M arco Bonato

Valeo Thermal System, La Verrière, France

Marco Bonato is Reliability Manager and Senior Expert, in Valeo since 2012. His responsibility includes the elaboration of new tailored validation tests, the design of reliability studies related to automotive components, and development and implementation of customer-based engineering and reliability topics. Marco holds a Ph.D. in Material Science from the University of Bristol (UK). Prior to this, he obtained a Master degree in Inorganic Chemistry at the University of Padua (Italy).


The reliability design process of automotive components requires the products to be validated according to sign-off vibration tests that are given by each car manufacturer.

From a supplier perspective, the  Finite Element Analysis (FEA) is a power tool applied to rapidly detect structural weaknesses that would compromise the reliability of the products.

One of the main challenges is the complexity of vibration signals that are provided by each carmaker (validation specifications). For FEA simulations, vibration analysis is performed in the frequency domain, therefore only “pure” random PSD (power spectrum density)  or harmonic (sine sweep) signals can be used. In case of complex vibration signals (sine-on-random, shocks-and-random, multiple-PSDs) an approach to tranform them to a fatigue damage equivalent random PSD or Sine Sweep has been developed by Valeo.

The choice of two main parameters plays an important role in the definition of the final equivalent signal: the fatigue life exponent (Basquin's factor) and the damping ratio (Q factor). Also the nature of the output signal (purely random or harmonic) highly affects the predicted fatigue damage.

In this study we analyze the influence of the variables on the generated equivalent-damage signal (PSD and sine sweep)  and the consequence on the fatigue simulation life predictions.

Numerical examples of vibration fatigue simulation will illustrate the effect of the mentioned parameters applied to sine-on-random and shock-and-random signals (used to validate the design of an alternator bracket and a  high voltage heater inverter, respectively) when transformed into an equivalent random PSD or sine sweep.


Poster Session00:00-00:00Marco Bonato

28 - Equivalence of Vibration Signals for Fatigue Simulation. Effect of parameters on durability predictions
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