This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Trimmed Body Static Stiffness Identification Using Dynamic Measurements: Test Methodology and Correlation with CAE Results
Technical Paper
2018-01-1496
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
A key metric of a car body structure is the body stiffness, which shows significant correlation with different vehicle performance attributes as NVH, comfort and vehicle handling.
Typical approaches to identify static stiffness characteristics are the use of a static stiffness test bench or the ‘static-from-dynamic’ approach in which free-free acquired transfer functions are used to build a modal model from which the static stiffness characteristics are extracted. Both of these approaches have limitations, the static stiffness bench with respect to clamping conditions and reproducing those in CAE, the static-from-dynamic with respect to the modal analysis (EMA) that needs to be performed. EMA is a subjective process, which can limit result robustness. In addition, performing EMA on a trimmed body is difficult due to the high modal density and the high level of damping. Strong benefit however of the static-from-dynamic approach is the ability to characterize the body stiffness without need for clamping of the structure.
In this paper a robust static-from-dynamic approach is described that allows static stiffness identification not only for Body-in-White but also on Trimmed Body structures. High robustness and accuracy is achieved by building a Trimmed Body modal model with a semi-automated EMA approach (Maximum Likelihood Modal Model). Result validation is done by comparison of the Trimmed Body hard-point static stiffness from Test with CAE results. Both global stiffness (torsion, bending) and local stiffness characteristics (hard-points) can be identified with this approach, enabling definition and evaluation of more localized body targets.
Recommended Content
Technical Paper | Improve Frame Assembly Flexibility with Low Investment |
Technical Paper | Modeling Tracked Vehicle to Determine Undercarriage Performance |
Technical Paper | Model Based Design of Chassis-Frame with MATLAB |
Authors
Citation
Ottaiano, S., Geluk, T., Teipen, E., and El-Kafafy, M., "Trimmed Body Static Stiffness Identification Using Dynamic Measurements: Test Methodology and Correlation with CAE Results," SAE Technical Paper 2018-01-1496, 2018, https://doi.org/10.4271/2018-01-1496.Also In
References
- Helsen , J. , Cremers , L. , Mas , P. , and Sas , P. Global Static and Dynamic Car Body Stiffness Based on a Single Experimental Modal Analysis Test Proceedings of ISMA 2010
- Young , A. , Poland , J.B. , Pasha , H.G. , Allemang , R.J. et al. Estimation of Torsional Compliance (Stiffness) from Free-Free FRF Measurements: eRCF Application SEM Conference 2015
- Pasha , H.G. , Allemang , R.J. , Phillips , A.W. , and A. Young Estimation of Bending Compliance (Stiffness) from Free-Free FRF Measurements: eBCF Theory SEM Conference 2015
- Merlette , N. , Puvilland , S. , Montaurier , H. , and Jund , A. Determination of the Static Torsion Angle Using Dynamic Measuremens of the Car Body: FRF Vs Modal Approach Proceedings of ISMA 2016
- Peeters , B. , Geluk , T. , and El-Kafafy , M. Deployment of a Robust Test-Based Modal Model Identification Method for Trimmed Car Bodies JSAE 2017
- Peeters , B. , Van der Auweraer , H. , Guillaume , P. , and Leuridan , J. The PolyMAX Frequency-Domain Method: A New Standard for Modal Parameter Estimation? Shock and Vibration 11 395 409 2004
- El-Kafafy , M. , Peeters , B. , Guillaume , P. , and De Troyer , T. Constrained Maximum Likelihood Modal Parameter Identification Applied to Structural Dynamics Mechanical Systems and Signal Processing 72-73 567 589 2016