Panel and method of forming a three-sheet panel

Abstract

A panel comprises a first face sheet and a second face sheet spaced apart from the first face sheet. The panel further comprises a core sheet intercoupled between the first face sheet and the second face sheet. Each of the first and second face sheets is made of a material having a thermal expansion that is different from the thermal expansion of the other face sheet.

What is claimed is: 
     
         1 . A panel comprising:
 a first face sheet;   a second face sheet spaced apart from the first face sheet; and   a core sheet intercoupled between the first face sheet and the second face sheet, wherein each of the first and second face sheets is made of a material having a thermal expansion that is different from the thermal expansion of the other face sheet.   
     
     
         2 . The panel of  claim 1  wherein the material of the first face sheet comprises a low thermal expansion material, and the material of the second face sheet comprises a high thermal expansion material. 
     
     
         3 . The panel of  claim 2  wherein the material of the first face sheet comprises INCOLOY Alloy 909, and the material of the second face sheet comprises INCONEL Alloy 625. 
     
     
         4 . The panel according to  claim 1  wherein the first face sheet has a coefficient of thermal expansion between about 4.0 ppm/° F. and about 5.5 ppm/° F. 
     
     
         5 . The panel according to  claim 4  wherein the second face sheet has a coefficient of thermal expansion between about 7 ppm/° F. and about 10 ppm/° F. 
     
     
         6 . The panel according to  claim 5  wherein the core sheet has a coefficient of thermal expansion between about 7 ppm/° F. and about 10 ppm/° F. 
     
     
         7 . The panel according to  claim 6  wherein the first face sheet can withstand a temperature up to or above 1000° F. higher than the second face sheet without degradation of the panel when the first face sheet is exposed to more heat than the second face sheet. 
     
     
         8 . The panel according to  claim 1  wherein the first face sheet has a thickness between about 0.10 inches (0.025 centimeters) and about 0.125 inches (0.318 centimeters) and the second face sheet has a thickness between about 0.01 inches (0.025 centimeters) and about 0.125 inches (0.318 centimeters). 
     
     
         9 . The panel according to  claim 8  wherein the core sheet has a thickness between about 0.01 inches (0.025 centimeters) and about 0.10 inches (0.254 centimeters). 
     
     
         10 . The panel according to  claim 1  wherein the first face sheet has a density between about 0.25 lbs/in 3  and about 0.40 lbs/in 3  and the second face sheet has a density between about 0.25 lbs/in 3  and about 0.40 lbs/in 3 . 
     
     
         11 . The panel according to  claim 10  wherein the core sheet has a density between about 0.25 lbs/in 3  and about 0.40 lbs/in 3 . 
     
     
         12 . The panel according to  claim 1  wherein the panel comprises a superplastic panel. 
     
     
         13 . The panel according to  claim 1  wherein the panel is an expanded panel. 
     
     
         14 . The panel according to  claim 1  wherein the first face sheet comprises an iron alloy and the second face sheet comprises a nickel alloy. 
     
     
         15 . The panel according to  claim 14  wherein the core sheet comprises a nickel alloy. 
     
     
         16 . The panel according to  claim 1  wherein the first face sheet comprises iron, nickel, cobalt, niobium and titanium, and wherein the second face sheet comprises nickel, chromium, iron, molybdenum and niobium. 
     
     
         17 . The panel according to  claim 16  wherein the core sheet comprises nickel, chromium, iron, molybdenum and niobium. 
     
     
         18 . The panel according to  claim 1  wherein the first face sheet is formed from an iron alloy comprising 35.0 wt % to 40.0 wt % nickel, 12.0 wt % to 16.0 wt % cobalt, 4.3 wt % to 5.2 wt % niobium, and 1.3 wt % to 1.8 wt % titanium. 
     
     
         19 . The panel according to  claim 1  wherein the second face sheet is formed from a nickel alloy comprising at least 58.0 wt % nickel, 20.0 wt % to 23.0 wt % chromium, at most 5.0 wt % iron, 8.0 wt % to 10.0 wt % molybdenum, and 3.15 wt % to 4.15 wt % niobium. 
     
     
         20 . The panel according to  claim 1  wherein the core sheet is formed from a nickel alloy comprising at least 58.0 wt % nickel, 20.0 wt % to 23.0 wt % chromium, at most 5.0 wt % iron, 8.0 wt % to 10.0 wt % molybdenum, and 3.15 wt % to 4.15 wt % niobium.