The development of a "Virtual Brake Testing" concept
is presented in the paper, showing how a "virtual disc brake
prototype" may be subject to "virtual testing" for
performance and reliability evaluation. For this purpose, a large
experience accumulated throughout many years of testing of various
vehicle brakes by means of a couple of full-scale inertia
dynamometers was collected in an appropriate Knowledge Database. It
is used in this project to enable (i) to create the test schedule,
(ii) to model the braking cycle influencing factors, and (iii) to
model factors expressing brake performance and reliability for
application within an advanced computer simulation.
The development of the virtual disc brake model that was then
subject to virtual testing was based on integrating Pro/Engineer
& Pro/Mechanica parametric design capabilities, while
subsequent virtual testing was performed by means of Pro/Motion.
Such integration is directed towards creation of possibilities to
predict performance and reliability of brakes, thus enabling
radical reduction of the amount of testing of physical prototypes
on inertia test benches.
Virtual brake testing designates "virtual test bench,"
where computer is used to enable a designated brake application to
be performed. The observed brake disc, "loaded" with
appropriate inertia, at prescribed initial interface temperature,
is driven to reach the prescribed initial speed. After short speed
stabilization period, brake is actuated with predetermined initial
control force/pressure. That is how a brake is decelerated to the
requested final speed, or even to the full stop.
A set of predetermined initial brake test condition parameters
(speed, pressure, temperature) under virtual brake testing was
subject to anticipated variations caused by friction. It would make
a brake to perform similarly to the way it would behave if a
physical model were tested.
The speed, pressure and temperature changes are represented by
means of appropriate analytical or numerical forms or
"drivers," and these were used to simulate initial test
condition parameters, and to duplicate their changes during
braking. That is how virtual testing differs from real dynamometer
tests, where these parameters are subject to direct influence of
friction and its changes. The braking torque was also modeled in
addition to friction that develops during braking, so as to enable
different "if-then" scenarios to be used for virtual
evaluation of brake performance and reliability.