Sökning: "Sigurdur Ormarsson"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Sigurdur Ormarsson.

1. 1. A Finite Element Study of the Shape Stability of Sawn Timber Subjected to Moisture Variations

   Författare :Sigurdur Ormarsson; Hans Petersson; Ola Dahlblom; Lund University; []
   Nyckelord :simulation; deformation; wood; moisture; finite element method; Byggteknik; Civil engineering;

   Sammanfattning : Shape instability in timber products exposed to moisture variation is a serious problem since it can make wood products unsuitable for construction purposes. In this thesis the finite element method has been used to simulate deformations during the drying process.….…. LÄS MER

3. 2. Numerical Analysis of Moisture-Related Distortion in Sawn Timber

   Författare :Sigurdur Ormarsson; Chalmers University of Technology; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computer simulations; Deformation; Wood; Moisture; Drying; Finite element method; Byggteknik; Civil engineering;

   Sammanfattning : A 3D theory for the numerical simulation of deformations and stresses in wood during moisture variation is described. The constitutive model employed assumes the total strain rate to be the sum of the elastic strain rate, the moisture-induced strain rate, the mechano-sorption strain rate and the creep strain rate. LÄS MER

4. 3. Moisture-induced stress and distortion of wood : A numerical and experimental study of wood's drying and long-term behaviour

   Författare :Sara Florisson; Sigurdur Ormarsson; Johan Vessby; Kent Persson; Linnéuniversitetet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; analytical method; calibration; controlled climate; creep; distortion; experimental methodology; FEM; fibre orientation; mechano-sorption; moisture transport; natural climate; Norway spruce; numerical model; three-dimensional; timber beam; validation; wood; Byggteknik; Civil engineering; Forestry and Wood Technology; Skog och träteknik;

   Sammanfattning : With the current advances made in three-dimensional modelling of wood, it is possible to provide an overall picture of moisture flow, and moisture-induced stress and deformations, whereas previously, experiments only provided local measurements. The main aim of the doctoral thesis is to investigate the possibilities of the developed three-dimensional numerical model to predict the behaviour of wood when simultaneously exposed to a mechanical load and a particular climate. LÄS MER

5. 4. Modelling Alternative Load Paths in Platform-Framed CLT Buildings : A Finite Element Approach

   Författare :Johannes Albert Josef Huber; Mats Ekevad; Ulf Arne Girhammar; Sven Berg; Sigurdur Ormarsson; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; timber; robustness; finite element method; alternative load paths; disproportionate collapse; Träteknik; Wood Science and Engineering;

   Sammanfattning : Timber has become more popular as a construction material during recent years. Engineered wood products, such as glued laminated timber and cross-laminated timber, have enabled the construction of multi-storey buildings. Tall buildings with many occupants need to resist a disproportional collapse in case of unexpected exposures, e.g. LÄS MER

7. 5. Moisture-Induced Strains and Stresses in Wood

   Författare :Sabina Huč; Staffan Svensson; E. Kristofer Gamstedt; Sigurdur Ormarsson; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mechanosorption; multi-Fickian moisture transport model; orthotropy; rheology; three-dimensional mechanical model; viscoelasticity; wood; Engineering science with specialization in Applied Mechanics; Teknisk fysik med inriktning mot tillämpad mekanik;

   Sammanfattning : To design safe, reliable and durable timber structures subjected to varying natural outdoor or indoor climates, understanding the long-term behavior of wood when mechanically loaded or restrained to deform is crucial. The present thesis focuses on the numerical modeling of the long-term mechanical behavior of wood. LÄS MER