Alex Hansen

Prof. Dr. Alex Hansen


Research Focus & Metrics

Academic Career Length

46Years (1981-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2010 in Reviews of Modern Physics
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Journal Article
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SPSrutarshi Pradhan
Srutarshi Pradhan
Alex HansenAlex Hansen
Alex Hansen
BCBikas K. Chakrabarti
Bikas K. Chakrabarti
The fiber bundle model describes a collection of elastic fibers under load. The fibers fail successively and, for each failure, the load distribution among the surviving fibers changes. Even though very simple, this model captures the essentials of failure processes in a large number of materials and settings. A review of the fiber bundle model is presented with different load redistribution mechanisms from the point of view of statistics and statistical physics rather than materials science, with a focus on concepts such as criticality, universality, and fluctuations. The fiber bundle model is discussed as a tool for understanding phenomena such as creep and fatigue and how it is used to describe the behavior of fiber-reinforced composites as well as modeling, e.g., network failure, traffic jams, and earthquake dynamics.

1 January 1989 in Physical Review B
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Journal Article
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HHHans J. Herrmann
Hans J. Herrmann
Alex HansenAlex Hansen
Alex Hansen
SRStephane Roux
Stephane Roux
We study via simulation how a lattice breaks if each bond is an elastic beam having longitudinal and flexural breaking thresholds randomly selected according to various probability distributions. We observe scaling of force, displacement, and number of broken beams in the controlled regime. The distribution of local forces just before breaking is characterized by a multifractal spectrum f(α).

13 January 1992 in Physical Review Letters
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KMKnut Jørgen Måløy
Knut Jørgen Måløy
Alex HansenAlex Hansen
Alex Hansen
EHEinar L. Hinrichsen
Einar L. Hinrichsen
SRStéphane Roux
Stéphane Roux
We record the height of the crack surface as a function of position along one-dimensional cuts orthogonal to the crack for six different brittle materials. We find that the width w of this one-dimensional trace as a function of its length L behaves as w∼Lζ, where ζ=0.87(7). This result is in agreement with recent conjectures of a universal roughness exponent ζ for these materials.

1 September 1998 in Physical Review E
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ISIngve Simonsen
Ingve Simonsen
Alex HansenAlex Hansen
Alex Hansen
ONOlav Magnar Nes
Olav Magnar Nes
We propose a method for (global) Hurst exponent determination based on wavelets. Using this method, we analyze synthetic data with predefined Hurst exponents, fracture surfaces, and data from economy. The results are compared to those obtained with Fourier spectral analysis. When many samples are available, the wavelet and Fourier methods are comparable in accuracy. However, when one or only a few samples are available, the wavelet method outperforms the Fourier method by a large margin.

1 December 1992 in Journal of Applied Mechanics
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PHPer C. Hemmer
Per C. Hemmer
Alex HansenAlex Hansen
Alex Hansen

14 August 2002 in Physical Review Letters
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Journal Article
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RMRafael Morgado
Rafael Morgado
FOFernando A. Oliveira
Fernando A. Oliveira
GBG. George Batrouni
G. George Batrouni
Alex HansenAlex Hansen
Alex Hansen
We present a simple criterion based on the Einstein relation for determining whether diffusion in systems governed by a generalized Langevin equation with long-range memory is normal, superdiffusive, or subdiffusive. We support our analysis with numerical simulations.