JPS61142438A - Impact liquid pressure test - Google Patents

Abstract

PURPOSE:To disperse the decompression in a cylinder evenly, by interposing an air bag in a cylinder into which a liquid is injected as pressure medium. CONSTITUTION:An air bag 16 is inserted into a cylinder 7 to form an air layer positively between a piston 8 and a liquid 11. The air bag 16 shall be selected from among those made of material tough and soft enough to withstand the breakage by impact pressure or the like and produced from airtight sheet-like material. The amount of air in the air bag 16 is regulated with a plug 17. This provides a stable impact pressure wave regardless of the type and mounting position of a pressure converter thereby assuring a highly reliable data. The impact force also can be adjusted freely by changing the amount of air in the air bag.

Description

[Detailed description of the invention] (Industrial application field)゛.

The present invention relates to an impact hydraulic pressure test device for measuring and recording the influence of hydraulic pressure due to impact force.

(Prior art) If you use this type of shock hydraulic pressure testing machine that has already been proposed and developed and measure pressure by changing the type of pressure transducer and the measurement position, the state of the hydraulic pressure will change depending on each type of pressure transducer and measurement position. complicated,
It has also been revealed that these pressure waveforms exhibit mutually incompatible pressure waveforms with different phases. For this reason, when conducting an impact hydraulic pressure test, the impact pressure However, according to this test method, there were the following problems.

(1) It is complicated to set up a plurality of pressure transducers in a narrow cylinder, and there is also the drawback that it takes time to measure pressure, read impact pressure (data organization), etc. (2) Since the entire inside of the cylinder is a rigid body, if impact water pressure occurs inside, it will exhibit a high frequency and complicated pressure waveform with complicated refraction and reflection, resulting in poor data reliability.・(3) Due to the low reliability of the data, it was necessary to conduct the test several times under the same conditions.
The number of consumables (recording paper, strain gauges, etc.) increased, and at the same time, they were forced to spend more time conducting tests and organizing data.

Below, the conventional measurement method using the previously developed impact hydraulic pressure tester will be explained based on the drawings. Figure 4 shows the previously developed impact hydraulic pressure tester, and 1 is the gate. In the base of the mold, a circular hole is drilled in the center of the base 1 to support a specimen such as tempered glass 2 at its inner edge, and a cylinder 7 is mounted on the specimen through an O-ring. Placed and fixed. Further, two columns 21 are erected on both sides of the base 1, and a frame is mounted on the upper end of the front column 21, forming a gate-shaped frame as a whole. The cylinder 7 is fixed at a fixed position by a pedestal horizontally suspended at the lower intermediate portion of the front support 21.

Reference numeral 4 denotes a weight, which is disposed so as to be movable up and down along a suitable track between the front columns 21. Normally, the weight 4 is hooked to a hook 6 at the tip of a lobe of the winch 3, and the weight 4 is attached to the front column 2 as shown in the figure.
It is located above 1.

On the other hand, a liquid as a pressurized medium is injected into the cylinder 7, and a piston 8 is fitted into the internal opening of the cylinder 7. Reference numeral 9 denotes an air venting mechanism, which is provided at an appropriate location in the cylinder 7 to exhaust the air inside the cylinder 7.

The measurement method according to the conventional method using the impact hydraulic pressure testing machine having the above-mentioned components will be explained with reference to Figures 4 and 5. Place the glass 2, attach the pressure transducer 10 to its top surface,
This tempered glass 2 is liquid-tightly fixed to the bottom of a cylinder 7 via an O-ring 12, and a liquid 11 serving as a pressurized medium is injected into the inside of the cylinder 7.

Next, open the air vent mechanism 9 and insert the piston 8 into the cylinder 7.
After fitting from above and expelling the air in the cylinder 7, the air vent mechanism 9 is closed.

Also, the weight of the weight 4 is determined, the appropriate weight of the weight 4 is hung on the hook 6, and it is pulled up with the winch 3 to a predetermined volume. Further, the rope 5 is pulled to separate the weight 4 from the hook 6 and drop it onto the piston 8.

In addition, the piston 8 sinks due to the falling energy of the weight 4, and an impact force using the liquid 11 as a medium acts on the reinforced glass 2 within the cylinder 7.Then, the impact pressure generated within the cylinder 7 is transferred to the pressure transducer 10. Convert it into an electrical signal and send it to the amplifier 13
The information is transmitted to the storage device 14 and the recorder 15, respectively.

Next, a comparative example using the above test machine will be described in order to compare with the later-described embodiment of the present invention.

FIG. 6 shows a comparative example, and the difference from the conventional example is that an iron plate 18 is used as a specimen instead of the tempered glass 2 shown in FIG.
A female threaded hole is provided in the center of the iron plate 18, and the fixed pressure transducer 10c is screwed and fixed into this hole. Converters 10a and 10b are installed and fixed.

Furthermore, a fixed pressure transducer 10d similar to that described above is screwed and fixed to the side wall of the cylinder 7. In the test machine prepared in this way, the pressure waveform measured from each pressure transducer was measured according to the same measurement method as the conventional method.
It was as shown in the figure.

When examining this waveform, it is found that there are many high frequency parts, the phases are significantly different depending on each pressure transducer 10a to 10d, and the pressure values are also different from each other, making them incompatible.

This confirms the conventional problem mentioned above.

(Problems to be Solved by the Invention) As stated above, the present invention is based on the fact that conventional testing machines of this type have low data reliability (as a result, in addition to the complexity of the test itself), This is an attempt to solve problems such as the long time it takes to organize data.

(Means for Solving the Problems) Therefore, the present invention provides a cylinder in which a specimen is liquid-tightly fixed to the bottom, a liquid as a pressurized medium is injected into the inside, and a cylinder in which a liquid as a pressurized medium is injected into the cylinder. In an impact hydraulic pressure testing machine equipped with a fitted piston, an air vent mechanism provided on the piston or the cylinder to exhaust the inside of the cylinder, and an impact load loading means for applying an impact load to the piston from the outside. The structure is such that an air bag is interposed inside the cylinder, and this is used as a means to solve the problem.

(Function) By interposing an air bag in the cylinder, an air layer is formed between the piston and the liquid, and as a result, the impact force is alleviated and the liquid pressure in the cylinder is evenly distributed. moreover,
By changing the amount of air in the air bag, the impact force can be freely adjusted.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 1st
The figure shows an embodiment of the present invention, which differs from the conventional example shown in FIG. The point is that an air layer is formed between the two.

The air bag 16 is made of a strong yet flexible material that will not be damaged by impact pressure or the like, and is made of an airtight sheet material. 17 indicates a stopper, which allows air bag 1
The amount of air inside 6 can be adjusted.

The results of an experiment using the impact hydraulic pressure test device according to this embodiment in which an air bag is inserted in the cylinder 7 and using the same measurement method as in the comparative example described above are shown in FIG. ing.

That is, in FIG. 1, an iron plate 18 is used as a specimen, and a fixed pressure transducer 10c is installed in the center of the iron plate 18.
In addition, the immersion type pressure transducer 1 with different heights is placed around it.
At the same time, a fixed pressure transducer 10d is fixed to the side wall of the cylinder 10d, and a weight is dropped from the top of the piston 8 to apply an impact force to the liquid 11.

Each pressure transducer 10a, 10b on the iron plate 18 at this time,
10c and the pressure waveforms received by the pressure transducer 10d provided in the cylinder 7 are as shown in FIG.

As is clear from FIG. 2, each pressure transducer 10a~
It can be seen that the impact pressure values received by 10d are almost the same, and the waveform phases are also roughly similar. However, the pressure waves received by the pressure transducer provided in the cylinder 7 are slightly out of phase with those on the iron plate 18, but this is probably due to the difference in position between the bottom and side surfaces of the cylinder.

However, the entire waveform is very similar,
This shows that impact pressure can be measured at any location within the cylinder 7.

This point can be said to be obvious when compared with the measurement results of the comparative example based on the conventional device shown in FIG.

(Effects of the Invention) As described in detail above, according to the present invention, a stable impact pressure waveform can be obtained regardless of the type of pressure transducer or the mounting position, and since the pressure transducer is compatible, one pressure transducer can be used. It is sufficient to install the equipment and conduct the test once, and highly reliable data can be obtained.

Furthermore, by changing the amount of air in the air bag, the impact force can be freely adjusted, and the range of applications of impact hydraulic pressure tests can be significantly expanded.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main parts of an impact hydraulic pressure testing device showing an embodiment of the present invention, FIG. 2 is an impact pressure waveform diagram when using the same device, and FIG. 3 is an impact pressure waveform diagram according to a comparative example. Fig. 4 is an overall perspective view of the impact hydraulic pressure testing device, Fig. 5 is a sectional view of the main part of the conventional same device, and Fig. 6 is a sectional view of the main part of the same device showing a comparative example with this example. . Explanation of the main parts of the figure 7 - Cylinder 8 - Pistons 10a, 10b, 10c, 10d - Pressure transducer 11
-・Liquid 16...-Air bag

Claims (1)

[Claims] A cylinder in which the specimen is liquid-tightly fixed to the bottom and a liquid as a pressurized medium is injected into the inside, a piston liquid-tightly fitted inside the cylinder, and a cylinder provided in the piston or the cylinder inside the cylinder. An impact hydraulic pressure testing machine equipped with an air venting mechanism for exhausting air, and an impact load applying means for applying an impact load to the piston from the outside, characterized in that an air bag is interposed inside the cylinder. Impact hydraulic pressure test equipment.