Using the irrotational intensity field to study vibration energy paths in automotive structures
Résumé
Although structural intensity was introduced in the 80’s, this
concept never found practical applications, neither for numerical
nor experimental approaches. Quickly, it has been pointed out that
only the irrotational component of the intensity offers an easy
interpretation of the dynamic behavior of structures by visualizing
the vibration energy flow. This is especially valuable at mid and
high frequency where the structure response understanding can be
challenging. A new methodology is proposed in order to extract this
irrotational intensity field from the Finite Element Model of
assembled structures such as Bodies In White. This methodology is
hybrid in the sense that it employs two distinct solvers: a dynamic
solver to compute the structural dynamic response and a thermal
solver to address a diffusion equation analogous to the thermal
conduction built from the previous dynamic response. The field
separation is based on the Helmholtz-Hodge theorem, which ensures
the computation’s full consistency. The methodology is first
implemented and validated in the case of a plate assembly, using
commercial FE software. This first approach immediately highlights
a bias in the current power flow computations, leading to erroneous
transmission path understanding. It also shows a remarkable
stability of the irrotational intensity patterns regarding
frequency. As one would expect, transmission path only makes sense
when they stand for a broad enough frequency range. The methodology
is then applied to an automotive structure, introducing specific
modeling of the mechanical connections between stamped steel parts
(spot welds, bolts, bids…). Again the method applies well and shows
fully consistent results.
Domaines
Mécanique [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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