44 PRODUCT PROFILE
A ‘game changer’ for
chassis development
Integrated test and simulation enables objective quantification of design changes, finds Siemens
VehicleDynamicsInternational.com •November/December 2019
ABOVE: Simcenter
can enhance track
testing through
model usage
FIGURE 1A (LEFT):
Roll angle measured
at a low level of
lateral acceleration,
reaching the
limitation of the
sensor resolution
FIGURE 1B (RIGHT):
Roll angle as
function of lateral
acceleration
motions next to the classic vehicle
performance characterisation at the CoG
level. As objective characterisation is
available at the axle level, and even the
chassis component level, decomposed
key chassis contributors can be
quantified at the full vehicle level.
Using the decomposition, the expert
can see how the performance changes,
for example gaining understanding of
the difference at the centre-of-gravity
level when using localised responses.
This solution provides engineers with
the insights necessary to understand
the impact of design variations, support
definition of objective metrics for
target setting and, moreover, to enable
them to link objective observations to
subjective perceptions.
›› With continuously shortening
development cycles, the
importance of early simulation
is increasing year over year. In addition,
and in support of simulation, testing
and validation needs to be carried out
with the highest possible efficiency.
This calls for an integrated test
and simulation solution for vehicle
development. The Simcenter portfolio
combines the best of testing and
simulation. Test-based solutions
identify and drive simulation models
for validation and analysis of functional
performance (test for simulation),
while simulation models maximise
the testing capabilities in terms of
measurement robustness, precision
and detail (simulation for test).
On both the chassis and full
vehicle performance level, Simcenter
Engineering experts deploy model-driven
test solutions. Using models of various
complexity, the engineering specialists
can speed up the testing process
(efficiency) and enhance the testing by
enabling higher precision and increased
robustness of the test results (quality).
The models that are used to drive
this enhanced testing can range from
detailed multi-body simulation,
to simplified vehicle representations
such as the bicycle model.
The Simcenter Tyre team develops
tyre testing methods to identify/drive
simulation models of tyres for use in
full vehicle simulation for different
performance attributes such as vehicle
dynamics, control system development
and comfort. The methodology delivers
models that fit the requirements and
improve the correlation between
simulations and vehicle tests.
Chassis & full vehicle performance
To consider chassis development in the
early design stages or to get insights
in vehicle performance, manufacturers
need to step away from the more
conventional testing approaches.
Simcenter Engineering uses model-driven
test approaches for the validation and
analysis of dynamic performance. They
identify chassis loads and/or chassis
The use of models to drive these
testing approaches ensures that testing
is faster and more efficient, while fewer
sensors are required to obtain the
required test results. Another major
advantage is the achieved robustness and
precision in test output. These qualities
offer benefits in challenging boundary
conditions, such as on-centre behaviour.
Due to the low (lateral) excitation levels,
the classic test approaches can have
limitations in terms of providing robust
and precise objective characterisation of
vehicle performance. This is related to
limited vehicle response amplitudes with
respect to measurement noise or sensor
drift. As a result, design iterations are
often based on experience rather than
objective metrics.
In the example as demonstrated in
Figure 1, vehicle testing is done at
various levels of lateral acceleration. This
example illustrates two challenges when
considering on-center behaviour. Firstly,
the vehicle response to different levels
of steering input is non-linear, especially
when considering small steering inputs.
This is relevant for both objective
performance characterisation as well as
the link to the subjective appreciation.
Secondly, objective characterisation at
low response levels is difficult, which is
demonstrated by the large measurement
variation, and the limited robustness of
the test results.
Simcenter Engineering experts
integrate the use of simulation models
to enable testing also in challenging
boundary conditions. This can be done
via two approaches: by using multibody
models to identify the chassis
/VehicleDynamicsInternational.com