Thesis-2005-Abidin.pdf (38.44 MB)
Vehicle ride under transient conditions using combined on-road testing and numerical analysis
thesis
posted on 2014-07-23, 12:21 authored by Mohd Azman Zainul AbidinThe thesis outlines a hierarchical modelling methodology for investigation in vehicle
dynamics, in particular for combined ride and handling manoeuvres. The
methodology involves the use of detailed multi-degrees of freedom models of
vehicles with the inclusion of sources of non-linearity, using a multi-body approach,
based on Lagrangian dynamics for constrained systems. It also includes the use of
simpler and task-specific models, formulated in Newton-Euler approach. These
simpler models with lower degrees of freedom, but with appropriate level of detail are
more efficient in the study of specific, but non-trivial problems such as transient
behaviour of vehicles in combined ride and handling, as encountered in many routine
daily manoeuvres.
The modelling methodology is supported by careful vehicle testing, both for
validation of the proposed approach, and assessment of the extent of applicability of
simple, intermediate and multi-degrees of freedom full-vehicle models. Certain
important vehicle handling and ride characteristics in pitch plane dynamics, roll
behaviour, vehicle body bounce and combination of these have been studied, as well
as the effectiveness of restraining action of chassis elements, such as the semileading
and trailing arms for passive control of vehicle squat and dive motions,
arising from acceleration from coast to drive and deceleration/brake of vehicle from
drive to coast. Combined pitch and bounce motions have been studied when
negotiating speed traps such as bumps, which also combine with significant body roll
when single event obstacles of this kind are introduced. The novelty of the research is in the detailed integrative numerical-experimental
approach, and the development of intermediate models that adequately predict
vehicle behaviour under steady and non-steady conditions for a wide range of ride
and handling manoeuvres.
The investigations have culminated in a significant number of findings of practical
use, particularly the ineffectiveness of anti-squat and dive features when combined
pitch and bounce motions limit the usefulness of these devices. On the contrary,
excessive roll dynamic behaviour of the vehicle is effectively palliated by the anti-roll
bar, even under complex combined pitch, roll and body bounce such as those
experienced in negotiating single event speed bumps.
Good agreement is found between the predictions of the intermediate model and
those of the multi-body model and the actual vehicle tests, particularly for pitch and
bounce dynamics.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Publisher
© Mohd Azman Zainul AbidinPublication date
2005Notes
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.421936Language
- en