Avalanches in wood compression

TL;DR

This study investigates avalanche phenomena in compressed wood samples, revealing scale-free crackling noise similar to earthquakes, with localization of deformation but consistent power-law distributions across scales.

Contribution

It demonstrates that wood exhibits avalanche behavior with scale-free distributions despite structural localization effects, linking wood mechanics to broader crackling noise phenomena.

Findings

Avalanche events follow power-law distributions.

Deformation localizes to weak softwood layers.

Crackling noise in wood resembles earthquakes.

Abstract

Wood is a multi-scale material exhibiting a complex viscoplastic response. We study avalanches in small wood samples in compression. "Woodquakes" measured by acoustic emission are surprisingly similar to earthquakes and crackling noise in rocks and laboratory tests on brittle materials. Both the distributions of event energies and of waiting (silent) times follow power-laws. The stress- strain response exhibits clear signatures of localization of deformation to "weak spots" or softwood layers, as identified using Digital Image Correlation. Even though material structure-dependent localization takes place, the avalanche behavior remains scale-free.