Finite element analysis of collapse of front side rails with new types of crush initiators

Today’s vehicles are designed with lighter weight to increase performance and to lower fuel consumption, while at the same time meeting the demands of safety requirements. Reducing the cross-section of structural elements to achieve weight reduction can lead to adverse effects on passive safety of the vehicle. In such cases, necessary design modifications must be created to overcome the adverse effects. For this purpose, front rail columns with crush initiators are used in the front zone of cars. These shock-absorbing elements act as energy consuming devices that convert impact energy (kinetic energy) into plastic deformation energy. Simulation of this energy conversion phenomenon is the subject of this paper. The primary objective of this study is to computationally determine how various crush initiators can reduce the maximum crushing force and how different types of structural modifications affect the observed folding form. The ribs near the crash area are placed in two rows and four different configurations on all facing sides of the column in order to decrease reaction forces and absorb more kinetic energy. These structures are analyzed under axially loaded crushing forces using the explicit nonlinear finite element analysis solver ANSYS/LS-DYNA.     

Towards a theoretical model for behavioural adaptations to changes in the road transport system

A preliminary theoretical model is developed for the mechanism of behavioural adaptations to changes in the road transport system, which describes the process of behavioural change, explains the nature of adaptation phenomenon, and predicts its effects on road safety programmes. It can be used as a basis to organize the body of adaptation research and to explain empirical results.     

The MEPLAN models of Bilbao,Leeds and Dortmund

A trio of closely related land‐use/transport interaction models was developed using Marcial Echenique & Partners’ software package MEPLAN. The models were for the cities of Bilbao, (Spain), Dortmund (West Germany) and Leeds (England). All were calibrated using data drawn from earlier studies. The three models were used to predict the effects (relative to a base case) of a common programme of land‐use and transport policies or scenarios. This paper explains briefly the theoretical basis of the MEPLAN package as applied to urban models such as these three; describes the types of policies that have been assessed; and presents some of the key results.     

Competition Between New Port Governance Models on the Iberian Peninsula

The aim of this article is to analyze the interaction between port devolution processes in Portugal and Spain in their common geographical environment, the Iberian Peninsula. Firstly a review is done of the different port devolution processes in the world which specifically analyses the transition of numerous public and centralized ports to the landlord model. Among the conclusions that we can highlight with respect to the Iberian port systems are the need for a reflection process before any change is made to the port governance model, and greater cooperation between the two countries to avoid any possible future port tariff price wars. The over-investment process that the Spanish port devolution process, especially, has generated must also be mentioned, for highlighting once again the almost inexhaustible ability of ports to eat up public funds for investment that precludes profitability.     

Neural network model for designing automotive devices using SMD LED

The advantages offered by the electronic component LED (Light Emitting Diode) have resulted in a quick and extensive application of this device in the replacement of incandescent lights. In this combined application, however, the relationship between the design variables and the desired effect or result is very complex and renders it difficult to model using conventional techniques. This paper consists of the development of a technique using artificial neural networks that makes it possible to obtain the luminous intensity values of brake lights using SMD (Surface Mounted Device) LEDs from design data. This technique can be utilized to design any automotive device that uses groups of SMD LEDs. The results of industrial applications using SMD LED are presented to validate the proposed technique.     

Performance analysis according to the combination of energy storage system for fuel cell hybrid vehicle

The need for the unmanned ground combat vehicle (UGCV), which is used for the surveillance, reconnaissance and targeting during extremely dangerous condition on the battlefield, has steadily increased, and the transition from manned ground combat vehicles to unmanned ground combat vehicles is expected to reduce the loss of lives during battle. The UGCV needs many types of capabilities to achieve satisfactory performance. This paper focuses on the modeling and control of the power system of the UGCV, and proposes the fuel cell hybrid system (FCHS) for the power system of the UGCV. The fuel cell hybrid system has many advantages in stealth drive and the system efficiency. In addition, the FCHS is much quieter than the engine generator and generates much less heat. The benefits of the FCHS are advantageous for use in Army operations, which require ‘silent watch’ capability and the ability to operate without showing up on an enemy’s radar screen. The FCHS has a fuel cell and uses an energy storage system (ESS) as a power source. The ESS (e.g., batteries or ultracapacitors) helps the fuel cell supply power to the electric drive system and also recovers energy during deceleration. The ESS makes it possible to improve the efficiency and dynamic characteristic of the power system. In this paper, the FCHS is composed of different combinations of component models. The component sizes are chosen to satisfy performance requirements. In order to determine the power distribution between the fuel cell and the ESS, a power management strategy based on the required power and the SOC (state of charge) of the ESS is proposed. Batteries and ultracapacitor, components of the ESS, have different characteristics. Accordingly, varying the combination of ESS components can change the performance of the power system. The performance of the FCHS with respect to different combinations of ESS is analyzed using simulated results.     

Modeling urban taxi services in road networks: Progress,problem and prospect

Traditionally, many economists have examined the models and economics of urban taxi services under various types of regulation such as entry restriction and price control in an aggregate way. Only recently have we modeled urban taxi services in a network context. A realistic method has been proposed to describe vacant and occupied taxi movements in a road network and taxi drivers' search behavior for customers. A few extensions have been made to deal with demand elasticity and congestion effects together with development of efficient solution algorithms. Calibration and validation of the network taxi service models have been conducted towards their practical applications. This paper presents an overview of the research that has been carried out by the authors to develop network equilibrium models and solution algorithms for urban taxi services, and offers perspectives for future researches.     

Book Review

Vehicle Replacement — A Management Guide. By John E. Sussams. (Gower, 1983.) [Pp. 102.] £19.50.     

Modeling of gasoline fuel spray penetration in SIDI engines

The paper presents a research on the fuel injection and atomization depending on the thermodynamic quantities inside the cylinder of a combustion engine. With the use of piezoelectric outward-opening injectors the changes in the geometrical quantities of the atomized fuel in the aspect of its injection were determined. The studies concerning the influence of the individual quantities on the fuel spray penetration injected by the outward-opening injectors comprise a synthesis of the injection and atomization tests. Own mathematical equation describing the fuel spray penetration was proposed. The exponents (equation coefficients) related to the influence of the fuel pressure, air backpressure, charge density and time of fuel spray development were determined with the coefficient of determination 0.9797, indicating a congruence of the experimental data with the values obtained on the basis of the mathematical equation.     

Prediction of antilock braking system condition with the vehicle stationary using a model-based approach

An Antilock Braking System (ABS) is one of the most important safety facilities equipped in modern vehicles. A self-test is therefore embedded into its ECU to identify any electronic malfunction. However there is no effective method to predict or check its mechanical conditions routinely to ensure its functionality. Because the ABS system is merely actuated above a particular speed in emergency stops, the current brake test facilities are not adequate for ABS test. Because of the dangers involved it would not be acceptable to use a public road to implement such a practice for fault detection so an alternative means must be sought. To provide a safe and convenient solution this paper proposes a novel method to predict ABS faults whilst the vehicle is stationary. In this situation a model-based approach is applied to predict various faults from the ABS, especially from its hydraulic subsystem. As such, a mathematic model is developed to describe the operating processes of ABS including possible faulty conditions. An autonomous control strategy is also designed to actuate the control module independently without the knowledge of the control algorithms embedded in an ABS control module. This approach is evaluated through a Simulink simulation.