Comprehensive validation of three-dimensional finite element modelling of wheel-rail high-frequency interaction via the V-Track test rig

Wheel-rail high-frequency interaction is closely related to the formation of railway short-wave defects. Finite element (FE) method has been widely used to simulate wheel-rail dynamic systems, but its validity in modelling high-frequency interaction has not been fully demonstrated in three dimensions (3D). This work aims at comprehensively...

New experimental evidences of corrugation formation due to rail longitudinal vibration mode

This paper aims at identifying the formation mechanism of short pitch rail corrugation using an improved configuration of a 1/5 scaled V-Track test rig. The loading conditions of the V-Track are designed to simulate the wheel-rail dynamic interactions on the tangent track. Corrugation initiation and consistent growth are successfully produced...

Ultrasonic friction modulating rings for endoscopes

The Hierarchical Subspace Iteration Method for Computing Vibration Modes of Elastic Objects

The Hierarchical Subspace Iteration Method is a novel method used to compute eigenpairs of the Laplace-Beltrami problem. It reduces the number of iterations required for convergence by restricting the problem to a smaller space and prolonging the solution as a starting point. This method has shown great performance improvements for Laplace...

Theory of Chirality Induced Spin Selectivity in Two Terminal Transport

In this thesis we perform a theoretical study on the Chirality Induced Spin Selectivity effect in the context of two-terminal measurements for realistic parameters. In twoterminal measurements on chiral molecules one of the leads is magnetized and the current is measured for opposite magnetizations. In experiment it is found that the currents...

Experimental study on the development mechanism of short pitch corrugation using a downscale V-Track test rig

This paper presents an experimental study on the development mechanism of short pitch corrugation using an innovative downscale V-Track test rig. Rail corrugation is reproduced in the V-Track with two wavelengths of 6.4 mm and 8.9 mm. Based on the measured wheel-rail contact forces, track dynamic behaviors, and observations, the consistent...

Vibration modes and wave propagation of the rail under fastening constraint

This paper investigates three-dimensional (3D) rail vibrations under fastening constraint up to 5000 Hz and provides insights into rail vibration control by fastening parameters. A methodology is proposed, including experimental investigation and numerical simulations of rail vibrations. Three steps are considered: 1) experimental investigation...

Probing the local environment of a single OPE3 molecule using inelastic tunneling electron spectroscopy

We study single-molecule oligo(phenylene ethynylene)dithiol junctions by means of inelastic electron tunneling spectroscopy (IETS). The molecule is contacted with gold nano-electrodes formed with the mechanically controllable break junction technique. We record the IETS spectrum of the molecule from direct current measurements, both as a...

Q-factor control of a microcantilever by mechanical sideband excitation

We demonstrate the coupling between the fundamental and second flexural modes of a microcantilever. A mechanical analogue of cavity-optomechanics is then employed, where the mechanical cavity is formed by the second vibrational mode of the same cantilever, coupled to the fundamental mode via the geometric nonlinearity. By exciting the cantilever...

Quantum transport through single molecules

This thesis describes three-terminal transport measurements through single molecules. The interest in this field stems from the dream that single molecules will form the building blocks for future nanoscale electronic devices. The advantages are their small size -nanometers-, and their synthetic tailorability which allows the molecules to be...

Molecular interpretation of nonclassical gas dynamics of dense vapors under the van der Waals model

The van der Waals polytropic gas model is used to investigate the role of attractive and repulsive intermolecular forces and the influence of molecular complexity on the possible nonclassical gas dynamic behavior of vapors near the liquid-vapor saturation curve. The decrease of the sound speed upon isothermal compression is due to the well-known...

Intermolecular interactions in solid benzene

The lattice dynamics and molecular vibrations of benzene and deuterated benzene crystals are calculated from force constants derived from density-functional theory (DFT) calculations and compared with measured inelastic neutron-scattering spectra. A very small change (0.5%) in lattice parameter is required to obtain real lattice-mode frequencies...

The vibrational spectrum of solid ferrocene by inelastic neutron scattering

We calculate the spectrum of internal vibrations of a single ferrocene Fe(C5H5)2 molecule using ab initio density functional theory (without free parameters) and compare this with inelastic neutron scattering data on ferrocene in the solid state at 28 K. Due to the good agreement, we can assign each vibrational mode to each observed peak in the...

Pin-pin resonance as a reference in determining ballasted railway track vibration behaviour

Pin-pin resonance is one of the most significant preferred vibration modes of beams, which are supported at equal distances, such as rails at sleepers in railway track structures do. Pin-pin resonance is a vibration that appears in one basic (first) mode and several higher modes, however the basic mode will have the highest amplitudes. In...

Raman scattering and ionic transport in SrCe1-xYbxO3

On fictitious joints modelling of manipulator link flexibility for the HERA simulation facility pilot

The mathematical model for the dynamics of HERA must take into account structural flexibility in the slender manipulator links. For the HERA Simulation Facility Pilot, the model will contain one bending mode in each bending plane, and one torsion mode. The present document describes how this model can be simulated with rigid body simulation...

NLR Contributions to the flutter certification of aircraft with external stores

An outline is given of store flutter clearance activities of the NLR carried out by order of the Royal Netherlands Air Force. Special attention is devoted to the store flutter clearance of the F16 aircraft. Presented at: 7th Aircraft/Stores Compatibility Symposium,Wright-Patterson AFB, Ohio, 8-10 April 1986 and at the 17th Annual Symposium of...

Methoden voor het verbeteren van dynamische modellen van constructies

A survey of computational methods to improve dynamic analytical models described in the literature is made. Both the matrix methods and the optimal correction method of the dynamic model using the measured modes are discussed.