel ◽  
Weibull Stress

This work describes a micromechanics methodology based upon a local failure criterion incorporating the strong effects of plastic strain on cleavage fracture coupled with statistics of microcracks. A central objective is to gain some understanding on the role of plastic strain on cleavage fracture by means of a probabilistic fracture parameter and how it contributes to the cleavage failure probability. A parameter analysis is conducted to assess the general effects of plastic strain on fracture toughness correlations for conventional SE(B) specimens with varying crack size over specimen width ratios. Another objetive is to evaluate the effectiveness of the modified Weibull stress (σ̃w) model to correct effects of constraint loss in PCVN specimens which serve to determine the indexing temperature, T0, based on the Master Curve methodology. Fracture toughness testing conducted on an A285 Grade C pressure vessel steel provides the cleavage fracture resistance (Jc) data needed to estimate T0. Very detailed non-linear finite element analyses for 3-D models of plane-sided SE(B) and PCVN specimens provide the evolution of near-tip stress field with increased macroscopic load (in terms of the J-integral) to define the relationship between σ̃w and J. For the tested material, the Weibull stress methodology yields estimates for the reference temperature, T0, from small fracture specimens which are in good agreement with the corresponding estimates derived from testing of much larger crack configurations.

Face/core mixed mode debond fracture toughness characterization using the modified TSD test method

2013 ◽  
Vol 48 (16) ◽  
pp. 1939-1945 ◽  
Author(s):  
Christian Berggreen ◽  
Amilcar Quispitupa ◽  
Andrei Costache ◽  
Leif A Carlsson
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Test Method

On the Interaction Between Indentation Cracks on Metallized Silicon

1998 ◽  
Vol 516 ◽  
Author(s):  
M. Manoharan ◽  
G. Muralidharan
Keyword(s):  
Thin Film ◽  
Fracture Toughness ◽  
Bulk Material ◽  
Small Sample Size ◽  
Industrial Process ◽  
Crack Size ◽  
Small Sample ◽  
Residual Stress Field ◽  
Metallization Layer ◽  
Free Material

AbstractThe metallization of Si represents a important industrial process and produces a bi-layered composite of a ductile metal film on a brittle substrate. The mechanical properties of such a composite are determined by the properties of the two layers and the interface and influenced by the fact that the metallized layer, being a very thin film, possesses properties different from those of a bulk material. The fracture toughness is also influenced by the nature and distribution of defects which may be generated during use of these materials, even if the manufacturing process produces a reasonably defect free material. Indentation cracking has been extensively used for the measurement of fracture toughness due to its small sample size requirements as well as a relatively good correlation with values obtained from traditional fracture mechanics tests. The indentation process, with its associated cracks, produces permanent plastic deformation and also introduces a residual stress field. This field influences the crack pattern generated in an adjacent indent and can be used as a methodology to model the influence of multiple defect sources.The present study was aimed at understanding the effect of a thin Ti alloy metallization layer sputtered on a Si wafer on the sizes of the cracks associated with the indents. It was also aimed at studying the interaction between cracks emanating from sequentially placed indentations. The distance between the indents which generated these cracks was varied from a level comparable to the crack size to a level where interaction could be ignored. This paper discusses the changes in the nature as well as the sizes of cracks due to the presence of the metallization layer as well as the interaction between the stress fields of the indents in this ductile thin film – brittle substrate composite and possible methodologies for delineating these effects.

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