Discussing Van Wyk's Theory[1] Concerning Compression of a Fibrous Mass

Van Wyk's theory on the compression of a fibrous mass is refuted by the authors on the ground that it ignores the substantial thickness of a fiber. The authors' formula, which shows the theoretical relation between the pressure and volume of a compressed specimen, explains the experimental tendency of the pressure-volume curve. However, it offers no strict experimental verification, because there are unavoidable limitations on the method of experiment at present usually employed and the authors have used that method to verify their formula. The following expression, which the authors believe useful for the theoretical treatment of the compression of a fibrous mass, has been obtained: Δl/Δt-Δl=1/λ(ω0+Pressure) where Δt and Δl are the apparent height and the substantial thickness of the elemental thin layer in a compressed specimen, and ω0 is the latent pressure of the specimen. This expression shows the proportional relation between the degree of packing, Δl/(Δt-Δl), and the pressure in an elemental thin layer of a compressed specimen. The symbol λ is named “the modulus of the degree of packing.”