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ROZPRAWY INŻYNIERSKIE

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Abstracts of papers for

Previous issue vol. 48, no. 2 (2000)

vol. 48, no. 3 (2000)

Next issue vol. 48, no. 4 (2000)

Contents of issue 3, vol. 48

1. P. Fundowicz and J. Wicher: Semi-empirical model of tire - pavement contact
2. J. de Pont and B. Steven: Suspension dynamics and pavement wear
3. Z. Lozia: Vehicle dynamics model as road pavement load generator
4. A. Faber and W.D. Hahn: COST 334 : effects of wide single tyres and dual tyres. A technical and economic approach
5. J.P. Talbot: Reduction of train-induced vibration in buildings
6. Cz. Bajer, R. Bogacz, Sz. Imiełowski: Passive control of a beam subject to travelling inertial load
7. R. Lammering and M. Plenge: Investigations on railway tracks with special emphasis on partially unsupported sleepers due to voids
8. A.T. Dempsey, D.L. Keogh, B. Jacob and J. Carracilli: The response of orthotropic steel decks to traffic loads
9. R. Bogacz, A. Kamiński, T. Krzyżyński: On influence of pad features on dynamics of a railway track

P. Fundowicz and J. Wicher: Semi-empirical model of tire - pavement contact

Mathematical model of the tire - pavement interaction is presented in the paper. One of the main features of the model is easy identification of the parameter values by means typical testing equipment. In the model the contact zone of the tire is divided into the adhesion zone and the slip zone. Influence of the water wedge has been examined. Some typical tire characteristics are shown as a result of application of the proposed model.

Contents

J. de Pont and B. Steven: Suspension dynamics and pavement wear

Recently a series of three accelerated dynamic loading tests was carried out at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF). The aim of these tests was to determine the influence of dynamic loading on pavement wear.

Contents

Z. Lozia: Vehicle dynamics model as road pavement load generator

This paper presents the models of vehicle that are treated as road pavement load generators for different motion cases. The key role of a tire model is discussed. The most complicated 14 degrees of freedom truck model is based on the structure of a biaxial vehicle with dependently suspended front and rear wheels. The road pavement is treated as rigid but uneven. The road irregularities have a determined 3D form and may also be the realisation of stationary Gaussian random process describing the real road according to ISO recommendations. The paper shows specific model application for generation of forces between tires and uneven road. The vehicle response (for given motion cases, e.g. straight constant velocity motion) may be presented as time histories of footprint forces as well as force's PSD. The simulation results may be treated as input data for the road pavement stress and wear analysis.

Contents

A. Faber and W.D. Hahn: COST 334 : effects of wide single tyres and dual tyres. A technical and economic approach

This paper deals with the comparison of technical and economic aspects for heavy commercial vehicles fitted with wide base single or dual tyres (Figure 1). The task is part of the European research project "COST 334: Effects of Wide Base Single Tyres and Dual Tyres" which includes pavement wear effects, vehicle operational and pavement maintenance cost models, non pavement effects and consequences. The paper presented here mainly describes the problems of driving behaviour and vehicle safety.

Contents

J.P. Talbot: Reduction of train-induced vibration in buildings

There are many ways of reducing the transmission of train-induced vibration into buildings. One such measure is the use of floating-slab track whereby the track is mounted on a concrete foundation resting on isolation bearings. Impressive claims are often made regarding its effectiveness by referring to simple mass-spring models. However, some recent work, reviewed in the initial part of this paper, suggests that the effectiveness of floating-slab track for underground railways can be severely limited by interactions with the tunnel and surrounding soil.

The paper goes on to discuss base isolation of buildings as an alternative to vibration countermeasures at source. Again, simple mass-spring models are often used to make predictions of isolation performance which are far too optimistic. Alternative models are discussed with a view to developing a more appropriate means of assessing isolation performance.

Contents

Cz. Bajer, R. Bogacz, Sz. Imiełowski: Passive control of a beam subject to travelling inertial load

The subject of the study is the minimization of transverse vibration of elastic guideway excited by high-speed travelling inertial load. Two types of systems of passive control are considered, the post truss system and the dynamic vibration absorbers. In the first one, the beam is supported by posts fixed to the beam span and prestressed by tendons connected to the ends of beam. The considered system corresponds to the experimental test stand. It is modelled by a simply supported Bernoulli-Euler beam, where the material passive damping is represented by means of the Voigt model. In the system the control is performed by point transverse forces and bending moments applied to the beam span.

The significant reduction of the amplitude of vibrations is achieved for a guideway supported by truss system consisting of two posts. The obtained results are compared with the data obtained for active control of the considered guideway.

Contents

R. Lammering and M. Plenge: Investigations on railway tracks with special emphasis on partially unsupported sleepers due to voids

A single sleeper, two adjacent sleepers and a track segment are investigated experimentally in order to get a basic knowledge of the dynamic response of a vertically loaded railway track up to 800 Hz. Since voids are often observed between sleepers and the underlying ballast, special emphasis is laid on investigations of partially unsupported sleepers. Detailed information on the dynamic displacement field is obtained by the holographic interferometry which is used beside conventional accelerometers to record the oscillations. The results show that deviations from optimal coupling to the ground result in significant changes of the dynamic behavior.

Contents

A.T. Dempsey, D.L. Keogh, B. Jacob and J. Carracilli: The response of orthotropic steel decks to traffic loads

This paper describes the instrumentation and load testing of a three span orthotropic steel bridge in France. Strain gauges were attached to the underside of the orthotropic plate to measure the dynamic response of the bridge to traffic loading. Two preweighed trucks were driven across the bridge at different velocities to investigate the influence of truck speed on the dynamic amplification of the bridge. A model suitable for the prediction of the dynamic response of the bridge is described. This consists of an elaborate finite element model to determine the natural frequencies and mode shapes of the bridge and a dynamic model which uses this information to determine the dynamic response. The results of the experimentation are presented and the relationship between truck speed and dynamic amplification are shown. Finally, the loads applied to the bridge by an instrumented truck driving over it are presented and comparisons are made with the loads applied at the bridge approaches.

Contents

R. Bogacz, A. Kamiński, T. Krzyżyński: On influence of pad features on dynamics of a railway track

The vertical track dynamic model is described in the paper as a periodic structure. It is composed of rails modelled as Timoshenko or Bernoulli-Euler beams, sleepers (lumped masses) and pads and ballast modelled as viscoelastic elements. Particular attention is paid to the influence of pad characteristics on the dynamic stiffness of the track. One of the ideas of the new pad generation is also presented in the paper. Some parameters of the pad are given.

Contents

Abstracts for 48, 2, 2000 (previous issue)

Abstracts for 48, 4, 2000 (next issue)

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