• damage accumulation modelADAMS
• durability events
• FFT LCC analysis
• Flexible body
• modal content
• multibody model
• suspension analysis
• vehicle simulation

In this present dissertation the effects of modelling of suspension flexibilities on fatigue service loads were analysed in full vehicle simulation of durability events. More precisely, the subject of study was the investigation of the effect on fatigue loads of the front suspension of sport car at the variation of the flexibility of some elements that constitute it.\\
Three different full vehicle models were made: the kinematic one (with ideal joints), the elastic-kinematic one with the concentrated flexibility on some joints (elastomeric joints) and the flexible one where some parts were modelled as flexible bodies. The tire model employed during the simulations was the CDTire 50 tire model for handling and durability analysis in respective multibody environment.
The study was carried out with the software environment Adams/Car for full vehicle multibody simulation, Abaqus for finite element analysis and Matlab for the analysis of the results.
Different roads and manoeuvres were simulated for each multibody model to perform handling and durability analyses. During each simulation the trend of loads and the damage accumulation index for the different components was reported and analysed.\\
The forces measured during the simulations were subjected to different types of analyses: analysis in the time domain, analysis in the frequency domain (FFT), level-crossing counting analysis (LCC) and Palmgren-Miner linear damage accumulation analysis to calculate the damage accumulation index in each analysed case.
The gathering data showed that the elasto-kinematic model and flexible one had so quite similar behaviour in the handling manoeuvres, whereas the kinematic one has reasonable difference (that depended by load direction) whit respect to the other two models.
In the durability manoeuvres the kinematic model tented to overestimate or to underrate in measure not acceptable the value of the load. Here, the elasto-kinematic model showed low differences whit respect to the the flexible one.\\
This work was carried out within the collaboration between the Department of Civil and Industrial Engineering of the University of Pisa and the Fraunhofer-Institute for Structural Durability and System Reliability LBF (Darmstadt, Germany).