Starch Impregnation Effect of Testliner Paper on Stiffness of Honeycomb Panels with Slender Cells

The study aimed to determine the effect of impregnation with modified starch of recycled paper (Testliner) on elasticity constants of slender core cells and the influence on the elasticity constants and strength of honeycomb with facings made of thin particleboards. The experimental tests were carried out on beams subjected to three-point bending. It was shown that slender hexagonal cells significantly differentiate their elastic properties and elastic properties of honeycomb panels in the main directions of orthotropy. Impregnation of the Testliner paper with modified starch reduces the values of the modulus of elasticity of the cells by about 8.8 % and reduces the values of the modulus of elasticity of the honeycomb panels by at least 6.9 %. Analytical solutions that do not take into account the structural form of the core cannot be used to calculate the modulus of elasticity of sandwich panels with hexagonal core cells.