Sökning: "flight friction"

Visar resultat 1 - 5 av 9 uppsatser innehållade orden flight friction.

  1. 1. Multibody modelling of the vibrations in an aircraft engine

    Master-uppsats, KTH/Lättkonstruktioner, marina system, flyg- och rymdteknik, rörelsemekanik

    Författare :Charly Mollet; [2022]
    Nyckelord :Vibrations; Multibody Modelling; Rolling Bearings; Rotor Dynamics; Reduction Processes; Vibrationer; multikroppsmodellering; rullingslager; rotordynamik; reducktionsprocesser;

    Sammanfattning : During the assembly of aircraft engines, some clearance is left in the rolling bearings mainly to reduce friction. However this clearance might allow the rolling element to vibrate during flight. Indeed, unwanted vibrations called non-synchronous vibrations (NSV) appear on the data recorded by the sensors on some development engines. LÄS MER

  3. 2. Simulation of ultrasonic time of flight in bolted joints

    Master-uppsats, KTH/Hållfasthetslära

    Författare :David Chlebek; [2021]
    Nyckelord :Acoustoelastic effect; User material subroutine; Murnaghan hyperelastic material model; Explicit FEM; Ultrasonic preload; Fortran; Akustoelastiska effekten; Användar material; Murnaghan hyperelastisk materialmodell; Explicit FEM; Ultraljudsmätning av klämkraft; Fortran;

    Sammanfattning : Ultrasonic measurements of the preload in bolted joints is a very accurate method since it does not depend on the friction and other factors which cause difficulties for common methods. The ultrasonic method works by emitting an ultrasonic pulse into the bolt which is reflected at the end and returned to the transducer, the change in the time of flight (TOF) can be related to the elongation of the bolt and therefore the preload. LÄS MER

  4. 3. Simulation and Analysis of Ultrasonic Wave Propagation in Pre-stressed Screws

    Uppsats för yrkesexamina på avancerad nivå, Luleå tekniska universitet/Institutionen för system- och rymdteknik

    Författare :Erik Andrén; [2019]
    Nyckelord :;

    Sammanfattning : The use of ultrasound to measure preload in screws and bolts has been studied quite frequently the last decades. The technique is based on establishing a relationship between preload and change in time of flight (TOF) for an ultrasonic pulse propagating back and forth through a screw. LÄS MER

  5. 4. Predicting bat occurrence : evaluation of a connectivity-based habitat index for Swedish bats

    Master-uppsats, SLU/Dept. of Ecology

    Författare :Gesa von Hirschheydt; [2018]
    Nyckelord :bats Chiroptera ; bat habitat index; ecological impact assessment; flight friction; cost distance analysis; landscape permeability;

    Sammanfattning : Ecological impact assessments are required for all large infrastructure or exploitation projects because of their effects on environment and species. Methods that would make such assessments more standardised, efficient and reliable are highly desirable in today’s society, where many species are decreasing due to human-induced habitat modifications. LÄS MER

  7. 5. Ultrasonic measurement and analysis of screw elongation

    Master-uppsats, KTH/Hållfasthetslära (Avd.)

    Författare :Anders Pärlstrand; [2018]
    Nyckelord :;

    Sammanfattning : Based on the customers' increasing demands on the precision of the preload in a screw joint Atlas Copco is investigating the opportunity to integrate ultrasonic technologies in their industrial tools in order to be able to measure the screw elongation and thereby preload. The preload in a screw joint is important when trying to optimize the joint in terms of weight and life time. LÄS MER