EFFECT OF CORE THICKNESS AND MOISTURE CONTENT ON MECHANICAL PROPERTIES OF TWORESIN-TREATED PAPER HONEYCOMB CORES.
FOREST PRODUCTS LAB MADISON WIS
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This report presents the results of compression and shear evaluations of two resin-treated paper honeycomb cores. The cores had densities of 1.7 and 3.7 pounds per cubic foot. Cores were evaluated in thicknesses of 14 to 2 inches and at several moisture contents ranging up to 80 percent. Compressive strength of 14-inchthick cores was 25 to 80 percent greater than that of 2inch-thick cores. Compressive strength and modulus of elasticity of cores at 10 percent moisture content were 50 to 70 percent of those at 4 percent moisture content. Cores soaked in water 60 to 80 percent moisture content had only 20 to 30 percent of the strength and modulus of elasticity of those at 4 percent moisture content. Core shear strength was two to four times as high for 14-inch as for 2-inch-thick cores. Core shear strength and modulus of rigidity at 10 percent moisture content was 50 to 70 percent of that at 4 percent moisture content cores soaked in water had 20 to 40 percent of the strength and modulus of rigidity of those at 4 percent moisture content. Specimens sheared parallel to the core ribbon direction had about twice the strength and three times the stiffness as those of the same core sheared perpendicular to the core ribbon direction. Author