Sökning: "material modelling of ballast"

Hittade 4 avhandlingar innehållade orden material modelling of ballast.

1. 1. Numerical Modelling of Self-Compacting Concrete Flow : Discrete and Continuous Approach

   Författare :Annika Gram; Johan Silfwerbrand; Ali Farhang; Mette R. Geiker; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SCC; rheology; Simulation of Flow; Simulering; Flöde; Självkompakterande Betong; Reologi; Construction materials; Konstruktionsmaterial;

   Sammanfattning : With the advent of Self-Compacting Concrete (SCC) that flows freely, under the soleinfluence of gravity, the wish for hassle-free and predictable castings even in complexcases, spurged the simulation of concrete flow as a means to model and predictconcrete workability. To achieve complete and reliable form filling with smoothsurfaces of the concrete, the reinforced formwork geometry must be compatible withthe rheology of the fresh SCC. LÄS MER

3. 2. On Mesoscale Modelling of Coupled Chloride-Moisture Transport in Concrete

   Författare :Filip Nilenius; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; coupled diffusion; concrete; moisture; mesoscale; chloride ions.; Multiscale modelling; computational homogenization;

   Sammanfattning : The service life behaviour of concrete structures is highly influenced by the ingress of chloride ions. At sufficiently high concentrations, chloride ions can initiate corrosion of embedded reinforcement bars, which may substantially reduce the structure's bearing capacity and ultimately lead to structural collapse. LÄS MER

4. 3. Wheel–Rail Impact Loads and Track Settlement in Railway Crossings

   Författare :Xin Li; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vehicle--track dynamics; wheel--rail contact; track settlement; material modelling of ballast; Switches and crossings; turnout; cyclic loading; Green s functions;

   Sammanfattning : Turnouts (Switches & Crossings, S&C) are critical components of a railway track requiring regular maintenance and generating high life cycle costs. A main driver for the high maintenance costs is the need to repair and replace switch rails and crossings as these components are subjected to a severe load environment. LÄS MER

5. 4. End-Shield Bridges for High-Speed Railway : Full scale dynamic testing and numerical simulations

   Författare :Hesham Elgazzar; Jean-Marc Battini; Mahir Ülker-Kaustell; Morgan Johansson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high-speed railway; end-shield bridges; structural dynamics; soil structure interaction; full scale bridge testing; controlled forced excitation; hydraulic bridge exciter; frequency response function; Civil and Architectural Engineering; Byggvetenskap;

   Sammanfattning : The increasing need for High-Speed Railway (HSR) to reduce the travelling time requires increasing research within this field. Bridges are main components of any railway network, including HSR networks, and the optimization of their design for this purpose would contribute to a faster and more cost effective development of the HSR network. LÄS MER