Sökning: "Crack width"

Visar resultat 11 - 15 av 44 avhandlingar innehållade orden Crack width.

1. 11. Strain-assisted corrosion cracking and growth rate inhibitors

   Författare :Andrey P Jivkov; Mekanik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; materialteknik; Mechanical engineering; Material technology; Materiallära; Stress intensity factor; Inhomogeneous materials; Crack evolution; Stress corrosion cracking; Moving boundary; hydraulics;

   Sammanfattning : A model for evolution of cracks as a result of strain-assisted corrosion is presented. The considered cracks possess a realistic geometry, where the tip region is an integral part of the crack surface instead of being a singular point. This geometry is either implicitly defined or is a consequence of crack nucleation from surface irregularities. LÄS MER

3. 12. 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

4. 13. Weakening of Crack-tip Singularity due to Buckling of Thin Bodies under Tension

   Författare :Li Chong; Hållfasthetslära; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thin foils; Fracture; Buckling;

   Sammanfattning : When thin sheets containing a crack is subjected to tensile loading in the direction perpendicular to the crack surface out of plane displacement will occur in areas surrounding the crack. By this the stress state in the vicinity of the crack tip is changed and leads to a weaker crack tip singularity than the r-1/2 by linear elastic fracture mechanics. LÄS MER

5. 14. Restraint factors and partial coefficients for crack risk analyses of early age concrete structures

   Författare :Martin Nilsson; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Structural Engineering; Konstruktionsteknik;

   Sammanfattning : It is well known for contractors that due to volume change during the hydration phase in concrete structures, large stresses can arise if the structures are restrained, stresses that may cause extensive cracking. Crack risk estimation of early age concrete structures can be based on five steps. LÄS MER

7. 15. Models for analysis of young cast and sprayed concrete subjected to impact-type loads

   Författare :Lamis Ahmed; Anders Ansell; Richard Malm; Lennart Elfgren; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Young concrete · Shotcrete · Rock · Impact-type vibration · Finite element method · Fracture mechanics model · Crack width;

   Sammanfattning : The strive for a time-efficient construction process naturally put focus on the possibility of reducing the time of waiting between stages of construction, thereby minimizing the construction cost. If recently placed concrete, cast or sprayed, is exposed to impact vibrations at an early age while still in the process of hardening, damage that threatens the function of the hard concrete may occur. LÄS MER