Sökning: "micro crack"

Visar resultat 21 - 25 av 54 avhandlingar innehållade orden micro crack.

1. 21. Dynamic Behaviour of Reinforced Concrete Structures: Analyses with a Strong Discontinuity Approach

   Författare :Per-Ola Svahn; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ; reinforcement; concrete; cohesive crack; anisotropic damage; X-FEM;

   Sammanfattning : Reinforced concrete is a widely used construction material. To obtain efficient design of new structures and to verify the real mechanical behaviour of existing ones, it is necessary to improve the understanding of advanced structural analyses of reinforced concrete structures. LÄS MER

3. 22. Lessons Learned in Structural Health Monitoring of Bridges Using Advanced Sensor Technology

   Författare :Merit Enckell; Johan Silfwerbrand; Konrad Bergmeister; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Structural Health Monitoring; Structural Health Monitoring System; bridges; sensor technology; emerging technology; fibre optics; fibre optic sensors concrete; creep; shrinkage; steel; distributed sensors; crack detection; Järnvägsgruppen - Infrastruktur; Järnvägsgruppen - Infrastruktur;

   Sammanfattning : Structural Health Monitoring (SHM) with emerging technologies like e.g. fibre optic sensors, lasers, radars, acoustic emission and Micro Electro Mechanical Systems (MEMS) made an entrance into the civil engineering field in last decades. Expansion of new technologies together with development in data communication benefited for rapid development. LÄS MER

4. 23. Micro-cracking and delaminations of composite laminates under tensile quasi-static and cyclic loading

   Författare :Hiba Ben Kahla; Janis Varna; Zoubir Ayadi; Federica Daghla; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laminate; Fatigue; damage growth; stiffness reduction; NCF; Polymeric Composite Materials; Polymera kompositmaterial;

   Sammanfattning : Aerospace industry is devoted to improving the aircraft performance while reducing its weight and limiting the emissions. Part of this objective can be accomplished with the use of high-performance long fibre reinforced polymer laminated composites. LÄS MER

5. 24. Hydrolytic degradation of dental composites and effects of silane-treatment and filler fraction on compressive strength and thermal expansion of composites

   Författare :Karl-Johan M. Söderholm; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Internal frictional theory; filler-matrix debonding; stress-corrosion; stressinfluenced diffusion; m icro-crack form ation; crazing; opacity; wear; osmotic pressure; hoop stresses;

   Sammanfattning : Some researchers have suggested that the weakest link of dental composites is the filler-matrix bond. However, due to incompleteness of information dealing with this bond and its stability in a humid environment, it was considered desirable to investigate the effect of water on this region, as well as the influence of filler bonding and filler fraction on compressive strength and thermal expansionExperimental composites containing different filler fractions of either silane-treated or untreated fillers were made. LÄS MER

7. 25. On the Volume Changes during the Solidification of Cast Irons and Peritectic Steels

   Författare :Abel Tadesse; Michael Vynnycky; Hasse Fredriksson; Jacques Lacaze; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Volume changes; Solidification; Peritectic steel; Micro- and Macro-shrinkage; LVDT; GCI; NCI; Hypo- and Hypereutectic; Austenite; DTA; Dilatometry; BSE; Nuclei; Flake graphite; SDAS; Eutectic cells; Undercooled graphite; Simulation; Cooling rate; Microsegregation; austenite; Metastable region; δ-ferrite; Stable phase diagram; Grain refinement; Strain.; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : This thesis work deals with the volume changes during the solidification of cast irons and peritectic steels. The volume changes in casting metals are related to the expansion and/or contraction of the molten metal during solidification. Often, different types of shrinkage, namely macro- and micro-shrinkage, affect the casting quality. LÄS MER