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    HOME EXAM

    The home exam paper is now uploaded and can be fond under "Assignments". Good luck!!


    Home Exam

    Just as a reminder to those of you who may have missed it, the exam for this course will be a "Home Exam", rather than the traditional format of a 4 hour exam on-site. The Home Exam format is "Open Book" and you will have one week to complete the exam (allowing for the fact that Easter will be in the middle). I will post the exam paper on Thursday, 14th April, at 09:00 and it will close on Friday 22nd April 2022 (at 23:59). A sample exam paper has been posted under "Materials", so you can familiarize yourselves with the guidelines and format. I hope that you will find that this format will aid the learning process. Good luck! And, of course, if you have questions, please don't hesitate to drop me an email.              

    Teaching arrangements for 2022

    Regrettably, due to the ongoing coronavirus pandemic, the 2022 edition of this course will again be held entirely online. All lectures and other sessions will be organized via Zoom or other appropriate platforms. 

    I hope that despite these restrictions, you will find the course interesting and informative and I look forward to "meeting" you virtually in January!        

    Course outline       


    Image: Sibelius Hall, Lahti, Finland (M. Hughes)

    A lightweight honeycomb structural material, with a specific strength three times greater than that of mild steel, made from an advanced, self-assembling, nano-composite synthesized from abundant, renewable resources and using only solar energy in its manufacture. Damage tolerant, long-lasting, but completely biodegradable when triggered to do so, this material is also widely available and can be further processed into a vast array of products and structures with minimal fuss or further energy input. This really sounds like a futuristic material, yet it is already being produced and has been for hundreds of millions of years – it is, of course, wood!

    Wood has been used for so long by humankind that we rarely, if ever, stop to think about what wood really is, yet when we start to study wood, we realize that is an extremely complex and elegant material that we really do not know much about. Wood is not without its problems that is for sure! It has a nasty habit of biodegrading when you least want it to – just add water and it will happily rot away, acting a food source to a wide variety of micro-organisms. It reacts to changes in humidity by altering its dimensions and sometimes its shape as well. However, as building material it is in many ways unparalleled, and by re-constituting wood in the form of a composite, many of its less desirable properties can be eliminated. In addition to wood’s interesting and very useful physical properties, of one the most attractive features of wood, in the drive for a more sustainable future, is its ability to store carbon from the atmosphere as part of its structure. During photosynthesis atmospheric carbon dioxide is sequestered and is used to form the wood structure. Approximately 1.8 kg of CO2 is required to make 1 kg of dry wood and this ‘captured’ CO2 is only released to back to the atmosphere when wood is burned or when it biodegrades. This means that long-lasting structures built of wood and wood-based composites actively store carbon, removing it from the atmosphere for as long as they exist, which can be for decades or even centuries, and in the end the wood can be burned, recovering its energy content, or, better still, used as a basis for chemicals, or other products. In addition, when we use wood rather than more "energy intensive" materials to construct buildings, there is often a reduction in emissions due to this substitution.    

    Wood’s propensity to interact with moisture can be put to good effect in helping to mediate the interior environments of buildings. As the humidity level rises, wood adsorbs moisture from the surroundings and, when the humidity drops, the stored moisture is released. In this way wood acts as a buffer, helping to reduce large fluctuations in relative humidity, arguably making for a more comfortable and healthy living environment. These attributes and others are gradually being recognized and there is greater-and-greater interest in the use of wood for construction as well as for a range of other applications. Many of the properties of wood - which are sometimes viewed as problems - can be altered by creating composites and engineered wood materials, like glue laminated timber ('glulam'), plywood and laminated veneer lumber. Wood can also be extremely resource efficient. By forming wood-composites, small dimensioned timbers, manufacturing wastes like sawdust or recovered wood can be used to create useful functional materials. Wood can also be modified in one of a number of ways to reduce its susceptibility to bio-deterioration and dimensional changes; by altering the chemical structure of wood new functionality can be added. Modified wood products such as ThermoWood is just one example of how research is now able to give a new lease of life to a very traditional material. Wood still has much to teach us and as we learn more we will find new ways in which it can be utilized in a sustainable future.

    Welcome to the Wood and Wood products course, where you will learn more about the intriguing properties of wood and what can be done with it! 

    Schedule

    Period III

    Date

    Topic/activity

    Content

    11.1

    Lecture: introduction

    Information about the course and background.

    Wood formation, environmental factors, wood structure, basic terms and concepts

    14.1

    NO LECTURE

    18.1

    Lecture: wood structure

    The anatomy of wood and relationship to properties

    21.1

    NO LECTURE

    25.1

    The cell wall and mass-volume relationships

    The wood cell wall - chemical composition, the microfibril and cell wall structure. Mass-volume relationships

    28.1

    NO LECTURE

    1.2

    Lecture: wood-water relationships I

    States of water in wood; moisture content; fibre saturation point; sorption; equilibrium moisture content

    4.2

    NO LECTURE

    8.2

    Lecture: wood-water relationships II

    Moisture buffering; heat of sorption; dimensional changes; effect on mechanical and physical properties

    11.2

    NO LECTURE

    15.2

    Lecture: mechanics of wood I - elastic and strength properties

    The orthotropic nature of wood; elastic properties of the wood cell wall and wood; tensile, compressive and shear properties

    18.2

    NO LECTURE

     

    Period IV

    Date

    Topic/activity

    Content

    1.3

    Lecture: mechanics of wood II - fracture and failure in wood

    Toughness; cracks and crack-like defects; the nature of cracks; fracture mechanics; interfaces as crack stoppers; energy absorbing mechanisms 

    4.3

    NO LECTURE

    8.3

    Lecture: mechanics of wood III - creep, stress relaxation and fatigue

    Creep and stress relaxation, fatigue: viscoelasticity, mechano-sorption, S-N curves etc. 

    11.3

    NO LECTURE

    15.3

    Lecture: manufacture of solid wood products

    Scanning, sawing, grading, drying

    18.3

    NO LECTURE

    22.3

    Lecture: manufacture of veneer-based wood products

    Plywood and LVL, soaking, peeling, drying, gluing, pressing and properties

    25.3

    NO LECTURE

    29.3

    Lecture: manufacture of wood-based panels

    Structure-property relationships, size reduction, drying , pressing physics, 

    1.4

    NO LECTURE