Mode III fracture energy of wood composites in comparison to solid wood

1999 ◽  
Vol 33 (5) ◽  
pp. 391-405 ◽  
Author(s):  
R. J. A. Ehart ◽  
S. E. Stanzl-Tschegg ◽  
E. K. Tschegg
Keyword(s):  
Fracture Energy ◽  
Solid Wood ◽  
Wood Composites ◽  
Mode Iii

Fracture Behaviour of Modified Spruce Wood: A Study Using Linear and Non Linear Fracture Mechanics

Holzforschung ◽  
2002 ◽  
Vol 56 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Alexander Reiterer ◽  
Gerhard Sinn
Keyword(s):  
Fracture Energy ◽  
Heat Treatments ◽  
Critical Stress Intensity Factor ◽  
Mode I ◽  
Mode Iii ◽  
Fracture Properties ◽  
Specific Fracture Energy ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Specific Fracture

Summary The fracture properties of unmodified and modified (heat treatments under various conditions and acetylation) sprucewood are investigated using the wedge splitting test. Fracture parameters measured include critical stress intensity factor and specific fracture energy under Mode I loading and specific fracture energy under Mode III loading. The Mode I fracture properties are reduced by all kinds of modification. However, acetylation leads to a reduction of only 20%whereas heat treatments reduce the properties to a much greater extent, approximately 50%to 80%. The Mode III fracture properties are influenced less. SEM pictures of the fracture surfaces support the described findings.

Fracture Energy of Elastomers in Mode I (Cleavage) and Mode III (Lateral Shear)

1975 ◽  
Vol 48 (5) ◽  
pp. 896-901 ◽  
Author(s):  
A. Ahagon ◽  
A. N. Gent ◽  
H. J. Kim ◽  
Y. Kumagai
Keyword(s):  
Fracture Energy ◽  
Strain Energy ◽  
Sheet Thickness ◽  
Shear Mode ◽  
Mode I ◽  
Input Energy ◽  
Mode Iii ◽  
Lateral Shear ◽  
Test Sheet ◽  
Filled Elastomers

Abstract Attention has been drawn here to three different reasons why measurements of fracture energy by different methods may not agree: (1) When the test involves propagation of a tear by stored strain energy, as in the method shown in Figure 1, the energy available to cause rupture will be less than that supplied, because of dissipation within the elastomer. Calculation of the fracture energy on the basis of input energy would then lead to an overestimate, by about 100 per cent or more for typical filled elastomers. (2) As shown in Figures 4a and 5, the tear path is sometimes wider than the thickness of the test sheet. In consequence, fracture energy calculated from the sheet thickness would be too large, by about 40 per cent in the cases considered here. (3) Even when allowance is made for the true width of the tear path, measurements of fracture energy in shear (Mode III) are about 50 per cent larger than in cleavage (Mode I). This is attributed to frictional work expended in sliding the rough torn surfaces past each other.

Polyurethane-solid wood composites. II. Flammability parameters

2009 ◽  
Vol 113 (5) ◽  
pp. 3279-3285 ◽  
Author(s):  
Zhenhua Gao ◽  
Wenqiang Su ◽  
Di Wu
Keyword(s):  
Solid Wood ◽  
Wood Composites ◽  
Flammability Parameters

Damage and Fracture Mechanisms during Mode I and III Loading of Wood

Holzforschung ◽  
2001 ◽  
Vol 55 (5) ◽  
pp. 525-533 ◽  
Author(s):  
E.K. Tschegg ◽  
K. Frühmann ◽  
S.E. Stanzl-Tschegg
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Fracture Energy ◽  
Fracture Mechanisms ◽  
Mode I ◽  
Mode Iii ◽  
Initiation Energy ◽  
Specific Fracture Energy ◽  
Damage And Fracture ◽  
Specific Fracture

Summary Tests under mode I and mode III loading were performed on side grooved Compact-Tension specimens of larch and beech under steady state crack propagation to study the damage and fracture behaviour and the influence of two fibre orientations. From the complete load-displacement diagram, all important damage and fracture mechanical values (stiffness/compliance, microstructural damage, crack initiation energy, specific fracture energy, etc.) have been determined. Crack initiation energy and specific fracture energy are approximately ten times higher for mode III loading than for mode I loading in both wood species. Crack initiation occurs in mode III under external mode III loading, crack propagation, however, takes place under mode I, owing to crack surface interference. The influence of fibre orientation on the (fracture) mechanical properties of beech and larch is different. This difference may be explained mainly by the high number of rays in beech.

scholarly journals Cellulose nanofibrils as filler for adhesives: effect on specific fracture energy of solid wood-adhesive bonds

Cellulose ◽  
2011 ◽  
Vol 18 (5) ◽  
pp. 1227-1237 ◽  
Author(s):  
Stefan Veigel ◽  
Ulrich Müller ◽  
Jozef Keckes ◽  
Michael Obersriebnig ◽  
Wolfgang Gindl-Altmutter
Keyword(s):  
Fracture Energy ◽  
Cellulose Nanofibrils ◽  
Wood Adhesive ◽  
Solid Wood ◽  
Adhesive Bonds ◽  
Specific Fracture Energy ◽  
Specific Fracture

Measurement of mode III fracture energy of concrete

1988 ◽  
Vol 106 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Zdeněk P. Bažant ◽  
Pere C. Prat
Keyword(s):  
Fracture Energy ◽  
Mode Iii

scholarly journals The Influence of Thickness on the Tensile Strength of Finnish Birch Veneers under Varying Load Angles

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Maximilian Pramreiter ◽  
Alexander Stadlmann ◽  
Christian Huber ◽  
Johannes Konnerth ◽  
Peter Halbauer ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Size Effect ◽  
High Performance ◽  
Mechanical Performance ◽  
Solid Wood ◽  
Strengthening Effect ◽  
Wood Composites ◽  
Design Flexibility ◽  
Wood Part ◽  
Load Angle

The development of high-performance, veneer-based wood composites is a topic of increasing importance due to the high design flexibility and the comparable mechanical performance to solid wood. Part of this improved mechanical performance can be contributed to the size effect present in wood. Based on previous findings in the literature, this size effect can be either strengthening or weakening. The presented study investigates the influence of thickness and load angle on the tensile strength and tensile stiffness of peeled veneers compared to thin sawn timber. Veneers with thicknesses of 0.5 ± 0.05 mm, 1.0 ± 0.05 mm and 1.5 ± 0.05 mm as well as sawn wood with thicknesses of 1.5 ± 0.1 mm, 3.0 ± 0.1 mm and 5.0 ± 0.1 mm were tested in tension under different load angles (0°, 45° and 90°). The results only partly confirm a size effect for strength parallel to the grain. The strength perpendicular to the grain increased significantly between 0.5 mm and 1.5 mm, with a significant decrease between 1.5 mm and 5.0 mm. The presence of lathe checks diminished the strength perpendicular to the grain of the veneers by about 70% compared to solid wood, partly overshadowing a possible strengthening effect. It was concluded that a transition from a strengthening to a weakening behaviour lies in the range of multiple millimetres, but further investigations are needed to quantify this zone more precisely. The presented results provide a useful basis for the development of veneer-based wood composites with a performance driven layer-thickness.

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