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Srdan Simunović

Publications and source records attributed to Srdan Simunović.

6 recordsLinked to original sources
PubMed2006

Crack surface roughness in three-dimensional random fuse networks.

Using large system sizes with extensive statistical sampling, we analyze the scaling properties of crack roughness and damage profiles in the three-dimensional random fuse model. The analysis of damage profiles indicates that damage accumulates in a diffusive manner up to the peak load, and localization sets in abruptly at the peak load, starting from a uniform damage landscape. The global crack width scales as W approximately L(0.5) and is consistent with the scaling of localization length xi approximately L(0.5) used in the data collapse of damage profiles in the postpeak regime. This consistency between the global crack roughness exponent and the postpeak damage profile localization length supports the idea that the postpeak damage profile is predominantly due to the localization produced by the catastrophic failure, which at the same time results in the formation of the final crack. Finally, the crack width distributions can be collapsed for different system sizes and follow a log-normal distribution.

Journal Article↗
PubMed2006

Crack-cluster distributions in the random fuse model.

Using large-scale numerical simulations and extensive sampling, we analyze the scaling properties of the crack-cluster distribution and the largest crack-cluster distribution at the peak load. The simulations are performed using both two-dimensional and three-dimensional random fuse models. The numerical results indicate that in contrast with the randomly diluted networks (percolation disorder), the crack-cluster distribution in the random fuse model at the peak load follows neither a power law nor an exponential distribution. The largest crack-cluster distribution at the peak load follows a lognormal distribution, and this is discussed in the context of whether there exists a relationship between the largest crack-cluster size distribution at peak load and the fracture strength distribution. Contrary to popular belief, we find that the fracture strength and the largest crack-cluster size at the peak load are uncorrelated. Indeed, quite often, the final spanning crack is formed not due to the propagation of the largest crack at the peak load, but instead due to coalescence of smaller cracks.

Journal Article↗
PubMed2005

Statistical physics models for nacre fracture simulation.

Natural biological materials such as nacre (or mother-of-pearl), exhibit phenomenal fracture strength and toughness properties despite the brittle nature of their constituents. For example, nacre's work of fracture is three orders of magnitude greater than that of a single crystal of its constituent mineral. This study investigates the fracture properties of nacre using a simple discrete lattice model based on continuous damage random thresholds fuse network. The discrete lattice topology of the proposed model is based on nacre's unique brick and mortar microarchitecture, and the mechanical behavior of each of the bonds in the discrete lattice model is governed by the characteristic modular damage evolution of the organic matrix that includes the mineral bridges between the aragonite platelets. The analysis indicates that the excellent fracture properties of nacre are a result of their unique microarchitecture, repeated unfolding of protein molecules (modular damage evolution) in the organic polymer, and the presence of fiber bundle of mineral bridges between the aragonite platelets. The numerical results obtained using this simple discrete lattice model are in excellent agreement with the previously obtained experimental results, such as nacre's stiffness, tensile strength, and work of fracture.

Animals↗
PubMed2005

Statistical properties of fracture in a random spring model.

Using large-scale numerical simulations, we analyze the statistical properties of fracture in the two-dimensional random spring model and compare it with its scalar counterpart: the random fuse model. We first consider the process of crack localization measuring the evolution of damage as the external load is raised. We find that, as in the fuse model, damage is initially uniform and localizes at peak load. Scaling laws for the damage density, fracture strength, and avalanche distributions follow with slight variations the behavior observed in the random fuse model. We thus conclude that scalar models provide a faithful representation of the fracture properties of disordered systems.

Journal Article↗
PubMed2005

Crack roughness and avalanche precursors in the random fuse model.

We analyze the scaling of the crack roughness and of avalanche precursors in the two-dimensional random fuse model by numerical simulations, employing large system sizes and extensive sample averaging. We find that the crack roughness exhibits anomalous scaling, as recently observed in experiments. The roughness exponents (zeta, zeta(loc) ) and the global width distributions are found to be universal with respect to the lattice geometry. Failure is preceded by avalanche precursors whose distribution follows a power law up to a cutoff size. While the characteristic avalanche size scales as s(0) approximately L(D) , with a universal fractal dimension D , the distribution exponent tau differs slightly for triangular and diamond lattices and, in both cases, it is larger than the mean-field (fiber bundle) value tau=5/2 .

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