Sökning: "normal loading"
Visar resultat 16 - 20 av 103 avhandlingar innehållade orden normal loading.
16. Influence of wheel tread damage on wheelset and track loading – Field tests and numerical simulations
Sammanfattning : Wheel tread damage leading to high magnitudes of vertical wheel–rail contact forces is a major cause of train delays in the Swedish railway network, in particular during the coldest months of the year. According to regulations, vehicles generating contact forces exceeding the limit value for allowed wheel–rail impact loads must be taken out of service for wheel maintenance. LÄS MER
17. Combined thermal and mechanical loading of railway wheel treads. A numerical study of material response and cracking under braking conditions
Sammanfattning : The scope of the thesis is prediction of the material response owing to combined thermal and mechanical loading of a railway wheel tread. The long-term objective is to improve models for prediction of surface-initiated Rolling Contact Fatigue (RCF) under the combined effect of mechanical loading due to rolling (and sliding) contact and thermal loading due to braking and/or wheel--rail friction. LÄS MER
18. Strain echocardiography in cardiac surgery - studies on the effects of loading conditions and inotropic agents on myocardial contraction and relaxation
Sammanfattning : Background: Although reductions in myocardial contractility and relaxation are key compo-nents in heart failure (HF), assessment of them is difficult, as clinical measurements deal with a net effect of myocardial contractility, heart filling (preload), outflow impedance (afterload) and heart rate (HR). Echocardiographic (echo) deformation parameters, like strain (myocardial shortening) and strain rate (the speed of deformation, SR), have been proposed to more accu-rately measure myocardial function, but incongruent previous studies have raised concerns that they may be load-dependent. LÄS MER
19. Psychomotor and cardiorespiratory functions during inert gas sedation
Sammanfattning : Relative hypoventilation and bradycardia are commonly observed in both resting and exercising divers. Divers are exposed to a complex environment where there are increases of hydrostatic pressure, gas density and partial pressure of sedating inert gas. LÄS MER
20. Laboratory studies of dynamic rock fracture and in-situ measurements of cutter forces for a boring machine
Sammanfattning : All forms of rock failure usually happen within a very wide range of loading rates covering static and dynamic loading. Since rock failure always results from fracture - the propagation of one or more cracks- the first part of the thesis is focused on laboratory studies of the influences of loading rates on rock fracture. LÄS MER
