Truck & Off-Highway Engineering - October 2021 - 23

PRODUCT DEVELOPMENT FEATURE
" Traditional methods for testing and
evaluating products virtually using
sporadic simulations, usually only of
the nominal machine, are useful but
only reflect specific conditions. "
frequency comfort goals, or by deterministic methods
such as finite elements to take into account the
precise shape of the interior and the detailed composition
of the sound package. With the advent of
hands-free devices and the need for the operator to
communicate with the construction cab, speech clarity
analyses become crucial to ensure that infotainment
systems are designed correctly.
Finally, tool noise can be an important contributor
to both interior and exterior noise performance. Being
able to predict the noise that will be emitted during
heavy machinery operations is instrumental to reach
acoustic targets. Oftentimes, engineers will use component-level
simulation using BEM that can then be
leveraged in system simulation.
Virtually testing vehicle dynamics
Another important aspect of operator comfort is the
vibrations that the driver feels in the cabin while operating
equipment. Using a physics-based model of the
machine to consider vehicle dynamics, it is possible to
calculate the propagation of forces, the torques and the
pressures and other physical quantities that are occurring
in the machine from their source through the vehicle
frame to the seat rail. In so doing, performance
indicators can be generated to predict how comfortable
the operator would be during typical operation cycles.
From early design stages, placing a virtual prototype
of a machine into a virtual proving ground enables
engineers to test out different design concepts
and evaluate their effect on operator comfort. Going
further through the development and test cycle, our
customers use these same models for additional analyses
such as stability or tipping safety as well as energy
efficiency.
Wheel loaders are subject to various vibration and
shock excitations during their work cycles. The integration
of suspension systems ensures high levels of operator
comfort and safety. Liebherr has been using ESI's
system modeling software SimulationX for several years
to improve the dynamics of their machines, avoiding
disturbances such as the " jumping man " effect.
" Using SimulationX, we can analyze and optimize the
vibrational behavior of our wheel loaders with virtual
TRUCK & OFF-HIGHWAY ENGINEERING
Testing a
virtual prototype
embedding realistic
physics on a virtual
proving ground
enables OEMs to test the
vibratory comfort of their
equipment once in use.
prototypes, all in a very efficient development environment, which
helps reduce our test efforts, " said Dr. Manuel Boes from LiebherrWerk
Bischofshofen GmbH, Austria.
As heavy equipment becomes fitted with more and more sensors,
the possibilities for developing advanced safety functionalities also
increase. For example, a virtual test platform for an emergency braking
function can use a system model to represent the machine dynamics
of the mechanical and hydraulic systems. Mounted on the
machine are virtual sensors, in particular a radar sensor that will simulate
the distance and angle between the machine and a vehicle. In
addition to the virtual machine and sensors, there is an emergency
braking algorithm, reading in the sensor data and sending an emergency
brake signal to the machine model.
All these examples show how virtual prototyping brings together
the various engineering tasks and groups to collaborate on one virtual
test platform for developing advanced functionalities for ultimate
comfort and safety.
October 2021 23
Exterior noise simulation using ESI's
vibro-acoustic simulation solution VA One.
Truck & Off-Highway Engineering - October 2021

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - October 2021
