A structural shear panel for forming a floor panel for support by a vehicle frame is formed by a composite of top and bottom sheets and a core with a vacuum infused resin. The core is formed of top and bottom layers each formed from a honeycomb panel defining an array of hexagonal tubular cells with walls which extend in the thickness direction filled with a foam material. A third layer is located between the first and second layers and is formed of a material such as foam, rubber or cork which is free from tubular cells in the thickness direction and free from rigid structural members in the thickness direction to reduce communication of sound through the panel.