The paper presents an experimentally validated 3D finite element modelling impacts of viscoelastic and natural materials. It considers, in particular, the material set of ash wood and rubber in the context of the impact between the bat (the “hurley” made of ash wood) and the ball (the “sliotar” made of polyurethane-cork composite) in the Irish game of hurling. The hurley is highly anisotropic in its mechanical properties and this impact system therefore presents a unique modelling challenge. The FE models do not rely on either the assumption of linear materials models or on calibrated materials models. The FE models are able to take all three geometric, status and material NONLINEARities into account yielding a close correlation with real-world impact scenario. The reported FE results were validated against experimental measurements showing an excellent correlation of more than 91% in term of maximum ball deformation.

One of the most important phenomena to a_ect the motion behavior of Micro Resonators is their thermal dependency. This has recently received the attention of researchers widely. A thermal phenomenon has two main effects, the first is damping, due to internal friction, and the second is softening, due to Young's modulus-temperature relationship. In this research work, some theoretical and experimental reported results are used to make a proper model, including thermal phenomena. Two Lorentzian functions are used to describe the restoring and damping forces caused by thermal phenomena. In order to emphasize the thermal effects, a NONLINEAR model of the MEMS, considering capacitor NONLINEARity and mid-plane stretching, has been used. The responses of the system are developed by employing a multiple time scale perturbation method on a non-dimensionalized form of the equations. Frequency response, resonance frequency and peak amplitude are examined by varying the dynamic parameters of the modeled system. Finally, Fuzzy Generalized Cell Mapping (FGCM) is introduced and applied to the Micro Resonator's dynamical system behavior. It is then concluded as to how the model uncertainties and different initial conditions can affect the working domain of the system and/or make it pull in instabilities. At the end, it can be seen that FGCM is a useful method for monitoring the working regions of Micro Resonators, while varying system parameters.