Heterogeneity, spatial correlations, size effects and dissipated energy in brittle materials

1994 ◽  
Vol 18 (2) ◽  
pp. 103-118 ◽  
Author(s):  
H. Dai ◽  
G. Frantziskonis
Keyword(s):  
Size Effects ◽  
Brittle Materials ◽  
Dissipated Energy ◽  
Spatial Correlations

On the Possibly Multifractal Properties of Dissipated Energy in Brittle Materials

1994 ◽  
Vol 47 (1S) ◽  
pp. S132-S140 ◽  
Author(s):  
G. Frantziskonis
Keyword(s):  
Crack Propagation ◽  
Pure Shear ◽  
Brittle Materials ◽  
Dissipated Energy ◽  
Dynamic Crack Propagation ◽  
Dynamic Crack ◽  
Spatial Correlations ◽  
Micro Deformation ◽  
The One ◽  
Scaling Fields

The paper reports an analytical study on the properties of fracture networks in brittle materials. Micro-deformation gradients are considered random fields and/or scaling fields. Under dynamic crack propagation conditions the possibly fractal properties of the (macro) crack pattern are governed by the interplay of fluctuations and spatial correlations. For “slow” crack propagation they are governed by the kinematic fields in the vicinity of crack or notch tips. The spatial distribution of dissipated energy, due to fracture, is evaluated. It is shown that there is a strong possibility that the dissipated energy is multifractal. Here, its properties are characterized in a fashion similar to the so-called p-model where p herein denotes normalized dissipated energy. For the three cases analyzed - uniaxial tension, pure shear, and dilatation - the dissipated energy under pure shear shows the strongest disorder, the one under dilatation the weakest, and the tension case is always between these two.

scholarly journals Modelling size effects for static strength of brittle materials

2020 ◽  
Vol 195 ◽  
pp. 109052
Author(s):  
A.P. Pagnoncelli ◽  
A. Tridello ◽  
D.S. Paolino
Keyword(s):  
Size Effects ◽  
Brittle Materials ◽  
Static Strength

Indentation Size Effects in Ductile and Brittle Materials

2013 ◽  
Vol 586 ◽  
pp. 51-54
Author(s):  
Jaroslav Menčík ◽  
Martin Elstner
Keyword(s):  
Size Effect ◽  
Size Effects ◽  
Indentation Size Effect ◽  
Brittle Materials ◽  
Indentation Hardness ◽  
Indentation Size ◽  
Homogeneous Materials

Indentation hardness of homogeneous materials should be constant. However, at very small depths, the apparent hardness often increases with decreasing imprint size. The paper discusses various cases of this indentation size effect in metals and ceramics and explains the extrinsic and intrinsic reasons.

Statistical Size Effects on Compressive Strength and Mechanical Behavior of Concrete

2017 ◽  
Vol 754 ◽  
pp. 317-320 ◽  
Author(s):  
Chi Cong Vu ◽  
Jérôme Weiss ◽  
Olivier Plé ◽  
David Amitrano
Keyword(s):  
Compressive Strength ◽  
Size Effects ◽  
Aggregate Size ◽  
Dissipated Energy ◽  
Compression Tests ◽  
Weakest Link ◽  
Link Theory ◽  
Long Time ◽  
Compressive Strength Of Concrete ◽  
Main Shortcoming

The size effect on strength of concrete has been studied for a long time from various approaches. In particular, the weakest-link theory remains nowadays the basic tool to interpret statistical size effects, i.e. how the probability of failure under a given stress depends on external size. The main shortcoming of Weibull’s theory is that the activation of fracture from the weakest flaw is assumed to set the final strength, i.e. possible interactions between microcracks and defects during progressive damage are implicitly neglected. The objective of this study is to determine experimentally the influence of “external” (sample) size and “internal” (microstructural) size on compressive strength of concrete. For this purpose, more than 250 uniaxial compression tests were conducted on concrete specimens with two different cylindrical sizes (110×220 mm and 160×320 mm) and prepared from three different compositions (mean aggregate size and proportion). The relationships between compressive strength, dissipated energy up to failure in one hand, and microstructural as well as specimen sizes on the other hand, were analyzed statistically. This demonstrated the failure of the weakest-link approach to describe size effects on compressive strength of concrete.

scholarly journals Patterns and Long Range Correlations in Idealized Granular Flows

1997 ◽  
Vol 08 (04) ◽  
pp. 953-965 ◽  
Author(s):  
J. A. G. Orza ◽  
R. Brito ◽  
T. P. C. van Noije ◽  
M. H. Ernst
Keyword(s):  
Long Range ◽  
Size Effects ◽  
Hard Spheres ◽  
Finite Size ◽  
System Size ◽  
Spatial Correlations ◽  
Finite Size Effects ◽  
Long Range Correlations ◽  
Intrinsic Length ◽  
Dynamics Simulations

An initially homogeneous freely evolving fluid of inelastic hard spheres develops inhomogeneities in the flow field u(r, t) (vortices) and in the density field n (r, t)(clusters), driven by unstable fluctuations, δa = {δn, δu}. Their spatial correlations, <δa(r, t)δa(r′,t)>, as measured in molecular dynamics simulations, exhibit long range correlations; the mean vortex diameter grows as [Formula: see text]; there occur transitions to macroscopic shearing states, etc. The Cahn–Hilliard theory of spinodal decomposition offers a qualitative understanding and quantitative estimates of the observed phenomena. When intrinsic length scales are of the order of the system size, effects of physical boundaries and periodic boundaries (finite size effects in simulations) are important.

Sign in / Sign up

Export Citation Format

Share Document