Golf Ball Impact: Material Characterization and Transient Simulation

This paper presents an LS-DYNA ® simulation of the impact event when a golf club hits a golf ball. This is a challenging subject for finite element simulations because it is characterized by high strain rate behavior: the impact occurs within milliseconds and the golf ball experiences very large deformation during this period because of the ball’s polymeric shell and core. The simulation strategy emphasizes on accurate material characterization and realistic model construction. Specifically, the Parallel Network Model (PNM), an advanced nonlinear viscoelastic and strain rate dependent material model from Veryst Engineering’s PolyUMod TM library is calibrated with high-rate testing data to accurately capture the highly nonlinear behavior of the golf ball core material during impact. At the same time, a detailed finite element model of the golf ball is constructed with multiple layers of structure. The complex dimple pattern on the ball cover as well as the grooves on the golf club are modeled, both potentially important factors in impact response. The simulation is validated by comparing the deformed shape at maximum impact to that in real experiments. The paper then discusses two important issues in material characterization: selection of the right material model and the availability of reliable high-rate testing data. The PNM material model is compared to a linear viscoelastic (LVE) model to demonstrate its superiority.