Fracture behaviour of wood and its composites. A review COST Action E35 2004–2008: Wood machining – micromechanics and fracture

Abstract

Fracturing of wood and its composites is a process influenced by many parameters, on the one hand coming from the structure and properties of wood itself, and on the other from influences from outside, such as loading mode, velocity of deformation, moisture, temperature, etc. Both types of parameters may be investigated experimentally at different levels of magnification, which allows a better understanding of the mechanisms of fracturing. Fracture mechanical methods serve to quantify the fracture process of wood and wood composites with different deformation and fracturing features. Since wood machining is mainly dominated by the fracture properties of wood, knowledge of the different relevant mechanisms is essential. Parameters that influence the fracture process, such as wood density, orientation, loading mode, strain rate and moisture are discussed in the light of results obtained during recent years. Based on this, refined modelling of the different processes becomes possible.

Influence of loading conditions on the measurement of mode I critical stress intensity factor for wood and medium-density fiberboard by the single-edge-notched tension test

“…To determine the fracture mechanics properties of the crackopening mode (mode I) of solid wood, various testing methods and numerical results have been described in the literature (Yoshihara 2006;Stanzl-Tschegg and Navi 2009), including single-edge-notched bending (SENB), single-edgenotched tension (SENT), compact tension (CT), and double cantilever beam (DCB) tests. Representative numerical analyses based on these methods were reported by Walsh (1972) and Valentin and Adjanohoun (1992).…”

Mode I Critical Stress Intensity Factor of Beech Wood (Fagus Sylvatica) in a TL Configuration: A Comparison of Different Methods

“…and matrix [ ] In the case of plane-stress condition, the a ij constants are equation 10, and in the case of plane-strain condition by equati (17) In the case of plane-stress condition, the a ij constants are compliance coefficients yielded by equation 10, and in the case of plane-strain condition by equation 9. Since the calculation takes account of the material deformation on only one side of the crack, the method can be used only for symmetric specimens with a symmetric load application.…”

Rational production of veneer by IR-heating of green wood during peeling: Modeling experiments

“…Thermoforming of wood veneers was discussed by Srinivasan et al (2007) and the complex interrelation between cutting forces in wood machining was reviewed by Marchal et al (2009) . In the same context, the properties of wood surfaces and the fracture behavior of wood was summarized by Sinn et al (2009) and Stanzl -Tschegg and Navi (2009) , respectively. The mechanical behavior of thin veneers is a special issue, as pointed out recently by Buchelt and Pfriem (2011) and Kl ü ppel and Mai (2012) .…”