PSI - Issue 24

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Vincenzo D’Addio et al. / Procedia Structural Integrity 24 (2019) 510–525 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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The results reported in Fig. 16 show the overload factor in the magnitude of the contact force between the rolling elements and the external ring and the magnitude of the vertical component of the force transmitted to the case. Such an excitation force is much more realistic compared to the one simulated, for the sake of simplicity, as sinusoidal with the fully flexible multibody model. 6. Conclusions Different models have been developed with commercial SWs for the rotordynamic analysis of an automotive component. Their increasing complexity was associated with increasing computation time, accuracy and quantity of results, thus indicating their preferred use in a preliminary or later design phase. In particular:  an analytical model made of rigid bodies and compliance concentrated in the supports that allowed to determine the first natural frequencies in a short time, proved to be useful for a preliminary analysis;  a FEM model with flexible shaft, concentrated masses and elastic supports, made it possible to determine a more significant Campbell's diagram and harmonic response in a relatively short time;  a multibody model with flexible bodies that allowed to determine the displacement, strain and stress fields of the various components, in a significantly longer time, appears to be justified for a detailed analysis in a later design phase. In addition, a multibody model with rigid bodies and defected rolling bearings allowed to replicate the impact phenomenon within the bearing and to determine more accurately the contact and transmitted forces. The results obtained from the analysis of the component showed dangerous crossings of natural frequencies and asynchronous forcing frequencies and suggested possible modifications of the pump assembly. Even if further adjustments will be necessary in the following design steps and after testing of prototypes, the outlined procedure is essential for the interpretation of experimental results and for preliminary simulation of the modified solutions. Acknowledgements The authors thank Emanuele Pellegrini and Alessandro Vestri of Pierburg Pump Technology for their valuable support in writing the scripts in the different environments. References ANSYS Inc., 2012. Mechanical APDL Rotordynamic Analysis Guide. Childs, D., 1993. Turbomachinery rotordynamics: phenomena, modeling, and analysis. Wiley. Ehrich, F.F., 1998. Handbook of Rotordynamics. McGraw - Hill. Genta, G., 2005. Dynamics of Rotating Systems. Hoepli. Géradin, M., Cardona, A., 2001. Flexible Multibody dynamics: a finite element approach. Wiley. Jung, HC. and Krumdieck, S., 2014. Rotordynamic Modelling and Analysis of a Radial Inflow Turbine Rotor - Bearing System. Int. J. Precis. Eng. Manuf. 15, 2285 - 2290.Kirchgaßner, B., 2016. Finite Elements in Rotordynamics. Procedia Engineering 144, 736 – 750. Krämer, E., 1993. Dynamics of rotors and foundation, Springer - Verlag. Longxi, Z., Shengxi, J., and Jingjing, H., 2017. Numerical and Experimental Study on the Multiobjective Optimization of a Two-Disk Flexible Rotor System. International Journal of Rotating Machinery 2017, paper # 9628181, 10p. Mishra, C., Samantaray, A.K., Chakraborty, G., 2017. Ball bearing defect models:A study of simulated and experimental fault signatures. Journal of Sound and Vibration 400, 86–112. Yang, Y., Yang, W., Jiang, D., 2018. Simulation and experimental analysis of rolling element bearing fault in rotor - bearing - casing system. Engineering Failure Analysis 92, 205–221.