Sökning: "point contacts"

Visar resultat 6 - 10 av 103 avhandlingar innehållade orden point contacts.

1. 6. On wear in rolling/sliding contacts

   Författare :Rickard Nilsson; Ulf Olofsson; I. Sherrington; KTH; []
   Nyckelord :Technology; wear; rolling; sliding; contact; environment; TEKNIKVETENSKAP; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : The aim of this thesis is to increase the understanding of wear in rolling/sliding contacts such as the wheel-rail contact for railroads and the roller-washer contact for roller bearings. The Stockholm commuter train network has been the subject of papers A and B in this thesis in which the wear and surface cracks on rails has been observed for a period of three years. LÄS MER

3. 7. On the asperity point load mechanism for rolling contact fatigue

   Författare :Johan Dahlberg; Bo Alfredsson; Sören Sjöström; KTH; []
   Nyckelord :Rolling contact fatigue; Spalling; Asperity contact; Point load; Micro-cracks; Traction; Applied slip; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Rolling contact fatigue is a damage process that may arise in mechanical applications with repeated rolling contacts. Some examples are: gears; cams; bearings; rail/wheel contacts. The resulting damage is often visible with the naked eye as millimeter sized surface craters. LÄS MER

4. 8. Ghosts and machines : regularized variational methods for interactive simulations of multibodies with dry frictional contacts

   Författare :Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Discrete mechanics; Variational method; Contact problems; Impacts; Least action principle; Saddle point problems; Lagrange Multipliers; Constrained systems; Multibody Systems; Numerical regularization; Constraint realization; Constraint stabilization; Dry friction; Differential Algebraic Equations; Nonsmooth problems; Linear Complementarity; Quaternion algebra; Numerical linear algebra; Physics modeling; Interactive simulation; Numerical stability; Rigid body dynamics; Dissipative systems; Computational physics; Beräkningsfysik;

   Sammanfattning : A time-discrete formulation of the variational principle of mechanics is used to provide a consistent theoretical framework for the construction and analysis of low order integration methods. These are applied to mechanical systems subject to mixed constraints and dry frictional contacts and impacts---machines. LÄS MER

5. 9. Lubrication of elastohydrodynamic contacts, mainly concerning low temperature

   Författare :Jan Ove Östensen; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Maskinelement; Machine Elements;

   Sammanfattning : The limiting shear stress coefficient has been studied in a impacting ball apparatus for four different lubricating oils at -30ºC and 20ºC. The results show that the most interesting effects are; oil type, maximum contact pressure, temperature, and the interaction between the above mentioned parameters. LÄS MER

7. 10. Vibrations induced by surface roughness in nonlinear rolling contacts

   Författare :Oskar Erik Lundberg; Ines Lopez Arteaga; Svante Finnveden; Will Graham; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rolling contact; nonlinear contact; contact stiffness; contact filter; state-dependent method; relative displacement; wheel-rail contact; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : For efficient transportation in either trains, busses or passenger cars, rolling elements such as wheels, tyres, bearings and transmission elements are fundamental. The energy efficiency and the generation of noise and vibrations in rolling contacts depend on the surface roughness of contacting bodies. LÄS MER