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351.
The Electric Power Steering (EPS) or Motor Driven Power Steering (MDPS) mechanism proves to be a bright prospect among passenger vehicles ensuring better vehicle safety and fuel economy. The car manufacturers are focusing on the production of Rack type EPS system (REPS). This paper describes the development of concurrent simulation technique using TruckSim and control strategy for analysing RMDPS control system with a dynamic vehicle system. A full Truck vehicle model interacting with RMDPS control algorithm was concurrently simulated on a sinusoidal steering input. The dynamic responses of vehicle chassis and steering system resulting were evaluated and compared with proving ground experimental data. The comparisons show reasonable agreement on steering wheel torque, lateral acceleration and yaw rate. This concurrent simulation research leads the possibility of RMDPS performance evaluation of Truck and Semi-bonnet cars. 相似文献
352.
J. H. Seo E. D. Lee J. W. Lee B. K. Han 《International Journal of Automotive Technology》2016,17(4):665-670
This study reports on the effect of vehicle tumble-home (side body inclination) on roof strength. The steep inclination of the side body of a vehicle increases its roof strength. Comprehensive analysis of the impact of high roof strength driven by the steep inclination on dynamic roof strength in rollover is described. Here, we have developed a numerical model using the ADAMS, which is capable of characterizing both of the static and the dynamic roof strength. According to the FMVSS 216 protocol, we achieve the strength to weight ratio (SWR; static roof strength) by applying loading plates to the roof of a vehicle. The Controlled Rollover Impact System (CRIS) allows us to quantitatively characterize the displacements of the top end of A-pillar and B-pillar, thus determining the dynamic roof strength by comparing the results. We demonstrated that the roof intrusion was one of the most critical causes which lead to injuries of occupants fastening seat belts. Our analysis revealed that the increase of the side body inclination of vehicles enhanced the static roof strength whereas it could not reduce the roof displacement (intrusion) in the dynamic rollover. 相似文献
353.
S. M. Yang S. H. Yoo D. S. Gi S. B. Choi K. S. Kim N. T. Jeong S. U. Choi M. W. Suh J. H. Lee 《International Journal of Automotive Technology》2016,17(4):671-679
While a screw is a fastening element that can tighten the two parts at low cost, the loosening of the screw is generated due to external forces such as repetitive load, vibration, and thermal stress. This phenomenon decreases the initial clamping force, and this can be a serious problem to the safety of the product. However, while fastening parts are handled through experiment and experience, there is a lack of research on the screw loosening of plastic fastening parts. For example, vehicles have various fastening parts. Among the fastening elements, screws are typically used for tightening parts of the vehicle door trim. Vehicle interior materials are mainly composed of plastic parts. Especially, the temperature of the vehicle interior changes from a sub-zero temperature to 100 degrees (°C) due to solar radiation. Unlike metals, plastic materials are commonly susceptible to the environment. In this study, the fastening screw of automotive door trim parts is selected. First, a screw loosening mechanism is implemented through Computer Aided Engineering (CAE) analysis and the influences of degradation are then analyzed. Secondly, the selecting method of clamping force is suggested through the analysis result of reduction according to the tightening torque. 相似文献
354.
Alexander B. Phillips Stephen R. Turnock Maaten Furlong 《Journal of Marine Science and Technology》2010,15(3):201-217
Manoeuvring underwater vehicles experience complex three-dimensional flow. Features include stagnation and boundary layer
separation along a convex surface. The resulting free vortex sheet rolls up to form a pair of streamwise body vortices. The
track and strength of the body vortex pair results in a nonlinear increase in lift as body incidence increases. Consequently,
accurate capture of the body vortex pair is essential if the flow field around a manoeuvring submarine and the resulting hydrodynamic
loading is to be correctly found. This work highlights the importance of both grid convergence and turbulence closure models
(TCMs) to the strength and path of the crossflow-induced body vortices experienced by the DOR submarine model at an incidence
angle of 15°. Five TCMs are considered; Spalart–Allmaras, k-ε, k-ω, shear stress transport, and the SSG Reynolds stress model. The SSG Reynolds stress model shows potential improvements in
predicting both the path and strength of the body vortex over standard one- and two-equation TCMs based on an eddy viscosity
approach. 相似文献
355.
Zina Armi Elbahri Trabelsi Souad Turki Béchir Béjaoui Naceur Ben Maïz 《Journal of Marine Science and Technology》2010,15(4):417-426
Phytoplankton community structure was investigated in a 1-year study period from January to December 2006 in the Tunis North
Lagoon (South Mediterranean). Twice a month, sampling was carried out from the whole water column. Phytoplankton species composition
showed seasonal dynamics following the general environmental variable trends in the study area, with variation in species
abundance levels within each season characterised by the presence of different phytoplankton communities. Analysis of environmental
variables indicated that phytoplankton-dominant communities were associated with various water physicochemical characteristics,
especially water temperature and salinity. Accordingly, significant correlation was recorded between water temperature and
dinoflagellates (r = 0.35; p < 0.05) in summer and diatoms (r = 0.69; p < 0.05) in autumn, whereas euglenophytes, cyanophytes and chlorophytes were slightly correlated with temperature in autumn.
Salinity was positively correlated with dichtyophytes (r = 0.41; p < 0.05) in winter and with diatoms (r = 0.65; p < 0.05) and euglenophytes (r = 0.57; p < 0.05) in autumn. On the other hand, relationships between high nitrogen nutrient concentration and phytoplankton concentration
were recorded for diatoms (r = 0.43; p < 0.05 with NO2; r = 0.49; p < 0.05 with NO3) in winter. Silicate concentration supported proliferation of diatoms (r = 0.58; p < 0.05) in autumn in our study period. In contrast, increase of dinoflagellate concentration was associated with the decrease
of these parameters in spring and summer. 相似文献
356.
Hiroshi Matsukura Maytouch Udommahuntisuk Hiroyuki Yamato A. A. B. Dinariyana 《Journal of Marine Science and Technology》2010,15(1):34-43
This research discusses domestic feeder container transportation connected with international trades in Japan. Optimal round
trip courses of container ship fleet from the perspective of CO2 emission reduction are calculated and analyzed to obtain basic knowledge about CO2 emission reduction in the container feeder transportation system. Specifically, based on the weekly origin–destination (OD)
data at a hub port (Kobe) and other related transportation data, the ship routes are designed by employing a mathematical
modeling approach. First, a mixed integer programming model is formulated and solved by using an optimization software that
employs branch and bound algorithm. The objective function of the model is to minimize the CO2 emission subject to necessary (and partially simplified) constraints. The model is then tested on various types of ships
with different speed and capacity. Moreover, it is also tested on various waiting times at hub port to investigate the effect
in CO2 emission of the designated fleet. Both the assessment method of container feeder transportation and the transportation’s
basic insights in view of CO2 emission are shown through the analysis. 相似文献
357.
U. B. Azimov K. S. Kim D. S. Jeong Y. G. Lee 《International Journal of Automotive Technology》2011,12(2):159-171
An experimental study has been performed on spray combustion and two-dimensional soot concentration in diesel (ULSD), GTL
and GTL-biodiesel fuel jets under high-pressure, high-temperature quiescent conditions. Instantaneous images of the fuel jets
were obtained with a high-speed camera. It was confirmed that by blending GTL with 20% rapeseed biodiesel, certain fuel properties
such as kinematic viscosity, density, surface tension, volatility, lower heating value and others may be designed and improved
to be more like those of conventional diesel fuel but with considerable decrease in the amount of sulfur, PAH, cold filter
plugging point, etc. The results showed that the spray tip penetration increased and the spray cone angle decreased when 20%
biodiesel fuel was added to GTL fuel. Autoignition of the GTL-biodiesel blend occurred slightly earlier than that of diesel
fuel. Experiments under high-pressure, high-temperature conditions showed that higher injection pressure induced a lower soot
formation rate. The integrated flame luminosity, which serves as an indicator of soot concentration in the fuel jet, was slightly
higher for the GTL-biodiesel blend than for pure GTL fuel due to the slightly higher sulfur content of pure biodiesel fuel. 相似文献
358.
Freight transport research has generally been limited by a lack of data of the breadth and quality available for passenger transport, particularly in terms of behavioural data. This paper discusses the survey design and implementation of a survey intended to collect longitudinal behavioural data on the responses of freight transport firms to environmental policies. The design of the survey is centred around a hypothetical scenario where respondents are asked how they would complete a given freight task within common constraints. One of the key components of the survey design is a dynamic component intended to simulate the changing business environment. The paper illustrates the many challenges in getting complex freight related surveys in the field. 相似文献
359.
正自适应AUTOSAR为实现车辆ECU软件的更大灵活性打下了坚实的基础。这些系统是可扩展的,是全自动和联网驾驶方向的重要一步。自适应AUTOSAR不是替代经典AUTOSAR,它的优势在于2种标准的巧妙结合。自动驾驶对车辆内部E/E架构提出了更高要求。自动驾驶功能需要越来越强大的控制单元,且越来越多地相互联网,并与基础设施(如云端系统)联网(图1)。通过使用来自各种车辆传感器以及外部(例如高精确地图资料)的数据,软件可创 相似文献
360.
Wang X.Wang B.Tan Z.Wang Y. 《现代隧道技术》2018,(3):37-45
With the rapid development of China high speed railway, there is a dramatic increase of deep-buried and long mountain tunnels, and more and more tunnels are disturbed by high water pressure during construction and operation. Design for tunnel lining with high water pressure is one of the central concerns in the field of tunnel engi-neering, and the key problem is to forecast water pressure on the secondary lining and determination of water pressure resistance grade. The upper limit of water pressure on the secondary lining is studied by investigation and analysis in this paper. The study shows: (1) There should be an upper limit for the grade of water pressure resistance; (2) It is not very effective to improve the tunnel structure bearing capacity by only increasing the lining thickness haphazard-ly, and the appropriate maximum thickness of secondary lining is 1 m; (3) It is also unsatisfactory to improve the tunnel structure bearing capacity by simply increase concrete strength grade. The appropriate concrete grade is between C40 and C50. (4) In view of tunnel structure safety and good operation performance, the upper limit of water pressure resist grade should be no more than 1.2 MPa. When water pressure on the secondary exceeds the designed value,comprehensive measures should be taken to adjust the value to the appropriate range. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献