Sökning: "rolling resistance coefficient"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden rolling resistance coefficient.

  1. 1. Roller skis' rolling resistance and grip characteristics : influences on physiological and performance measures in cross-country skiers

    Författare :Mats Ainegren; Peter Carlsson; Marko Laaksonen; Mittuniversitetet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Adjustable grip; blood lactate; centre of pressure; cycle length; cycle rate; economy; efficiency; friction coefficient; heart rate; normal force; OBLA; oxygen uptake; power; ratcheted wheel; ratings of perceived exertion; roller skis; rolling resistance; tangential force; time to exhaustion;

    Sammanfattning : The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers. LÄS MER

  2. 2. Extended Computational Module for Tractive Effort at Rolling and Spinning Point Contacts

    Författare :Mikael Törmänen; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spin; thermal effects; Hertzian contact; continuously variable transmission; rolling resistance; speed pole; traction drive; multi-body system; efficient numerical procedure;

    Sammanfattning : One category of mechanical systems that contains power-transferring point contacts is traction drive variators. These variators can be used in different concepts for Continuously Variable Transmissions (CVTs) and in vehicle applications, in order to achieve optimum engine operating conditions leading to improved driveability, reduced fuel consumption and an increase in overall vehicle performance. LÄS MER

  3. 3. The rolling resistances of roller skis and their effects on human performance during treadmill roller skiing

    Författare :Mats Ainegren; Peter Carlsson; Marko Laaksonen; Per Tesch; Mittuniversitetet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Blood lactate; cycle length; cycle rate; heart rate; oxygen uptake; performance; power; roller skis; rolling resistance; ratings of perceived exertion; work economy; Sports; Idrott;

    Sammanfattning : Modern ski-treadmills allow cross-country skiers, biathletes and ski-orienteers to test their physical performance in a laboratory environment using classical and freestyle techniques on roller skis. For elite athletes the differences in performance between test occasions are quite small, thus emphasising the importance of knowing the roller skis’ rolling resistance coefficient, µR, in order to allow correct comparisons between the results, as well as providing the opportunity to study work economy between different athletes, test occasions and core techniques. LÄS MER

  4. 4. Mathematical modelling for optimization of truck tyres selection

    Författare :Zuzana Sabartova; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; simulation-based optimization; truck tyres selection; surrogate model; radial basis function interpolation; rolling resistance coefficient; combinatorial set of problem instances; global optimization; global optimization;

    Sammanfattning : This thesis, which consists of an introduction and three appended papers, concerns the optimal selection of tyres for a given vehicle configuration and an operating environment in which the vehicle is to be used. The optimization problem stems from an industrial project performed in cooperation between Chalmers University of Technology and Volvo Group Trucks Technology (GTT). LÄS MER

  5. 5. Optimization of truck tyres selection

    Författare :Zuzana Nedelkova; Göteborgs universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; radial basis function; categorical variables; truck tyres; simulation-based optimization; surrogate model; approximately optimal solution; efficient solution; rolling resistance coefficient; vehicle dynamics; simulation-based optimization;

    Sammanfattning : This thesis, which consists of an introduction and five appended papers, concerns the optimal selection of tyres for a variety of vehicle configurations as well as operating environments. The selection problem stems from a project cooperation between Chalmers University of Technology and Volvo Group Trucks Technology. LÄS MER