Composite panel assembly comprising: - a first panel comprising; • a first layer forming a first skin, • a second layer forming a second skin, • a third layer forming a core, the core being arranged between the first skin and the second skin, • an assembly flange in which the first skin and the second skin are arranged directly against each other, - a second panel comprising; • a first layer forming a first skin, • a second layer forming a second skin, • a third layer forming a core, the core being arranged between the first skin and the second skin, • an assembly flange in which the first skin and the second skin are arranged directly against each other, - at least a fastening device (22, 30, 31) adapted to fasten the assembly flange of the first panel to the assembly flange of the second panel, wherein - the core (7, 8) of at least one of the first panel or the second panel at least partly comprises reinforcing pins (9, 10), - the core (7, 8) comprises: • a low-density portion with a first density, • a high-density portion (29, 28) with a second density, the second density being higher than the first density, and - the high-density portion (29, 28) of the core (7, 8) forms a reinforcing edge of the core, said reinforcing edge being placed along the assembly flange (17, 18), - wherein the assembly flange of the first panel is angled relative to at least another portion of the first panel and the assembly flange of the second panel is angled relative to at least another portion of the second panel, and characterised in that: - the assembly comprises a cover element, adapted to be mounted at least partially on at least part of the assembly flange of the first panel and on at least part of the assembly flange of the second panel, wherein the cover element comprises an elastomer. - a first panel comprising; • a first layer forming a first skin, • a second layer forming a second skin, • a third layer forming a core, the core being arranged between the first skin and the second skin, • an assembly flange in which the first skin and the second skin are arranged directly against each other, • a first layer forming a first skin, • a second layer forming a second skin, • a third layer forming a core, the core being arranged between the first skin and the second skin, • an assembly flange in which the first skin and the second skin are arranged directly against each other, - a second panel comprising; • a first layer forming a first skin, • a second layer forming a second skin, • a third layer forming a core, the core being arranged between the first skin and the second skin, • an assembly flange in which the first skin and the second skin are arranged directly against each other, • a first layer forming a first skin, • a second layer forming a second skin, • a third layer forming a core, the core being arranged between the first skin and the second skin, • an assembly flange in which the first skin and the second skin are arranged directly against each other, - at least a fastening device (22, 30, 31) adapted to fasten the assembly flange of the first panel to the assembly flange of the second panel, wherein - the core (7, 8) of at least one of the first panel or the second panel at least partly comprises reinforcing pins (9, 10), - the core (7, 8) comprises: • a low-density portion with a first density, • a high-density portion (29, 28) with a second density, the second density being higher than the first density, and • a low-density portion with a first density, • a high-density portion (29, 28) with a second density, the second density being higher than the first density, and - the high-density portion (29, 28) of the core (7, 8) forms a reinforcing edge of the core, said reinforcing edge being placed along the assembly flange (17, 18), - wherein the assembly flange of the first panel is angled relative to at least another portion of the first panel and the assembly flange of the second panel is angled relative to at least another portion of the second panel, and characterised in that: - the assembly comprises a cover element, adapted to be mounted at least partially on at least part of the assembly flange of the first panel and on at least part of the assembly flange of the second panel, wherein the cover element comprises an elastomer.