Sökning: "random load"

Visar resultat 21 - 25 av 65 avhandlingar innehållade orden random load.

1. 21. Dynamic Train-Turnout Interaction – Mathematical Modelling, Numerical Simulation and Field Testing

   Författare :Elias Kassa; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; contact forces; Karhunen–Loève expansion; dynamic train–turnout interaction; field test; wheel–rail contact geometry; stochastic analysis; switches and crossings; SRA - Transport;

   Sammanfattning : Two models for simulation of dynamic interaction between train and turnout are developed. The first one is derived using a commercial software for dynamics of multi-body systems. LÄS MER

3. 22. Modeling, Analysis and Design of Wireless Sensor Network Protocols

   Författare :Pangun Park; Karl Henrik Johansson; Pravin Varaiya; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wireless Sensor Network; Markov Chain Model; Optimization; Electrical engineering; Elektroteknik; SRA - ICT; SRA - Informations- och kommunikationsteknik;

   Sammanfattning : Wireless sensor networks (WSNs) have a tremendous potential to improve the efficiencyof many systems, for instance, in building automation and process control.Unfortunately, the current technology does not offer guaranteed energy efficiencyand reliability for closed-loop stability. LÄS MER

4. 23. Predictive Modelling of Aquatic Ecosystems at Different Scales using Mass Balances and GIS

   Författare :Andreas Gyllenhammar; Lars Håkanson; Lars Brydsten; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; mass balance model; dynamic model; scales; marine fish farms; rainbow trout; nutrients; suspended particulate matter; phosphorus; nitrogen; GIS; basin delineation; regionalisation; coastal areas; aquatic foodweb; fishing quotas; Baltic Sea; Archipelago Sea; Okavango Delta; Geovetenskap; Earth sciences; Geovetenskap;

   Sammanfattning : This thesis presents models applicable for aquatic ecosystems. Geographical Information Systems (GIS) form an important part of the thesis. The dynamic mass balance models focus on nutrient fluxes, biotic/abiotic interactions and operate on different temporal and spatial scales (site, local, regional and international). LÄS MER

5. 24. On dynamic crack growth in discontinuous materials

   Författare :Johan Persson; Per Gradin; Per Isaksson; Sverker Edvardsson; Pär Jonsén; Mittuniversitetet; []
   Nyckelord :;

   Sammanfattning : In this thesis work numerical procedures are developed for modeling dynamic fracture of discontinuous materials, primarily materials composed of a load-bearing network. The models are based on the Newtonian equations of motion, and does not require neither stiffness matrices nor remeshing as cracks form and grow. LÄS MER

7. 25. Fracture mechanics analysis of damage initiation and evolution in fiber reinforced composites

   Författare :Andrejs Pupurs; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymera konstruktionsmaterial; Polymeric Composite Materials;

   Sammanfattning : When a unidirectional (UD) fiber reinforced polymer composite is loaded in fiber direction in quasi-static or in a high stress cyclic tension-tension regime, many fiber breaks may occur in random positions already during the load increase in the first cycle. This is because fiber strain to failure in UD composites is lower than the polymer matrix strain to failure. LÄS MER