In certain simulations where bodies have large slow motion and very low stress, for example, a body toppling down to the ground under gravity only, high hourglass energy may be observed in Energy Summary. To reduce the hourglass energy, user should make sure the Hourglass Control is set to Flanagan Belytschko with the stiffness coefficient equal to 0.1. If the new hourglass damping doesn’t reduce the hourglass energy significantly, user can increase the stiffness coefficient. Furthermore, user can plot user-defined results – viscous pressure. If the Visc. Pressure increases quickly, user can increase the Linear Artificial Viscosity value under Damping in Analysis Settings to further reduce the hourglass energy. The default viscosity values are for the physical events that have quick motion and high stress. Thus they may not apply to the simulations having large slow motion and low stress.