Micromechanical approach to wood fracture by three-dimensional mixed lattice-continuum model at fiber level

Sedighi-Gilani, Marjan; Navi, Parviz

doi:10.1007/s00226-007-0133-x

Cited by 22 publications

(9 citation statements)

References 9 publications

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“…In addition, it was observed that fracture in spruce earlywood goes through the thin cell walls, as described by Gibson and Ashby (1997) for r/r s -0.2 with r/r s being the mean density related to the cell wall density, whereas interlamellar fracturing (in the middle lamella) was observed in latewood. Similar results are reported by Sedighi-Gilani et al (2007).…”

Section: Fracture At Cellular Levelsupporting

confidence: 92%

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

Stanzl-Tschegg

Navi

2008

HFSG

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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.

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Section: Fracture At Cellular Levelsupporting

confidence: 92%

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

Stanzl-Tschegg

Navi

2008

HFSG

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“…Introduced for wood by Landis et al (2002), this distinct view consists of modeling by a series of linear elements similar to the real wooden fibers. It was demonstrated that this approach provides satisfactory results at smaller scales, despite the higher complexity Brought to you by | University of Georgia Libraries Authenticated Download Date | 6/5/15 10:28 PM of construction and calibration (Davids et al 2003;Fournier 2005;Fournier et al 2007;Sedighi-Gilani and Navi 2007;Vasic and Stanzi-Tschegg 2007;Landis and Navi 2009;Nagy 2010;Nagy et al 2010). This approach facilitated the application of additional concepts in numerical wood models such as growth rings, mechanical variability, and heterogeneous failure patterns.…”

Section: Introductionmentioning

confidence: 92%

Numerical modeling of timber with knots: the progressively damaged lattice approach vs. the equivalent damaged continuum

Guindos¹

2013

Holzforschung

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Two new numerical models for simulating structural timber with knots are presented. The first one, the lattice model (LM), was built from an arrangement of linear truss elements, meanwhile, the second one, the continuum model (CM), was constructed of nonquadratic quadrilateral elements. Both models shared similar characteristics, which allows for an objective comparison between the two approaches. Common characteristics are as follows: they (1) possess identical geometry and node locations, (2) consider the fiber deviation of wood based on the flow-grain theory, (3) account for the longitudinal and transverse plasticity, and (4) permit tensile damage. Experimental four-point bending tests were performed to compare failure prediction, failure location, deflection, and qualitative failure pattern. Considerable construction and calibration work were required for the LM approach in comparison with the CM approach. However, the LM acceptably predicted the behavior of wood at the macroscale, and previous research documented satisfactory predictions for small scales. This suggests the lattice paradigm to be a valid approach for multiscalar simulations of wood. Moreover, complex mechanical principles (e.g., plasticity and damage) were found to be easier to incorporate into lattice elements. This can lead to deeper material understanding and innovation, as limitations for multiscale modeling may be more computational than theoretically constrained.

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“…Sedighi-Gilani and Navi (2007) introduced longitudinally oriented beam elements in a 3D simulation of RL fracture. In both of these cases, the natural outcomes are damage patterns that mimic those observed in real specimens, as well as reasonable predictions of load-deformation measurements.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Acoustic emission measurements and lattice simulations of microfracture events in spruce

2010

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A statistical lattice model was developed to investigate the energy associated with damage and failure of wood. The model incorporates several important morphological aspects of wood such as grain direction, early wood percentage and grain geometry. The model was developed to investigate progressive damage under enforced boundary displacements and has been adapted to predict fracture energy related phenomena. In this particular study, notched specimens were loaded in uniaxial tension while monitored by a passive acoustic emission (AE) measurement system. The energy associated with the mechanical damage was measured by the AE instruments and compared with the energy released by ruptured elements in the lattice model. Cumulative energy release was tracked as a function of specimen load and deformation in both model and experiment. A ratio was established between the cumulative AE energy released at the first drop in load and the cumulative fracture energy released when the model load-deformation relationship becomes significantly nonlinear. An additional ratio was established between the total fracture energy measured prior to 50% of peak strain and the total fracture energy measured prior to peak strain. The magnitudes of these energy release ratios vary owing to a change in failure modes between the short model and the larger specimens; however, the shape of the AE energy release curve up to failure coincides well with that predicted by the model simulations.

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Micromechanical approach to wood fracture by three-dimensional mixed lattice-continuum model at fiber level

Cited by 22 publications

References 9 publications

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

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

Numerical modeling of timber with knots: the progressively damaged lattice approach vs. the equivalent damaged continuum

Acoustic emission measurements and lattice simulations of microfracture events in spruce

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