BULK MODULUS MEASURING APPARATUS FOR SOFT MATERIAL

摘要

PURPOSE:To achieve accurate measurement of bulk modulus by compressing a soft material as measuring material within a liquid having a known compression modulus to allow the loading of a uniform pressure through the liquid. CONSTITUTION:A cylinder 1 is filled with a measuring material as soft material and the liquid 4 having a known compression modulus k2 and a pressurization is performed with a piston 2 to read a displacement value with a displacement meter 5 while a pressurizing force P is measured simultaneously with a manometer 6. When the bulk modulus of the measuring material is represented by k1, the volume of a mixed body of the measuring material and the liquid by V, volumetric distortion by epsilonv, volume and volumetric distortion of the measuring material by V1 and epsilonv1 and volume and volumetric distortion of the liquid by V2, epsilonv2, the bulk modulus k1 of the measuring material is determined by k1=P/3ev1=P.V1 (V.epsilonv-V2.P/k2)-1. This can prevents the lowering of accuracy of a measuring data as caused by the mixing of air to allow the loading of a uniform pressure on a sample thereby achieving an accurate measurement of bulk elasticity of the soft material.