Ship hull plate processing surface fairing with constraints based on B-spline

The problem of ship hull plate processing surface fairing with constraints based on B-spline is solved in this paper. The algorithm for B-spline curve fairing with constraints is one of the most common methods in plane curve fairing. The algorithm can be applied to global and local curve fairing. It can constrain the perturbation range of the control points and the shape variation of the curve, and get a better fairing result in plane curves. In this paper, a new fairing algorithm with constraints for curves and surfaces in space is presented. Then this method is applied to the experiments of ship hull plate processing surface. Finally numerical results are obtained to show the efficiency of this method.     

A new model for soil consolidation based on microstructure

This paper introduces a new means to predict consolidation deformation of soil from its microstructure. Based on a kind of pore-size distribution density function, a fractal model for soil consolidation is established. Through this model, the relation between macroscopic deformation and microcosmic pore property of soil is founded. In order to justify this proposed model for soil consolidation, consolidation experiments of soft clay are performed. Afterward, the microstructure of soft clay unconsolidated and consolidated under every pressure is studied by a scanning electron microscope (SEM). The results show that the proposed model for soil consolidation is valid in predicting consolidation deformation.     

Numerical simulation of non-destructive testing of stainless steel composites plate by infrared thermography

The non-destructive testing (NDT) of debonding in stainless steel composites plate (SSCP) is performed by infrared thermography, finite element analysis (FEA) software ANSYS is taken as the simulative tool, and 2D simulative model has been set up to investigate effect of the thickness of coating and/or substrate on the detectibility of debonging in SSCPs. Two parameters, namely the maximum defect temperature difference and defect appearing index, are defined to evaluate the detectivity of defects, and their computational methods and formulas are given respectively. The preliminary changing tendency of the maximum defect temperature difference and defect appearing index with the thickness of coating and/or substrate is found by numerical simulation.     

Fatigue life prediction of welded stiffened 350WT steel plates

The propagation of fatigue cracks under constant amplitude cyclic loading was studied in welded stiffened steel plates. The residual stresses in the stiffened plates were measured using the neutron diffraction strain-scanning technique. A finite element model of the stiffened plate was constructed to simulate the residual stresses by an uncoupled thermal and thermo-mechanical analysis. Both the finite element model and the neutron diffraction measurements indicated that in general the residual stresses were tensile near the welded stiffeners and compressive between the stiffeners and ahead of the starter notch tip. Fatigue testing indicated that the fatigue crack growth rates of the stiffened plates were in general lower than that of a corresponding unstiffened plate, especially near the notch tip where compressive residual stresses existed. Both the finite element method and Green's function predicted the fatigue crack growth rates with reasonable accuracy.     

Simulation of unsteady free-surface flow around a ship hull using a fully coupled multi-phase flow method

An accurate, efficient algorithm for solving free surface flows around ship hulls is described. Accuracy is achieved using a compressive advection discretization which maintains a sharp free surface interface representation without relying on a small time step. Efficiency is obtained using a solution algorithm which implicitly couples velocity, pressure, and volume fractions. The algorithm has been implemented in a computational fluid dynamics code called CFX and is validated by means of a comparisonwith experimental data of benchmark cases in both steady and transient conditions.     

Development of an electric motor-driven pump unit for electro-hydraulic power steering with 42V power-Net

Motorization in vehicles is expanding rapidly for fuel efficiency, customer comfort, convenience, and safety features. These new electric loads represent an increase in the required electric power. This has generated interest in new, higher power systems such as the 42V Power Net. The electro-hydraulic power steering (EHPS) system is one of these systems. This paper presents the development of the electric motor-driven pump unit for the EHPS system using a 42V power-Net. The interior type permanent magnet synchronous motor (IPMSM) can be applied to this system with more power density per volume for compactness of the EHPS. In order to improve the system, the IPMSM and its control method was optimized for improved torque characteristics and electric power consumption. The performances of both the pump unit and the IPMSM have been verified by experimental results. Finally, all in one type the electric motor-driven pump unit are developed from the experiment verification.     

GPS-based speed collection method for road traffic noise mapping

One of the most difficult and expensive tasks in making noise pollution maps is the collection and processing of the data needed to create acoustic models. In the case of road traffic noise maps, obtaining speed data for light and heavy vehicles a problem that has usually been avoided by using a road’s speed limit or by making assumptions based on experience from similar road types. Here global positioning systems-based techniques are applied for acquiring vehicle speed data and adapted to fulfill the requirements of noise prediction models.     

L’intégration territoriale des gares sur lignes à grande vitesse en France : une approche typologique

Construction of high-speed railway lines (Lignes à Grande Vitesse — LGV in French) in France and in other European countries has brought considerable changes in railway accessibility for the areas linked to this fast transport network. The new stations on the high-speed lines take maximum advantage of such relational gains. However, mass transit access to these stations often constitutes a problem. Their locations, which are frequently exurban, are not determined by considerations involving efficient mass transit service links, and especially railway links. This situation creates difficulties for prior and subsequent passenger travel, and it means that the local players have to develop new access routes of variable quality. The present article puts forward a quality analysis covering territorial integration of high-speed railway stations via typology of the interactions between these new service points and the established stations in central locations. In a context marked by the increasing burdens placed on local authorities regarding financing for new high-speed railway infrastructures, we examine whether these changes in the players’ roles encourage enhanced consideration as to positioning of high-speed railway stations in relation to accessibility criteria for mass transit.     

Designing a non-linear tracking controller for vehicle active suspension systems using an optimization process

In this paper, a new non-linear tracking controller for vehicle active suspension systems is analytically designed using an optimization process. The proposed scheme employs a realistic non-linear quarter-car model, which is composed of a hardening spring and a quadratic damping force. The control input is the external active suspension force and is determined by minimizing a performance index defined as a weighted combination of conflicting objectives, namely ride quality, handling performance and control energy. A linear skyhook model with standard parameters is used as the reference model to be tracked by the controller. The robustness of the proposed controller in the presence of modeling uncertainties is investigated. The performed analysis and the simulation results indicate that both vehicle ride comfort and handling performance can be improved using the minimum external force when the proposed non-linear controller is engaged with the model. Meanwhile, a compromise between different objectives and control energy can easily be made by regulating their respective weighting factors, which are the free parameters of the control law.     

Safety in Greek coastal shipping: The role and risk of human factor revisited

The comprehensive analysis presented in this paper investigates the links and comparative assets between human factor and other factors that are important determinants of maritime transport risk. In this outline, the identification of factors, such as age and ship size, that can be statistically linked (i.e. statistical significance) to whether an accident in a passenger vessel can be attributed to human factor or other causes is addressed accordingly. This way, the role of human factor in relation to safety of Greek coastal shipping is revealed and the spotlight is able to focus on the various aspects and points that manifest the importance of human element in the maritime industry. The risk assessment of the transportation with Greek passenger ships is being used in order for the safety level of Greek coastal shipping to be adequately estimated. Moreover, the comparison between the values of risk for accidents caused by human factor and those attributed to other causes is an established way to bring to the fore the unbroken relationship between the human factor and marine accidents’ consequences. The paper is concluded with interesting insights and comments drafted through the aforementioned tasks.