JPH0269629A - Method and instrument for measuring tension of film structure - Google Patents

Abstract

PURPOSE:To monitor the tension lowering phenomenon of a film structure and to improve the reliability of the film structure by facilitating the management of the introduction of film tension performed in a try and error state based on experiences and indirect measurement when the tension of the film structure is measured. CONSTITUTION:A tube 8 from a pressure reducing mechanism 7 is connected with the cylindrical box body 6 of this instrument for measuring tension of film structures in a state where the tube 8 can be controlled by an electric valve 9. A semiconductor pressure converter 10 is fitted to the box body 6 and a differential transformer type displacement gauge 11 is fitted to the inner surface of the box body 6. In addition, a pulley 11d is provided on the front end of a leg 11c protruding toward a film material 4' from a core 11b on the moving side of the gauge 11. The displacement is detected with displacement output caused by the displacement of the core 11b attending with the displacement of the film material 4'. Then the cylindrical box body whose inside is reduced in pressure is closely pressed against one surface of the film material pulled with prescribed tension to form spherically bent deformation and the tension N of the film material is calculated from a prescribed equation measured based on the measured pressure P inside the cylindrical box body and displacement delta of the top of the deformed section.

Description

[Detailed description of the invention] "Industrial application field" The present invention relates to a method and apparatus for measuring membrane tension in a membrane structure.

"Prior Art" In membrane structures, especially suspension membrane structures, it is important to manage the introduced membrane tension during construction in order to ensure rigidity through tension on the membrane surface.

In addition, in terms of maintenance and management, monitoring of tension is necessary in order to understand the amount of decrease in membrane tension due to creep, relaxation, etc., and to decide when to reintroduce tension.

At present, there is no suitable membrane tension measurement equipment, and management is based on the experience of the constructor or maintenance manager, or the ability to predict the degree of membrane tension based on the shape of the membrane surface and the measured values of the tension of the holding cables and boundary cables. . In other words, for wires (cables) that can be clipped with a cotton body instead of a face piece,
As shown in FIG. 4, the wire tension T can be calculated from the load P which causes a predetermined deflection by sandwiching the upper and lower parts of the wire 1 under tension T between rollers 2, 3.3.

However, when measuring the tension of a membrane material, the object to be measured is not a cotton body but a face piece, so the method of sandwiching it from the top and bottom (front and back) is not practical, and the above procedure cannot be applied as is. This is because there is no

"Problem that the invention attempts to solve" However, at present, it is difficult to accurately grasp membrane tension.

Therefore, since accurate tension values for the membrane itself cannot be measured either at the time of introducing membrane tension or during maintenance and management, rational design cannot be expected.

The present invention was made in view of the above circumstances, and it is possible to generate a measurement deflection by abutting only one side of a membrane against which a deflection generating contact cannot be brought into scissor contact. It is an object of the present invention to provide a measuring method and a measuring device that can calculate membrane tension.

"Means for Solving the Problems" In order to achieve the above object, the method of the present invention is to form a spherical shape by tightly pressing an inner cylinder whose inside is depressurized against one side of a membrane material that is stretched with a predetermined tension. A bending deformation is formed, and the membrane tension N is calculated based on the measured P and δ values using a predetermined formula (% formula %) δ: displacement (m) of the zenith portion of the deformed portion.

Further, in the device of the present invention, a pressure reducing mechanism is connected to the cylindrical box body, and a pressure gauge of the membrane surface displacement type and the pressure gauge for the internal pressure of the box is assembled.

Furthermore, in addition to the input/output control unit and input/output control unit that calculates and outputs the membrane tension from the measured values obtained in addition to the above configuration, it also performs control to ensure that the internal pressure value does not exceed a preset value. It is designed to incorporate a control section.

"Operation" The present invention configured as described above is established based on the following principle. That is, when pressure P is applied to the spherical membrane material 4 as shown in FIG. 1, the membrane stress N expressed by the following equation
occurs.

R N=□・・・・・・・・・・・・・・・・・・
・・・・・・・・・(1) However, P: Pressure (kg/bo), R: Radius of curvature of membrane curved surface (m) N: Membrane stress (kg/m) Here, a certain tension as shown in Figure 2 A pressure P that causes local spherical deformation in the membrane material 4'' under tension with N.
The balance equation after deformation when adding .

In addition, the displacement δ of the zenith portion of the deformed part of the membrane material 4 at this time is:
It is expressed by the following relationship with the radius of curvature R.

D: Diameter of deformed spherical surface (m) (2) Substituting 2 into equation (1), the increase in membrane tension due to the membrane material 4'' being deformed by δ is, when δ is smaller than D, Can be ignored.

Therefore, if we set δ to D and omit the quadratic term, equation (3) becomes P
D” ・・・・・・・・・・・・・・・・・・・・・
・(3・), and equation (3) is the displacement δ at the zenith and the pressure P
If is known, it can be interpreted as an equation for determining the membrane tension N.

Note that although the target is an isotropic membrane here, it is believed that sufficient accuracy can be ensured for construction management or maintenance management even when applied to commonly used orthotropic membranes.

In addition, the above-mentioned items that were ignored when introducing the formula are items that can be expected to improve accuracy by performing calibration using the same type of membrane material.

In order to bring about the spherical deformation to the membrane material 4'', it is sufficient to press the cylindrical body 5 whose interior is depressurized against the membrane material 4'', as shown by the imaginary line in the figure.

Based on the above principle, the present invention allows calculation of membrane tension by forming a bending deformation for measurement from one side of the membrane material.

“Example” An example will be described with reference to the drawings. In FIG.
is connected and controlled by an electric valve 9.

Further, a semiconductor pressure transducer 10 is attached to the box body 6. Furthermore, inside the box body 6, a differential transformer type displacement meter 11 is provided.
In the figure, 11a is a differential transformer on the fixed side, 11b is a core on the movable side, and the tip of the leg 11c protruding from the membrane material 4' attached to the core llb is a corresponding one. A pulley lid for contact is provided. However, the membrane material 4
The displacement δ can be detected from the displacement output generated by the core Ilb being displaced according to the displacement .

Reference numeral 12 in the figure indicates a ring-shaped neoprene rubber seal that is suitable for being placed around the open bottom edge of the box 6.

The opening of the cylindrical box 6 is pressed against the membrane material 4'' under tension N, and the decompression mechanism 7 is applied to cause bending deformation, thereby converting the semiconductor pressure transducer 10. 1
By obtaining P and δ from 1, according to the equation (3゛) mentioned above,
N can be calculated.

In order to automatically calculate the upward slope, it is sufficient to input the above-mentioned P and δ into an arithmetic unit programmed with (3゛)2 and output the calculated values.

In addition to the above-mentioned input/output control, the arithmetic unit and the connection control unit are designed to prevent deformation exceeding a preset maximum deformation amount from occurring, so as not to undermine the premise that δ becomes D as described above. ,
It is preferable to adjust the electric valve 9 to lower the pressure.

"Effects of the Invention" Since the present invention is configured as described above, it produces the effects described below.

(1) In the construction of a suspension membrane structure, the introduction membrane tension construction management, which had been carried out by trial and error based on experience (hunch) or indirect measurements, becomes easier and reliability is improved.

(2) The phenomenon of decrease in membrane tension due to creep, relaxation, etc. can be easily monitored, which is useful in terms of maintenance and management.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the relationship with membrane stress when pressure is applied to a spherical membrane material, and Figure 2 is an explanatory diagram of the relationship when local deformation is applied to the membrane material under a certain tension. , FIG. 3 is an explanatory diagram of the structure of the apparatus of the present invention, and FIG. 4 is an explanatory diagram of the principle of measuring tension in cotton. Step 2 Lid...Wire, 2.3...Roller, 4,4
″... Membrane material, 5... Cylindrical body, 6... Cylindrical box body, 7... Pressure reduction mechanism, 8... Tube, 9...
...Electric valve, 10...Semiconductor pressure transducer, 11
...Differential transformer type displacement meter, lla...Differential transformer, llb...Moving side core, 11c...Leg,
lid...Pulley, 12...Secret neoprene rubber. Nkupi/a 11-1 λL 9 dora/su type concubine Isu 11゜-1, ri【Mo2,2+b---ntqi history 1. nr7
1 Ic---IF I Id---
410,000 ゛Vnco゛A 12- Obscene HikineP

Claims (3)

[Claims] (1) An inner cylinder with a reduced internal pressure is tightly pressed against one side of the membrane material that is being pulled at a predetermined tension to form a spherical deflection deformation, and the predetermined formula N={P(δ^2+[D^ 2/4])}/4δN: Membrane stress (kg/m) P: In-cylinder pressure (kg/m^2) D: Spherical diameter (m) δ: Displacement at the zenith of the deformed part (m) A method for measuring membrane tension in a membrane structure, characterized in that the membrane tension N is calculated based on the P and δ values obtained. (2) A membrane tension measuring device having a membrane structure, characterized in that a pressure reducing mechanism is connected to a cylindrical box body, and a membrane surface displacement gauge and a pressure gauge for measuring the pressure inside the box are assembled. (3) In addition to an arithmetic unit and input/output control having a function of calculating and outputting the membrane tension from the measured value obtained by adding it to the device according to claim 2, the internal pressure value does not exceed a preset value. A membrane tension measurement device with a membrane structure that incorporates a control unit that performs such control.