Continuation analysis of cam-follower mechanisms considering time-varying stiffness and loss of contact

The dynamic behaviour of cam-follower systems for automotive applications is investigated. This mechanism is modelled by means of a SDOF scheme, capable of capturing the fundamentals of the problem, considering external excitation, loss of contact and parametric excitation due to contact stiffness variation. The main novelty pertains to the qualitative characterization of the dynamic behaviour of cam-follower systems by means of continuation analysis considering both loss of contact and parametric excitation. Moreover, to the best knowledge of the authors, for the first time emphasis has been devoted to the evaluation and identification of the different internal and external forcing terms and their effect on the dynamic response and stability of the system. A parametric study is reported in the form of response diagrams to show how the variation of key parameters, such as stiffness and damping, influences the system behaviour. Numerical results obtained by direct integration of the equation of motion are presented, demonstrating the existence of rich dynamics in the examined system. Finally, the actual dynamic loads are exhibited for different system modelling complexities, highlighting the necessity for the followed approach.