Container inspection method, program, and container inspection apparatus

Abstract

To provide an excellent container inspection method, program, and container inspection device.SOLUTION: An inspection method of a container 200 includes: a detection step of sequentially detecting an AE wave 40 to be generated in the container by an AE sensor 12 while raising inner pressure of the container; a calculation step of sequentially calculating dimensionless AE average energy Z by dividing AE average energy Eb by predetermined AE intrinsic average energy Est; and a determination step for determining whether the AE wave having the dimensionless AE average energy exceeding a predetermined threshold value Za which indicates a symptom of destruction of the container is observed before the inner pressure of the container reaches a predetermined inspection pressure upper limit value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for inspecting a container, a program, and a container inspection apparatus.

Background Art

[0002] In recent years, research and development have been conducted on fuel cell systems that contribute to energy efficiency in order to enable more people to access affordable, reliable, sustainable, and modern energy. A fuel cell system includes a container for filling a fuel gas (e.g., hydrogen gas).

[0003] This type of container has a hollow liner filled with a fluid inside, and a fiber layer formed by winding a fiber member around the outer peripheral surface of the liner. Patent Document 1 discloses a method for inspecting such a container. In this inspection method, signs of fatigue failure of the liner are inspected based on AE (Acoustic Emission) waves generated in the container when the pressure inside the container is increased. Hereinafter, Acoustic Emission is referred to as AE.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is a need for a better method for inspecting a container, a program, and a container inspection apparatus.

[0006] The present invention aims to solve the above-described problems.

Means for Solving the Problems

[0007] A first aspect of the present disclosure is a method for inspecting a container formed by winding a fiber member around an outer peripheral surface of a hollow liner, the method including: a detection step of sequentially detecting AE waves generated in the container by an AE sensor while increasing the pressure inside the container; a calculation step of sequentially calculating a dimensionless AE average energy by dividing an AE average energy, which is an average energy of a plurality of partial AE waves included in the AE waves detected by the AE sensor, by a predetermined AE specific average energy that is the specific AE average energy of the container; and a determination step of determining whether or not an AE wave having the dimensionless AE average energy exceeding a predetermined threshold indicating a sign of fracture of the container is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value.

[0008] A second aspect of the present disclosure is a program for causing a computer to execute the above-described method for inspecting a container.

[0009] A third aspect of the present disclosure is an inspection apparatus for a container formed by winding a fiber member around an outer peripheral surface of a hollow liner, the apparatus including: an acquisition unit that sequentially acquires AE waves generated in the container while increasing the pressure inside the container; a calculation unit that sequentially calculates a dimensionless AE average energy by dividing an AE average energy, which is an average energy of a plurality of partial AE waves included in the AE waves acquired by the acquisition unit, by a predetermined AE specific average energy that is the specific AE average energy of the container; and a determination unit that determines whether or not an AE wave having the dimensionless AE average energy exceeding a predetermined threshold indicating a sign of fatigue fracture is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value.

Advantages of the Invention

[0010] According to the present invention, a better method for inspecting a container, a program, and an inspection apparatus for a container can be obtained.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0012] When manufacturing a container by winding a fiber member around the outer peripheral surface of a liner, variations in the shape of the container are likely to occur. Therefore, there are individual differences in the shape of the containers manufactured in this way. In addition, since it is difficult for the outer peripheral surface of the fiber layer to come into uniform contact with the AE sensor, variations are also likely to occur in the mounting state of the AE sensor with respect to the outer peripheral surface of the fiber layer. Therefore, when accurately inspecting the signs of container breakage using an AE sensor, it was necessary to individually set in advance the determination conditions for AE waves indicating the signs of container breakage for all containers.

[0013] However, when mass-producing containers, such a method is not practical. In view of such problems, the present disclosure can provide a container inspection method, a program, and a container inspection apparatus that can standardize (unify) the determination conditions for AE waves indicating signs of container breakage.

[0014] The inspection method for the container 200 of the present disclosure and the container inspection apparatus 10 will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the container inspection apparatus 10 for the container 200. First, the container 200 to be inspected will be described. As shown in FIG. 1, the container 200 is a pressure vessel configured to be fillable with a fluid. The container 200 is, for example, a gas tank used in a fuel cell system (not shown). The gas tank can be filled with a fuel gas such as hydrogen gas. The container 200 is not limited to a gas tank.

[0015] The container 200 is a composite container. The container 200 includes a hollow liner 202, a first base 204, a second base 206, a sealing member 208, a plug 210, and a fiber layer 212. The liner 202 is made of resin, but may be made of metal. The liner 202 is composed of, for example, high-density polyethylene (HDPE) or nylon resin (PA6) that suppresses the permeation of hydrogen gas.

[0016] The liner 202 has an intermediate portion 214, a first end portion 216, and a second end portion 218. The intermediate portion 214 is formed in a cylindrical shape. The first end portion 216 is provided at one end of the intermediate portion 214. The second end portion 218 is provided at the other end of the intermediate portion 214. Each of the first end portion 216 and the second end portion 218 is formed in a hemispherical shape.

[0017] The first base 204 is attached to the first end portion 216. The second base 206 is attached to the second end portion 218. The sealing member 208 is attached to the first base 204 so as to seal the hole of the first base 204. The plug 210 is attached to the second base 206. A flow path 220 is formed in the plug 210 to enable filling of fluid into the liner 202 and discharge of fluid from the inside of the liner 202. The fiber layer 212 is formed by winding a fiber member 222 around the outer peripheral surface of the liner 202. The fiber member 222 is wound around the liner 202 by a filament winding device (not shown).

[0018] Next, the inspection device 10 for the container 200 will be described. The inspection device 10 inspects for the presence or absence of signs of rupture (fatigue rupture) of the container 200. Specifically, the inspection device 10 inspects for the presence or absence of signs of rupture of the fiber layer 212. Note that the inspection device 10 can also inspect for the presence or absence of signs of rupture of the liner 202.

[0019] The inspection device 10 includes a plurality of AE sensors 12 and an inspection control unit 14. The AE sensors 12 are attached to the outer peripheral surface of the fiber layer 212. The attachment position and number of the AE sensors 12 with respect to the container 200 are appropriately set according to the shape and size of the container 200 and the like. The AE sensors 12 detect AE waves 40 (see FIG. 3) generated in the container 200. In other words, the AE sensors 12 can sequentially measure the AE waves 40 generated in the container 200.

[0020] The inspection control unit 14 includes an arithmetic unit 16, a storage unit 18, an operation unit 20, and a display unit 22. The arithmetic unit 16 is constituted by a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). That is, the arithmetic unit 16 is constituted by a processing circuitry.

[0021] The calculation unit 16 includes a control unit 24, an acquisition unit 26, a calculation unit 28, a determination unit 30, and a notification unit 32. The control unit 24, the acquisition unit 26, the calculation unit 28, the determination unit 30, and the notification unit 32 can be realized by the execution of a program stored in the storage unit 18 by the calculation unit 16.

[0022] Note that at least a part of the control unit 24, the acquisition unit 26, the calculation unit 28, the determination unit 30, and the notification unit 32 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). Also, at least a part of the control unit 24, the acquisition unit 26, the calculation unit 28, the determination unit 30, and the notification unit 32 may be configured by an electronic circuit including discrete devices.

[0023] The storage unit 18 is composed of a volatile memory (not shown) and a non-volatile memory (not shown). Examples of the volatile memory include a RAM (Random Access Memory). The volatile memory is used as the working memory of the processor and temporarily stores data and the like necessary for processing or calculation. Examples of the non-volatile memory include a ROM (Read Only Memory), a flash memory, and the like. The non-volatile memory is used as a storage memory and stores programs, tables, maps, and the like. At least a part of the storage unit 18 may be provided in the above-described processor, integrated circuit, etc.

[0024] The operation unit 20 is used when the user operates the inspection control unit 14. Examples of the operation unit 20 include, but are not limited to, a keyboard, a mouse, and the like.

[0025] The display unit 22 is provided with a display element (not shown). Examples of the display element include a liquid crystal display element, an organic electroluminescence display element, and the like. The operation unit 20 and the display unit 22 may be configured by a touch panel (not shown) provided with such a display element.

[0026] The control unit 24 controls the overall inspection device 10. The acquisition unit 26 can grasp the AE wave 40 based on the signal supplied from the AE sensor 12. The calculation unit 28 calculates a dimensionless AE average energy Z, which will be described later, from the AE wave 40 acquired by the acquisition unit 26. The determination unit 30 determines whether the dimensionless AE average energy Z calculated by the calculation unit 28 is greater than a predetermined threshold value Za. The notification unit 32 notifies the determination result of the determination unit 30.

[0027] FIG. 2 is a flowchart for explaining an example of the inspection method of the container 200. As shown in FIG. 2, in step S1, the inside of the container 200 is pressurized. Specifically, a fluid is introduced into the inside of the container 200 (liner 202) through the flow path 220 of the plug 210. The fluid used here is not particularly limited, and examples include helium gas and the like. When the inside of the container 200 is pressurized, the liner 202 presses the fiber layer 212 outward. As a result, when the container 200 is deformed or cracks or the like occur in the container 200, an AE wave 40 is generated in the container 200. The AE wave 40 generated in the container 200 is detected by the AE sensor 12. The signal of the AE sensor 12 is supplied to the inspection control unit 14. Thereafter, the process proceeds to step S2.

[0028] In step S2, the acquisition unit 26 acquires information indicating the AE wave 40 based on the signal supplied from the AE sensor 12. FIG. 3 is an explanatory diagram of the AE wave 40 that can be detected by the AE sensor 12. As shown in FIG. 3, the AE wave 40 includes a plurality of AE continuous waves 42. The AE continuous wave 42 is one continuous wave. The AE continuous wave 42 includes a plurality of partial AE waves 44 and noise waves 46.

[0029] The partial AE wave 44 is a wave of one cycle having an amplitude greater than a predetermined amplitude threshold value. The partial AE wave 44 is a wave (sound wave) generated due to deformation, cracks, etc. of the container 200. The noise wave 46 is a wave having an amplitude equal to or less than the amplitude threshold value. The amplitude threshold value is stored in the storage unit 18. The amplitude threshold value is set to a magnitude such that the noise wave 46 and other waves (partial AE wave 44) can be distinguished. Specifically, the amplitude threshold value is set based on the shape of the container 200, etc. (including shape, size, material, etc.), the performance of the AE sensor 12, etc. Thereafter, the process proceeds to step S3.

[0030] In step S3, the determination unit 30 determines whether the amplitude of the AE wave 40 exceeds the amplitude threshold value. That is, the determination unit 30 determines whether an AE wave 40 including the partial AE wave 44 is generated. In other words, the determination unit 30 can determine whether the AE sensor 12 or the like is operating normally. In step S3, if the determination unit 30 determines that the amplitude of the AE wave 40 does not exceed the amplitude threshold value (NO in step S3), the process proceeds to step S4. In step S3, if the determination unit 30 determines that the amplitude of the AE wave 40 exceeds the amplitude threshold value (YES in step S3), the process proceeds to step S5.

[0031] In step S4, the determination unit 30 determines whether the pressure inside the container 200 has reached the inspection pressure upper limit value. The inspection control unit 14 can acquire the pressure inside the container 200 detected by a pressure sensor (not shown). The inspection pressure upper limit value is a predetermined value and is stored in the storage unit 18. In step S4, if the determination unit 30 determines that the pressure inside the container 200 has not reached the inspection pressure upper limit value (NO in step S4), the process proceeds to step S1. In step S4, if the determination unit 30 determines that the pressure inside the container 200 has reached the inspection pressure upper limit value (YES in step S4), the process proceeds to step S7.

[0032] In step S5, the calculation unit 28 calculates the dimensionless AE average energy Z. First, the calculation unit 28 calculates the AE average energy Eb. The AE average energy Eb is the average energy of a plurality of partial AE waves 44 included in the AE continuous wave 42. Specifically, the calculation unit 28 calculates the AE average energy Eb by the following formula (1). However, in formula (1), Ea is the energy of a plurality of partial AE waves 44 included in the AE continuous wave 42, and Na is the number of partial AE waves 44 included in the AE continuous wave 42.

[0033]

Number

[0034] Subsequently, the calculation unit 28 calculates the dimensionless AE average energy Z by the following formula (2). However, in formula (2), Est is the AE eigen average energy, which is the eigen AE average energy of the container 200's own AE average energy Eb. The AE eigen average energy Est is determined in advance and stored in the storage unit 18. The method for setting the AE eigen average energy Est will be described later. After that, the process proceeds to step S6.

[0035]

Number

[0036] In step S6, the determination unit 30 determines whether the dimensionless AE average energy Z calculated by the calculation unit 28 exceeds a predetermined threshold value Za indicating a sign of destruction of the container 200. The method for setting the threshold value Za will be described later. When the determination unit 30 determines that the dimensionless AE average energy Z is equal to or less than the threshold value Za (NO in step S6), the process proceeds to step S4. When the determination unit 30 determines that the dimensionless AE average energy Z exceeds the threshold value Za (YES in step S6), the process proceeds to step S7.

[0037] In step S7, the notification unit 32 notifies the determination result. That is, when an AE wave 40 having a non-dimensional AE average energy Z exceeding the threshold value Za is not observed until the pressure inside the container 200 reaches the inspection pressure upper limit value (NO in step S6, YES in step S4), the notification unit 32 notifies, for example, a determination result indicating that no AE wave 40 indicating a sign of rupture of the container 200 has been detected. Further, when an AE wave 40 having a non-dimensional AE average energy Z exceeding the threshold value Za is observed until the pressure inside the container 200 reaches the inspection pressure upper limit value (YES in step S6), the notification unit 32 notifies, for example, a determination result indicating that an AE wave 40 indicating a sign of rupture of the container 200 has been detected. The notification unit 32 notifies, for example, by causing the display unit 22 to display the determination result, but is not limited thereto. Thereafter, the process proceeds to step S8. In step S8, the inspection of the container 200 is terminated. Thereafter, the process shown in FIG. 2 is completed.

[0038] In the inspection method of the container 200, in step S7, when a plurality of AE waves 40 having a non-dimensional AE average energy Z exceeding the threshold value Za are observed until the pressure inside the container 200 reaches the inspection pressure upper limit value (YES in step S6), the notification unit 32 may notify, for example, a determination result indicating that an AE wave 40 indicating a sign of rupture of the container 200 has been detected.

[0039] In the above-described inspection method, steps S1 and S2 correspond to a detection step of sequentially detecting AE waves 40 generated in the container 200 by the AE sensor 12 while increasing the pressure inside the container 200. Step S5 corresponds to a calculation step of sequentially calculating the non-dimensional AE average energy Z. Step S6 corresponds to a determination step.

[0040] Next, a method for setting the AE specific average energy Est and the threshold value Za will be described. The AE specific average energy Est and the threshold value Za can be set, for example, when conducting a test using the test container 300. In this test, the inspection device 10 described above is used. As shown in FIG. 1, the test container 300 is configured in the same manner as the container 200 described above. FIG. 4 is a flowchart for explaining a test for setting the AE specific average energy Est and the threshold value Za.

[0041] As shown in FIG. 4, the processes of steps S21 to S23 are the same as the processes of steps S1 to S3 described above, except that the test container 300 is used. Therefore, a specific description of the processes of steps S21 to S23 will be omitted. When it is determined by the determination unit 30 that the amplitude of the AE wave 40 exceeds the amplitude threshold value (YES in step S23), the process proceeds to step S24.

[0042] In step S24, the determination unit 30 determines whether the test has ended. When the test is a rupture test, the determination unit 30 determines that the test has ended when the test container 300 has ruptured, and determines that the test has not ended when the test container 300 has not ruptured. Also, when the test is a pressure increase test, the determination unit 30 determines that the test has ended when the pressure inside the test container 300 reaches a predetermined test pressure upper limit value, and determines that the test has not ended when the pressure inside the test container 300 has not reached the test pressure upper limit value.

[0043] When it is determined by the determination unit 30 that the test has ended (YES in step S24), the process proceeds to step S25. When it is determined by the determination unit 30 that the test has not ended (NO in step S24), the process returns to step S21.

[0044] In step S25, the AE specific average energy Est and the threshold value Za are set. FIGS. 5A to 6B are graphs showing the test results when the rupture test of the test container 300 is performed. Specifically, FIG. 5A is a graph showing the relationship between the pressure inside the test container 300 and the number of partial AE waves 44. The plots shown in FIG. 5A represent one AE continuous wave 42 (see FIG. 3). The same applies to FIG. 5B. The number of partial AE waves 44 for each plot shown in FIG. 5A can be calculated from the AE wave 40 acquired by the acquisition unit 26.

[0045] FIG. 5B is a graph showing the relationship between the pressure inside the test container 300 and the AE energy. The AE energy for each plot shown in FIG. 5B is the energy of a plurality of partial AE waves 44 included in the AE continuous wave 42. The AE energy for each plot shown in FIG. 5B can be calculated from the AE wave 40 acquired by the acquisition unit 26.

[0046] FIG. 6A is a graph showing the relationship between the integrated number of partial AE waves 44 and the integrated AE energy. The integrated number of partial AE waves 44 in FIG. 6A is calculated by sequentially integrating the number of partial AE waves 44 shown in FIG. 5A as the pressure inside the test container 300 increases. The integrated AE energy in FIG. 6A is calculated by sequentially integrating the AE energy shown in FIG. 5B as the pressure inside the test container 300 increases. As shown in FIG. 6A, the slope of the graph of the integrated AE energy is constant from when the partial AE wave 44 starts to be detected until the integrated number of partial AE waves 44 reaches Nb. The slope of the integrated AE energy until the integrated number of partial AE waves 44 reaches Nb can be calculated using the above-described formula (1). The integrated AE energy rapidly increases when the integrated number of partial AE waves 44 exceeds Nb. In the present embodiment, in FIG. 6A, the stage where the integrated number of partial AE waves 44 and the integrated AE energy show a proportional relationship is referred to as the steady state period. Also, the stage immediately after the steady state period and where the integrated AE energy rapidly increases is referred to as the rapid increase period.

[0047] The AE inherent average energy Est is set as follows. That is, the calculation unit 28 calculates the AE inherent average energy Est by the following mathematical formula (3). However, in the mathematical formula (3), Nb is the integrated number of partial AE waves 44 in the steady state (immediately before the rapid increase period). Ec is the integrated AE energy in the steady state (immediately before the rapid increase period).

[0048]

Number

[0049] As shown in FIG. 6A, the AE inherent average energy Est is the slope of the graph of the integrated AE energy in the steady state. The AE inherent average energy Est varies greatly depending on the size, shape, etc. of the container 200.

[0050] FIG. 6B is a graph showing the relationship between the pressure inside the test container 300 and the dimensionless AE average energy Z. The dimensionless AE average energy Z in FIG. 6B is calculated from the above-described mathematical formula (2). As shown in FIG. 6B, in the rapid increase period, an AE wave 40 having a dimensionless AE average energy Z larger than the dimensionless AE average energy Z in the steady state is detected. As a result of intensive studies, the present inventors have found that the magnitude of the dimensionless AE average energy Z of the AE wave 40 leading to the destruction (fatigue failure) of the container 200 is substantially constant and not very dependent on the size, shape, etc. of the test container 300.

[0051] The threshold value Za can be set based on the peak value (maximum value) of the dimensionless AE average energy Z in the rapid increase period. The threshold value Za can be set smaller than the peak value of the dimensionless AE average energy Z in the rapid increase period. The threshold value Za may be set based on the test results of a plurality of test containers 300. In this case, the threshold value Za may be set based on the average value of a plurality of test results (the peak value of the dimensionless AE average energy Z in the rapid increase period), or may be set based on the value with the lowest peak value among a plurality of test results (the peak value of the dimensionless AE average energy Z in the rapid increase period). After that, the process shown in FIG. 4 is completed.

[0052] The setting of the AE inherent average energy Est and the threshold value Za may be performed, for example, when conducting a cycle test. The cycle test is a test for confirming the durability of the test container 300 by repeating a cycle of filling the inside of the test container 300 with fluid and discharging the fluid from the inside of the test container 300 a plurality of times. FIG. 7 is a flowchart showing a method for setting the AE inherent average energy Est and the threshold value Za when conducting a filling / discharging durability test of the test container 300.

[0053] As shown in FIG. 7, the processes of steps S31 to S33 are the same as the processes of steps S1 to S3 described above, except that the test container 300 is used. Therefore, the specific description of the processes of steps S31 to S33 is omitted. When it is determined by the determination unit 30 that the amplitude of the AE wave 40 exceeds the amplitude threshold value (YES in step S33), the process proceeds to step S34.

[0054] In step S34, the determination unit 30 determines whether or not the pressure inside the test container 300 has reached a predetermined first design pressure. When it is determined by the determination unit 30 that the pressure inside the test container 300 has not reached the first design pressure (NO in step S34), the process proceeds to step S31. When it is determined by the determination unit 30 that the pressure inside the test container 300 has reached the first design pressure (YES in step S34), the process proceeds to step S35.

[0055] In step S35, the control unit 24 reduces the pressure inside the test container 300 to a second design pressure. Thereafter, the process proceeds to step S36.

[0056] In step S36, the determination unit 30 determines whether the number of cycles has reached a preset number of set cycles. If the determination unit 30 determines that the number of cycles has not reached the preset number of set cycles (NO in step S36), the process proceeds to step S31. If the determination unit 30 determines that the number of cycles has reached the preset number of set cycles (YES in step S36), the process proceeds to step S37.

[0057] The process of step S37 is the same as the process of step S25 described above. Therefore, the detailed description of the specific content of step S37 is omitted. After this, the process shown in FIG. 7 is completed.

[0058] According to the present embodiment, it is determined whether an AE wave 40 having a dimensionless AE average energy Z exceeding a preset threshold value Za indicating a sign of breakage of the container 200 is observed before the internal pressure of the container 200 reaches a preset inspection pressure upper limit value. The dimensionless AE average energy Z of the AE wave 40 indicating a sign of breakage of the container 200 does not depend much on the size, shape, etc. of the container 200. Therefore, it is not necessary to individually set in advance the determination conditions for the AE wave 40 indicating a sign of breakage of all the containers 200. That is, the determination conditions for the AE wave 40 indicating a sign of breakage of the container 200 can be made uniform. Thus, a better inspection method for the container 200 and an inspection apparatus 10 for the container 200 can be provided.

[0059] Regarding the above embodiment, the following additional remarks are further disclosed.

[0060] (Additional Remark 1) The inspection method of the container of the present disclosure is an inspection method of a container (200) formed by winding a fiber member (222) around the outer peripheral surface of a hollow liner (202), including: a detection step of sequentially detecting AE waves (40) generated in the container by an AE sensor (12) while increasing the pressure inside the container; a calculation step of sequentially calculating a dimensionless AE average energy (Z) by dividing an AE average energy (Eb), which is an average energy of a plurality of partial AE waves (44) included in the AE waves detected by the AE sensor, by a predetermined AE specific average energy (Est) that is the AE average energy specific to the container; and a determination step of determining whether an AE wave having the dimensionless AE average energy exceeding a predetermined threshold value (Za) indicating a sign of breakage of the container is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value.

[0061] According to such a method, it is determined whether an AE wave having a dimensionless AE average energy exceeding a predetermined threshold value indicating a sign of breakage of the container is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value. The dimensionless AE average energy of an AE wave leading to a sign of breakage of the container does not depend much on the size, shape, etc. of the container. Therefore, it is not necessary to individually set in advance the determination conditions for AE waves indicating a sign of breakage of the container for all containers. That is, the determination conditions for AE waves indicating a sign of breakage of the container can be made uniform. Therefore, a better inspection method can be provided.

[0062] (Appendix 2) The inspection method of the container according to Appendix 1, wherein the partial AE wave may be a wave of one cycle having an amplitude larger than a predetermined amplitude threshold value.

[0063] According to such a method, since the influence of noise waves included in the AE waves can be removed, the accuracy of the inspection of the container can be improved.

[0064] (Appendix 3) In the container inspection method described in Supplementary Note 2, the AE-specific average energy may be the average energy of the partial AE waves in a steady phase, which is acquired in advance using a test container (300), and the steady phase may be a phase in which an integrated number obtained by integrating the number of partial AE waves when the pressure inside the test container increases and an integrated AE energy obtained by integrating the energy of the partial AE waves when the pressure inside the test container increases are proportional to each other.

[0065] (Appendix 4) In the container inspection method according to Supplementary Note 3, the threshold value may be determined based on the dimensionless AE average energy when the integrated number and the integrated AE energy no longer show the proportional relationship.

[0066] According to this method, the accuracy of the threshold indicating the onset of breakdown can be improved.

[0067] (Appendix 5) The container inspection method according to any one of Supplementary Notes 1 to 4 may further include a notification step of issuing a notification based on the determination result of the determination step.

[0068] This method allows the user to know the test results.

[0069] (Appendix 6) In the container inspection method according to any one of Supplementary Notes 1 to 5, the container may have the liner made of resin.

[0070] (Appendix 7) The program of the present disclosure is a program for causing a computer to execute the container inspection method described in any one of Supplementary Notes 1 to 6.

[0071] (Appendix 8) The inspection device (10) of the container of the present disclosure is an inspection device of a container formed by winding a fiber member around the outer peripheral surface of a hollow liner. While increasing the pressure inside the container, an acquisition unit (26) that sequentially acquires AE waves generated in the container, and an AE average energy that is the average energy of a plurality of partial AE waves included in the AE waves acquired by the acquisition unit is divided by a predetermined AE intrinsic average energy that is the AE average energy specific to the container, and a calculation unit (28) that sequentially calculates a dimensionless AE average energy, and a determination unit (30) that determines whether an AE wave having the dimensionless AE average energy exceeding a predetermined threshold indicating a sign of fatigue failure is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value.

[0072] Although the present disclosure has been described in detail, the present disclosure is not limited to the above-described individual embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the gist of the present disclosure or without departing from the gist of the present disclosure derived from the content described in the claims and its equivalents. Also, these embodiments can be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as an example and are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the above-described embodiments.

Explanation of Reference Numerals

[0073] 10…Inspection device 12…AE sensor 26…Acquisition unit 28…Calculation unit 30…Determination unit 40…AE wave 44…Partial AE wave 200…Container 202…Liner 222…Fiber member 300…Test container Z…Dimensionless AE average energy Za…Threshold value

Claims

1. A method for inspecting a container formed by winding a fiber member around an outer peripheral surface of a hollow liner, comprising: a detection step of sequentially detecting AE waves generated in the container by an AE sensor while increasing the pressure inside the container; a calculation step of sequentially calculating a dimensionless AE average energy by dividing an AE average energy, which is an average energy of a plurality of partial AE waves included in the AE waves detected by the AE sensor, by a predetermined AE inherent average energy that is the AE average energy specific to the container; a determination step of determining whether an AE wave having a dimensionless AE average energy exceeding a predetermined threshold indicating a sign of breakage of the container is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value; A method for inspecting a container, comprising the above steps.

2. The method for inspecting a container according to claim 1, wherein the partial AE wave is a wave having a period with an amplitude greater than a predetermined amplitude threshold.

3. The method for inspecting a container according to claim 2, wherein the AE inherent average energy is an average energy of the partial AE waves in a steady state, which is obtained in advance using a test container, and the steady state is a stage in which a proportional relationship is shown between an integrated number obtained by integrating the number of the partial AE waves when the pressure inside the test container increases and an integrated AE energy obtained by integrating the energy of the partial AE waves when the pressure inside the test container increases.

4. The method for inspecting a container according to claim 3, wherein the threshold is determined based on the dimensionless AE average energy when the proportional relationship between the integrated number and the integrated AE energy is no longer shown.

5. The method for inspecting a container according to claim 1, further comprising a notification step of performing notification based on the determination result of the determination step.

6. The method for inspecting a container according to claim 1, wherein the container has a liner made of resin.

7. A program for causing a computer to execute the method for inspecting a container according to any one of claims 1 to 6.

8. An inspection apparatus for a container formed by winding a fiber member around an outer peripheral surface of a hollow liner, comprising: An acquisition unit that sequentially acquires AE waves generated in the container while increasing the pressure inside the container; A calculation unit that sequentially calculates a dimensionless AE average energy by dividing an AE average energy, which is an average energy of a plurality of partial AE waves included in the AE waves acquired by the acquisition unit, by a predetermined AE inherent average energy that is the AE average energy inherent to the container; A determination unit that determines whether or not an AE wave having the dimensionless AE average energy exceeding a predetermined threshold value indicating a sign of fatigue failure is observed before the pressure inside the container reaches a predetermined inspection pressure upper limit value; A container inspection device having the above.

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