JournalTOCs

International Journal of Heavy Vehicle Systems
Journal Prestige (SJR): 0.23

Number of Followers: 7

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1744-232X - ISSN (Online) 1741-5152
Published by Inderscience Publishers

[450 journals]

Introducing a revised model for determination of rollover threshold speed
of buses
- Authors: Mohammadreza Sabouri, Arman Hamidi
  Pages: 723 - 742
  Abstract: Rollover is critical for intercity bus vehicles, as they often carry a large number of passengers while having a relatively high centre of gravity. Utilising the same models for determining the rollover threshold speed (RTS) of different types of vehicles may induce some errors, as most of the existing models do not consider several factors such as vehicle type and dimension, vehicle load, turning radius of the axles, and diversion angle of the curve. This study intends to propose a more accurate relationship for determining the rollover speed of the intercity bus vehicles considering the aforementioned factors. Using the revised model, it was shown that when both the radius of the horizontal curve and the diversion angle are small, the diversion angle plays an important role in determining the RTS. The results also suggest that under the assumptions of this study, the RTS for three-axle buses happens at lower speeds compared to two-axle buses.
  Keywords: centre of gravity height; curve radius; diversion angle; heavy vehicles; intercity bus; payload; regression model; rollover collisions; RTS; rollover threshold speed; superelevation; traffic accidents; TruckSIM
  Citation: International Journal of Heavy Vehicle Systems, Vol. 27, No. 6 (2020) pp. 723 - 742
  PubDate: 2021-02-12T23:20:50-05:00
  DOI: 10.1504/IJHVS.2020.112974
  Issue No: Vol. 27, No. 6 (2021)
Experimental and numerical studies on improvement of drag force of a bus
model using different spoiler models
- Authors: Bayindirli Cihan, Akansu Yahya Erkan, Celik Mehmet
  Pages: 743 - 776
  Abstract: The purpose of this paper is to reduce the drag force of a bus model by using four different spoiler models. The tests carried out at six different free stream velocities and in the range of 3.8 ×10<SUP align="right">5</SUP> - 7.9 ×10<SUP align="right">5</SUP> Reynolds numbers. The drag coefficient (CD) of the bus model was determined as 0.633 in a wind tunnel and 0.645 in Fluent® package program. The first spoiler model consists of a combination of airfoil and vortex generator mounted at five different locations (L/H) on bus model to improve the drag force. The drag reduction was obtained in the range of 12.25-4.35% in five different L/H rates by using spoiler 1 model. The spoiler 2 model has airfoil shape and maximum drag coefficient was improved by 3.34% experimentally. A 23.49% reduction was obtained by using spoiler 3 in L/H = 0.1 and 18.49% reduction by using spoiler 4 in L/H = 0.15. The numerical flow analyses were performed at the same wind tunnel conditions at six free stream velocities for the base model and best results for each spoiler model. The drag coefficients of best models were reduced by 11.48% and 8.59%, 15.90% and 19.05% respectively in Fluent®.
  Keywords: bus model; drag coefficient; wind tunnel; CFD; computational fluid dynamic; aerodynamic; spoiler; fluid; turbulent flow; airfoil; Reynolds number; passive flow control
  Citation: International Journal of Heavy Vehicle Systems, Vol. 27, No. 6 (2020) pp. 743 - 776
  PubDate: 2021-02-12T23:20:50-05:00
  DOI: 10.1504/IJHVS.2020.112975
  Issue No: Vol. 27, No. 6 (2021)
Development for generalised multi-axle steering vehicle handling
- Authors: Xiang Chen, Kong-hui Guo
  Pages: 777 - 799
  Abstract: This paper devotes main effort to develop the generalised multi-axle steering vehicle handling for more comprehensive analysis with the factors of vehicle body roll, multi-axle, unsprung mass, steering centre distance, steering ratio coefficient and steering delay. A linear vehicle dynamic model is established firstly. Then the multi-axle steering vehicle handling is analysed from two aspects of steady-state and transient-state. For the steady-state, the expressions of equivalent wheelbase and steady factor are derived from the generalised vehicle dynamic equations and some special conditions are discussed inextenso. For the transient-state, the expressions of frequency characteristics and root locus are deduced from the generalised vehicle dynamic equations and the influences of steering delay and steering ratio coefficient to multi-axle steering vehicle handling are analysed deeply. The corresponding results derived from the generalised dynamic model can be used for analysing the various influences to multi-axle steering vehicle handling.
  Keywords: multi-axle steering vehicle handling; vehicle dynamic model; steady-state characteristics; transient-state characteristics
  Citation: International Journal of Heavy Vehicle Systems, Vol. 27, No. 6 (2020) pp. 777 - 799
  PubDate: 2021-02-12T23:20:50-05:00
  DOI: 10.1504/IJHVS.2020.112971
  Issue No: Vol. 27, No. 6 (2021)
Optimised coordinated chassis stability control using fuzzy genetic
algorithm
- Authors: A. Elhefnawy, H. Ragheb, A.M. Sharaf, S. Hegazy
  Pages: 800 - 816
  Abstract: Owing to proficient constraints of distinct vehicle subsystems, numerous individual active control systems are optimised individually in specific handling areas. Consequently, there is no solitary system which can be operative over the entire range of vehicle stability and handling. In this study, an optimised coordinated control system comprising two controllers namely direct yaw control (DYC) and active front steering (AFS) has been developed based on fuzzy logic control to boost vehicle handling, cornering stability, and rollover anticipation. Moreover, genetic algorithm has been accustomed to optimise the offered coordinated control system in two phases; initially, optimising the fuzzy logic controller for both DYC and AFS by linear scaling of the inputs and outputs of each controller, and by the weight of each rule. Different benchmark test manoeuvres have been carried out at different driving conditions to scrutinise the offered coordinated control effectiveness. Simulation results shows a significant enhancement in vehicle stability.
  Keywords: DYC; direct yaw control; AFS; active front steering; FLC; fuzzy logic control; GA; genetic algorithm; coordinated control
  Citation: International Journal of Heavy Vehicle Systems, Vol. 27, No. 6 (2020) pp. 800 - 816
  PubDate: 2021-02-12T23:20:50-05:00
  DOI: 10.1504/IJHVS.2020.112976
  Issue No: Vol. 27, No. 6 (2021)
Research on partially filled characteristics of vehicular hydrodynamic
retarders
- Authors: Lingxing Kong, Wei Wei, Hongbin Mu, Qingdong Yan
  Pages: 817 - 839
  Abstract: Hydrodynamic retarders are widely used on heavy vehicles as auxiliary braking components. Figuring out the partially filled characteristics is of practical significance for the design and control of retarders. In this paper, torque characteristics under variable filling rate of a dual-torus hydrodynamic retarder is studied and verified with experimental data. 1D flow theory was implemented to calculate the circulating flow rate and brake torque. 3D CFD simulation was conducted and VOF model was adopted to simulate air-oil two phase flow when the chamber is partially filled. The results showed that unlike common assumption that brake torque is in direct proportion with filling ratio of the chamber, the torque presents a non-linear relationship vs. filling ratio. In the bench test, filling ratio is derived by monitoring the flow rate into and out from the chamber and the experimental results validated the non-linear relationship between brake torque and filling ratio.
  Keywords: brake torque characteristics; CFD; computational fluid dynamics; filling ratio; vehicular hydrodynamic retarder; two phase flow
  Citation: International Journal of Heavy Vehicle Systems, Vol. 27, No. 6 (2020) pp. 817 - 839
  PubDate: 2021-02-12T23:20:50-05:00
  DOI: 10.1504/IJHVS.2020.112973
  Issue No: Vol. 27, No. 6 (2021)
New method to predict truck-semitrailer jackknifing effect
- Authors: Lingxing Kong, Wei Wei, Hongbin Mu, Qingdong Yan
  Pages: 840 - 860
  Abstract: A new method based on two articulated bodies with internal inertial force, similar to the structural buckling effect, is proposed to describe the unstable yaw relative angular movement between truck and semitrailer, known as jackknifing. An analytic expression is derived from the proposed linear model, allowing the prediction of the deceleration limit prior to the yaw instability phenomenon. A detailed non-linear model with 19 degrees of freedom was developed and used as a simulations tool to verify dynamic performance. The analytical results of the jackknife effect were validated by comparison with the instability tendency simulated with a complete vehicle dynamic model. The results show good agreement between the proposed analytical expression and the numerical simulation. The proposed analytic expression is independent of the vehicle speed and does not require a stability analysis or an integration process, unlike all other techniques available in the literature.
  Keywords: jackknifing; truck; dynamic; safety; instability
  Citation: International Journal of Heavy Vehicle Systems, Vol. 27, No. 6 (2020) pp. 840 - 860
  PubDate: 2021-02-12T23:20:50-05:00
  DOI: 10.1504/IJHVS.2020.112972
  Issue No: Vol. 27, No. 6 (2021)