Docentship lecture: Size effect on mechanical properties: wood material
In the areas such as cultural heritage preservation, there are various non-standard sample sizes and shapes to characterize the mechanical properties of materials. In addition, there is a need for minimum intervention, which necessitates minimization of samples in sizes and numbers.
The mechanical properties of both green as well as dry wood are the result of its complex structure from the macroscale annual rings down to the composite-like microstructure of its cell walls. The properties vary within a single tree, between species and due to growth conditions. Even after harvesting, the properties of wood depend on the climate (humidity and temperature) and change over time due to chemical and biological influences. The mechanical properties of wooden specimens even vary with the specimen dimensions, which is often called size effect.
In this lecture, the first part will be focused on different theories regarding size effect on structural strength of materials. In the second part, size effect in wood material will be discussed, where the approaches in design codes will be presented and compared with some recent scientific developments.
The lecture is an obligatory teaching test for those applying for admittance as docent and it should be possible for students and others with basic academic education in the relevant field to follow it. The lecture lasts 40-45 minutes with subsequent discussion. The lecture will be given in English.