Parameter Study on a Fully Trimmed Body: Opening Distortion Fingerprint of a Finite Element Model imported to Multibody Dynamics through a Modal Neutral File Compared to Test Data
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
A complete vehicle model in a multibody dynamics simulation is considered constituting
a key enabler for virtual development within the automotive industry. In
collaboration with Zeekr Technology Europe, a multibody dynamics model of a
robot-taxi has been studied. The multibody dynamics model includes a so-called
fully trimmed body of a finite element model through a so-called modal neutral file.
In particular, the opening distortion fingerprint consisting of diagonals over body
openings and cross-sections, has been used as a measure to evaluate how well the
simulation model correlate to test data. The main topic of this master’s thesis has
been to perform a parameter study in order to investigate what parameters affect
the correlation.
In addition to simulations, a literature review has been conducted in order to understand
the impact from the parameters related to the modal neutral file. From
the literature review, examples of component mode synthesis by Guyan and Craig-
Bampton on a beam are presented. The examples illustrate that the definition of
the interface between the finite element model and the rigid components as well
as the modes included in the synthesis have an impact on how well eigenpairs can
be represented. Additionally, a physical beam has been utilized in order to understand
the impact from rigidbody motions in simulations and on test data. The
physical beam example illustrates that the accelerometers used measure the gravity
field when being rotated. These rotations must be taken into account for lower
frequencies.
The outcomes of the parameter study are that the diagonals over the side doors
and the A-pillar section show a poor correlation to the test data, while the remaining
diagonals show a similar fingerprint to the one obtained from the test data.
Furthermore, none of the studied parameters has shown a significant impact on the
fingerprint over the side doors. Nevertheless, the considered frequency range used to
obtain the fingerprint has shown to impact the correlation over the side doors. However,
all diagonals require further investigation for the fingerprint to be correlated.
The further investigation may include a review of the simulation models, a study
on combined parameter effects, studying animations of the eigenmodes, dive deeper
into the component mode synthesis or review the parameter settings, in particular
the frequency range, of the fingerprint.
Beskrivning
Ämne/nyckelord
Opening Distortion Fingerprint (ODF), Component Mode Synthesis (CMS), E-line method, Modal Neutral File (MNF), Multibody Dynamics (MBD), solidity, MSC Nastran, MSC Adams, fully trimmed body