 Plate rigidity has units of Pascal·m3 (equivalent to N·m), since it refers to the moment per unit length per unit of curvature, and not the total moment.Of course, wood is not isotropic, it's orthotropic, so this equation is at best an approximation.The value for formula_7 shown in the table was calculated using this formula and a thickness formula_5 of ⅛″=3.175mm.