JPS6093941A - Material strength testing apparatus - Google Patents

Abstract

PURPOSE:To make it possible to perform a strength test in such a state testing stress is set arbitrarily, by a small apparatus having such a mechanism that the piston in a pressure chamber having a test piece fixed thereto is formed into a two-step diameter structure having different diameters and providing three pressure chambers so as to correspond to the leading end part, intermediate part and rear end part of the piston. CONSTITUTION:The upper end of a test piece 1 is fixed to a casing 2a and the lower end thereof is fixed to a piston part 3a. A piston 3 is formed onto a two- step diameter structure having different diameters and seal mechanisms 9, 10 for performing water seal are provided between the piston 3 and the casing 2a. A pressure chamber A sets the pressure environment of the test piece 1 and high temp. and high pressure water is introduced into said chamber A. A pressure chamber B is filled with pressure water for loading the test piece 1 and, by controlling differential pressure between the pressures of the pressure chamber B and a pressure chamber C, arbitrary load can be loaded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a special environment raw material strength testing device that can perform strength testing of materials in a high-pressure water environment, and in particular, to a fatigue test or Suitable for material strength testing equipment with autoclave for constant load testing.

[Background of the invention]

The disadvantages of conventional material strength testing equipment, in which a test piece is placed in high-pressure water and this high-pressure water is used as a driving source for applying a load to the test piece, will be explained using Figures 1 to 3. .

In FIG. 1, a test piece 1 is placed in a pressure chamber A filled with high-pressure water, and is fixed to a casing 2 at one end and to a piston 3 at the other end. The pressure water drains from the inlet 115 to the outlet 6, and the environment of the pressure chamber A is kept constant at all times. Also,
Below the piston 3 is a pressure chamber C that is open to atmospheric pressure through a hole 7. Therefore, the differential pressure between pressure chambers A and C and piston 3
A constant load calculated by the area of
(2) It is necessary to change the pressure in pressure chamber A. but,
In the former case, since the test piece surface f~ changes, it is conceivable that the surface area may have an effect on the occurrence of 9 cracks, and the cross-sectional area may have an effect on the test results on the propagation of cracks. On the other hand, in the latter case, the pressure conditions of high-pressure water vary from test piece to test piece, which is also not an appropriate method.

Furthermore, FIG. 2 shows a test device (2) that takes the above-mentioned drawbacks into consideration, and allows the dimensions of the test piece and the pressure conditions of the pressure chamber A to be kept constant at all times. That is, a pressure chamber B connected to a pressure chamber A is provided, and a sleeve 8 is further provided between the casing 2b and the piston 3. Since the pressure receiving area of the piston 3 is determined by the area in contact with the pressure chambers A and B, an arbitrary load can be applied to the test piece 1 by changing the thickness of the sleeve 8 and the outer diameter of the piston 3 located in the pressure chamber B. It is possible to do so. However, with this testing machine, the combination of sleeve 8 and piston 3 must be manufactured in advance for each test load, and the piston 3 and sleeve 8 must be disassembled and reassembled each time the test load is changed. It was complicated.

Furthermore, in these test devices, when performing tests that change the pressure conditions of pressure chamber A, pressure chamber C is opened to the atmosphere, so it is necessary to change the cross-sectional dimensions of the test piece for each pressure condition of pressure chamber A. Therefore, it was not possible to conduct tests using test pieces of the same size.

In Figure 3, back pressure exceeding atmospheric pressure is applied to the pressure difference C using a pump or high-pressure gas, and this pressure is adjusted (3) to adjust the stress applied to the test piece. When the pressure conditions are low, it is necessary to increase the pressure-receiving area of the piston 3 in order to produce a predetermined load, and this increases the size of the pressure chamber, which is a problem, especially in testing machines for high-temperature, high-pressure wood.

[Purpose of the invention]

The present invention provides a testing device that allows the test stress to be easily set arbitrarily without changing the test piece dimensions or test pressure conditions, and that allows tests to be performed using test pieces of the same size even when the test pressure conditions are changed. The goal is to provide 1rl.

[Summary of the invention]

In the material strength test equipment of the present invention, three pressure chambers are provided, and one pressure chamber is used to set the m Ht and pressure of 11 test pieces, and the other two pressure chambers are used to set the ILr weight acting on the test piece. It is controlled by differential pressure.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

The upper end of one test piece is fixed to the casing 2a, and the lower end is fixed to the piston 3a. The piston 3 is a two-stage piston having a smaller diameter on the 2nd (4) side and a larger diameter on the lower side, and is provided with seal mechanisms 9 and 10 for sealing water with the casing 2. Seals 9 seal pressure chambers A and B, and seals 10 seal pressure chambers B and C, respectively. In this test device, pressure chamber A is used to set the pressure environment of the test piece, but when performing high temperature and high pressure water environment tests, the smaller the size, the better, considering the danger of the test. . In addition, the pressure chamber B is filled with pressure water to apply a predetermined load to the test piece 1, but when the pressure chamber C is released to the atmosphere, the pressure is adjusted using the pressure water inlet 11 depending on the load condition. By doing so, it becomes possible to generate an arbitrary load.

That is, the piston diameter of pressure chamber A is Dj, +pressure chamber B.

If the diameter of the piston in contact with C is Dl, and the pressure in each pressure chamber is P^+pHl+PC, then the load F acting on the test piece can be expressed by the following equation.

F=π/4 D 12 (P A P 8 ) 1π/4
D22 (PB Pc) (1) Now, Dl = 3cm, PA = 70Kg/am2y
When Dl(5) = 5 cm, it is found that the load capacity becomes 1 to 3 tons when the pressure P is set to 100 to 300 Kg/eJ as shown in Fig. 5.

Further, in FIG. 6, another embodiment will be explained. FIG. 6 is a test machine in which the test section is at a high temperature, so in order to avoid deterioration of the seal, the seal mechanism between pressure chambers A and 13 was removed to make the pressures in both pressure chambers the same. This example is particularly suitable for use in a high-temperature Takae Mukan Jn material testing machine. That is, there is no sealing mechanism between pressure chambers A and B, and the problem of seal deterioration is severe.Also, low-humidity, high-pressure water is sent to pressure chamber B, and the wood taken out from outlet 12 is heated with a preheater etc. and enter pressure chamber A [if connected to 15, pressure chamber A
, B requires only one pressurizing source, and since the pressure chamber B is filled with cold water, the seal 10 is in a low-temperature environment and has the advantage of being less susceptible to deterioration.

In this example, the load acting on test piece 1 is F=π/4D
22 (Ps Pc) (2), and in order to calculate the maximum generated load in this example, Pc” is set to atmospheric pressure, and D2
= 5cm, (6) As shown in Figure 7, F-2 on P day = 100Kg/-
It can be seen that a testing machine with a sufficiently large load capacity can be obtained. The load can be controlled by adjusting the pressure in pressure chamber C, and if the pressure source for pressure chamber C is branched from the pressure source for pressure chamber B, then all pressure chambers can be controlled. Pressure can be supplied with one pump. Furthermore, since the volume of the high-temperature, high-pressure chamber A is reduced, it goes without saying that the electric capacity of the heater 15 can be reduced.

〔Effect of the invention〕

As described above, according to the present invention, the applied capacity of the testing machine can be easily increased in size, and in particular, in the case of a high-temperature and high-pressure testing machine, there is an advantage that the highly dangerous high-temperature and high-pressure section can be miniaturized.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional constant load testing device that uses high-pressure water, Figure 2 is a cross-sectional view of another conventional device, and Figure 3 is a conventional test device that can also perform fatigue tests using high-pressure water. A cross-sectional view of
4th. FIG. 6 is a sectional view of a test device according to the present invention;
FIG. 7 is an explanatory diagram showing a trial calculation of the relationship between the load capacity and the acting force of the test device according to the present invention (7). 1... Test piece, 2... Pressure vessel casing, 3...
・Piston, 5, 7, 1.1.13...pressure water inlet,
6゜12.14... Same exit, A, B, C... Pressure chamber agent valve 7! lj person Akio Takahashi (8) Fig. 1'vJ21 ¥] Fig. 3 ¥J 4 Fig. 5 Fig. 6 Fig.'''fJ 7 Fig. F'a (KVeina')

Claims (1)

[Claims] 1. A material in which a test piece is placed in a pressure chamber using a fluid as a medium, is fixed to a slidable piston provided in the pressure chamber, and a load is applied to the test piece using the cavity pressure medium. A strength testing device characterized in that the piston has a two-stage shaft with different diameters, and a pressure chamber exclusively for loading is provided in the middle of the piston.