Tyre Dynamics, Vehicle ride and handling dynamics, Vehicle durability assessment, Brake noise
Work in this area has spanned over 25 years starting with the commissioning of an electro-hydraulic driven tri-axial tyre test facility in conjunction with digital control and analysis software capable of carrying out automatic testing cycles of tyres. At this time, analytical lumped parameter system models were developed to enable both linear and non-linear modal parameters of vehicle tyres to be determined. Subsequently emphasis changed to the use of analytical techniques, simulation and virtual testing.
This has resulted in the development of Finite Element models of vehicle tyres for the simulation of tyre behaviour and performance. These models can be used in product design verification as they are able to represent the detail design of a tyre. Therefore, the effects of any changes to the design can be simulated by the models.
For example a 2-D model was developed for the mandatory tyre burst test while 3-D models were developed for simulating the tyre forces generated during cornering manoeuvres. These models have been developed in collaboration with the tyre industry through direct grants as well as a TCS grant (in collaboration with Dunlop Aircraft Tyre Ltd).
These series of validated tyre FE models, supported by laboratory testing, form the basis for the development of a tyre design system which is currently on-going with DATL and Airbus, supported by AWM under the Aerospace Technology Exploitation Programme (ATEP). In addition, work is ongoing to integrate sensors into a tyre to study its structural deformation under the action of tyre forces with a view to producing an intelligent tyre with ability to predict tyre/road interface forces for vehicle chassis control systems.
Vehicle Durability Assessment
Initial research in this area involved the development of vehicle durability cycles using remote parameter control, a programme which was funded by a direct grant from MG-Rover over the period 2001 to 2005. This has been followed up with a collaborative study with Jaguar Land Rover (JLR) on the application of artificial intelligence in vehicle development, specifically the development of a Reliability Improvement Expert System (RIES) which can be applied in the early stages of vehicle development to predict the reliability performance of a new vehicle and therefore identify the critical areas into which resources need to be concentrated to improve reliability performance.
The structure of the system also allows lessons learned from previous vehicle programmes to be stored in a manner that makes it easy to access when required so that loss of knowledge is eliminated and Knowledge Transfer is enhanced. Further work on developing an artificial road load data generation tool for vehicle durability assessment has been proposed.
Using artificial intelligence techniques, road load data for new vehicle prototypes will be generated by adaptation of available load history based on changes to vehicle design and configuration even from the early CAD/CAE stages of the vehicle development. It will also provide realistic road load data to drive component and vehicle test rigs as soon as new vehicle prototypes are available thus shortening vehicle development time considerably.
Vehicle Structural Dynamics
The vehicle structural dynamics performance standards which were established by Dr Olatunbosun in the late 1970s are still routinely applied in industry for assessing the vibro-acoustic performance of vehicle structures. Recent work has been targeted at updating the standards and extending the diagnostic application of the standards in the design of better vehicle structures from a vibro-acoustic point of view. A recent study involved the optimisation of the vibro-acoustic package of a low noise light weight vehicle structure by the application of spray-on visco-elastic treatment.
A study of the vibrational characteristics of disk brakes has just been initiated with a view to understanding the mechanism of brake noise generation in collaboration with Jaguar/LandRover. The study will include the coupling of the brake system with the dynamics of the vehicle chassis through the flexibility of the tyres, a radical concept in the study of brake instability.