Panel apparatus with supported connection

A composite mat, comprising:

• a fiber-reinforced polymer composite first panel comprising (i) a fiber reinforced upper skin having an upwardly facing upper surface, (ii) a fiber-reinforced lower skin having a downwardly facing lower surface, (iv) a core sandwiched between the upper and lower skins, (v) a fiber-reinforced polymer edge skin extending at least between the upper and lower skins, (vi) a fiber-reinforced polymer top extension extending outwardly from the edge skin, the top extension including a substantially planar upper surface coplanar with the upper surface of the upper skin and a substantially planar downwardly facing lower surface generally parallel to the upper surface of the top extension, and (vii) a fiber-reinforced polymer bottom extension extending outwardly from the edge skin, the bottom extension including a substantially planar upwardly facing upper surface facing the lower surface of the top extension with a space formed therebetween to form a groove, and a downwardly facing lower surface, and
• a fiber-reinforced polymer composite second panel comprising (i) a fiber reinforced upper skin having an upwardly facing upper surface, (ii) a fiber-reinforced lower skin having a downwardly facing lower surface, (iv) a core sandwiched between the upper and lower skins, (v) a fiber-reinforced polymer edge skin extending at least between the upper and lower skins, (vi) a fiber-reinforced polymer tongue extending outwardly from the edge skin, the tongue including a substantially planar upper surface and a substantially planar lower surface, the tongue received in the groove of the first panel such that the upper surface of the tongue engages the lower surface of the upper extension of the first panel and the lower surface of the tongue engages the upper surface of the lower extension of the first panel, and (vii) a fiber-reinforced polymer support extending outwardly from the lower fiber-reinforced polymer skin beyond the edge skin and underlying the tongue to form a space between the support and the tongue,
• wherein the lower extension of the first panel is received in the space between the support and the tongue such that the support engages the lower extension of the first panel so as to support the tongue-in-groove connection when the first and second components are mated together in the tongue-in-groove connection and a load is applied.