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831.
M. Demić D. Diligenski M. Demić I. Demić 《International Journal of Automotive Technology》2010,11(6):801-808
Macro and micro road profiles are of significant importance for vehicular motion studies, reliable calculations of vehicle
system properties, and ensuring vehicular safety. As such, road profiles should be considered carefully. Macro profiles consider
the spatial geometry of the road (curves, longitudinal and lateral slopes) while micro profiles consider roughness in longitudinal
and lateral directions. These profiles have random characteristics that can be quantified under onroad and off-road conditions
using a road profiler. This paper presents an analysis of a new concept for a universal profiler without gyroscopic stabilizers. 相似文献
832.
Rollover mitigation for a heavy commercial vehicle 总被引:1,自引:0,他引:1
Y. I. Ryu D. O. Kang S. J. Heo J. H. In 《International Journal of Automotive Technology》2010,11(2):283-287
A heavy commercial vehicle has a high probability of rollover because it is usually loaded heavily and thus has a high center
of gravity. An anti-roll bar is efficient for rollover mitigation, but it can cause poor ride comfort when the roll stiffness
is excessively high. Therefore, active roll control (ARC) systems have been developed to optimally control the roll state
of a vehicle while maintaining ride comfort. Previously developed ARC systems have some disadvantages, such as cost, complexity,
power consumption, and weight. In this study, an ARC-based rear air suspension for a heavy commercial vehicle, which does
not require additional power for control, was designed and manufactured. The rollover index-based vehicle rollover mitigation
control scheme was used for the ARC system. Multi-body dynamic models of the suspension subsystem and the full vehicle were
used to design the rear air suspension and the ARC system. The reference rollover index was tuned through lab tests. Field
tests, such as steady state cornering tests and step steer tests, demonstrated that the roll response characteristics in the
steady state and transient state were improved. 相似文献
833.
Active Suspension Control; Performance Comparisons Using Control Laws Applied to a Full Vehicle Model 总被引:1,自引:0,他引:1
D.A. Crolla M.B.A. Abdel-Hady 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1991,20(2):107-120
Based on a mathematical model of an actively suspended vehicle, the effects of the following issues in deriving the control laws are studied:
(a)representation of the ground surface as integrated or filtered white noise.
(b)cross-correlation between left and right track inputs.
(c)wheelbase time delay between front and rear inputs.
The third of these issues is shown to be by far the most important. Considerable improvements at the rear suspension can be obtained if the control law includes the information that the rear input is simply a delayed version of the front input. Effectively this provides feedforward terms in the control law for the rear actuator. For the full state feedback case, these improvements are indicated by reductions in the rear body acceleration and rear dynamic tyre load of around 20% and 40% respectively with no increase in suspension working space. 相似文献
(a)representation of the ground surface as integrated or filtered white noise.
(b)cross-correlation between left and right track inputs.
(c)wheelbase time delay between front and rear inputs.
The third of these issues is shown to be by far the most important. Considerable improvements at the rear suspension can be obtained if the control law includes the information that the rear input is simply a delayed version of the front input. Effectively this provides feedforward terms in the control law for the rear actuator. For the full state feedback case, these improvements are indicated by reductions in the rear body acceleration and rear dynamic tyre load of around 20% and 40% respectively with no increase in suspension working space. 相似文献
834.
835.
Recent measurements of wave induced hull strain and flexure in RN warships are presented together with the derivation of the current design criteria for extreme hull girder bending loads. The history of the development of the shipboard instrumentation used is given and recent developments to improve the quality and ease of analysis of the data are described. An unexpectedly high transverse asymmetry in the longitudinal strains measured in destroyers is shown to be the result of a combination of vertical and lateral bending in oblique seas. Finally recent theoretical comparisons between the loading of Deep-Vee hulls and conventional UK rounded bilge hulls are presented which demonstrate the higher loading experienced by this type of hull form. 相似文献
836.
837.
Results from four different methods for stochastic dynamic response analysis of a proposed jack-up platform are compared. This structure exhibits both significant dynamic amplification and non-linear transfer of sea elevation into load effects. Both estimation of extreme response and fatigue damage are considered. The most complex procedure based on time-domain simulation and step-by-step integration is employed as a benchmark for assessment of three simplified methods. The simplifications consist of various types of linearization in conjunction with transfer function approximations. Applicability of the methods to structures with increasingly non-linear behaviour and dynamic amplification is briefly discussed. 相似文献
838.
The implications of increased competition among ports for port policy and management 总被引:1,自引:0,他引:1
Trevor D. Heaver 《Maritime Policy and Management》1995,22(2):125-133
The increased competition faced by ports is more focused than previously on the performance of logistics systems of which the individual terminals in ports are critical hubs. The changes in competitive conditions raise issues about appropriate public port policies and strategies of port managements. This paper argucs that the port industry should (and is) moving in the direction of more harmonized policies based on economic principles. Port policies based on cost recovery from users of port facilities and services need to be adopted as the international standard. The competitive environment favours considerable local autonomy. Port management, in addition to possible direct responsibility for terminal management, needs to focus on activities with economies of scale or scope. Such activities, which span the requirements of terminals and may even warrant inter-port cooperation, enhance the services available for many port users. 相似文献
839.
M. Masson A. W. van Weers R. E. J. Groothuis H. Dahlgaard R. D. Ibbett K. S. Leonard 《Journal of Marine Systems》1995,6(5-6)
99Tc and 125Sb have been released in low level liquid waste at the reprocessing plant at La Hague (Fr). Over a number of years data have been obtained on the concentration of 99Tc in sea water and in seaweed from sampling locations close to and at increasing distances north and east of the point of release into the English Channel.In addition such data have been obtained on 125Sb for a small number of sampling points. These time series, and the information derived from their intercomparison and from comparison with the release data, are presented in this paper.Time series on 99Tc as well as 125Sb in sea water and seaweed clearly confirm a considerable decrease in release rates at La Hague over the years 1986–1993. Transit times and transfer factors derived from the series are generally in good agreement with the results of modelling efforts. The data do not provide evidence for a time lag between levels of the radionuclides in sea water and those in seaweed longer than a few months.The very high concentration factors for 99Tc in brown seaweeds make these seaweeds very useful for environmental monitoring the radionuclide at low release rates and to trace releases in areas remote from the point of release. 相似文献
840.