Hierarchical honeycomb core with sandwich cell walls

A hierarchical sandwich core in the form of a macroscopic honeycomb comprising:

• a first macroscopic cell with first sandwich cell walls connected by a connection to neighbouring macroscopic cells with neighbouring sandwich cell walls;
• the first and the neighbouring sandwich cell walls being made of a sandwich material having a width, a mesoscopic core, a first skin layer on a first major surface of said sandwich material and a second skin layer on a second major surface of the sandwich material, both said first and second skin layers being attached to the mesoscopic core forming each said sandwich cell wall of the macroscopic honeycomb;
• the first and the neighbouring sandwich cell walls having a height, the height being defined by the width of the sandwich material, both first and second skin layers of each of the first sandwich cell walls being permanently connected together by a first permanent connection along the height of the first cell walls and both said first and second skin layers of each said neighbouring sandwich cell walls being connected together by a second permanent connection along the height of the neighbouring cell walls;
• the first or the second permanent connections being a fusion bond, or an adhesive bond or a glue bond;
• and both said first and second skin layers of each of the first sandwich cell walls being connected to both said first and second skin layers of at least one of said neighbouring cell walls along the height of the first cell wall.