Sökning: "elastic constants"

Visar resultat 1 - 5 av 68 avhandlingar innehållade orden elastic constants.

1. 1. Local variability in chemical and physical properties of spruce wood fibers

   Författare :Anna Bergander; KTH; []
   Nyckelord :cell walls; chemical composition; elastic constants; elastic strength; Fiber properties; Fibril angles; Mathematical models; Microscopy techniques; Picea Abies; Stiffness; Tensile properties; Wood polymers; Wood;

   Sammanfattning : Wood is well known to be a heterogeneous native materialwith large variations in its composite properties, includingvariations whose origins have not yet been completelyidentified. Traditionally, the macroscopic variations in woodhave received the most attention; for example, the variation indensity from the pith to the bark in trees. LÄS MER

3. 2. Thermodynamic and kinetic properties of Fe-Cr and TiC-ZrC alloys from Density Functional Theory

   Författare :Vsevolod Razumovskiy; Pavel Korzhavyi; Andrei Ruban; Malin Selleby; Sergei Dudarev; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio; first principles; point defects; vacancy clusters; alloys; steels; iron; carbides; diffusion; phase diagram; density functional theory; elastic constants; elastic properties; thermodynamic modelling;

   Sammanfattning : The complete and accurate thermodynamic and kinetic description of any systemis crucialfor understanding and predicting its properties. A particular interest is in systemsthat are used for some practical applications and have to be constantly improved usingmodification of their composition and structure. LÄS MER

4. 3. Mechanical Characterization of Engineering Materials by Modal Testing

   Författare :Daniel Larsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; material variability; modal testing; non-destructive test methods; damping ratios; timber beams; plastic panels; aluminium panel; elastic constants; concrete curing; wood-based panels; solids; high-strength concrete; anisotropic materials;

   Sammanfattning : This thesis deals with the use of modal testing for establishing elastic constants of engineering materials and for indicating material variability in terms of stiffness and damping properties. The methodology using modal testing techniques, is applied to timber beams, high strength concrete prisms, wood-based panels (oriented strand board and chipboard), an aluminium alloy panel and plastic laminate panels (high-pressure laminate). LÄS MER

5. 4. Static and time-dependent mechanical behaviour of preserved archaeological wood : Case studies of the seventeenth century warship Vasa

   Författare :Alexey Vorobyev; Kristofer Gamstedt; Eiichi Obataya; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; archaeological wood; compression test; cubic samples; elastic constants; oak wood; barrelling formation; quasi-static loading; resonant ultrasound spectroscopy RUS ; Vasa ship; creep; 3D laser scanning; Time-dependent behaviour;

   Sammanfattning : Wooden objects have been widely used in the history of humanity and play an important role in our cultural heritage. The preservation of such objects is of great importance and can be a challenging task. This thesis investigates the static and time-dependent mechanical behaviour of archaeological oak wood from the Vasa warship. LÄS MER

7. 5. Energy Relevant Materials: Investigations Based on First Principles

   Författare :Erna-Krisztina Delczeg-Czirjak; Levente Vitos; Manuel Richter; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; magneto-caloric; DFT; elastic constants; Materials science; Teknisk materialvetenskap;

   Sammanfattning : Energy production, storage and efficient usage are all crucial factors for environmentally sound and sustainable future technologies. One important question concerns the refrigeration industry, where the energy efficiency of the presently used technologies is at best 40% of the theoretical Carnot limit. LÄS MER