Offset corrugated panel with curved corrugations for increased strength

Abstract

A corrugated panel having a core between two faceplates where the core andaceplates are comprised of curable material and where the core is comprised of undulate strips that are disposed in parallel relation to each other. The strips define peaks and valleys connected by diagonally-extending segments that have non-planar cross-sections. The peaks and valleys in adjacent strips are 180 degrees out of phase with respect to each other. The faceplates and the strips are joined at the peaks and valleys. A method of making a corrugated panel assembly comprising the steps of providing upper and lower faceplates and a core of strips, all made from curable material. Mandrels and inserts are used to form the strips into alternately-arranged peaks and valleys that are interconnected by diagonal segments where the diagonally-extending segments have non-planar cross-sections. The strips are 180 degrees out of phase with respect to each other. The mandrels are replaced by granular particles and the assembly is cured.

What is claimed: 
     
       1. A corrugated panel, comprising: means defining a pair of spaced planes;   a core including a plurality of spaced parallel strips of undulate shape disposed between said pair of spaced planes to define peaks and valleys connected by diagonally-extending segments, each of said segments having an arcuately-shaped transverse cross-section.   
     
     
       2. The panel as defined by claim 1, wherein said peaks and valleys of adjacent strips are 180 degrees out of phase with respect to each other. 
     
     
       3. The panel as defined by claim 2, wherein adjacent ones of said strips are slightly spaced from each other. 
     
     
       4. The panel as defined by claim 1 wherein: said means defining a pair of spaced planes comprises a pair of plane faceplates;   said core is disposed between said faceplates; and   said faceplates and strips are comprised of a heat-curable composite material.   
     
     
       5. The panel as defined by claim 4, wherein said faceplates are parallel. 
     
     
       6. The panel as defined by claim 4, wherein said faceplates are arcuate. 
     
     
       7. The panel as defined by claim 4, wherein said faceplates are not parallel. 
     
     
       8. A corrugated panel, comprising: means defining a pair of spaced planes;   a core structure including a plurality of spaced, parallel, undulate strips disposed between said pair of spaced planes, said plurality of spaced parallel, undulate strips defining peaks and valleys connected by diagonally-extending segments, each of said diagonally-extending segments having a non-planar cross-section which tends to resist a force applied in a direction generally perpendicular to the strips.   
     
     
       9. A method of making a rigid, strong corrugated panel assembly, comprising the steps of: providing upper and lower faceplates comprised of curable material;   providing a plurality of strips of curable material;   providing a plurality of mandrels;   arranging said mandrels in a side-by-side relation;   wrapping said strips of curable material alternately over and under adjacent ones of said mandrels so that adjacent strips are out of phase with each other;   putting indentations in said strips of curable material, said indentations being operative to increase the strength of said panel; and   heating and curing said assembly whereby a rigid, strong corrugated panel assembly is made.   
     
     
       10. The method as defined by claim 9, including the steps of: providing each of said strips of curable material with a plurality of alternately-arranged peaks and valleys that are interconnected by diagonal segments; and   placing said peaks and valleys adjacent said upper and lower faceplates.   
     
     
       11. The method as defined in claim 9, wherein said indentations are made in said diagonal segments. 
     
     
       12. The method as defined in claim 9, wherein said step of putting indentations in said strips includes the step of providing inserts between said mandrels and said strips. 
     
     
       13. The method as defined by claim 9, wherein said top and bottom faceplates are comprised of the same material as said strips. 
     
     
       14. A method of manufacturing a corrugated panel having a core structure which includes a plurality of spaced, parallel undulate strips between a pair of spaced faceplates to define peaks and valleys connected by diagonally-extending segments, each of said diagonally-extending segments being characterized by a non-planar cross-section which tends to resist a bending force applied in a direction generally perpendicular to the strips, said method comprising the steps of: providing a plurality of elongated mandrels;   providing a plurality of flexible strips containing a curable material;   wrapping said flexible strips over and under said elongated mandrels to define an assembly;   placing shaped inserts between said flexible strips and said elongated mandrels;   placing said assembly between said faceplates; and   curing said assembly.   
     
     
       15. The method as defined in claim 14, including the steps of: providing films of release material; and   wrapping each of said mandrels in said release film before placing said shaped inserts and wrapping said flexible strips over and under said elongated mandrels.   
     
     
       16. The method as defined in claim 15, including the steps of: providing a curing cavity;   placing said assembly in said curing cavity; and removing said mandrels from said cavity while leaving the release films.   
     
     
       17. The method as defined in claim 16, including the steps of: filling the space occupied by the solid mandrels with non-curable granules before said assembly is cured; and   removing said non-curable granules, release films and shaped inserts from the assembly.   
     
     
       18. The method as defined in claim 14, wherein said mandrels are hexagonal in cross-section. 
     
     
       19. The method as defined in claim 18, including the steps of: providing films of release material;   wrapping each of said mandrels in said films of release material;   arranging the wrapped hexagonal mandrels side by side and parallel to each other so that opposing planar surfaces of the mandrels are parallel to the plane of the corrugated panel being produced; and   diagonally positioning said shaped inserts between adjacent mandrels.   
     
     
       20. The method as defined in claim 14, including the steps of: placing said top and bottom faceplates comprising a curable material atop and below the assembly before the assembly is cured, so that the panel is produced in a single curing operation.   
     
     
       21. The method as defined in claim 20, wherein said top and bottom faceplates are comprised of the same material as are said flexible strips.