Two-Dimensional Motion of Vehicles Damaged due to Collision

This paper deals with two-dimensional motion analysis of vehicles damaged due to collision. Various parts of vehicles are damaged due to collision in general. The effects of the damage in vehicle body and wheels on the vehicle motions are investigated. The center of gravity of the vehicle and the polar moment of inertia are changed by the deformation of vehicle body. Furthermore, the geometrical relations of wheels like wheelbase, treads and steering angles may be changed by damage of the wheels. Thus the vehicle loses symmetry with respect to the vehicle axis. The four-wheel vehicle model is extended to take into account the vehicle damage due to collision. The motions of damaged vehicles are compared with those of undamaged vehicles. It is found that vehicle damages have a significant influence on vehicle motion after impact.     

Vehicle Motion Analysis in Relation to Vehicle Safety

The influence of vehicle handling on the possible avoidance of accident situations is discussed. lit is shown that accident reconstruction at present does not provide the necessary information to relate the cause of accidents to the lack of road worthiness of vehicles. It follows that the vehicle behavior in proximity of its performance limit must be determined in order to infer its accident avoidance potential.

The paper presents a review of the state-of-the-art of vehicle modeling, simulation of vehicle maneuvers and full scale testing. The application of the direct method of the stability theory is suggested as a possible means of obtaining performance limit envelopes which are necessary for establishing standards of the performance of vehicles.     

Flutter and Divergence Instabilities in Systems of Railway Wheelsets with Semi-rigid Articulation

For railway vehicles having coned wheels mounted on solid axles there is, in general, a conflict between stability of lateral deviations from the motion along the track and ability to steer round curves. However, certain configurations of three-axle vehicle can satisfy the requirement of perfect curving and for certain values of the system parameters are dynamically stable. In the case where three wheelsets have semi-rigid articulation and either the distribution of conicity amongst the wheelsets or the position of the articulation joint are varied, it is shown that both flutter and divergence instabilities can occur at low speeds, in contrast to the more common dynamic instabilities of other forms of railway vehicle which are driven by the inertia forces.     

Port managment development—a strategy for the provision of a training capability in developing countries

The absence of formal career-development programmes and the apparent low priority given to the development of human resources in the ports of developing countries has led to a severe shortage of suitably qualified and experienced managers. At the centre of this problem lies the formidable barriers to the establishment of a local training capability to meet the diverse and often specialized needs of this industry. This paper examines the nature and scale of the management-training requirements of the ports of developing countries. Further, it briefly describes the background to UNCTAD's role in the field of management training and outlines the objectives of its training strategy for the 1980s. An important component of this strategy is the 'Improving port performance project which is designed to prepare structured learning materials using audio-visual techniques and is proposed as one solution to establishing a local training capability in developing countries.     

In-Plane and Out-of-Plane Dynamics of Pneumatic Tyres

During the last decade research has been conducted on the dvnamics of the tvre considered as a vehiclecomponent. Asurvey is given of these developments where tyre mass plays an important role. The underlying theoretical considerations concerning the massless tyre have been discussed as well. Two groups of tyre response have been distinguished: the lateral (out-of-plane) response and the vertical/longitudinal (in-plane) response to motions of the wheel. In both categories tyre compliance, slip and inertia have influence. The dynamic properties of the rolling tyre have been presented in the form of transfer functions and/or differential equations. The frequency of the imposed oscillations is assumed to be below ca. 40 Hz. Non-linear effects and modelling have been briefly touched on.     

Bulk service queues with deviations from departure schedules: The problem of correlated headways

The usual approach to studying bulk service queues is to assume that successive headways are independent. This assumption is frequently violated in systems where vehicles depart according to a fixed schedule, but where deviations from the schedule may occur. A late departure implies there is one long headway followed by a shorter one. This problem is solved exactly using both classical transform techniques and iterative numerical methods. Experiments with the latter approach are presented, and comparisons between the exact results and those obtained by ignoring correlations between headways are performed. The results suggest that upper and lower bounds may be developed using existing results, where the upper bound is accurate in light traffic while the lower bound is accurate in heavy traffic.