The compressive behavior of advanced double hull structure—A review of current research at David Taylor

It has long been recognized that the compressive behavior of primary ship structural components plays a vital role in the design of surface ship hulls. This is equally as true for the new advanced double hull concept as it is for the more conventional surface ship configurations. What is different, however, is the nature of the structural mechanics phenomena which must be addressed due to the double hull's more radical departure from conventional design and construction practices. With increasing interest and attention being shown in this new concept, the David Taylor Model Basin has over the past few years initiated a number of research efforts which have and are continuing to address various aspects of the behavior of double hulls and their components to primary compressive loadings. These studies have as their ultimate goal the development of practical, user oriented design methods for double hull structure and as such currently focus on more approximate, rather than mathematically rigorous, approaches to the various structural phenomena being considered. This paper is in essence a progress report on a selected number of these efforts and describes the results achieved to date as well as the ongoing efforts and those planned for the future. This report focuses primarily on three recent studies: (1) a preliminary look at the relative significance of local versus general instability failure of double hull structure; (2) small scale experimental analysis of double hull sections using rigid vinyl modelling; and (3) the application of beam-on-elastic-foundation analysis methods for high aspect stiffened plates as it relates to double hull structure. In addition to these major topics, the report also includes a brief discussion of other ongoing and planned efforts relevant to the advanced double hull.     

Wheel/Rail Contact: Geometrical Study*

Before trying to ascertain the precise nature of the Wheel-Rail contact (internal stresses and strains, wear and friction, security against a derailment, dynamic behaviour of the vehicle, etc.) the geometrical problem must necessarily be solved. That is, for each position of the wheelset (this is defined by 6 parameters, of which only 4 are independent) the two dependent parameters and the coordinates of the points of contact of each wheel, and rail must be obtained. A new method is proposed of obtaining the spatial position of a wheelset with reference to the rails, from the most general point of view.     

Rail freight transportation: A review of recent optimization models for train routing and empty car distribution

This paper describes two types of rail transportation problems in detail. These are train routing and makeup, and empty car distribution problems. Some of the recent optimization models which address these problems are reviewed and the areas for potential improvements in rail transportation literature are identified. The type of interactions which exist between routing, makeup, and empty car distribution decisions are highlighted and potential areas for future research are identified.     

Dynamic Interactions Between Travelling Vehicles and Guideway Systems

The technical state-of-the-art of ground transportation vehicles interacting with flexible, perturbed guideway systems is reviewed with emphasis on high-speed passenger-carrying systems. Currently available modelling, analysis, and simulation techniques as well as parametric results illustrating the dominant interaction dynamics are summarized. Experimental studies and correlations of field data with analytical results are described and areas in which further research is required are identified.     

Shipping control and the changing use of marine space

In this paper Professor Couper discusses the divisions of marine space as set out in the Revised Single Negotiating Text of UNCLOS III in relation to maritime accidents. This is followed by a contribution by Mr Burger on statistical material related to the incidence of marine accidents in North-West European waters. The third section of the paper by Captain S. Abdelgalil, is devoted to a technical discussion on traffic lanes in confined waters.