Container inspection method, computer program product, and container inspection device

Abstract

The invention provides a container inspection method, a computer program product, and a container inspection apparatus. This method for inspecting a container (200) comprises: a detection step in which AE waves (40) generated in the container are sequentially detected by an AE sensor (12) while increasing the internal pressure of the container; a calculation step in which a dimensionless AE average energy (Z) is sequentially calculated by dividing the AE average energy (Eb) by a predetermined AE intrinsic average energy (Est); in the determination step, it is determined whether an AE wave having a dimensionless AE average energy exceeding a predetermined threshold value (Za) is observed before the internal pressure of the container reaches a predetermined check pressure upper limit value, the predetermined threshold value representing a sign of destruction of the container. As a result, a better container inspection method, program, and container inspection device can be obtained.

Description

Technical Field

[0001] The present invention relates to a method for inspecting a container, a program, and an inspection device for a container. Background Art

[0002] In recent years, in order to ensure that more people can obtain affordable, reliable, sustainable, and advanced energy, research and development of fuel cell systems that contribute to energy efficiency have been underway. A fuel cell system has a container for filling a fuel gas (e.g., hydrogen).

[0003] Such a container has a hollow inner liner and a fiber layer, with a fluid filled inside the inner liner; the fiber layer is formed by winding a fiber member around the outer peripheral surface of the inner liner. An inspection method for such a container is disclosed in International Publication No. 2014 / 057987. In this inspection method, signs of fatigue failure of the inner liner are inspected based on AE (acoustic emission) waves generated in the container when the internal pressure of the container is increased. Hereinafter, acoustic emission will be referred to as AE. Summary of the Invention

[0004] There is a need for a better method for inspecting a container, a program, and an inspection device for a container.

[0005] An object of the present invention is to solve the above technical problems.

[0006] A first aspect of the present invention is a method for inspecting a container, wherein the container is formed by winding a fiber member around the outer peripheral surface of a hollow inner liner, and has a detection step, a calculation step, and a determination step. In the detection step, while increasing the internal pressure of the container, AE waves generated in the container are sequentially detected by an AE sensor; in the calculation step, a dimensionless AE average energy is sequentially calculated by dividing an average energy of a plurality of partial AE waves included in the AE waves detected by the AE sensor, i.e., an AE average energy, by an AE average energy inherent to the container, i.e., a predetermined AE inherent average energy; in the determination step, it is determined whether an AE wave having a dimensionless AE average energy exceeding a predetermined threshold is observed before the internal pressure of the container reaches a predetermined inspection pressure upper limit value, and the predetermined threshold indicates signs of damage to the container.

[0007] A second aspect of the present invention is a program for causing a computer to execute the above-described method for inspecting a container.

[0008] A third aspect of the present invention is an inspection device for a container, wherein the container is formed by winding a fiber member around the outer peripheral surface of a hollow inner liner, and has an acquisition unit, a calculation unit, and a determination unit. The acquisition unit sequentially acquires AE waves generated in the container while increasing the internal pressure of the container. The calculation unit sequentially calculates a dimensionless AE average energy by dividing the average energy of a plurality of partial AE waves included in the AE waves acquired by the acquisition unit, i.e., the AE average energy, by the AE average energy inherent to the container, i.e., a predetermined AE inherent average energy. The determination unit determines whether an AE wave having a dimensionless AE average energy exceeding a predetermined threshold is observed before the internal pressure of the container reaches a predetermined inspection pressure upper limit value, and the predetermined threshold indicates a sign of fatigue failure.

[0009] According to the present invention, a better inspection method, program, and inspection device for a container can be obtained.

[0010] The above objects, features, and advantages should be easily understood from the following description of the embodiments with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of an inspection device for a container according to an embodiment of the present invention.

[0012] Figure 2 It is a flowchart for explaining an example of an inspection method for a container.

[0013] Figure 3 It is an explanatory diagram of an AE wave that can be detected by an AE sensor.

[0014] Figure 4 It is a flowchart for explaining an experiment for setting an AE inherent average energy and a threshold value.

[0015] Figure 5A It is a graph showing the relationship between the internal pressure of a test container and the number of partial AE waves. Figure 5B It is a graph showing the relationship between the internal pressure of a test container and the AE energy.

[0016] Figure 6A It is a graph showing the relationship between the cumulative number of partial AE waves and the cumulative AE energy. Figure 6B It is a graph showing the relationship between the internal pressure of a test container and the dimensionless AE average energy.

[0017] Figure 7 It is a flowchart showing a method for setting an AE inherent average energy and a threshold value when performing a durability test of filling and discharging a test container. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] When manufacturing a container by winding a fiber component around the outer peripheral surface of an inner container, the shape of the container is likely to change. Therefore, there are individual differences in the shape of the containers manufactured in this way. In addition, it is difficult for the outer peripheral surface of the fiber layer to come into uniform contact with the AE sensor. Therefore, the mounting state of the AE sensor with respect to the outer peripheral surface of the fiber layer is also likely to deviate. Therefore, when using an AE sensor to detect signs of damage to a container with high precision, it is necessary to separately set in advance the judgment conditions for AE waves indicating signs of damage to the container for all containers.

[0019] However, in the case of mass-producing containers, this method is not practical. The present invention has been completed in view of such technical problems, and can provide an inspection method, program, and inspection device for a container that can unify (standardize) the judgment conditions for AE waves indicating signs of damage to the container.

[0020] Hereinafter, an inspection method for the container 200 and an inspection device 10 for the container 200 of the present invention will be described with reference to the drawings. Figure 1 It is a schematic diagram of the inspection device 10 for the container 200. First, the container 200 to be inspected will be described. As Figure 1 shown, the container 200 is a pressure vessel configured to be filled with a fluid. The container 200 is, for example, a gas tank for a fuel cell system (not shown). Fuel gas such as hydrogen can be filled in the gas tank. The container 200 is not limited to a gas tank.

[0021] The container 200 is a composite container. The container 200 includes a hollow inner container 202, a first interface 204, a second interface 206, a sealing member 208, a plug 210, and a fiber layer 212. The inner container 202 is made of resin, but it can also be made of metal. The inner container 202 is made of, for example, high-density polyethylene (HDPE) or nylon resin (PA6) that inhibits hydrogen permeation.

[0022] The inner container 202 has a middle portion 214, a first end portion 216, and a second end portion 218. The middle portion 214 is formed in a cylindrical shape. The first end portion 216 is provided at one end of the middle portion 214. The second end portion 218 is provided at the other end of the middle portion 214. The first end portion 216 and the second end portion 218 are each formed in a hemispherical shape.

[0023] The first interface 204 is installed at the first end portion 216. The second interface 206 is installed at the second end portion 218. The sealing member 208 is installed on the first interface 204 so as to seal the hole of the first interface 204. The plug 210 is installed on the second interface 206. A flow path 220 is formed in the plug 210, and through the flow path 220, fluid can be filled into the interior of the inner container 202 or discharged from the interior of the inner container 202. The fiber layer 212 is formed by winding a fiber member 222 around the outer peripheral surface of the inner container 202. The fiber member 222 is wound around the inner container 202 by a fiber winding device (not shown).

[0024] Next, the inspection device 10 for the container 200 will be described. The inspection device 10 inspects whether there are signs of damage (fatigue damage) in the container 200. Specifically, the inspection device 10 inspects whether there are signs of damage in the fiber layer 212. In addition, the inspection device 10 can also inspect whether there are signs of damage in the inner container 202.

[0025] The inspection device 10 includes a plurality of AE sensors 12 and an inspection control unit 14. The AE sensors 12 are installed on the outer peripheral surface of the fiber layer 212. The installation positions and the 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 generated in the container 200 (refer to Figure 3 ). In other words, the AE sensors 12 can sequentially measure the AE waves 40 generated in the container 200.

[0026] 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 can be constituted by, for example, a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). That is, the arithmetic unit 16 can be constituted by a processing circuit.

[0027] The arithmetic 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 implemented by the arithmetic unit 16 executing a program stored in the storage unit 18.

[0028] In addition, at least a part of the control unit 24, acquisition unit 26, calculation unit 28, determination unit 30, and notification unit 32 can also be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). In addition, at least a part of the control unit 24, acquisition unit 26, calculation unit 28, determination unit 30, and notification unit 32 can also be constituted by an electronic circuit including discrete devices.

[0029] The storage unit 18 is composed of a volatile memory (not shown) and a non-volatile memory (not shown). As the volatile memory, for example, a RAM (Random Access Memory) etc. can be cited. The volatile memory is used as the working memory of the processor and temporarily stores data etc. required for processing or operation. As the non-volatile memory, for example, a ROM (Read Only Memory), a flash memory etc. can be cited. The non-volatile memory is used as a storage memory and stores programs, tables, maps etc. At least a part of the storage unit 18 can also be provided in the above-mentioned processor, integrated circuit etc.

[0030] The operation unit 20 is used when the user operates the inspection control unit 14. As the operation unit 20, a keyboard, a mouse etc. can be cited, but it is not limited thereto.

[0031] The display unit 22 has a display element (not shown). As the display element, for example, a liquid crystal display element, an organic electroluminescence display element etc. are used. The operation unit 20 and the display unit 22 can also be constituted by a touch screen (not shown) having such a display element.

[0032] The control unit 24 is responsible for the overall control of the inspection device 10. The acquisition unit 26 can grasp the AE wave 40 based on the signal supplied by the AE sensor 12. The calculation unit 28 calculates a dimensionless AE average energy Z (described later) based on 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.

[0033] Figure 2 It is a flowchart for explaining an example of the inspection method of the container 200. As Figure 2As shown, in step S1, the interior of container 200 is pressurized. Specifically, a fluid is introduced into the interior of container 200 (inner liner 202) through flow path 220 of plug 210. The fluid used here is not particularly limited, and for example, helium gas can be cited. When the interior of container 200 is pressurized, inner liner 202 presses fiber layer 212 outward. Accordingly, when container 200 is deformed or cracks are generated in container 200, AE wave 40 is generated in container 200. AE wave 40 generated in container 200 is detected by AE sensor 12. The signal of AE sensor 12 is supplied to inspection control unit 14. After that, it transfers to step S2.

[0034] In step S2, acquisition unit 26 acquires information representing AE wave 40 based on the signal supplied by AE sensor 12. Figure 3 It is an explanatory diagram showing AE wave 40 that can be detected by AE sensor 12. As Figure 3 shown, AE wave 40 includes a plurality of AE continuous waves 42. AE continuous wave 42 is one continuous wave. AE continuous wave 42 includes a plurality of partial AE waves 44 and interference waves 46.

[0035] Partial AE wave 44 is a wave of one cycle having an amplitude larger than a predetermined amplitude threshold. Partial AE wave 44 is a wave (sound wave) generated due to deformation, cracking, etc. of container 200. Interference wave 46 is a wave having an amplitude below the amplitude threshold. The amplitude threshold is stored in storage unit 18. The amplitude threshold is set to a size that can distinguish interference wave 46 from other waves (partial AE waves 44). Specifically, the amplitude threshold is set according to the shape of container 200, etc. (including shape, size, material, etc.), the performance of AE sensor 12, etc. After that, it transfers to step S3.

[0036] In step S3, determination unit 30 determines whether the amplitude of AE wave 40 exceeds the amplitude threshold. That is, determination unit 30 determines whether AE wave 40 including partial AE wave 44 is generated. In other words, determination unit 30 can determine whether AE sensor 12, etc. are operating normally. When it is determined by determination unit 30 in step S3 that the amplitude of AE wave 40 does not exceed the amplitude threshold (No in step S3), it transfers to step S4. When it is determined by determination unit 30 in step S3 that the amplitude of AE wave 40 exceeds the amplitude threshold (Yes in step S3), it transfers to step S5.

[0037] In step S4, the determination unit 30 determines whether the internal pressure of the container 200 has reached the upper limit value of the inspection pressure. In addition, the inspection control unit 14 can obtain the internal pressure of the container 200 detected by a pressure sensor (not shown). The upper limit value of the inspection pressure is a pre-determined value and is stored in the storage unit 18. When it is determined by the determination unit 30 in step S4 that the internal pressure of the container 200 has not reached the upper limit value of the inspection pressure (No in step S4), the process proceeds to step S1. When it is determined by the determination unit 30 in step S4 that the internal pressure of the container 200 has reached the upper limit value of the inspection pressure (Yes in step S4), the process proceeds to step S7.

[0038] 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 using the following mathematical formula (1). Here, Ea in the mathematical formula (1) is the energy of a plurality of partial AE waves 44 included in the AE continuous wave 42. Na represents the number of partial AE waves 44 included in the AE continuous wave 42.

[0039]

[0040] Next, the calculation unit 28 calculates the dimensionless AE average energy Z using the following mathematical formula (2). Here, Est in the mathematical formula (2) is the AE average energy Eb inherent to the container 200, that is, the AE inherent average energy. The AE inherent average energy Est is pre-determined and is stored in the storage unit 18. The method for setting the AE inherent average energy Est will be described later. After that, the process proceeds to step S6.

[0041]

[0042] In step S6, the determination unit 30 determines whether the dimensionless AE average energy Z calculated by the calculation unit 28 exceeds a pre-determined threshold value Za indicating a sign of damage to the container 200. The method for setting the threshold value Za will be described later. When it is determined by the determination unit 30 that the dimensionless AE average energy Z is below the threshold value Za (No in step S6), the process proceeds to step S4. When it is determined by the determination unit 30 that the dimensionless AE average energy Z exceeds the threshold value Za (Yes in step S6), the process proceeds to step S7.

[0043] In step S7, the notification unit 32 notifies the determination result. That is, when no AE wave 40 having a dimensionless AE average energy Z exceeding the threshold value Za is observed even before the internal pressure of the container 200 reaches the upper limit value of the inspection pressure (No in step S6, Yes in step S4), the notification unit 32 notifies, for example, a determination result meaning that no AE wave 40 indicating a sign of damage to the container 200 is detected. Further, when an AE wave 40 having a dimensionless AE average energy Z exceeding the threshold value Za is observed before the internal pressure of the container 200 reaches the upper limit value of the inspection pressure (Yes in step S6), the notification unit 32 notifies, for example, a determination result meaning that an AE wave 40 indicating a sign of damage to the container 200 is detected. The notification unit 32 notifies, for example, by displaying the determination result on the display unit 22, but is not limited thereto. After that, the process proceeds to step S8. In step S8, the inspection of the container 200 ends. After that, Figure 2 the processing shown is completed.

[0044] In the inspection method of the container 200, in step S7, when a plurality of AE waves 40 having a dimensionless AE average energy Z exceeding the threshold value Za are observed before the internal pressure of the container 200 reaches the upper limit value of the inspection pressure (Yes in step S6), the notification unit 32 may also notify, for example, a determination result meaning that an AE wave 40 indicating a sign of damage to the container 200 is detected.

[0045] In the above 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 internal pressure of the container 200. Step S5 corresponds to a calculation step of sequentially calculating the dimensionless AE average energy Z. Step S6 corresponds to a determination step.

[0046] Next, a method for setting the AE intrinsic average energy Es t and the threshold value Za will be described. The AE intrinsic average energy Est and the threshold value Za can be set, for example, when conducting an experiment using the test container 300. In this experiment, the above-described inspection device 10 is used. As Figure 1 shown, the test container 300 is configured in the same manner as the above-described container 200. Figure 4 is a flowchart of an experiment for setting the AE intrinsic average energy Es t and the threshold value Za.

[0047] As Figure 4 shown, the processing of steps S21 to S23 is the same as the processing of steps S1 to S3 described above except for using the test container 300. Therefore, a detailed description of the processing of steps S21 to S23 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 S23), the process proceeds to step S24.

[0048] In step S24, the determination unit 30 determines whether the test is completed. In the case where the test is a rupture test, the determination unit 30 determines that the test is completed when the test container 300 reaches rupture, and determines that the test is not completed when the test container 300 does not reach rupture. Further, in the case where the test is a pressure increase test, the determination unit 30 determines that the test is completed when the internal pressure of the test container 300 reaches a predetermined upper limit value of the test pressure, and determines that the test is not completed when the internal pressure of the test container 300 does not reach the upper limit value of the test pressure.

[0049] When it is determined by the determination unit 30 that the test is completed (Yes in step S24), the process proceeds to step S25. When it is determined by the determination unit 30 that the test is not completed (No in step S24), the process proceeds to step S21.

[0050] In step S25, the AE inherent average energy Es t and the threshold value Za are set. Figures 5A - 6B is a graph showing the test results in the case of performing a rupture test on the test container 300. Specifically, Figure 5A is a graph showing the relationship between the internal pressure of the test container 300 and the number of partial AE waves 44. Figure 5A The plotted graph shown represents one AE continuous wave 42 (refer to Figure 3 ). Figure 5B The same applies. Figure 5A The number of partial AE waves 44 in each of the plotted graphs shown can be calculated from the AE waves 40 acquired by the acquisition unit 26.

[0051] Figure 5B is a graph showing the relationship between the internal pressure of the test container 300 and the AE energy. Figure 5B The AE energy in each of the plotted graphs shown is the energy of a plurality of partial AE waves 44 included in the AE continuous wave 42. Figure 5B The AE energy in each of the plotted graphs shown can be calculated from the AE waves 40 acquired by the acquisition unit 26.

[0052] Figure 6A is a graph showing the relationship between the cumulative number of partial AE waves 44 and the cumulative AE energy. Figure 6A The cumulative number of partial AE waves 44 of Figure 5A is calculated by sequentially accumulating the number of partial AE waves 44 shown as the internal pressure of the test container 300 rises. Figure 6A The cumulative AE energy of Figure 5B is calculated by sequentially accumulating the AE energy shown as the internal pressure of the test container 300 rises. As shown in Figure 6AAs shown, the slope of the graph of the cumulative AE energy is constant from the start of detection to the point where the cumulative number of partial AE waves 44 reaches Nb. The slope of the cumulative AE energy up to the point where the cumulative number of partial AE waves 44 reaches Nb can be calculated using the above mathematical formula (1). The cumulative AE energy surges when the cumulative number of partial AE waves 44 exceeds Nb. In the present embodiment, in Figure 6A the stage where the cumulative number of partial AE waves 44 and the cumulative AE energy exhibit a proportional relationship is called the stable period. In addition, the stage immediately after the stable period and where the cumulative AE energy surges is called the surge period.

[0053] The AE inherent average energy Es t is set as follows. That is, the calculation unit 28 calculates the AE inherent average energy Es t by the following mathematical formula (3). Here, Nb in the mathematical formula (3) is the cumulative number of partial AE waves 44 in the stable period (immediately before the surge period). Ec is the cumulative AE energy in the stable period (immediately before the surge period).

[0054]

[0055] As Figure 6A shown, the AE inherent average energy Es t is the slope of the graph of the cumulative AE energy in the stable period. The AE inherent average energy Est varies greatly depending on the size, shape, etc. of the container 200.

[0056] Figure 6B is a graph showing the relationship between the internal pressure of the test container 300 and the dimensionless AE average energy Z. Figure 6B The dimensionless AE average energy Z of Figure 6B is calculated according to the above mathematical formula (2). As

[0057] shown, in the surge period, an AE wave 40 with a dimensionless AE average energy Z larger than that in the stable period is detected. As a result of in-depth research by the inventors of the present application, it was found that the magnitude of the dimensionless AE average energy Z of the AE wave 40 that causes the failure (fatigue failure) of the container 200 is roughly constant and does not depend much on the size, shape, etc. of the test container 300. Figure 4 The processing shown above is completed.

[0058] The setting of the AE inherent average energy Est and the threshold value Za can also be set, for example, when conducting a cyclic test. The cyclic test is a test for confirming the durability of the test container 300 by repeatedly filling the inside of the test container 300 with a fluid and discharging the fluid from the inside of the test container 300 multiple times. Figure 7 It is a flowchart showing a method for setting the AE inherent average energy Est and the threshold value Za when conducting a durability test of filling and discharging the test container 300.

[0059] As Figure 7 shown, the processes of steps S31 to S33 are the same as the processes of steps S1 to S3 described above, except for using the test container 300. 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.

[0060] In step S34, the determination unit 30 determines whether the internal pressure of the test container 300 has reached a predetermined first design pressure. When it is determined by the determination unit 30 that the internal pressure of 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 internal pressure of the test container 300 has reached the first design pressure (Yes in step S34), the process proceeds to step S35.

[0061] In step S35, the control unit 24 reduces the internal pressure of the test container 300 to the second design pressure. After that, the process proceeds to step S36.

[0062] In step S36, the determination unit 30 determines whether the number of cycles has reached a predetermined set number of cycles. When it is determined by the determination unit 30 that the number of cycles has not reached the predetermined set number of cycles (No in step S36), the process proceeds to step S31. When it is determined by the determination unit 30 that the number of cycles has reached the predetermined set number of cycles (Yes in step S36), the process proceeds to step S37.

[0063] The process of step S37 is the same as the process of step S25 described above. Therefore, the specific content of step S37 is omitted. After that, Figure 7 the process shown is completed.

[0064] According to the present embodiment, it is determined whether an AE wave 40 having a dimensionless AE average energy Z exceeding a predetermined threshold Za is observed before the internal pressure of the container 200 reaches a predetermined inspection pressure upper limit value, where the predetermined threshold Za indicates a sign of damage to the container 200. The dimensionless AE average energy Z of the AE wave 40 indicating a sign of damage to the container 200 does not depend much on the size, shape, etc. of the container 200. Therefore, it is not necessary to separately set in advance for each of all the containers 200 the determination conditions for the AE wave 40 indicating a sign of damage to the container 200. That is, the determination conditions for the AE wave 40 indicating a sign of damage to the container 200 can be unified. Therefore, a better inspection method for the container 200 and an inspection device 10 for the container 200 can be provided.

[0065] The computer program (computer software) of the present embodiment can also be referred to as a computer program product. The computer program product is not limited to the computer program stored in the storage medium, and also includes programs transmitted, sent, and downloaded via the Internet or the like.

[0066] Regarding the above embodiment, the following remarks are also disclosed.

[0067] (Remark 1) The inspection method for the container of the present invention is an inspection method for a container (200) formed by winding a fiber member (222) around the outer peripheral surface of a hollow inner container (220), and has a detection step, a calculation step, and a determination step. In the detection step, while increasing the internal pressure of the container, AE waves (40) generated in the container are sequentially detected by an AE sensor (12); in the calculation step, the dimensionless AE average energy (Z) is sequentially calculated by dividing the AE average energy (Eb) of a plurality of partial AE waves (44) included in the AE wave detected by the AE sensor by the AE average energy inherent in the container, that is, a predetermined AE inherent average energy (Es t); in the determination step, it is determined whether an AE wave having the dimensionless AE average energy exceeding a predetermined threshold (Za) is observed before the internal pressure of the container reaches a predetermined inspection pressure upper limit value, where the predetermined threshold indicates a sign of damage to the container.

[0068] According to this method, it is determined whether an AE wave having a dimensionless AE average energy exceeding a predetermined threshold value is observed before the internal pressure of the container reaches a predetermined upper limit value of the inspection pressure, wherein the predetermined threshold value indicates a sign of damage to the container. The dimensionless AE average energy of the AE wave related to the sign of damage to the container does not depend much on the size, shape, etc. of the container. Therefore, it is not necessary to separately set in advance for all containers the judgment conditions for the AE wave indicating the sign of damage to the container. That is, the judgment conditions for the AE wave indicating the sign of damage to the container can be unified. Therefore, a better inspection method can be provided.

[0069] (Supplementary Note 2) According to the inspection method of the container described in Supplementary Note 1, it can be that the partial AE wave is a wave of one cycle having an amplitude larger than a predetermined amplitude threshold value.

[0070] According to this method, since the influence of interfering waves contained in the AE wave can be eliminated, the inspection accuracy of the container can be improved.

[0071] (Supplementary Note 3) According to the inspection method of the container described in Supplementary Note 2, it can be that the AE inherent average energy is obtained in advance using a test container (300), and is the average energy of the partial AE wave in the stable period, where the stable period is a stage in which the cumulative number and the cumulative AE energy show a proportional relationship, wherein the cumulative number is obtained by accumulating the number of the partial AE waves when the internal pressure of the test container rises; the cumulative AE energy is obtained by accumulating the energy of the partial AE waves when the internal pressure of the test container rises.

[0072] (Supplementary Note 4) According to the inspection method of the container described in Supplementary Note 3, it can be that the threshold value is determined according to the dimensionless AE average energy when the cumulative number and the cumulative AE energy no longer show the proportional relationship.

[0073] According to this method, the accuracy of the threshold value indicating the sign of damage can be improved.

[0074] (Supplementary Note 5) According to the inspection method of the container described in any one of Supplementary Notes 1 to 4, it can be that there is also an informing step, in which an informing is performed according to the determination result of the determination step.

[0075] According to this method, the user can know the inspection result.

[0076] (Supplementary Note 6) According to the inspection method of the container described in any one of Supplementary Notes 1 to 5, it can be that the container has the inner container made of resin.

[0077] (Supplementary Note 7) The program of the present invention is a program for causing a calculated value to execute the inspection method of the container described in any one of Supplementary Notes 1 to 6.

[0078] (Supplementary Note 8) The inspection device (10) of the container of the present invention is an inspection device of a container formed by winding a fiber member around the outer peripheral surface of a hollow inner container, and includes an acquisition unit (26), a calculation unit (28), and a determination unit (30). The acquisition unit (26) sequentially acquires AE waves generated in the container while increasing the internal pressure of the container. The calculation unit (28) sequentially calculates a dimensionless AE average energy by dividing the average energy of a plurality of partial AE waves included in the AE waves acquired by the acquisition unit, that is, the AE average energy, by the AE average energy inherent to the container, that is, a predetermined AE inherent average energy. The determination unit (30) determines whether an AE wave having the dimensionless AE average energy exceeding a predetermined threshold value is observed before the internal pressure of the container reaches a predetermined inspection pressure upper limit value, wherein the predetermined threshold value indicates a sign of fatigue failure.

[0079] The present invention has been described in detail, but the present invention is not limited to the above-described embodiments. These embodiments can be subjected to various additions, replacements, changes, partial deletions, etc. within the scope of not departing from the gist of the present invention, or within the scope of not departing from the gist of the present invention described in the technical solution and equivalents derived therefrom. In addition, 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, but are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the above-described embodiments.

Claims

1. A method for inspecting a container, wherein the container is formed by winding a fiber component around the outer peripheral surface of a hollow inner liner, characterized in that: It has a detection step, a calculation step and a determination step, wherein: In the detection step, the internal pressure of the container is increased while the AE waves generated in the container are sequentially detected by the AE sensor; In the calculation step, the dimensionless AE average energy is calculated in sequence by dividing the average energy of a plurality of partial AE waves included in the AE wave detected by the AE sensor, that is, the AE average energy, by the AE average energy inherent to the container, that is, the predetermined AE inherent average energy; In the determination step, it is determined whether the AE wave having the dimensionless AE average energy exceeding a predetermined threshold is observed before the internal pressure of the container reaches a predetermined inspection pressure upper limit value, wherein the predetermined threshold indicates a sign of damage to the container.

2. The container inspection method according to claim 1, characterized in that: The partial AE wave is a wave of one cycle having an amplitude greater than a predetermined amplitude threshold value.

3. The container inspection method according to claim 2, characterized in that: The AE inherent average energy is obtained in advance using a test container and is the average energy of the partial AE wave in the stable period. The stable period is a stage in which the cumulative number and the cumulative AE energy are in proportional relationship, wherein the cumulative number is obtained by accumulating the number of the partial AE waves when the internal pressure of the test container rises; and the cumulative AE energy is obtained by accumulating the energy of the partial AE waves when the internal pressure of the test container rises.

4. The container inspection method according to claim 3, characterized in that: The threshold is determined according to the dimensionless AE average energy when the cumulative number and the cumulative AE energy no longer present the proportional relationship.

5. The container inspection method according to claim 1, characterized in that: The method further comprises a notification step in which notification is made according to the determination result of the determination step.

6. The container inspection method according to claim 1, characterized in that: The container has the inner liner made of resin.

7. A computer program product, characterized in that The computer program product is used to cause a computer to execute the container inspection method according to any one of claims 1 to 6.

8. A container inspection device, wherein the container is formed by winding a fiber component around the outer peripheral surface of a hollow inner container, characterized in that: It has an acquisition unit, a calculation unit and a determination unit, wherein: The acquisition unit sequentially acquires AE waves generated in the container while increasing the internal pressure of the container; The calculation unit sequentially calculates dimensionless AE average energy by dividing the average energy of a plurality of partial AE waves included in the AE wave acquired by the acquisition unit, that is, the AE average energy, by the AE average energy inherent to the container, that is, the predetermined AE inherent average energy; The determination section determines whether the AE wave having the dimensionless AE average energy exceeding a predetermined threshold value is observed before the internal pressure of the container reaches a predetermined inspection pressure upper limit value, wherein the predetermined threshold value indicates a sign of fatigue damage.

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