FE Test Correlation
Material layout optimization can be performed effectively using finite element
analysis. The results of the optimization need to be validated by measuring the vibration performance of real prototypes.
Scanning vibrometry speeds up the process of matching models to reality:
- No mass loading — the results represent real vibrational characteristics
- FE-like data density — modal analysis can also be performed for higher modes
- Measurement grid is generated from the FE grid — no interpolation of data, FE coordinate system is used
- "Virtual" measurement points — not limited by the number of physical sensors
FE Validation of a Gearbox
The validation of structural dynamic FE models requires experimental modal testing to extract the modal parameters and to update the FE model.
During test preparation the connection to the CAE data pool breaks up and the model´s complexity has to be reduced dramatically if contact sensors like accelerometers are used. Coordinate system and measurement point locations need manual interaction and involve sources of error like the measurement of the Euler angle etc.
A paper presented at the 2010 ANSYS Conference and 28th CADFEM Users´ Meeting shows an approach to bridge the data gap with automated 3-D scanning vibrometry.
To download the full paper, please click on tab "Technical Papers" (registration required)
FE Modelling of a Rear Axle Carrier
The rear axle carrier (RAC) is the central part of the rear-axle construction on rear-wheel-driven BMW vehicles and provides support and isolation for the wheels and the differential. Finite element (FE) modelling is used to optimize the design of the RAC and to guarantee superior performance. The model was validated using experimental modal analysis (EMA) and precision dynamic data was measured with a 3-D Scanning Vibrometer.
Squeak & Rattle Simulation
Squeak & Rattle performance is an increasingly important component to customer satisfaction in the automobile industry. Normally Squeak & Rattle performance in a new car is tested during the validation phase prior to the start of production. In order to reduce the number of Squeak & Rattle issues during validation, a robust design is required. To achieve right the first time designs for GM projects, thus avoiding unnecessary development delays, a comprehensive Squeak & Rattle simulation tool was used. However, before the simulation tool can be used effectively, the correct representation of a part’s dynamic behavior must be known. Therefore, a 3-D scanning vibrometer was used to measure the dynamic behavior of each interior car part in order to improve the modal correlation. The combination of the 3-D vibrometer data and the simulation tool has helped engineers achieve a better understanding of how to correctly assemble automotive interior parts to avoid disturbing squeaks and rattles.