JP2005345228A - Volume elasticity measuring method and measuring instrument therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a volume elasticity measuring method which is simple, high in precision, excellent in reproducibility and enables a wide range of measurement using a small amount of a sample piece, and a measuring instrument therefor. <P>SOLUTION: A sample and a liquid are put in a measuring cell equipped with a volumetric change detecting part and pressure P is isotropically applied to the sample in the measuring cell through the liquid in the measuring cell by isotropically applying pressure P to the sample in the measuring cell to calculate the volume elasticity of the sample from the volumetric change of the sample with respect to the pressure P. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bulk modulus measurement method and a measurement apparatus. More specifically, the present invention relates to a volume elastic modulus measurement method and a measurement apparatus that are simple and capable of highly accurate measurement.

  Conventionally, as a method for measuring the bulk modulus of a sample, for example, a method of measuring the bulk modulus of a sample by an ultrasonic pulse (see Patent Document 1), or filling a sample into a cylindrical cavity without a gap and compressing the sample. A method of measuring the volume modulus of elasticity (see Patent Document 2) is known. However, these methods have a problem that the apparatus is large and expensive, and the form of the sample that can be measured is limited.

Further, when the sample is an isotropic material, the Young's modulus E, the rigidity G and the Poisson's ratio μ are obtained from the relational expression established between the bulk modulus κ, the Young's modulus E, the rigidity G and the Poisson's ratio μ. Two values are measured, and the relationship of κ = GE · (9G-3E), κ = 2 (1 + μ) G / 3 (1-2μ), κ = E / 3 (1-2μ) A method for calculating a bulk modulus based on an equation is known (see Non-Patent Document 1). However, the rigidity G and Poisson's ratio μ have a problem that it is difficult to obtain a highly accurate measurement value.
JP-A-6-324023 JP-A-8-282210 "Mechanical properties of polymers and composites" by LE Nielsen, published by Chemical Doujin (1976)

  SUMMARY OF THE INVENTION An object of the present invention is to provide a volume elasticity measurement method and apparatus that are simple, highly accurate, excellent in reproducibility, and capable of measuring a wide range with a small amount of sample piece.

  The volume modulus measurement method of the present invention includes a sample and a liquid placed in a measurement cell equipped with a volume change detection unit, and isotropically applies pressure to the entire measurement cell. This is a method for measuring a bulk elastic modulus, wherein a pressure P isotropically applied to a sample via a liquid in the measurement cell, and a volume elastic modulus of the sample is obtained from a volume change with respect to the pressure P.

The volume modulus measurement method of the present invention includes the following preferred embodiments.
(a) Use a measurement cell in which the internal volume of the measurement cell does not substantially change with respect to the pressure applied isotropically to the entire measurement cell.
(b) The sample and liquid are put into the measurement cell, and the volume change V1 when the pressure P is applied isotropically to the whole of the measurement cell, and the container is filled with water without putting the sample in the measurement cell. The volume elastic modulus of the sample is obtained from the volume change ΔV = V1−V0 with respect to the volume change V0 when isotropic pressure P is applied to the entire container.
(c) The volume change detection unit detects a volume change from a change in liquid level.
(d) The liquid placed in the measurement cell is water.
(e) Isotropic pressure is applied to the whole measurement cell by gas.
(f) Place the measurement cell in a pressure vessel, introduce gas into the pressure vessel, and apply pressure isotropically to the entire measurement cell.
(g) The gas that isotropically applies pressure to the entire measurement cell is nitrogen or air.
(h) The isotropic pressure applied to the entire measurement cell is 0.5 MPa or less.
(i) The internal volume of the pressure vessel has an internal volume that is 10 times or more the internal volume of the measurement cell provided with the volume change detection unit.

  In addition, the volume modulus measuring apparatus of the present invention includes a sample cell having a volume change detection unit and a measurement cell for containing a liquid, and isotropically pressurizing the measurement cell, and the measurement cell An apparatus for measuring bulk modulus, characterized in that it has means for isotropically applying pressure P to the sample inside through the liquid in the measurement cell.

  According to a preferred aspect of the measuring apparatus for bulk modulus of the present invention, the liquid to be put into the measuring cell is water, and isotropic pressure is applied to the whole measuring cell by a gas such as nitrogen or air. And a means for placing the measurement cell in a pressure vessel, introducing a gas into the pressure vessel, and applying pressure isotropically to the entire measurement cell. ing.

  According to the measuring method and measuring apparatus of the present invention, the bulk modulus of a sample can be measured simply, with high accuracy, with a small amount of sample piece, and it has excellent reproducibility and can be measured over a wide range. Is possible. In addition, according to the bulk modulus of the present invention, a wide range of bulk modulus from a foam type sample that easily changes in volume to a pressure to a solid rubber-based sample with small volume change is simple and accurate. Measurements can be made with good reproducibility.

  The bulk modulus κ is given by κ = P / (ΔV / Vi) = P / ((Vi−Vp) / Vi) when the sample receives a uniform pressure P and the sample volume changes from Vi to Vp. Defined.

  The volume modulus measurement method of the present invention is a measurement in which a volume modulus is measured by placing a sample in a liquid, applying a uniform pressure to the sample through the liquid, and directly reading the volume change of the sample. Is the method. Specifically, a sample and a liquid are put into a measurement cell equipped with a volume change detection unit, and the measurement is performed on the sample in the measurement cell by applying isotropic pressure to the whole measurement cell. This is a method for measuring a bulk modulus, wherein a pressure P is applied isotropically through a liquid in a cell, and a volume modulus of the sample is obtained from a volume change with respect to the pressure P.

  The measurement cell used in the present invention basically includes a container for containing a sample and a liquid, and a volume change detection unit.

  As a container for containing a sample and a liquid, a metal container having a small internal volume change due to pressure is preferable. Specifically, a stainless steel container that does not easily generate rust is preferably used. The shape of the container is not particularly limited, but a cylindrical container is preferably used. The internal volume of the container for containing the sample and the liquid is not particularly limited, but is preferably 1/10 or less, more preferably 1/100 or less with respect to the internal volume of the pressure vessel.

  The volume change detection unit needs to be able to detect a volume change with respect to a pressure applied isotropically to the entire measurement cell. In this invention, it is preferable that the volume change detection part with which the measurement cell is equipped has a mechanism which detects a volume change from the change of the liquid level height of the liquid introduce | transduced into a measurement cell. Specifically, there can be mentioned a mechanism in which a glass pipette or the like is connected to a container for containing a sample and a liquid, and volume change is read from the scale of the pipette.

  In the measurement cell used in the present invention, the internal volume of the measurement cell does not substantially change with respect to the pressure applied isotropically to the whole of the measurement cell at the time of measuring the bulk modulus. It is preferable that the volume does not substantially change due to the pressure applied at times, and a liquid leakage preventing rubber or a sealing tape may be used for a part of the measurement cell. In that case, it is important to calculate the volume modulus of the sample in consideration of the volume change derived from the rubber or the seal tape in addition to the volume change of the liquid itself at the time of pressurization.

  If pressure is applied from one side to the measurement cell, the sample in the measurement cell, and the liquid, liquid leakage will occur from the measurement cell, etc., and an accurate volume change cannot be measured, so an accurate bulk modulus can be obtained. Can not. For example, when a pressurizing branch pipe is attached to the measurement cell and pressurized, liquid leakage occurs from other parts of the measurement cell, particularly the fitting portion. In the present invention, a measurement cell is placed in a pressure vessel, a gas is introduced into the entire pressure vessel, and the entire measurement cell is pressurized isotropically, whereby a sample and a liquid container, a volume change detection unit Since any part of the measurement cell is pressurized with the exact same pressure, the pressure does not escape from anywhere, so it is possible to accurately measure the volume change of the sample due to the applied pressure. Accurate bulk modulus can be measured.

  The pressure to be applied is not particularly limited as long as it is equal to or lower than the pressure resistance of a measurement cell, a pressure vessel, etc., but a pressure in the range of 0.001 to 10 MPa is preferable, more preferably 0.01 to 1 MPa, and particularly preferably 0.00. 5 MPa or less.

  Examples of the liquid filled in the measurement cell used in the present invention include water and silicone oil, but water is preferably used because it is easily available.

  The sample to which the method for measuring the bulk modulus of the present invention is applied is not particularly limited, but it is important that the volume change ΔV can be measured with respect to the pressure of 0.001 to 10 MPa. Further, a sample capable of measuring the volume change ΔV with respect to a pressure of 0.01 to 1 MPa is preferable, and a sample capable of measuring the volume change ΔV with respect to a pressure of 0.01 to 0.5 MPa is more preferable. As such a sample having a large volume change with respect to a pressure change, a material having voids such as a foaming material can be cited. The firing material may be continuous firing or independent firing.

  In the present invention, it is preferable to use gas as means for pressurizing the liquid filled in the measurement cell. It is preferable to pressurize the liquid with gas and apply pressure isotropically to the sample through the liquid. Examples of such a gas include nitrogen and air. The pressure applied by gas is preferably 0.01 to 0.5 MPa.

  In order to apply pressure isotropically to the measuring cell of the present invention, the measuring cell can be placed in a pressure vessel and measured. In this case, the pressure vessel is preferably transparent so that the volume change detecting unit can be read visually. That is, it is preferable that at least a part of the pressure vessel is made of transparent plastics such as polyvinyl chloride. Moreover, it is preferable that the internal volume of the pressure vessel used by this invention has an internal volume 10 times or more of the internal volume of the measurement cell provided with the volume detection part. The upper limit is not particularly limited, but if the internal volume of the pressure vessel is 100 times or more the internal volume of the measurement cell provided with the volume detection unit, measurement with sufficiently high accuracy during pressure adjustment is possible.

  In the present invention, a measurement cell is placed in a pressure vessel, a gas is introduced into the pressure vessel, and pressure is applied to the entire measurement cell isotropically. Specifically, a sample and a liquid are put into a measurement cell, and volume change V1 when pressure P is applied isotropically to the whole measurement cell, and water is put into a container without putting a sample in the measurement cell. For the volume change V0 when the pressure P is applied to the entire container in an isotropic manner, the volume modulus of elasticity of the sample is expressed as κ = P / (ΔV from the volume change ΔV = Vi−Vp = V1−V0. / Vi).

  Next, based on the drawings, the measurement cell used in the present invention and the bulk modulus measurement apparatus of the present invention will be described.

  FIG. 1 is a schematic side view illustrating a measurement cell including a volume change detection unit used in the present invention. In FIG. 1, the measurement cell 1 includes a volume change detection unit such as a measuring pipette 2. Specifically, the measurement cell 1 basically includes a stainless steel container 3 for containing a sample and a liquid and a borosilicate glass measuring pipette 2 for detecting a volume change. The container 3 includes a sample chamber 5, a lid 6 and a lid 7, all of which are made of stainless steel. The female pipette 2 is vertically fixed to the upper part of the container 3 through a rubber plug 4 made of silicon, and the rubber plug 4 is fixed by a stainless lid 6 and a lid 7. The fitting portion 7 between the sample chamber 5 and the lid 6 and the fitting portion 9 between the lid 6 and the lid 7 are structured such that screws can be cut and disassembled. As described above, the fitting portion 8 and the fitting portion 9 are tightened with screws, and a sealing tape or the like made of polytetrafluoroethylene resin (not shown) is wound around the fitting portion so that water in the container 3 does not leak It can also be used.

  FIG. 2 is a schematic side view for illustrating the bulk modulus measurement apparatus of the present invention. 2, the measurement cell 1 of FIG. 1 is housed in a pressure vessel 10 made of polyvinyl chloride resin. A pressure gauge 11, a pressurization valve 12 and a pressure release valve 13 are connected to a pipe 10 made of polyvinyl chloride by piping, and a nitrogen cylinder (not shown) can be used for pressurization.

  Next, the procedure of the bulk modulus measurement method of the present invention will be described based on FIG. 1 and FIG.

  A sample weighed in advance was put in the container 3, and a measurement cell 1 equipped with a measuring pipette was assembled so that air did not enter in water. The water adhering to the outside of the container 3 was wiped off, and the measurement cell 1 was placed in the pressure container 10. Nitrogen was introduced into the pressure vessel 10 from the nitrogen cylinder using the pressure valve 12, and the pressurized pressure P and the volume change V1 at that time were measured.

  Next, a sample was not put in the measurement cell, and a measurement cell equipped with a pipette was assembled in the same manner as described above so that air did not enter in water. The water adhering to the outside of the measurement cell was wiped off and placed in the pressure vessel 10. Nitrogen was introduced into the pressure vessel 10 from the nitrogen cylinder using the pressure valve 12, and the pressurized pressure P and the volume change V0 at that time were measured. Using the pressurized pressure P and the value of the volume change ΔV = V 1 −V 0 of the sample at that time, the value of the volume elastic modulus κ = P / (ΔV / Vi) of the sample is calculated.

  The bulk modulus measurement method of the present invention is suitably used as a bulk modulus measurement method for continuous or independent firing foam materials, solid rubber materials, and the like.

(Example 1)
A sample piece of polyurethane impregnated non-woven fabric SUBA-400 manufactured by Rodel, USA, is placed in a stainless steel measuring cell having an internal volume of about 40 mL, and a capacity of 0.5 mL is added thereto as shown in FIG. A borosilicate glass pipette (minimum scale 0.005 mL) was attached. Separately, a polyvinyl chloride resin tube (inner diameter: 90 mmφ × 2000 mm, wall thickness: 5 mm) was used as a pressure vessel, and the measurement cell containing the sample piece was placed therein, and nitrogen was applied at the pressure P shown in Table 1. Pressurized and measured volume change V1. Subsequently, the sample was not put in the measurement cell, and nitrogen was pressurized at the pressure P shown in Table 1, and the volume change V0 was measured. A value obtained by dividing the pressure P by ΔV / Vi = (V1−V0) / Vi was calculated as the volume modulus of the sample.
The results are shown in Tables 1 and 2.

(Example 2)
In the same manner as in Example 1, volume modulus of elasticity was measured on 0.481 g (specific gravity 0.470) of a sample piece of polyurethane-impregnated nonwoven fabric SUBA-800 manufactured by Rodel, USA. The results are shown in Tables 1 and 2.

(Example 3)
In the same manner as in Example 1, volume modulus of elasticity was measured for 5.78 g (specific gravity 0.825) of a sample piece of microballoon-containing polyurethane IC-1000 manufactured by Rodel, USA. The results are shown in Tables 1 and 2.

Example 4
In the same manner as in Example 1, the volume modulus of elasticity was measured for 25.00 g (specific gravity 1.279) of a commercially available nitrile rubber (Miyasaka Rubber Co., Ltd.) (durometer A hardness 60). The results are shown in Tables 1 and 2.

  As described above, according to the bulk modulus measurement method and measurement apparatus of the present invention, a wide range of volumes from foam type samples that easily change in volume to pressure to solid rubber-based samples with small volume changes. The elastic modulus is simple and accurate, and can be measured with good reproducibility.

  The method for measuring bulk modulus of the present invention is suitably used as a method for measuring volume modulus of elasticity of a continuous or independent firing foam material or a solid rubber-based material, and is useful.

FIG. 1 is a schematic side view illustrating a measurement cell including a volume change detection unit used in the present invention. FIG. 2 is a schematic side view for illustrating the bulk modulus measurement apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measurement cell 2 Mespipet 3 Container 4 Rubber stopper 5 Sample chamber 6 Lid 7 Lid 8 Fitting part 9 Fitting part 10 Pressure vessel 11 Pressure gauge 12 Pressure valve 13 Pressure release valve

Claims (15)

  A sample and a liquid are placed in a measurement cell having a volume change detection unit, and pressure isotropically applied to the entire measurement cell, whereby the liquid in the measurement cell is applied to the sample in the measurement cell A method for measuring a bulk elastic modulus, comprising applying a pressure P isotropically to obtain a volume elastic modulus of a sample from a volume change with respect to the pressure P.   2. The method of measuring bulk modulus according to claim 1, wherein a measuring cell in which the internal volume of the measuring cell does not substantially change with respect to a pressure applied isotropically to the whole measuring cell is used. .   A sample and a liquid are put into a measuring cell, and volume change V1 when pressure P isotropically applied to the whole measuring cell, and water is put into a container without putting a sample in the measuring cell, The volume modulus of elasticity of a sample according to claim 1 or 2, wherein the volume modulus of elasticity of the sample is obtained from the volume change ΔV = V1-V0 with respect to the volume change V0 when the pressure P is applied isotropically to the whole. Elastic modulus measurement method.   The volume elastic modulus measuring method according to any one of claims 1 to 3, wherein the volume change detecting unit detects a volume change from a change in the liquid surface height.   The method for measuring a bulk modulus according to any one of claims 1 to 4, wherein the liquid put into the measurement cell is water.   6. The bulk modulus measurement method according to claim 1, wherein pressure isotropically applied to the entire measurement cell with gas.   The measurement cell is placed in a pressure vessel, a gas is introduced into the pressure vessel, and isotropic pressure is applied to the whole measurement cell. Measurement method of bulk modulus.   The method for measuring a bulk modulus according to claim 7, wherein the gas that isotropically applies pressure to the entire measurement cell is nitrogen or air.   The method for measuring bulk modulus according to any one of claims 1 to 8, wherein an isotropic pressure applied to the entire measurement cell is 0.5 MPa or less.   The method for measuring a bulk modulus according to any one of claims 7 to 9, wherein the internal volume of the pressure vessel has an internal volume that is 10 times or more the internal volume of the measurement cell provided with the volume change detection unit.   A measurement cell for containing a sample and a liquid having a volume change detection unit, and isotropic pressure is applied to the whole measurement cell, and the liquid in the measurement cell is applied to the sample in the measurement cell. A device for measuring bulk modulus, characterized in that it has means for applying pressure P isotropically.   12. The apparatus for measuring bulk modulus according to claim 11, wherein the liquid put into the measuring cell is water.   13. The bulk modulus measurement apparatus according to claim 11 or 12, further comprising means for isotropically applying pressure to the entire measurement cell with gas.   14. The bulk modulus measurement apparatus according to claim 13, wherein the gas is nitrogen or air.   The measurement cell is placed in a pressure vessel, gas is introduced into the pressure vessel, and a means for applying pressure isotropically to the whole measurement cell is provided. The volume elastic modulus measuring device described in 1.

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