Exhaust flexible pipes are components characterised by a complex dynamic behaviour. Friction is generated by internal contacts in the interlock and entails a dynamic softening phenomenon as the excitation amplitude increases. Due to their complex geometry, the modelling is complicated. The purpose of the thesis is to improve the dynamic model by investigating different Finite Element formulations. Shell, connector, and thin-walled pipe elements are implemented in Abaqus, and numerical modal analysis is run. The models are adjusted in order to fit the first two experimental eigenfrequencies identified by running frequency sweeps in shaker tests. Depending on the method, either manual or automatic parametric optimization in Heeds is performed.