Lightweight high-sound-insulation floor for motor train unit and design method thereof

The invention provides a light high-sound-insulation floor of a motor train unit and a design method of the light high-sound-insulation floor. The light high-sound-insulation floor of the motor train unit comprises a bearing layer, a middle filling layer, a metamaterial plaque layer and a shock absorber array. Wherein damping slurry layers with high loss factors are arranged on the top surface and the bottom surface of the bearing layer; the middle filling layer comprises a draining board layer, a sound absorption cotton layer and a sound insulation felt layer which are sequentially stacked and laid from bottom to top; the metamaterial plaque layer is located above the middle filling layer, the bottom face of the metamaterial plaque layer is attached to the sound insulation felt layer, and modal structure units used for providing damping are periodically distributed in the metamaterial plaque layer in an array mode; the shock absorber array comprises a plurality of zero-hertz shock absorbers distributed in an