scholarly journals Limb: Rethinking Heavy Timber Joinery Through Analysis of Tree Crotches

2018 ◽  
Author(s):  
Kasey Vliet ◽  
◽  
Peter Von Buelow ◽  
Steven Y. Mankouche ◽  
◽  
...  
Keyword(s):  
Wood Species ◽  
Natural Occurrence ◽  
Steel Connections ◽  
Timber Construction ◽  
Mortise And Tenon ◽  
Vital Element

LIMB reconsiders historic heavy timber construction across cultures to develop new joinery methods by focusing on the natural occurrence of branch bifurcation in different wood species. Because of its low value, often the crotch of a tree is not harvested for commercial purposes. This project uses this vital element to design connections that replace traditional mortise and tenon or steel connections.

Verification and further study on method of measuring contact force between mortise and tenon joint

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 263-276
Author(s):  
Wei-Lian Fu ◽  
Hui-Yuan Guan ◽  
Xin-Yi Zhang
Keyword(s):  
Contact Force ◽  
Wood Species ◽  
Grain Orientation ◽  
Measuring Method ◽  
Load Resistance ◽  
Resistance Testing ◽  
Initial Contact ◽  
Fagus Orientalis Lipsky ◽  
Wood Grain ◽  
Mortise And Tenon

This work verified the direct measuring method of the contact force and its relaxation behavior between mortise and tenon joints through withdrawal load resistance testing of T-shaped mortise-and-tenon joint specimens. Further, it also studied the influence of wood species, beech (Fagus orientalis Lipsky) and Mongolian Scots pine (Pinus sylvestris var. mongolica), interference fitness (0.1, 0.2, 0.3, and 0.4 mm; 0.2, 0.4, 0.6, and 0.8 mm), and wood grain orientation (radial, diagonal, and tangential) on the contact force and its relaxation. The results showed that the direct measuring method had good feasibility for measuring the contact force and its relaxation of the beech and it showed good feasibility on measuring initial contact force of pine. However, it showed low feasibility for measuring the relaxed contact force when the interference was 0.2 mm, but showed good feasibility on measuring the relaxed contact force with larger interference of pine. Interference fitness, wood grain orientation, and wood species had a significant effect on initial contact force and contact force after 5 h relaxation. This study showed feasibility and application scope of the method for direct measuring contact force and provided additional fundamental data to contribute to further study of the internal mechanical mechanism of mortise and tenon joints.

Effect of wood species and glue type on contact stresses in a mortise and tenon joint

2008 ◽  
Vol 222 (12) ◽  
pp. 2293-2299 ◽  
Author(s):  
J Smardzewski
Keyword(s):  
Linear Elasticity ◽  
Wood Species ◽  
New Technologies ◽  
Elasticity Modulus ◽  
Adhesive Joints ◽  
Building Construction ◽  
Normal Stresses ◽  
Wood Compression ◽  
Mortise And Tenon ◽  
The Impact

New technologies for wood building construction continue to employ various profile-adhesive joints, with mortise and tenon joints being the most popular. Their strength depends both on the wood species and type of the applied glue, as well as the execution accuracy of individual elements. The aim of the performed experiments was to determine the size of normal stresses in places of mutual pressures of the tenon and mortise and the impact of the change of wood species and the type of glue (or lack of glue) applied to the joint on the value of those stresses. It was established, on the basis of numerical calculations, that the phenomena of the tenon and mortise contact are caused both by the bending of the tenon as well as by the torsion of the glue bond. Stresses in the direction perpendicular to the fibre course generating pressures exceeding wood compression strength turned out to be the most dangerous for the tenon and mortise joint. The value of the linear elasticity modulus of the glue bond exerts a decisive influence on the stress values caused by the mutual pressures of the elements of the examined joint.

scholarly journals Effect of wood species, adhesive type, and annual ring directions on the stiffness of rail to leg mortise and tenon furniture joints

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 7016-7031
Author(s):  
Vladimír Záborský ◽  
Vlastimil Borůvka ◽  
Václava Kašičková ◽  
Daniel Ruman
Keyword(s):  
Wood Species ◽  
Polyvinyl Acetate ◽  
Bending Moment ◽  
Elastic Stiffness ◽  
Annual Rings ◽  
Fagus Sylvatica L ◽  
Species Type ◽  
Mortise And Tenon ◽  
Loading Type ◽  
Half Thickness

The effects of selected factors, wood species (Fagus sylvatica L. and Picea abies L.), type of joint (haunched mortise and tenon, and haunched dovetail mortise and tenon), tenon thickness (one-third and half-joint thickness), type of adhesive (polyvinyl acetate and polyurethane adhesive), loading type (compressive and tensile), and direction of the annual rings were evaluated relative to the elastic stiffness. The testing samples were loaded by bending moment with tensile and compressive forces in the angular plane. The wood species, type of joint, tenon dimension, and type of adhesive all had a statistically significant effect on the elastic stiffness. However, the interaction of those factors was statistically insignificant. The loading type and direction of the annual rings did not have a significant effect on the elastic stiffness. For spruce, the use of mortise and tenon with a toothed feather (MTTF) was found to be disadvantageous, whereas the use of a toothed feather was favorable for beech. Half thickness of the joint was always an advantage, such that the stiffness increased. For spruce joints, the type of glue was not important, whereas for beech, the stiffness of joints glued with PVAc was significantly higher than with PUR adhesive.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Influence of anatomy on the adhesion performance of four wood species

2020 ◽  
Vol 9 (4) ◽  
pp. e31942727
Author(s):  
João Gabriel Missia da Silva ◽  
Pedro Nicó de Medeiros ◽  
Denise Ransolin Soranso ◽  
Vinicius Peixoto Tinti ◽  
José Tarcísio da Silva Oliveira ◽  
...  
Keyword(s):  
Shear Strength ◽  
Specific Gravity ◽  
Wood Species ◽  
Tectona Grandis ◽  
Glue Line ◽  
Anatomical Characteristics ◽  
Ray Cells ◽  
Adhesion Performance ◽  
Adhesion Process

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

Determination of natural radionuclides in waste generated in the potable water treatment plants of the Zona da Mata of the state of Pernambuco- Brazil

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Adriana Muniz De Almeida Albuquerque
Keyword(s):  
Water Treatment ◽  
Potable Water ◽  
Natural Radionuclides ◽  
The United States ◽  
Radioactive Material ◽  
Human Consumption ◽  
Radiological Protection ◽  
Natural Occurrence ◽  
Water Treatment Plants ◽  
Potable Water Treatment

The water purification procedure aims to obtain a product appropriate for human consumption, minimizing the presence of contaminants and toxic substances present in the water. Among these contaminants, some radionuclides of natural origin, such as uranium, thorium and their descendants, have been identified. Studies have shown that the stages of purification are quite effective in removing the radionuclides contained in water. The removal is due to co-precipitation of the radionuclides with the suspended materials and the precipitated material is accumulated and characterized as a Technologically Concentrated Natural Occurrence Radioactive Material (TENORM) by the United States Environmental Protection Agency (USEPA). This residue can present significant levels of radioactivity and, when discarded in the environment without any treatment, can generate a problem of environmental impact and a risk to the health of the population. In this way, some gamma emitters of the series of U, Th and the K-40 were determined in the residues generated at the Potable Water Treatment Plants – PWTPs in six municipalities of Pernambuco. The results obtain corroborate the classification of the residues generated in the PWTPs as concentrators of the radioactive components contained in the water supplied to the system and reinforce the need for the release to the environment, which is the usual way of disposal of this waste, to be carried out only after considering the radiological protection standards established.

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