A structural panel is provided that includes a first core structure and a second core structure. The second core structure includes a plurality of core components, which components includes a corrugated ribbon, a first wall and a second wall. The corrugated ribbon includes a plurality of baffles and a plurality of porous septums. The baffles and the porous septums are laterally between and connected to the first wall and the second wall. Each of the porous septums are longitudinally between a respective adjacent pair of the baffles. A first of the core components projects longitudinally into and/or along the first core structure at a splice joint between the first core structure and the second core structure.