Applied Mechanics and Materials Vols. 178-181

Abstract: In order to solve cost-sharing problems for taxi-carpooling passengers, the optimization model of sharing taxi-carpooling expenses was established taking both taxi-driver and passengers’ benefits into fully consideration. Based on the fact that passengers would pay for their own share in proportion, the optimization model was made with the objective function aiming at minimum consumption of time and money. In view of its features, the theoretical model was further developed comparing expenses in theory with that under existing conditions. The results show that this optimization model of sharing taxi-carpooling expenses can meet the need of both passengers and taxi driver. Moreover, the research findings will provide a firm technical support and guarantee for a satisfactory solution to cost-sharing problems on taxi-carpooling.

Abstract: According to the characters, technological condition and requirements of automotive front axle forging, the advantage of the roll forging and integral die forging complex process for automobile front axle were explained, including the determination of roll- forging parts chart, selection of billet dimension, decision of roll- forging steps, special roller- shaped design of typical section, and the front sliding parameter is calculated, its effect to length of forging parts gets analyzed. In this paper, taking NHR front axle as an instance, both the process of exact roll- forging billet and die design are studied, as the result, roll- forging die、 performing roll- forging die and final roll-forging die are design respectively. The process for roll forging was simulated by the three dimensional finite element analyses under isothermal condition, and metal flow procedure and force time curve were obtained. The connection among metal flow law and die cavity design and forming load were also analyzed. To verify the reliability of the simulation, the results for profile was compared with the tested forging part, showing that metal flow law of both are coincident and FE simulation of roll forging is accurate. Practice testify that FE simulation of roll forging for front axle can reduce the time of process design and procedure debugging and be helpful to response the market demand.

Abstract: A mathematical model of airside pressure drop was established, and calculations were conducted respectively under dry condition and wet condition for evaporators with hydrophilic treatment and without hydrophilic treatment. Experimental results demonstrate the proposed model. The results reveal a significant improvement of hydrophilic treatment, and air resistance drops to 53% when relative humidity is 50%, while it drops to 50% when relative humidity is 90%.

Abstract: Crew rostering is one of the most important scheduling problems for large airlines. In this study, a LP resolving algorithm in the B&B tree context and a heuristic for the IP solution of the crew rostering problem were proposed. The efficiency mainly comes from the special structure of the crew rostering problem. The computational experiments on the real-world problems showed that the time of the proposed resolving algorithm doesn't exceed 30% of that solves from scratch although the problem has largely changed, and the heuristic for the IP solution can rapidly get a sufficiently good scheme for all crew.

Abstract: This paper investigates the effects of two driving behaviors on driving performance, the driving with eco-driving support and the general driving. Through observing and analyzing these driving behaviors in a variety of situations, driving performance under conditions of with and without eco-driving was evaluated. Based on the measurements on fuel consumption, speed control and gear use, it was found that eco-driving device can guide drivers to take proper driving behavior, such as in which way to drive and how to drive in order to achieve energy saving. The paper revealed the effects of eco-driving and how to drive efficiently.

Abstract: The main purpose of this paper is to analyze the operation strategies of the world’s top 20 shipping companies by using SWOT (Strength, Weakness, Opportunity, and Threat) analysis method. Finally, some conclusions and suggestions are given to shipping companies, port managers, and departments of governmental maritime transportation as references.

Abstract: The Weihai-Dalian route is a busy route, in which many ro-ro passenger ships sail. It takes an important part in the economy development of North China. Based on the special weather conditions and geographical conditions, some statistical data are analyzed to find the elements which can influence the navigation safety, and problems in weather forecast. Some countermeasures are put forward to ensure the safety of navigation.

Abstract: Hydrofoil is the important part of ship design and diverse motion equipment. The optimization design of hydrofoil section on lift-to-drag radio with genetic algorithm (GA) and simulated annealing algorithm are demonstrated, and the method on the hydrofoil section design of the propeller design will be done. Objective function and fitness of every individual are provided by flow solver of panel method. The optimization method on design of hydrofoil section on lift-to-drag is successfully used. The optimization results show the combination of optimization algorithm is feasible at the optimal design of hydrofoil sections. What’s more, a comparison between two different optimization algorithms is made, a conclusion that the simulated annealing algorithm is better then the genetic algorithm is obtained.

Abstract: Owing to the advantages of weight loss and security, duplex steel plate has been the priority for the saloon car body instead of ordinary one among a majority of engine factories. While there are undesirable phenomena because of its high strength at normal temperature, such as its formability is worsened dramatically, and failure and fracture always occur in the stamping. So hot stamping process must be adopted to make the formability available. Based on the Bumper chain of Beijing Hyundai Reina and taken DP600 high strength steel as research object, this paper analyzes the distributions of stress, strain and thickness changes during the process of sheet metal forming by using eta/DYNAFORM software, simulates the spring-back quantity after hot stamping forming, and the numerical simulation of the temperature field distribution with time during stamping process was done. The result shows that duplex steel plate can meet the performance requirements of automotive chain forming, which offers theory basis for the production of such parts.

Abstract: This paper describes how the wing surfaces are defined by aerodynamic, stability/control, layout and structural requirements. The size of the wing (area) will usually be dictated by aircraft performance requirements(e.g. field length) but the shape of the planform and other geometry may be influenced by wing layout factors. In the early design stages choices need to be made on the position of the wing relative to the fuselage (e.g. high, mid or low position) and then on the overall envelope. This will include selection of aspect ratio, taper ratio, sweepback angle, thickness ratio and section profile, and dihedral. Each of these decisions is explained. A brief introduction on flap design of the aerodynamic (lift and drag) characteristics of flaps are also described, which is added to explain the wing layout of aircraft.