Life testing method and life testing device of resin pipe

Abstract

To provide a life testing method and a life testing device which can calculate long-term characteristics of a resin pipe by a test in a short period.SOLUTION: A life testing device of a resin pipe includes: a tensile loading jig for pulling a short pipe formed by cutting out a cylindrical resin pipe as a test body in a vertical direction; a heat insulation device which is composed of a heat insulation material, covers the front and rear, right and left and upper parts of the tensile loading jig, and has a heat dissipation plate mounted therein; a load loading device which is provided on the lower end of the tensile mounting jig, and applies a mechanical tensile load to the test body; a heating device for heating the air in the heat insulation device; a temperature controller which controls the heating device, and maintains the constant temperature in the heat insulation device; a displacement meter for measuring a displacement amount of the test body; and a support tool having a lifting device for lifting the tensile mounting jig. Other embodiment includes a strain gauge in place of the displacement meter, and other embodiment includes a load meter in place of the displacement meter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a life test method and a life test device for a resin pipe, and more particularly to a life test method and a life test device for a resin pipe that can easily perform accelerated testing in a high-temperature environment. [Background technology]

[0002] It is known that resin pipes used for agricultural water and sewerage systems, which are made of resin materials, deteriorate over the years, reducing their durability and causing significant changes in their rigidity. In recent years, this long-term deterioration phenomenon has frequently led to sudden failure of resin pipes, resulting in the interruption of water supply and secondary damage such as the collapse of roads and surrounding facilities.

[0003] Design standards for plastic pipes and pipe rehabilitation manuals stipulate that the load-bearing capacity of the plastic pipes to be used 50 years from now and their rigidity at that time must be presented. There are two types of test methods for determining the long-term properties of plastic pipes: an external pressure test (Figure 14) for the bending strength and deformation of the pipe, and an internal pressure test (Figure 15) for determining the properties of the tensile strength. In both tests, a specified load condition is maintained until the pipe breaks. In simple terms, the water tank is kept at a reference temperature of 23°C, and the test is conducted with load and pressure for 10,000 hours (approximately 1.2 years).

[0004] As a result, testing plastic pipes requires a long period of time, and the cost of testing is extremely high because the breaking load at different loads is also required. Furthermore, the use of constant temperature equipment to maintain the water tank at a constant temperature makes the equipment large-scale. This has been an obstacle to the development of new plastic pipes. While this series of test methods is accepted as a way to understand the long-term properties of the test material, they are not time- and economically viable test methods for empirically evaluating plastic pipes used for agricultural water and water and sewerage systems. For this reason, there is a need for technology that can understand the long-term properties of plastic pipes in a short period of time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-299734 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a life test method and a life test device for a resin pipe that can calculate the long-term characteristics of the resin pipe through a short-term test. [Means for solving the problem]

[0007] The first lifespan testing method for plastic pipes according to the present invention is a method for testing a lifespan of plastic pipes, in which a short pipe cut out from a cylindrical plastic pipe is used as a test specimen, the test specimen is set in an insulation device, and a mechanical tensile force is applied to the test specimen while the air in the insulation device is kept at a temperature higher than the reference temperature (T0) at which the plastic pipe is buried, thereby predicting the lifespan of the plastic pipe.The method is characterized in that at each of at least two temperatures (T1, T2) higher than the reference temperature (T0), the time (m1, m2) for the deformation amount of the test specimen to reach a predetermined value (λ) is measured to determine the deformation rates (k1, k2), and then the deformation rate (k0) at the reference temperature (T0) is extrapolated from the deformation rates (k1, k2) at the two temperatures (T1, T2), and the time (m0=λ / k0) required for deformation at the reference temperature (T0) is calculated based on the extrapolated deformation rate (k0).

[0008] The second lifespan testing method for plastic pipes according to the present invention is a method for testing a lifespan of plastic pipes, in which a short pipe cut out from a cylindrical plastic pipe is used as a test specimen, the test specimen is set in an insulation device, and a mechanical tensile force is applied to the test specimen while the air in the insulation device is kept at a temperature higher than the reference temperature (T0) at which the plastic pipe is buried, thereby predicting the lifespan of the plastic pipe.The method is characterized in that at each of at least two temperatures (T1, T2) higher than the reference temperature (T0), the time (m1, m2) for the amount of strain of the test specimen to reach a predetermined value (λ) is measured to determine the strain rates (k1, k2), and then the strain rate (k0) at the reference temperature (T0) is extrapolated from the strain rates (k1, k2) at the two temperatures (T1, T2), and the time (m0=λ / k0) required for strain at the reference temperature (T0) is calculated based on the extrapolated strain rate (k0).

[0009] The third lifespan testing method for plastic pipes according to the present invention is a method for testing a lifespan of plastic pipes, in which a short pipe cut out from a cylindrical plastic pipe is used as a test specimen, the test specimen is set in an insulation device, and a mechanical tensile force is applied to the test specimen while the air in the insulation device is kept at a temperature higher than the reference temperature (T0) at which the plastic pipe is buried, thereby predicting the lifespan of the plastic pipe.The method is characterized in that at each of at least two temperatures (T1, T2) higher than the reference temperature (T0), the time (m1, m2) for the test specimen to reach its fracture stress (σ) is measured to determine the fracture speeds (k1, k2), and then the fracture speed (k0) at the reference temperature (T0) is extrapolated from the fracture speeds (k1, k2) at the two temperatures (T1, T2), and the time required for fracture at the reference temperature (T0) (m0=σ / k0) is calculated based on the extrapolated fracture speed (k0).

[0010] The mechanical tensile force is applied by lifting the test specimen.

[0011] The first resin pipe life testing device according to the present invention is characterized by comprising a tensile loading jig that pulls a short pipe cut out of a cylindrical resin pipe in the vertical direction as a test specimen; a heat insulation device made of insulating material that covers the front, back, left, right, and top of the tensile loading jig and has a heat sink attached to the inside; a load application device that is attached to the lower end of the tensile loading jig and applies a mechanical tensile load to the test specimen; a heat generation device that heats the air inside the heat insulation device; a temperature controller that controls the heat generation device to maintain a constant temperature inside the heat insulation device; a displacement meter that measures the deformation of the test specimen; and a support device equipped with a lifting device that hoists the tensile loading jig.

[0012] The second resin pipe life testing device according to the present invention is characterized by comprising a tensile loading jig that pulls a short pipe cut out of a cylindrical resin pipe in the vertical direction as a test specimen; a heat insulation device made of insulating material that covers the front, back, left, right, and top of the tensile loading jig and has a heat sink attached to the inside; a load application device that is provided at the lower end of the tensile loading jig and applies a mechanical tensile load to the test specimen; a heat generation device that heats the air inside the heat insulation device; a temperature controller that controls the heat generation device to maintain a constant temperature inside the heat insulation device; a strain gauge that measures the strain of the test specimen; and a support device equipped with a lifting device that hoists the tensile loading jig.

[0013] A third resin pipe life testing device according to the present invention is characterized by comprising a tensile loading jig that pulls a short pipe cut out of a cylindrical resin pipe in the vertical direction as a test specimen; a heat insulation device made of insulating material that covers the front, back, left, right, and top of the tensile loading jig and has a heat sink attached to the inside; a load application device that is provided at the lower end of the tensile loading jig and applies a mechanical tensile load to the test specimen; a heat generation device that heats the air inside the heat insulation device; a temperature controller that controls the heat generation device to maintain a constant temperature inside the heat insulation device; a load meter that measures the load applied to the test specimen; and a support device equipped with a lifting device that hoists the tensile loading jig. [Effects of the Invention]

[0014] According to the first life test method for plastic pipes of the present invention, since plastic pipes deform little by little over a long period of time, the deformation rate (k) (= deformation amount (λ) / time (m) to reach a predetermined deformation amount) is introduced, and since a certain relationship (Arrhenius equation) holds between the test temperature (T) and the deformation rate (k), a tensile test is conducted at a high temperature where the deformation rate (k) is large, and the time (m) to reach a predetermined deformation amount (λ) is measured, and the deformation rate (k) at a lower temperature is then extrapolated from this. Therefore, the time (m) to reach the deformation amount (λ) at the standard room temperature of 23°C can be calculated from a short test of about one week.

[0015] According to the second life test method of the present invention, the strain rate (k') (= strain amount (ε) / time (m) to reach a predetermined deformation amount) is introduced from the time it takes for the resin pipe to reach a predetermined strain amount, and a certain relationship (Arrhenius equation) is established between the test temperature (T) and the strain rate (k'). Therefore, a tensile test is conducted at a high temperature where the strain rate (k') is large, and the time (m) to reach the predetermined strain amount (ε) is measured. From this, the strain rate (k') at a lower temperature is calculated by extrapolation. Therefore, the time (m) required to reach the strain amount (ε) at the standard room temperature can be calculated from a short test of about one week.

[0016] According to the third life test method of the present invention, the fracture rate (k') (= fracture stress (σ) / time to fracture (m)) is derived from the time until the resin pipe breaks, and a certain relationship (Arrhenius equation) is established between the test temperature (T) and the fracture rate (k'). Therefore, a tensile test is conducted at a high temperature where the fracture rate (k') is large, and the time (m) until the fracture stress (σ) is measured. From this, the fracture rate (k') at a lower temperature is calculated by extrapolation. Therefore, the time (m) required to reach the critical stress (σ) at the standard room temperature can be calculated in a short test of about one week.

[0017] Mechanical tension force is applied by lifting the test specimen, allowing for space-saving testing on-site or in a research laboratory.

[0018] According to the first to third resin pipe life test devices of the present invention, a heat insulation device made of insulating material and a heating device for heating the inside of the heat insulation device are provided, so the temperature inside the heat insulation device can be raised to a high temperature. A temperature controller maintains a constant temperature, allowing accelerated testing at high temperatures. Since a large-scale constant temperature facility using a water tank is not required, equipment costs can be reduced and the development of new resin pipes can be promoted. A support device equipped with a lifting device for lifting the test specimen is provided, making it easy to lift a heavy load-loading device, allowing testing to be performed easily even on-site or in a laboratory. Since a short pipe cut from a cylindrical resin pipe is used as the test specimen, data closer to the actual buried environment can be obtained compared to testing on a plate piece. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a front view showing the internal configuration of a life testing device according to the present invention; [Figure 2] FIG. 2 is a right side view showing the internal configuration of the life test device of FIG. 1. [Figure 3] FIG. [Figure 4] This is a diagram showing the application of tensile force to the test specimen using a tensile loading jig. [Figure 5] This is a photograph used in place of a drawing showing a tensile loading jig suspended from a support fixture. [Figure 6] This is a photograph used as a drawing showing a tensile loading jig covered with a heat insulation device and hung down. [Figure 7] There is a photo that serves as a drawing showing the front panel of the heat preservation device from the inside. [Figure 8] This is a photograph in lieu of a drawing showing the side and back panels of the heat insulation device from the inside. [Figure 9] FIG. [Figure 10] 1 is a photograph showing the appearance of a temperature controller. [Figure 11] FIG. 1 is a mathematical diagram showing the Arrhenius equation. [Figure 12] 1 is a graph showing the relationship between deformation speed and the inverse of temperature. [Figure 13] 1 is a flowchart of a life test method. [Figure 14] FIG. 1 is a diagram showing the configuration of a conventional external pressure testing device. [Figure 15] FIG. 1 is a diagram showing the configuration of a conventional internal pressure testing device. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed description of a resin pipe life test method and life test device according to the present invention will be given below with reference to the drawings.

[0021] FIG. 1 is a front view of the internal structure of a life test apparatus 100 according to the present invention. The test specimen 12 is a short pipe cut from a cylindrical resin pipe, approximately 470 mm in diameter and 50 mm in length. A tensile loading jig 5 is attached to the test specimen 12 so that the diameter is pulled vertically. The tensile loading jig 5 consists of two semicircular divided plates 5b, 5b inserted into the test specimen 12, connecting metal fittings 5d, 5d connecting the divided plates 5b, 5b, and hanging metal fittings 5a, 5a pulling the divided plates 5b vertically. The test specimen 12 attached to the tensile loading jig 5 is covered on all sides, front, back, left, right, and top by a heat insulation device 4. The heat insulation device 4 is made of polystyrene foam plates, which are insulating materials, to maintain a constant internal temperature. In this example, the heat insulation device 4 is box-shaped. A heating device 3 is installed inside the heat insulation device 4 to heat the interior. Inside the heat retaining device 4, aluminum heat sinks 2, 2 are provided.

[0022] Specifically, the heating device 3 is a surface heater with dimensions (length x width x thickness) of 100 x 200 x 2 (mm) and a power of approximately 120 W. In Figure 1, the circles on the top, bottom, left and right of the test piece 12 indicate temperature measurement points 6. The temperature measurement points 6 are 13 points in total: eight points at the front and back of the test piece 12, four points on the heating device 3, and one point on the outside of the heat retention device 4. The heating device 3 is powered by a temperature controller 10 and controlled to a constant temperature. The temperature controller 10 is equipped with a thermocouple temperature sensor 11, which is brought into contact with the temperature measurement points.

[0023] Figure 2 is a right-side view of the internal structure of the life test apparatus 100 of Figure 1. The heat-generating devices 3 are located inside the heat-retaining device 4, with a total of four devices, two on the front side and two on the rear side. The tensile loading jig 15 consists of a hanging metal fitting 5a that pulls the test specimen 12 upward, connecting metal fittings 5d, 5d that connect the two divided plates 5b, 5b so that they can move up and down, and another hanging metal fitting 5a that pulls the test specimen 12 downward. The test specimen 12 is approximately 50 mm long in the front-to-rear direction. The bottom of the heat-retaining device 4 is open, and no bottom plate is provided.

[0024] FIG. 3 is an explanatory diagram of the tensile loading jig 5. The tensile loading jig 5 is known as a tensile test jig using divided plates (JISK7037). In the tensile loading jig 5, the upper divided plate 5b is lifted up by a hoisting fixture 5a, and the lower divided plate 5b is pulled down by a hoisting fixture 5a. The divided plate 5b and the hoisting fixture 5a are connected by a pin 5c. The divided plates 5b, 5b are inserted into the test specimen 12, and the tensile loading jig 5 is assembled.

[0025] Figure 4 shows the application of a tensile force to the test specimen 12 using the tension loading jig 5. The load application device 7 is specifically a weight weighing approximately 100 kg. The top of the tension loading jig 5 is connected to a support with a wire and suspended. The pinhole of the connecting fitting 5d is elongated to prevent the load from being applied. The test specimen 12 deforms due to the weight of the load application device 7, and the deformation amount λ is measured by the displacement meter 14. A laser displacement meter can be used as the displacement meter. Alternatively, a strain gauge 13 is installed on the outside of the test specimen 12 to measure the amount of strain. The strain gauge 13 converts the expansion and contraction of the object into a change in resistance and detects it as a voltage. Only one of the displacement meter or strain gauge may be installed. A load meter 9 is placed between the load application device 7 and the suspension fitting 5a. The load meter 9 can confirm the weight of the weight. Therefore, the load meter 9 can measure the load at which the test specimen 12 breaks. If the load (F) is known and the stress at that time is taken as the breaking stress (σ), then the breaking stress (σ) can be calculated from σ = F / A, where A is the cross-sectional area. The load meter 9 may be placed at the location of the upper suspension wire.

[0026] Figure 5 is a photograph, used in place of a drawing, showing the tensile loading jig 5 suspended from a support 15. Specifically, the support 15 is a tripod. However, it is not limited to this and can also be a rectangular frame. A scaffold is provided at the bottom of the tensile loading jig 5 to support the tensile loading jig 5. The scaffold can prevent load from being applied to the test specimen 12 before the test begins. Furthermore, the tensile loading jig 5 is raised and lowered by a lifting device 8. Specifically, the lifting device 8 is a manual chain block. The chain of the chain block can be operated to lift the load application device 7 and the tensile loading jig 5, which are heavy objects. Instead of a chain block, a lever block (registered trademark) that is operated by moving a hoist lever up and down may also be used.

[0027] Figure 6 is a photograph, used as a substitute for a drawing, of a tensile loading jig 5 covered with a heat insulation device 4 and hung. The front panel of the heat insulation device 4 has been removed. A temperature controller 10 is attached to the support 15. The support 15 can be installed outdoors, making on-site testing easy. In a laboratory environment, a tensile life test can be performed without the need for special hanging devices on the ceiling.

[0028] Figure 7 is a photograph, used as a substitute for a drawing, showing the front panel 4a of the heat retention device 4 from the inside. Two heat sinks 2 are attached, and heat generation devices 3, 3 are attached to the underside of the heat sinks 2, 2. The heat sink 2 absorbs heat from the heat generation devices 3 and dissipates it into the heat retention device 4, thereby making the internal temperature uniform.

[0029] Figure 8 is a photograph showing the side panel 4c and back panel 4b of the heat retention device 4 from the inside. Two heat sinks 2 are attached to the inside of the back panel 4b. Heat generating devices 3, 3 are attached to the underside of the heat sinks 2, 2, but are not installed in this photograph.

[0030] 9 is a perspective view of the heat generating device 3. The heat retaining device 4 has dimensions of, for example, height x width x depth, of 850 mm x 700 mm x 300 mm. The inside of the heat retaining device 4 is heated by four heat generating devices 3.

[0031] FIG. 10 is a photograph of the temperature controller 10. The temperature controller 10 is equipped with a thermocouple temperature sensor 11 and a power supply line to the heating device 3. The temperature can be set using the push buttons on the panel, and the temperature can be controlled by controlling the current to the heating device 3. The set temperature can be set between 40 and 80°C. In the heat retention device 4 of this embodiment, the specified temperature can be reached stably approximately two hours after the start of power supply to the heating device 3.

[0032] Figure 11 shows the Arrhenius equation. k on the left side is the deformation rate or strain rate expressed in logarithm. This equation shows that k, the deformation rate or strain rate, is a linear function of the reciprocal (1 / T) of the test temperature T expressed in absolute temperature. If the reference temperature is 23°C in Celsius, then the absolute temperature is 293°C (= 23°C + 273°C). The scale on the horizontal axis is the reciprocal of the absolute temperature (1 / T) x 10 3 In units of degrees Celsius, 23 degrees Celsius is approximately 3.4, and 80 degrees Celsius is approximately 2.8.

[0033] Figure 12 is a graph showing the relationship between the deformation rate (k) of the specimen 12 and the reciprocal of the absolute temperature (i.e., the test temperature). The vertical axis represents the logarithmic deformation rate (k). As shown at the bottom of Figure 12, the deformation rate (k) is calculated by dividing the deformation amount (λ) by time (m), where time (m) is the time required to reach that deformation. For example, if a tensile test is performed at a high temperature of 80°C, the deformation is accelerated, allowing the time required to reach the specified deformation amount (λ) in a short period of time to be determined, and the deformation rate (k) can be calculated. For example, if a tensile test is performed at a high temperature of 40°C, the deformation is also accelerated, allowing the time required to reach the specified deformation amount (λ) in a short period of time to be determined. This gives the deformation rate at 40°C. The deformation rate at a reference temperature of 23°C is then extrapolated from the deformation rates (k) at 80°C and 40°C. If the extrapolated deformation rate is used as the denominator and the deformation amount (λ) is used as the numerator, the time (m) required to reach the deformation amount (λ) at 23°C can be calculated.

[0034] As shown in Fig. 12, measurements are taken at several large, medium, and small deformation amounts (λ), and the deformation rate at the reference temperature of 23°C is extrapolated. In addition, since tests at 80°C and 40°C can be performed in parallel, if two life test devices 100 are prepared, two sets of results can be obtained in approximately half the time.

[0035] Figure 13 is a flowchart of a life test method based on the deformation rate of a test specimen 12. S1 is the step in which the time (m1) for the deformation amount of the test specimen to reach a predetermined value (λ) is measured at a temperature (T1) higher than the reference temperature (T0) to determine the deformation rate (k1 = λ / m1). In the example of Figure 12, T1 can be set to 80°C. That is, an accelerated test is performed by setting the test temperature to a temperature higher than the reference temperature of 23°C.

[0036] S2 is the step in which the deformation rate (k2 = λ / m2) is determined by measuring the time (m2) for the deformation amount of the test specimen to reach a predetermined value (λ) at a temperature (T2) higher than the reference temperature (T0). In the example of Figure 12, T2 can be set to 60°C. Since 60°C is a lower temperature than 80°C, the deformation rate (k2) is slower and smaller than the deformation rate (k1).

[0037] S3 is the step of extrapolating the deformation rate (k0) at the reference temperature (T0) from the deformation rate (k1) at temperature (T1) and the deformation rate (k2) at temperature (T2). Coordinates P1 (1 / T1, k1) and P2 (1 / T2, k2) are defined on a plane whose horizontal axis is the reciprocal of temperature and whose vertical axis is the deformation rate, and the deformation rate (k0 = λ / m0) at the reciprocal of the reference temperature (1 / T0) is extrapolated from the slope connecting coordinates P1 and P1.

[0038] In step S4, the time required for deformation at the reference temperature (T0) (m0 = λ / k0) is calculated from the extrapolated rate of change (k0) and amount of deformation (λ). This allows the amount of deformation after 5, 10, 50 years, etc. to be calculated.

[0039] In the present invention, a life test of a plastic pipe can be performed based on the strain rate of the test specimen 12. The strain rate (k') is calculated by dividing the amount of strain (ε) by the time (m) required to reach that amount of strain. The amount of strain (ε) can be measured using a strain gauge 13, as shown in Figure 4. The Arrhenius equation can also be applied using the strain rate (k'). By substituting the deformation rate (k) for the strain rate (k') using the procedure shown in Figure 13, the time required to reach the amount of strain (ε) at the reference temperature (T0) (m0 = ε / k'0) can be calculated.

[0040] In this invention, a lifespan test of a plastic pipe can be performed based on the fracture speed of the test specimen 12. The fracture speed (k') of a plastic pipe is defined as the fracture stress (σ) divided by the time (m) required to reach the fracture stress of the plastic pipe. The fracture stress (σ) is determined by constantly monitoring the load electrically using a load sensor on a load meter 9 and determining when the load decreases. The fracture stress (σ) is the stress that causes the plastic pipe to reach a "state where it can no longer be used or is at its limit." If the test specimen loses elasticity, the semicircular dividing plates 5b, 5b inserted inside the test specimen will separate from each other, but they are connected by connecting metal fittings 5d, 5d so that they do not separate by more than a certain distance. Therefore, the subsequent 100 kg load is supported by the tensile loading jig 5. If the load (F) that results in fracture stress is known, the fracture stress (σ) can be calculated using the equation σ = F / A. The Arrhenius equation can also be applied to the fracture speed (k'), allowing the deformation rate (k) to be replaced with the fracture speed (k'). By using a procedure similar to that shown in FIG. 13, the time (m0=σ / k′0) required to reach the fracture stress (σ) at the reference temperature (T0) can be calculated. [Industrial Applicability]

[0041] The life test method and life test apparatus according to the present invention are easy to use and extremely convenient, since they cover the resin pipe test specimen with a heat-retaining device, increase the temperature of the test environment, and accelerate the life test, making it possible to complete the test in a short period of time, such as about one week. [Explanation of symbols]

[0042] 1. Insulation 2 Heat sink 3 Heating device 4 Heat retention device 4a Front plate 4b Rear plate 4c side plate 5 Tensile loading jig 5a Hanging hardware 5b split plate 5c pin 5d Connecting hardware 6 temperature measurement points 7 Load bearing device 8 Lifting device 9 Load cell 10 Temperature Controller 11 Temperature sensor (thermocouple) 12 Test specimen (plastic pipe) 13 Strain gauge 14 Displacement meter 15 Supports 100 Life Test Equipment T, T', T” Temperatures higher than the reference temperature (T0) λ deformation amount ε Strain amount

Claims

1. A short pipe cut out from a cylindrical resin pipe is used as a test specimen, and the test specimen is set in a heat-retaining device. The air in the heat-retaining device is heated to the reference temperature (T ０ ) and apply a mechanical tensile force to the test specimen in a state where the test specimen is in a temperature higher than the specified temperature, thereby predicting the life of the resin pipe, Reference temperature (T ０ ) at least two temperatures (T １ , T ２ ) and the time (m) until the deformation of the test specimen reaches a predetermined value (λ). １ , m ２ ) and measure the deformation rate (k １ , k ２ ) are calculated, and then the two temperatures (T １ , T ２ ) deformation rate (k １ , k ２ ) to the reference temperature (T ０ ) deformation rate (k ０ ) and extrapolate the extrapolated deformation rate (k ０ ) based on the reference temperature (T ０ Time required for deformation (m ０ = λ / k ０ A life test method for a resin pipe, characterized by calculating the life span of the resin pipe.

2. A short pipe cut out from a cylindrical resin pipe is used as a test specimen, and the test specimen is set in a heat-retaining device. The air in the heat-retaining device is heated to the reference temperature (T ０ ) and apply a mechanical tensile force to the test specimen in a state where the test specimen is in a temperature higher than the specified temperature, thereby predicting the life of the resin pipe, Reference temperature (T ０ ) at least two temperatures (T １ , T ２ ) and the time (m) until the strain amount of the test specimen reaches a predetermined value (λ). １ , m ２ ) and measure the strain rate (k １ , k ２ ) are calculated, and then the two temperatures (T １ , T ２ ) strain rate (k １ , k ２ ) to the reference temperature (T ０ ) strain rate (k ０ ) and extrapolate the extrapolated strain rate (k ０ ) based on the reference temperature (T ０ Time required for distortion at ０ = λ / k ０ A life test method for a resin pipe, characterized by calculating the life span of the resin pipe.

3. A short pipe cut out from a cylindrical resin pipe is used as a test specimen, and the test specimen is set in a heat-retaining device. The air in the heat-retaining device is heated to the reference temperature (T ０ ) and apply a mechanical tensile force to the test specimen in a state where the test specimen is in a temperature higher than the specified temperature, thereby predicting the life of the resin pipe, Reference temperature (T ０ ) at least two temperatures (T １ , T ２ ) at each time point, the time (m) until the fracture stress (σ) of the test specimen is reached １ , m ２ ) was measured to determine the fracture rate (k １ , k ２ ) are calculated, and then the two temperatures (T １ , T ２ ) at the fracture speed (k １ , k ２ ) to the reference temperature (T ０ ) at the fracture speed (k ０ ) and extrapolate the extrapolated fracture velocity (k ０ ) based on the reference temperature (T ０ ) the time (m) required for breaking stress (σ) ０ =σ / k ０ A life test method for a resin pipe, characterized by calculating the life span of the resin pipe.

4. 4. The method for testing a life span of a resin pipe according to claim 1, wherein the mechanical tensile force is applied by suspending the test specimen.

5. a tensile loading jig that pulls a short pipe cut out from a cylindrical resin pipe in the vertical direction as a test specimen; A heat insulation device made of a heat insulating material, covering the front, back, left, right and top of the tensile loading jig and having a heat sink attached to the inside; a load applying device provided at a lower end of the tensile loading jig and applying a mechanical tensile load to the test specimen; a heating device that heats the air in the heat retaining device; a temperature controller that controls the heat generating device to maintain a constant temperature in the heat retaining device; a displacement meter for measuring the deformation amount of the test specimen; a support tool having a lifting device for lifting the tensile loading jig.

6. a tensile loading jig that pulls a short pipe cut out from a cylindrical resin pipe in the vertical direction as a test specimen; A heat insulation device made of a heat insulating material, covering the front, back, left, right and top of the tensile loading jig and having a heat sink attached to the inside; a load applying device provided at a lower end of the tensile loading jig and applying a mechanical tensile load to the test specimen; a heating device that heats the air in the heat retaining device; a temperature controller that controls the heat generating device to maintain a constant temperature in the heat retaining device; a strain gauge for measuring the strain of the test specimen; a support tool having a lifting device for lifting the tensile loading jig.

7. a tensile loading jig that pulls a short pipe cut out from a cylindrical resin pipe in the vertical direction as a test specimen; A heat insulation device made of a heat insulating material, covering the front, back, left, right and top of the tensile loading jig and having a heat sink attached to the inside; a load applying device provided at a lower end of the tensile loading jig and applying a mechanical tensile load to the test specimen; a heating device that heats the air in the heat retaining device; a temperature controller that controls the heat generating device to maintain a constant temperature in the heat retaining device; a load meter that measures the load applied to the test specimen; a support tool having a lifting device for lifting the tensile loading jig.

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