What are the mechanical properties of wood?
Wood, steel, concrete… all materials frequently used in residential and commercial construction have mechanical properties that make them more or less efficient in different contexts and applications.
However, in this respect, wood has unique characteristics that make it extremely versatile. This has undoubtedly contributed to making wood structures particularly popular with building contractors.
In this article, learn more about the mechanical properties of wood that make it such a unique and popular material.
Factors to consider when assessing the mechanical properties of wood
As you can imagine, each species of wood has distinctive features, making their properties comparable, but not identical. It can even be said that no two pieces of wood are perfectly alike, each having its own natural defects. Moreover, the performance of a piece of wood will vary according to factors such as its density and moisture content. Finally, products such as glulam, structural composite lumber and structurally engineered wood naturally have different properties (and often perform even better) than traditional sawn timber.
Wood passes various resistance tests with flying colours
The strength of a material can be measured by means of various tests. These tests help in understanding how the material reacts to different types of stress to which it may be subjected during its service life.
In engineering, bending strength or flexion is measured by applying compressive or tensile forces eccentric to the neutral axis of an element.
In such tests, light structural lumber has a strength of around 11.8 MPa, while the densest and strongest woods can reach up to 35 MPa.
The shear strength of the wood will be influenced by the cross-sectional area of the test piece. For example, a piece of structural lumber such as a floor joist will have a lower shear strength when it is drilled to accommodate cables.
That said, the performance of wood in shear tests can range from 1.5 MPa (light structural lumber) to 3.65 MPa (structural engineered wood).
Wood cells are all oriented longitudinally, which means that compression test results for wood are different when tested parallel or perpendicular to the grain of the wood.
Since the internal structure of the wood could be compared to small tubes welded in the direction of the grain, it is very resistant to compression parallel to the grain, whereas it is much less resistant when the compression is applied perpendicular to the grain.
As with the compressive strength of wood, tensile test results will vary greatly depending on the axis in which the test is conducted.
If the test is done parallel to the grain of the wood, the wood will show very good tensile strength.
Note that knots in the wood reduce its tensile strength.
Wood is also very resistant to fatigue
No, the fatigue referred to here is not the same fatigue you may feel after a workout or a day’s work, but rather the ability of a material to withstand cyclical loads. In the case of a building material, these additional loads will come from wind or earthquakes, for example.
Faced with this fatigue, wood and structural wood products are particularly effective!
At UsiHome, we are proud of our commitment to a material with exceptional mechanical properties
In conclusion, when it comes to performance, wood has no reason to envy other building materials. The mechanical properties of wood compare favourably with concrete and steel and it has a much lower density, which makes it easier to transport to construction sites.
At UsiHome Prefabricated Structures, we are proud to manufacture all of our structural wood products, from roof trusses to prefabricated walls. They share many of the mechanical properties of wood, in addition to benefiting from computer design and ultra-precise assembly that makes them even more resistant.
Contact one of our representatives to learn more about our products!