Composite cores and panels
The plurality of pieces of low density cellular material, such as foam plastics, form a core panel having opposite side surfaces and with adjacent pieces having opposing edge surfaces extending between the side surfaces. Sheets of flexible material, such as veils or mats or scrim, are adhesively attached to the side surfaces, and portions of one sheet extend between the opposing adjacent edge surfaces for limiting flexing of the panel. The pieces may be tapered, and portions of the one sheet may project between the edge surfaces either partially or fully to form double wall webs. The webs may have flanges adhesively attached to the other sheet on the opposite side. One sheet may also be stretchable in areas not adhesively attached to the pieces to provide for curving the panel from a planar position maintained by the sheet on the opposite side.
1. A composite panel having an upper side and a lower side comprising:
a plurality of elongated strips of cellular material selected from the group consisting of balsa wood and foam plastic positioned to form a core panel, wherein the elongated strips have a generally rectangular cross-section having flat and opposite side surfaces and with adjacent elongated strips having flat and opposing edge surfaces extending between the side surfaces, wherein the side surfaces are generally perpendicular to the edge surfaces within each strip;
a first sheet of flexible material adhesively attached to the side surfaces of each of the elongated strips facing the upper side of the composite panel;
a second sheet of flexible material adhesively attached to the side surfaces of each of the elongated strips facing the lower side of the composite panel with portions of the second sheet extending between the opposing edge surfaces of adjacent the elongated strips, wherein the portions of the second sheet are effective to limit flexing of the first sheet for limiting curvature of the panel.
2. The composite panel of claim 1 , wherein the portions of the second sheet extending between the opposing edge surfaces extend completely through the thickness of the panel to form double wall webs and wherein adhesive attaches the double wall webs to the first sheet.
3. The composite panel of claim 2 , wherein the double wall webs include structural flanges extending parallel to the first sheet of material, and the structural flanges are adhesively attached to the first sheet of material.
4. The composite panel of claim 3 , further comprising a third sheet of flexible material attached by adhesive to the second sheet of flexible material and having double wall portions projecting between the double wall webs to limit flexing of the panel.
5. The composite panel of claim 2 , further comprising a first sandwich panel skin of rigid material adhesively attached to the first sheet of material and a second sandwich panel skin of rigid material adhesively attached to the second sheet of flexible material.
6. The composite panel of claim 1 , wherein the opposing edge surfaces of the elongated strips are tapered to form V-shaped spaces between the adjacent elongated strips and the portions of the second flexible sheet project into the spaces between the opposing edge surfaces of the elongated strips in response to flexing of the panel.
7. A composite panel having an upper side and a lower side comprising:
a plurality of elongated strips of cellular material selected from the group consisting of balsa wood and foam plastic positioned to form a core panel, wherein the elongated strips have a generally rectangular cross-section having flat and opposite side surfaces and with adjacent elongated strips having flat and opposing edge surfaces extending between the side surfaces, wherein the side surfaces are generally perpendicular to the edge surfaces within each strip;
a first sheet of flexible material adhesively attached to the side surfaces of each of the elongated strips facing the upper side of the composite panel;
a second sheet of flexible material adhesively attached to the side surfaces of each of the elongated strips facing the lower side of the composite panel, wherein the second sheet of flexible material comprises stretchable material having portions unattached to the side surfaces of each of the elongated strips facing the lower side of the composite panel and which stretches in response to flexing of the panel for fitting the panel to a curved surface.