Design support system and design support method

Abstract

To support designing of a pressure container properly.SOLUTION: A specification reception part 101 receives specifications of a setting pressure which is a pressure set for a pressure container, and a cubic capacity corresponding value which corresponds to a setting cubic capacity which is a cubic capacity set for the pressure container. A liner design part 102 designs a liner on the basis of the cubic capacity corresponding value and outputs liner information including an inner diameter of the liner, a thickness of the liner, and a liner rupture pressure which is a pressure at which the liner is ruptured. A reinforcement layer design part 103 designs a reinforcement layer on the basis of the setting pressure and the liner information and outputs reinforcement layer information including a thickness of the reinforcement layer. A container information output part 104 outputs container information, including a dimension of the pressure container and mass of the pressure container, on the basis of the liner information and the reinforcement layer information.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This disclosure relates to a design support system and a design support method. [Background technology]

[0002] Currently, pressure vessels are known for storing air used by divers and firefighters, oxygen used by patients infected with COVID-19, and hydrogen used in hydrogen-powered vehicles. Pressure vessels are manufactured, for example, by processing aluminum alloy plates to form a hollow liner that contains gas or liquid, and then forming a reinforcing layer made of fiber-reinforced resin on the outer surface of the liner by filament winding molding. When designing a pressure vessel, it is desirable to determine the dimensions of the liner, the thickness of the reinforcing layer, etc., taking into consideration safety, convenience, etc.

[0003] Currently, various technologies are known to support the design of pressure vessels. For example, Patent Document 1 describes a technology for analyzing the strength of a high-pressure gas tank. In the technology described in Patent Document 1, a finite element model is generated by dividing the high-pressure gas tank into multiple micro-regions, and the strength of the high-pressure gas tank is analyzed using the finite element method with this finite element model. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-047486 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the technology described in Patent Document 1 requires the repeated generation and analysis of numerous finite element models to obtain satisfactory physical properties and strength for a high-pressure gas tank, which is extremely time-consuming. In other words, the technology described in Patent Document 1 makes it difficult to efficiently design pressure vessels by minimizing the number of models generated and analyses, thereby shortening the design time. For this reason, a design support system that appropriately assists in the design of pressure vessels is desired.

[0006] This disclosure has been made in view of the above-mentioned issues and aims to provide a design support system, etc., that appropriately assists in the design of pressure vessels. [Means for solving the problem]

[0007] To achieve the above objectives, the design support system relating to the first aspect of this disclosure is: A design support system for designing a pressure vessel comprising a hollow liner for containing a gas or liquid and a reinforcing layer made of fiber-reinforced resin formed on the outer surface of the liner, A specification receiving means for receiving a specified set pressure, which is the pressure set for the pressure vessel, and a volume corresponding value, which is the volume set for the pressure vessel. Liner design means for designing the liner based on the volume correspondence value and outputting liner information including the inner diameter of the liner, the wall thickness of the liner, and the liner burst pressure which is the pressure at which the liner bursts, A reinforcing layer design means that designs the reinforcing layer based on the set pressure and the liner information, and outputs reinforcing layer information including the thickness of the reinforcing layer, The system includes a container information output means that outputs container information, including the dimensions and mass of the pressure vessel, based on the liner information and the reinforcing layer information.

[0008] The aforementioned set pressure is the minimum burst pressure, which is the pressure specified in the test of the pressure vessel. The designated receiving means receives a designation of fiber-reinforced resin information indicating the composition of the materials contained in the fiber-reinforced resin and the configuration of the fiber orientation angle during the formation of the fiber-reinforced resin. The system includes a ratio calculation means for calculating a stress pressure ratio, which is the ratio of the stress generated in the fiber-reinforced resin when pressure is applied to the fiber-reinforced resin and the fiber-reinforced resin is destroyed, to the stress generated in the pressure vessel when the minimum burst pressure is applied to the pressure vessel, based on the fiber-reinforced resin information. The container information output means may output the container information including the stress pressure ratio calculated by the ratio calculation means.

[0009] The aforementioned designation acceptance means accepts the designation of the plate thickness, which is the thickness of the aluminum alloy plate used to form the liner. The liner design means may design the liner based on the set pressure, the volume correspondence value, and the plate thickness.

[0010] The liner comprises a cylindrical liner body, a dome-shaped liner bottom provided at one end of the liner body, and a dome-shaped liner head provided at the other end of the liner body, having a nozzle. The aforementioned designation receiving means accepts the designation of the length of the pressure vessel and the inner diameter of the liner as the volume corresponding values, The liner design means may calculate the thickness of the bottom of the liner based on the plate thickness, calculate the thickness of the liner body based on the thickness of the bottom of the liner, calculate the liner burst pressure based on the inner diameter of the liner and the thickness of the liner body, and calculate the thickness of the top of the liner based on the set pressure, the liner burst pressure and the thickness of the bottom of the liner.

[0011] The reinforcing layer design means may calculate the thickness of the reinforcing layer based on the outer diameter of the liner body, which is determined by the inner diameter of the liner and the thickness of the liner body, the set pressure, and the liner burst pressure.

[0012] In order to achieve the above object, a design support method according to a second aspect of the present disclosure is a design support method for supporting the design of a pressure vessel including a hollow liner that houses a gas or a liquid and a reinforcing layer made of a fiber-reinforced resin formed on an outer surface of the liner, receiving a designation of a set pressure that is a pressure set for the pressure vessel and a volume corresponding value corresponding to a set volume that is a volume set for the pressure vessel, designing the liner based on the volume corresponding value, and outputting liner information including an inner diameter of the liner, a wall thickness of the liner, and a liner rupture pressure that is a pressure at which the liner ruptures, designing the reinforcing layer based on the set pressure and the liner information, and outputting reinforcing layer information including a wall thickness of the reinforcing layer, outputting container information including dimensions of the pressure vessel and a mass of the pressure vessel based on the liner information and the reinforcing layer information.

Advantages of the Invention

[0013] According to the present disclosure, the design of a pressure vessel can be appropriately supported.

Brief Description of the Drawings

[0014] [Figure 1] Configuration diagram of a design support system according to an embodiment [Figure 2] Cross-sectional view of a pressure vessel [Figure 3] Explanation diagram of the winding method of reinforcing fibers in filament winding molding, (A) is an explanation diagram of hoop winding, (B) is an explanation diagram of high-angle helical winding, and (C) is an explanation diagram of low-angle helical winding [Figure 4] Functional configuration diagram of a design support system according to an embodiment [Figure 5] Diagram showing specifications of an FRP pressure vessel model [Figure 6] Diagram showing the relationship between the volume at the bottom of the liner and the volume per unit length of the liner body [Figure 7]This figure shows the relationship between the ratio of the liner burst pressure to the pressure test pressure and the volume ratio of the liner head to the liner bottom. [Figure 8] This figure shows the relationship between the ratio of the liner burst pressure to the minimum burst pressure and the volume ratio of the liner head to the liner bottom. [Figure 9] This figure shows the relationship between the difference between the pressure test pressure and the liner burst pressure, and the ratio of the CFRP layer thickness to the liner outer dimensions. [Figure 10] This figure shows the relationship between the difference between the minimum burst pressure and the liner burst pressure, and the ratio of the CFRP layer thickness to the liner's outer dimensions. [Figure 11] This figure shows the calculation results of the specifications for an FRP pressure vessel model. [Figure 12] This figure shows the relationship between nominal and analytical values ​​for the volume of a pressure vessel. [Figure 13] This figure shows the relationship between the nominal value and the analytical value of the mass of a pressure vessel. [Figure 14] This figure shows the relationship between the drawing value and the analytical value for the wall thickness of CFRP in a pressure vessel. [Figure 15] This figure shows the relationship between the drawing value and the analytical value for the wall thickness of the liner head of a pressure vessel. [Figure 16] Diagram showing Young's modulus and stress in the axial and circumferential directions. [Figure 17] This figure shows the proportion of each orientation angle in the FRP pressure vessel model. [Figure 18] A diagram showing the approximate composition ratio of each orientation angle. [Figure 19] Diagram showing stress when minimum burst pressure is applied. [Figure 20] A diagram showing the stress pressure ratio. [Figure 21] A flowchart illustrating the design support process performed by the design support system according to the embodiment. [Figure 22] Figure 21 shows a flowchart illustrating the liner design process. [Modes for carrying out the invention]

[0015] Embodiments of this disclosure will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[0016] (Embodiment) First, with reference to Figure 1, the configuration of the design support system 1000 according to the embodiment will be described. The design support system 1000 is a system that supports the design of pressure vessels. Pressure vessels are containers that store air used by divers, firefighters, etc., oxygen used by patients such as those infected with COVID-19, hydrogen used by hydrogen fuel cell vehicles, etc. Pressure vessels are manufactured, for example, by processing an aluminum alloy plate to form a hollow liner that contains gas or liquid, and then forming a reinforcing layer made of fiber-reinforced resin on the outer surface of the liner by filament winding molding.

[0017] Referring to Figure 2, the configuration of the pressure vessel 200, which is supported in the design by the design support system 1000, will be described. The pressure vessel 200 has an overall elongated cylindrical shape. Figure 2 is a cross-sectional view of the pressure vessel 200 when it is cut by a plane including the central axis of the cylinder. The pressure vessel 200 comprises a cylindrical body 201, a dome-shaped bottom 202, and a dome-shaped head 203.

[0018] The body 201 is the part that stores most of the gas or liquid. The bottom 202 is the part provided at the bottom of the pressure vessel 200 and is provided at one end of the body 201. A plug member 205 may be provided at the center of the bottom 202. When forming a reinforcing layer on the outer surface of the liner, it is necessary to fix both ends of the liner and rotate the liner around an axis connecting the two ends of the liner. The upper part of the liner is fixed by a nozzle 206, and the bottom part of the liner is fixed by a jig. The plug member 205 is the remaining material after cutting this jig. The head 203 is the part provided at the top of the pressure vessel 200 and is provided at the other end of the body 201. The head 203 is equipped with a nozzle 206.

[0019] Furthermore, the pressure vessel 200 includes an internal storage space 204 for storing gas or liquid. The storage space 204 may be filled with gas at atmospheric pressure or with gas at a pressure higher than atmospheric pressure. For example, when the pressure vessel 200 is used in a fuel cell system, a fuel gas, such as hydrogen, is filled into the storage space 204 at high pressure, and this fuel gas is depressurized and used for power generation in the fuel cell.

[0020] The nozzle 206 is a component to which a valve assembly 250 or piping (not shown) is connected. The nozzle 206 is located at the center of the hemispherical end wall portion of the pressure vessel 200. The nozzle 206 is made of a metal such as aluminum alloy or stainless steel. A female thread (not shown) is formed on the inner circumferential surface of the opening 207 provided in the nozzle 206. The valve assembly 250 or piping can be screwed into the nozzle 206 via the female thread.

[0021] For example, when the pressure vessel 200 is used in a fuel cell system, the storage space 204 is connected to an external gas flow path (not shown) via a valve assembly 250, which integrates piping elements such as valves and fittings. This allows hydrogen to be filled into the storage space 204 from the outside, and hydrogen to be released from the storage space 204 to the outside. The nozzle 206 may be provided not only at the top 203 but also at the bottom 202.

[0022] The pressure vessel 200 also includes a liner 210 and a reinforcing layer 220. The liner 210 is disposed inside the pressure vessel 200 and is a component that seals and contains gas or liquid. The liner 210 includes a liner body 211 which corresponds to the body 201, a liner bottom 212 which corresponds to the bottom 202, and a liner head 213 which corresponds to the head 203.

[0023] The liner 210 has the function of suppressing the permeation of gas or liquid stored in the storage space 204 and preventing the gas or liquid from coming into contact with the reinforcing layer 220. The liner 210 is made of a material that has excellent performance in suppressing the permeation of gas or liquid, that is, a gas or liquid barrier. The liner 210 is made of an aluminum alloy, a resin material, a non-metallic elastic material, etc. In this embodiment, the liner 210 is made of an aluminum alloy. As the aluminum alloy used in the manufacture of the liner 210, an A6000 series aluminum alloy is preferred.

[0024] The manufacturing process for the liner 210 is described below. In step 1, an aluminum alloy sheet is prepared and placed into a machine tool. The aluminum alloy sheet is a disc-shaped sheet made of aluminum alloy. In step 2, the aluminum alloy sheet is subjected to press cupping. Step 2 forms the bottom portion 202, which is the dome-shaped lower part of the pressure vessel 200. In step 3, the cup-shaped aluminum alloy that has undergone press cupping is subjected to forming, also known as stretching. Step 3 forms the body portion 201, which is the central cylindrical part of the pressure vessel 200. The shape of the processed product in step 3 is similar to a test tube used in chemical experiments, with an opening at one end.

[0025] In step 4, the opening of the roughly test tube-shaped aluminum alloy processed in steps 1 to 3 is subjected to spinning. In step 4, the head 203, which is the dome-shaped upper part of the pressure vessel 200, is formed. Steps 2 to 4 complete the pressure vessel 200 into a roughly vessel shape. In step 5, heat treatment is performed. In step 6, thread cutting is performed on the pressure vessel 200. In step 6, the nozzle 206 is threaded and shaped by machining. By performing steps 1 to 6, the liner 210 is completed.

[0026] The reinforcing layer 220 is primarily a layer that compensates for the insufficient strength of the liner 210 alone and enhances the strength of the pressure vessel 200. The reinforcing layer 220 is composed of, for example, fiber-reinforced plastics (FRP), which are fiber-reinforced resins. Examples of fiber-reinforced resins include carbon fiber reinforced plastics (CFRP), which are carbon fiber reinforced resins containing epoxy resin or phenolic resin and carbon fibers, and glass fiber reinforced plastics (GFRP), which are carbon fiber reinforced resins containing epoxy resin or phenolic resin and glass fibers. In this embodiment, the reinforcing layer 220 is formed by sequentially laminating layers of CFRP and GFRP around the outer circumference of the liner 210.

[0027] The process for forming the reinforcing layer 220 will now be described. In this embodiment, the reinforcing layer 220 is formed on the outer circumference of the liner 210 by filament winding molding. In filament winding molding, reinforcing fibers made of carbon fiber or glass fiber that have been pre-impregnated with a thermosetting resin, such as epoxy resin, are wound around the outer circumference of the liner 210, and the reinforcing layer 220 is formed by thermosetting the thermosetting resin.

[0028] Methods for winding carbon fiber or glass fiber reinforcement include hoop winding and helical winding. In this embodiment, a reinforcing layer 220 is formed by laminating a fiber winding layer of carbon fiber reinforced resin on the outer circumference of the liner 210, and then laminating a fiber winding layer of glass fiber reinforced resin. In other words, in this embodiment, first, multiple fiber winding layers with different carbon fiber winding methods are laminated on the outer circumference of the liner 210. Then, multiple fiber winding layers with different glass fiber winding methods are laminated onto the carbon fiber reinforced resin fiber winding layer formed on the outer circumference of the liner 210.

[0029] Hoop winding is a method of winding fibers 221, which are carbon fibers or glass fibers, onto a cylindrical liner 210 at a winding angle approximately perpendicular to the central axis AX, while moving the winding position along the central axis AX. The winding angle is the angle between the winding direction of the fiber 221 and the direction in which the fiber 221 extends. The winding direction of the fiber 221 is the direction of movement of the reel (not shown) on which the fiber 221 is wound, and is the direction in which the central axis AX extends. α1, which represents the winding angle of hoop winding, is approximately 90 degrees. Hereafter, the fiber winding layer formed by hoop winding will be referred to as the hoop layer. Since it is difficult to wind the fiber 221 onto the liner bottom 212 and the liner top 213 using hoop winding, the hoop layer is basically formed over the entire liner body 211.

[0030] As shown in Figures 3(B) and 3(C), helical winding is a method in which the fibers 221 are spirally wound around the liner 210 while maintaining a constant winding angle, and at the end of the liner 210, the winding direction is switched and the fibers 221 are spirally wound around the liner 210 again while maintaining a constant winding angle. In helical winding, the winding direction is switched many times, so a fiber-wound layer in which the fibers 221 are spread in a mesh-like pattern is formed on the outer surface of the pressure vessel 200. There are two types of helical winding: high-angle helical winding and low-angle helical winding.

[0031] Figure 3(B) shows how the fibers 221 are wound onto the liner 210 by high-angle helical winding. α2, which represents the winding angle of the high-angle helical winding, is a relatively large winding angle such that the fibers 221 can complete at least one full turn around the liner body 211. The approximate range for the angle of α2 is, for example, around 30 degrees to less than 80 degrees. Hereafter, the fiber winding layer formed by high-angle helical winding will be referred to as the high-angle helical layer.

[0032] Figure 3(C) shows how the fibers 221 are wound onto the liner 210 by low-angle helical winding. α3, which represents the winding angle of the low-angle helical winding, is a relatively small winding angle such that the winding direction is switched before the fibers 221 complete one turn on the liner body 211. The approximate range for the angle of α3 is, for example, around 10 to 30 degrees. Hereafter, the fiber winding layer formed by low-angle helical winding will be referred to as the low-angle helical layer. Hereafter, the winding angle will be referred to as the orientation angle.

[0033] The design support system 1000 includes at least one information processing device 100. In this embodiment, the design support system 1000 includes one information processing device 100. The information processing device 100 is a device that performs design support processing to assist in the design of the pressure vessel 200. The information processing device 100 may be a terminal device operated by a user who is the designer of the pressure vessel 200, or it may be a device that can communicate with this terminal device. In this embodiment, the information processing device 100 is a terminal device operated by a user. As shown in Figure 1, the information processing device 100 includes a control unit 11, a storage unit 12, a display unit 13, an operation reception unit 14, and a communication unit 15.

[0034] The control unit 11 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), RTC (Real Time Clock), etc. The CPU is also called a central processing unit, central computing unit, processor, microprocessor, microcomputer, DSP (Digital Signal Processor), etc., and functions as a central computing unit that executes processing and calculations related to the control of the information processing device 100. In the control unit 11, the CPU reads programs and data stored in ROM and uses RAM as a work area to comprehensively control the information processing device 100. The RTC is, for example, an integrated circuit with a timing function. The CPU can determine the current date and time from the time information read from the RTC.

[0035] The storage unit 12 is equipped with non-volatile semiconductor memory such as flash memory, EPROM (Erasable Programmable ROM), and EEPROM (Electrically Erasable Programmable ROM), and plays the role of a so-called auxiliary storage device. The storage unit 12 stores programs and data used by the control unit 11 to execute various processes. The storage unit 12 also stores data generated or acquired by the control unit 11 as a result of executing various processes.

[0036] The display unit 13 displays various images according to the control of the control unit 11. For example, the display unit 13 displays a screen for receiving various operations from the user. The display unit 13 includes a touch screen, a liquid crystal display, etc. The operation reception unit 14 receives various operations from the user and supplies information indicating the content of the received operation to the control unit 11. The operation reception unit 14 includes a touch screen, buttons, levers, etc.

[0037] The communication unit 15 communicates with various devices in accordance with the control of the control unit 11. The communication unit 15 communicates with various devices in accordance with well-known wired communication standards or well-known wireless communication standards. Well-known wired communication standards include USB (Universal Serial Bus, registered trademark) and Thunderbolt (registered trademark). Well-known wireless communication standards include Wi-Fi (registered trademark), Bluetooth (registered trademark), and Zigbee (registered trademark). The communication unit 15 is equipped with a communication interface compliant with various communication standards.

[0038] Next, the functions of the design support system 1000 will be described with reference to Figure 4. Functionally, the design support system 1000 comprises a designation reception unit 101, a liner design unit 102, a reinforcement layer design unit 103, a container information output unit 104, and a ratio calculation unit 105. Each of these functions is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the ROM or storage unit 12. The CPU then realizes each of these functions by executing the programs stored in the ROM or storage unit 12.

[0039] The specification reception unit 101 receives various specifications from the user. For example, the specification reception unit 101 receives various data regarding the specifications of the pressure vessel 200. These specifications are the specifications or data of the individual elements that make up the pressure vessel 200, such as performance, properties, form, shape, material, etc. Hereinafter, values ​​indicating the specifications will be referred to as specification values. Specification values ​​for the entire pressure vessel 200, which has a nearly cylindrical shape, include volume, mass, dimensions, maximum filling pressure, pressure resistance test pressure, minimum burst pressure, etc. The dimensions of the entire pressure vessel 200 include the length of the pressure vessel 200 and the diameter of the pressure vessel 200, and these determine the approximate volume of the pressure vessel 200.

[0040] The maximum filling pressure, pressure resistance test pressure, and minimum burst pressure are specifications related to the pressure required for the pressure vessel 200, and are defined by various standards and tests. The maximum filling pressure is the pressure that serves as a guideline for the amount of filling when using the pressure vessel 200. The pressure resistance test pressure is the pressure set in the demonstration test conducted at a pressure exceeding the design pressure to confirm the safety of the pressure vessel 200. The minimum burst pressure is the greater of either "3.4 times the maximum filling pressure" or "the pressure at which the stress on the carbon fibers in the liner body 211, calculated using the design wall thickness including the glass fiber layer, becomes the stress at which the carbon fibers break." Details of these pressures are described, for example, in "Technical Standards for General Composite Containers Made of Aluminum Alloy Liners and Carbon Fibers KHKS0121 (2016)."

[0041] Specifications for the cylindrical liner body 211 include mass and dimensions. The dimensions of the liner body 211 include length, outer diameter, inner diameter, and wall thickness, which determine the more detailed volume of the pressure vessel 200. Specifications for CFRP and GFRP include wall thickness. Specifications for the liner bottom 212 and liner top 213 include mass and wall thickness of each part.

[0042] Figure 5 shows the specifications of an FRP pressure vessel model. The FRP pressure vessel model is a model of a pressure vessel 200 having an aluminum alloy liner, and is, for example, a fiber-reinforced resin pressure vessel that has been approved by the High Pressure Gas Safety Association and is already commercially available. Figure 5 shows the specifications of 10 types of FRP pressure vessel models. The model information, which is the information showing each of the specifications shown in Figure 5, is stored in, for example, the memory unit 12.

[0043] Important physical properties include volume, mass, diameter, length, and pressure setting. Note that volume corresponds to capacity, and diameter corresponds to external dimensions. Pressure settings include nominal operating pressure, maximum filling pressure, pressure test pressure, minimum burst pressure, and design failure pressure. These physical properties are determined by considering the balance between the consumption rate and duration of the gas used, the dimensions of the container related to the installation location, and the pressure of the gas used.

[0044] Regarding volume, for example, firefighting air cylinders generally come in 4-liter, 6-liter, and 8-liter sizes. The filling pressure is set at 29-30 MPa for the 4-liter and 6-liter cylinders, and 15 MPa or 29-30 MPa for the 8-liter cylinder. This is to ensure that, for example, if firefighters use an air cylinder during a disaster and consume 40 liters of air per minute, they can work at the disaster site for approximately 30 minutes, 45 minutes, or 60 minutes or more. For instance, a 4-liter air cylinder can store 4 liters of air at 29 MPa (approximately 300 atmospheres), which translates to approximately 1200 liters of air at normal pressure. Therefore, if 40 liters of air are consumed per minute, approximately 1200 liters of air will be consumed in about 30 minutes. The diameter and length of the pressure vessel 200 are significant factors influencing the volume.

[0045] Regarding mass, a pressure vessel 200 with a large volume has a large mass, and a pressure vessel 200 with a high maximum filling pressure and thick walls also has a large mass. While a pressure vessel 200 with a large volume or high maximum filling pressure and a large mass can supply air for extended periods, if it is too heavy, prolonged operation may become difficult.

[0046] Regarding various pressure settings, the pressure vessel 200 is desirable to be compact, lightweight, and capable of supplying a large volume of air. To meet these requirements, it is desirable that it has high pressure settings, sufficient strength to prevent rupture and failure even at high pressures, and to be safe even if it does rupture or fail. Therefore, in order to handle a safe and secure pressure vessel 200 as a product, it is necessary to apply for "design confirmation as an FRP pressure vessel" with, for example, an aluminum alloy liner, and obtain review and approval from the High Pressure Gas Safety Association.

[0047] The following explains the "design verification for FRP pressure vessels." The "design verification for FRP pressure vessels" specifies the following: "1. Design inspection," "2. Interlaminar shear test," "3. Burst test," "4. Room temperature pressure cycle test," "5. Environmental pressure cycle test," "6. Temperature pressure cycle test," "7. Minimum wall thickness confirmation test," "8. Fire exposure test," and "9. Drop test."

[0048] "1. Design Inspection" specifies the relationships between materials, wall thickness, stress, etc. For example, it is stipulated that the wall thickness must be such that the stress of the carbon fibers at the maximum filling pressure, calculated using the wall thickness obtained by subtracting the glass fiber layer from the design wall thickness, is 3 / 10 or less of the stress of the carbon fibers at the minimum burst pressure. "2. Interlaminar Shear Test" specifies the interlaminar shear strength. "3. Burst Test" specifies that the material must burst at a pressure equal to or greater than the minimum burst pressure, and that the point of bursting is the body, etc.

[0049] "4. Room Temperature Pressure Cycle Test" specifies that there should be no deformation or leakage even when pressure fluctuations are repeatedly performed between atmospheric pressure and an upper limit pressure above the maximum filling pressure, and that there should be no deformation or leakage even when pressure fluctuations are repeatedly performed between atmospheric pressure and an upper limit pressure above the pressure test pressure. "5. Environmental Pressure Cycle Test" specifies that, for example, under various environmental conditions, there should be no deformation or leakage even when pressure fluctuations are repeatedly performed between atmospheric pressure and an upper limit pressure above the maximum filling pressure. "6. Temperature Pressure Cycle Test" specifies that, for example, under environmental conditions where the temperature changes, there should be no deformation or leakage even when pressure fluctuations are repeatedly performed between atmospheric pressure and an upper limit pressure above the maximum filling pressure.

[0050] "7. Minimum Wall Thickness Confirmation Test" specifies that, for example, a container with its body cut to a DC depth should not deform or leak even when subjected to repeated pressure fluctuations between atmospheric pressure and an upper limit pressure exceeding the maximum filling pressure at room temperature. "8. Fire Exposure Test" specifies that, for example, even if a combustion fire occurs while the container is filled with air or nitrogen gas to the maximum filling pressure, the contents should be discharged from the safety valve and the container should not be damaged. "9. Drop Test" specifies that even when subjected to repeated drop tests under pressure fluctuations from atmospheric pressure to the maximum filling pressure, there should be no expansion of damage or leakage.

[0051] Furthermore, the "Design Verification Based on the Technical Standards for Compressed Hydrogen Vehicle Fuel System Containers" also specifies various tests, similar to the "Design Verification for FRP Pressure Vehicles." The "Design Verification Based on the Technical Standards for Compressed Hydrogen Vehicle Fuel System Containers" specifies tests such as: "1. Design Inspection," "2. Initial Rupture Test," "3. Initial Room Temperature Pressure Cycle Test," "4. Durability Performance Test," "5. Continuous Gas Pressure Test," and "6. Fire Exposure Test."

[0052] As mentioned above, FRP pressure vessels undergo inspections according to their type, design verification is carried out, and only those that receive approval are commercialized. Here, a particularly important element in "design verification as an FRP pressure vessel" is the "minimum burst pressure." Specifically, in "1. Design Inspection," the "minimum burst pressure" is the target. In "3. Burst Test," the "minimum burst pressure" is also the target. In "4. Room Temperature Pressure Cycle Test," the "minimum burst pressure" is the target after repeated loading against the "maximum filling pressure" and the "pressure resistance test pressure."

[0053] In "5. Environmental Pressure Cycle Test," the target is the "minimum burst pressure" after repeated loading against the "maximum filling pressure" under high and low temperature and humidity conditions. In "6. Temperature Pressure Cycle Test," the target is the "minimum burst pressure" after repeated loading against the "maximum filling pressure" under high temperature conditions. In "7. Minimum Wall Thickness Confirmation Test," the target is repeated loading against the "maximum filling pressure." In "8. Fire Exposure Test," the target is the "maximum filling pressure." In "9. Drop Test," the target is repeated loading against the "maximum filling pressure" and the "minimum burst pressure."

[0054] Furthermore, the most important elements in the "Design Verification Based on the Technical Standards for Compressed Hydrogen Vehicle Fuel Containers" are the "minimum burst pressure" and the "design burst pressure." Specifically, in "2. Initial Burst Test," the "minimum burst pressure" and the "design burst pressure" are targeted. In "3. Initial Room Temperature Pressure Cycle Test," repeated loading at pressures above the "maximum filling pressure" is performed. In "4. Durability Performance Test," the "pressure resistance test pressure," "maximum filling pressure," etc., are targeted in various tests. In "5. Continuous Gas Pressure Test," the "pressure resistance test pressure," "maximum filling pressure," etc., are targeted in various tests.

[0055] Thus, for any FRP pressure vessel, the key point of design verification is that it can withstand the "minimum burst pressure," "design burst pressure," etc. Therefore, it is preferable for the designation reception section 101 to accept specifications for the "minimum burst pressure," "design burst pressure," etc.

[0056] The specification reception unit 101 may accept specification values ​​as values ​​that must be achieved in the design of the pressure vessel 200, or it may accept specification values ​​as target values ​​that are targeted in the design of the pressure vessel 200. Specifically, the specification reception unit 101 accepts the specification of a set pressure, which is a pressure set for the pressure vessel 200. The set pressure is the maximum filling pressure, the pressure resistance test pressure, the minimum burst pressure, etc. In this embodiment, the set pressure is a specification value, and the pressure vessel 200 is designed so that the specified set pressure is achieved. Note that the specification value is a single value, and a certain degree of error may be allowed. Alternatively, the specification value may have a certain range.

[0057] Furthermore, the designation reception unit 101 accepts the designation of a volume corresponding value that corresponds to the set volume, which is the volume set for the pressure vessel 200. The volume corresponding value can be any value as long as it is a value relative to the set volume. For example, the volume corresponding value may be a specification value that indicates the set volume itself, or a specification value that allows the set volume to be calculated. For example, the volume corresponding value may be a specification value that indicates the overall length of the pressure vessel 200 and a specification value that indicates the inner diameter of the liner body 211. Note that once the overall length of the pressure vessel 200 and the inner diameter of the liner body 211 are determined, the volume of the pressure vessel 200 is also largely determined. Furthermore, it is preferable that the length and dimensions of the pressure vessel 200 be determined by considering how the pressure vessel 200 will be held, where it will be fixed, etc. In other words, the length and dimensions of the pressure vessel 200 are constrained by the method of holding the pressure vessel 200, the fixing location, etc. Consequently, the volume of the pressure vessel 200 is also constrained to some extent by the method of holding the pressure vessel 200, the fixing location, etc. In this embodiment, the set volume is a specification value, and the pressure vessel 200 is designed so that the specified set volume is achieved. The specified receiving section 101 is an example of a specified receiving means.

[0058] The liner design unit 102 designs the liner 210 based on the specifications received by the specification reception unit 101. For example, the liner design unit 102 designs the liner 210 based on the volume correspondence value received by the specification reception unit 101. For example, the liner design unit 102 determines the dimensions of the liner 210 so that the specified set volume is achieved. For example, if the total length of the pressure vessel 200 is specified as the volume correspondence value, the liner design unit 102 calculates the length of the liner body 211 from the total length of the pressure vessel 200.

[0059] The liner design unit 102 calculates the inner diameter and wall thickness of the liner 210 based on the specifications received by the specification reception unit 101. It also calculates the liner burst pressure, which is the pressure at which the liner 210 will burst, based on the inner diameter and wall thickness of the liner 210. The liner design unit 102 outputs liner information obtained through the design of the liner 210. This liner information includes, for example, the inner diameter, wall thickness, and liner burst pressure of the liner 210. The liner design unit 102 is an example of a liner design means.

[0060] The reinforcement layer design unit 103 designs the reinforcement layer 220. For example, the reinforcement layer design unit 103 designs the reinforcement layer 220 based on the set pressure and liner information. For example, the reinforcement layer design unit 103 compares the set pressure with the liner burst pressure included in the liner information and determines the thickness of the reinforcement layer 220 so that the liner 210 alone lacks sufficient strength and can be compensated for by the reinforcement layer 220. The reinforcement layer design unit 103 outputs reinforcement layer information obtained through the design of the reinforcement layer 220. The reinforcement layer information includes, for example, the thickness of the reinforcement layer 220. The reinforcement layer design unit 103 is an example of a reinforcement layer design means.

[0061] The container information output unit 104 outputs container information, which is information relating to the pressure vessel 200, based on the liner information and the reinforcing layer information. For example, the container information output unit 104 calculates the overall specifications of the pressure vessel 200 based on the liner information and the reinforcing layer information, and outputs container information including the overall specifications of the pressure vessel 200. Specifically, the container information output unit 104 outputs container information including the dimensions and mass of the pressure vessel 200. The container information output unit 104 is an example of a container information output means.

[0062] Here, the set pressure may be the minimum burst pressure, which is the pressure specified in the test of the pressure vessel 200. The designation reception unit 101 also accepts designations for fiber-reinforced resin information, which indicates the composition of the materials contained in the fiber-reinforced resin and the configuration of the fiber orientation angle during the formation of the fiber-reinforced resin.

[0063] The ratio calculation unit 105 calculates the stress pressure ratio based on the fiber-reinforced resin information. The stress pressure ratio is the ratio of the stress generated in the pressure vessel 200 when the minimum burst pressure is applied to the pressure vessel 200 to the stress generated in the fiber-reinforced resin when pressure is applied to the fiber-reinforced resin and the fiber-reinforced resin is fractured. The reciprocal of the stress pressure ratio generally corresponds to the safety factor. That is, the lower the stress pressure ratio, the greater the pressure margin and the higher the safety factor. The container information output unit 104 outputs container information including the stress pressure ratio calculated by the ratio calculation unit 105. The ratio calculation unit 105 is an example of a ratio calculation means.

[0064] The specification reception unit 101 may also accept a specification for the plate thickness, which is the thickness of the aluminum alloy plate used to form the liner 210. In this case, the liner design unit 102 designs the liner 210 based on the set pressure, the volume correspondence value, and the plate thickness.

[0065] In this embodiment, the liner 210 comprises a cylindrical liner body 211, a dome-shaped liner bottom 212 provided at one end of the liner body 211, and a dome-shaped liner head 213 provided at the other end of the liner body 211, having a nozzle 206. The designation reception unit 101 accepts the length of the pressure vessel 200 and the inner diameter of the liner 210 as volume-corresponding values.

[0066] The liner design unit 102 calculates the wall thickness of the liner bottom 212 based on the plate thickness, and calculates the wall thickness of the liner body 211 based on the wall thickness of the liner bottom 212. The liner design unit 102 also calculates the liner burst pressure based on the inner diameter of the liner 210 and the wall thickness of the liner body 211. Furthermore, the liner design unit 102 calculates the wall thickness of the liner head 213 based on the set pressure, the liner burst pressure, and the wall thickness of the liner bottom 212.

[0067] The reinforcement layer design unit 103 calculates the thickness of the reinforcement layer 220 based on the outer diameter of the liner body 211, the set pressure, and the liner burst pressure. The outer diameter of the liner body 211 can be calculated based on the inner diameter of the liner 210 and the thickness of the liner body 211.

[0068] Next, we will explain in detail each process performed by the design support system 1000. The design support system 1000 basically performs the following: (1) setting the target pressure for the pressure vessel 200, (2) designing the liner 210, (3) calculating the liner burst pressure, (4) calculating the wall thickness of the reinforcing layer 220 by comparing the target pressure and the liner burst pressure, (5) calculating the specifications of the pressure vessel 200, and (6) calculating the stress pressure ratio. The design support system 1000 is a system that calculates and presents an estimate of the specifications of the pressure vessel 200 by performing processes (1) to (6). Furthermore, the design support method performed by the design support system 1000 is a method of calculating and presenting an estimate of the specifications of the pressure vessel 200 by performing processes (1) to (6).

[0069] According to the design support system 1000, when generating each model of the finite element method, the specifications of the pressure vessel 200 become clearer, reducing the number of models generated and analyses performed, and thus shortening the design time. In particular, since the specifications of the pressure vessel 200 are basically derived from the trends of dozens of different pressure vessel 200 products that have been commercialized in the past, a significant reduction in the number of analyses performed and a substantial reduction in design time can be expected.

[0070] First, (1) the setting of the pressure for the pressure vessel 200 will be explained. As mentioned above, it is desirable for the pressure vessel 200 to be compact, lightweight, and capable of supplying a large amount of air. For this reason, it is desirable that the various pressure settings be high, that it has the strength to not burst or break even at high pressure, and that it be safe even if it does burst or break. Accordingly, the set pressure is determined by considering the amount of air that can be supplied, the dimensions and mass of the pressure vessel 200, etc. In this embodiment, the set pressure is basically not a value calculated by the design support system 1000, but a value set by the user as a specification value.

[0071] Next, (2) the design of the liner 210 will be explained. Designing the liner 210 basically involves determining the dimensions of the liner 210, that is, the length of the liner 210, the outer diameter of the liner 210, the inner diameter of the liner 210, the wall thickness of the liner 210, etc. Here, the volume of the pressure vessel 200 is basically determined by the dimensions of the liner 210. Therefore, for example, if the volume of the pressure vessel 200 is set as a specification value, the dimensions of the liner 210 are determined so that the set volume is realized. Also, for example, if the thickness of the aluminum alloy sheet used to manufacture the liner 210 is specified, the wall thickness of the liner 210 is determined to some extent.

[0072] The following describes how to calculate the dimensions of the liner 210 when the length of the pressure vessel 200, the inner diameter of the liner body 211, and the thickness of the aluminum alloy plate are specified. First, the liner bottom 212 is formed by press cupping, and the liner body 211 is formed by forming. In press cupping and forming, the aluminum alloy plate is stretched during processing to prevent wrinkles from forming. If it is not stretched enough, wrinkles will remain, and if it is stretched too much, the wall thickness will not be stable. Also, the smaller the outer diameter of the liner 210, the more wrinkles there are. Therefore, we investigated the relationship between various data of the liner bottom 212 and the liner body 211 for several commercially available FRP pressure vessel models, and in particular, we investigated the relationship between the volume of the liner bottom 212 and the volume per unit length of the liner body 211.

[0073] Figure 6 shows the relationship between the volume of the liner bottom 212 and the volume per unit length of the liner body 211. As shown in Figure 6, there is a correlation between the volume of the liner bottom 212 and the volume per unit length of the liner body 211. Here, basically, the volume of the liner bottom 212 corresponds to the thickness of each part of the liner bottom 212, and the volume per unit length of the liner body 211 corresponds to the thickness of the liner body 211. Also, the thickness of the liner bottom 212 is basically close to the thickness of the aluminum alloy sheet.

[0074] Therefore, if the thickness of the aluminum alloy plate and the shape of the liner bottom 212 are specified, the thickness distribution of the liner bottom 212 can be calculated. Note that if the shape of the liner bottom 212 is a predetermined shape, the shape of the liner bottom 212 does not need to be specified. Also, considering the relationship shown in Figure 6, the thickness of the liner body 211 can be calculated from the thickness distribution of the liner bottom 212. Furthermore, if the inner diameter of the liner body 211 is specified, the outer diameter of the liner body 211 can be calculated from the thickness of the liner body 211. In addition, if the length of the pressure vessel 200 is specified, the length of the liner body 211 can be calculated. In this way, the dimensions of the liner body 211 and the liner bottom 212 are calculated.

[0075] Next, we will explain how to calculate the dimensions of the liner head 213. The liner head 213 is formed by spinning. In this spinning process, the cylindrical molded product (roughly with a test tube-shaped opening) of roughly equal thickness formed by forming is narrowed, reducing its diameter and increasing its thickness. In other words, spinning makes it possible to increase the thickness of the part that needs to be reinforced.

[0076] Here, we will explain (3) the calculation of the liner rupture pressure. The liner rupture pressure is the pressure at which the liner 210 ruptures. The pressure resistance strength of the aluminum alloy liner 210 is described in the reference "A Study on the Structural Behavior and Pressure Resistance Strength of Pressure-Resistant PET Bottles," Faculty of Information Engineering, Okayama Prefectural University, Tadao Fukuda et al., JHPI (Pressure Technology) Vol. 49 No. 3 (2011) pp. 118-123. This reference describes applying the NLSvensson analysis, which is referenced in various standards and documents for the rupture analysis of metal pressure vessels, to the rupture of pressure-resistant PET bottles.

[0077] The references state that in the NLSvensson analysis, the bursting pressure of a thin-walled cylinder is P. * Let e ​​be the base of the natural logarithm, and t i Initial wall thickness, R i Let be the initial inner radius, E0 and n be the nth power hardening formula σ = E0·ε n The coefficients and exponents in this context are described as being determined by the following equation (1). Furthermore, the references show that burst pressure can be estimated for a homogeneous, isotropic, and incompressible pressure vessel 200 using NLSvensson analysis.

number

[0078] In aluminum alloys, the n-th power hardening characteristic is the tensile yield stress σ y Equation (2) was calculated, which expresses the relationship between true stress σ and true strain ε up to the vicinity using the n-th power hardening formula. σ = 3136.5·ε 0.802(MPa) ··· (2)

[0079] In this embodiment, for multiple commercially available FRP pressure vessel models, NLSvensson analysis is used, and the n-th power hardening formula of equation (2) is used, and the burst pressure P is calculated by equation (1). * The following was calculated. Figure 7 shows the relationship between the ratio of the liner burst pressure to the pressure test pressure and the volume ratio of the liner head 213 to the liner bottom 212. Figure 8 shows the relationship between the ratio of the liner burst pressure to the minimum burst pressure and the volume ratio of the liner head 213 to the liner bottom 212. Note that both the pressure test pressure and the minimum burst pressure are set pressures for the pressure vessel 200. Basically, the volume of the liner head 213 corresponds to the wall thickness of the liner head 213, and the volume of the liner bottom 212 corresponds to the wall thickness of the liner bottom 212.

[0080] In both Figure 7 and Figure 8, the smaller the liner burst pressure is relative to the set pressure of the pressure vessel 200, that is, the smaller the ratio shown on the horizontal axis in Figures 7 and 8, the larger the volume of the liner head 213 is relative to the volume of the liner bottom 212. From the relationship shown in Figures 7 and 8, it can be seen that when the set pressure of the pressure vessel 200 is large relative to the liner burst pressure, the liner head 213 should be reinforced by increasing its thickness compared to the liner bottom 212 in order to withstand the filling and release of high-pressure gas.

[0081] In this embodiment, the dimensions of the liner head 213 are designed by referring to the relationship between the specifications of several commercially available FRP pressure vessel models. Specifically, first, the liner burst pressure is calculated from the dimensions of the liner body 211, i.e., the outer diameter, inner diameter, and wall thickness of the liner body 211, using NLSvensson analysis. Then, using the relationship shown in Figure 7 or Figure 8, the wall thickness distribution of the liner head 213 is calculated from the specified set pressure, the calculated liner burst pressure, and the wall thickness distribution of the liner bottom 212. The shape of the liner bottom 212 and the shape of the liner head 213 are assumed to be predetermined.

[0082] Next, (4) the calculation of the thickness of the reinforcing layer 220 by comparing the set pressure and the liner burst pressure will be explained. After the liner 210 is designed by processes (1) to (3), the reinforcing layer 220 is designed based on the design results of the liner 210. The reinforcing layer 220 includes a CFRP layer, which is a carbon fiber reinforced resin layer, and a GFRP layer, which is a glass fiber reinforced resin layer.

[0083] Figure 9 shows the relationship between the difference between the pressure test pressure and the liner rupture pressure and the ratio of the CFRP layer thickness to the liner outer dimensions. Figure 10 shows the relationship between the difference between the minimum rupture pressure and the liner rupture pressure and the ratio of the CFRP layer thickness to the liner outer dimensions. The relationships shown in Figures 9 and 10 were obtained from the specifications of several commercially available FRP pressure vessel models.

[0084] In both Figure 9 and Figure 10, the smaller the liner rupture pressure is relative to the set pressure of the pressure vessel 200, that is, the larger the value on the horizontal axis in Figures 9 and 10, the larger the ratio of the CFRP layer thickness to the liner outer dimensions. The liner outer dimensions basically correspond to the outer diameter of the liner body 211. From the relationship shown in Figures 9 and 10, it can be seen that when the liner rupture pressure is small relative to the set pressure of the pressure vessel 200, the CFRP layer should be reinforced by increasing its thickness to cover the insufficient pressure resistance in the liner 210 portion.

[0085] In this embodiment, the reinforcing layer 220 is designed by referring to the relationship between the specifications of several commercially available FRP pressure vessel models. Specifically, using the relationship shown in Figure 9 or Figure 10, the thickness of the CFRP layer to be formed on the surface of the liner body 211 is calculated from the specified set pressure, the calculated liner burst pressure, and the dimensions of the liner body 211. The GFRP layer serves to protect the surface of the CFRP layer, but it does not fundamentally contribute to improving the strength of the pressure vessel 200. Therefore, it is preferable that the thickness of the GFRP layer be determined without considering the set pressure. For example, the thickness of the GFRP layer is set to a value of about 0.5 to 0.7 mm based on the specifications of several commercially available FRP pressure vessel models. The thickness of the reinforcing layer 220 is the sum of the thickness of the CFRP layer and the thickness of the GFRP layer.

[0086] Next, (5) the calculation of the specifications of the pressure vessel 200 will be explained. The specifications of the pressure vessel 200 include the outer diameter, length, volume, mass, etc. The specifications of the pressure vessel 200 can basically be calculated from the design results of the liner 210 and the design results of the reinforcing layer 220. In this embodiment, some of the specifications of the pressure vessel 200 are specified, the pressure vessel 200 is designed based on the specified specifications, and the remaining specifications are calculated.

[0087] Figure 11 shows the actual and calculated specifications for four FRP pressure vessel models E, F, I, and J, after applying processes (1) through (4). In Figure 11, the specifications indicated by "E," "F," "I," and "J" are the actual specifications, while the specifications indicated by "E solution," "F solution," "I solution," and "J solution" are the specifications calculated by the inverse analysis performed by processes (1) through (4). The overall length of the pressure vessel 200, the pressure resistance test pressure, the minimum burst pressure, the inner diameter of the liner body 211, and the wall thickness of the liner bottom 212 are the specifications entered into the design support system 1000, i.e., the specifications specified by the user. On the other hand, the total volume of the pressure vessel 200, the total mass of the pressure vessel 200, the total diameter of the pressure vessel 200, the outer diameter of the liner body 211, the wall thickness of the liner body 211, the wall thickness of the liner bottom 212, the wall thickness of the CFRP, and the wall thickness of the liner head 213 are specifications calculated by the design support system 1000.

[0088] Good agreement can be confirmed between the actual and calculated specifications for the total volume of the pressure vessel 200, the total mass of the pressure vessel 200, the wall thickness of the CFRP, and the wall thickness of the liner head 213. As a result, it can be seen that the specifications can be appropriately calculated for volumes up to about 10 liters, masses up to about 8 kg, diameters up to about 200 mm, lengths up to about 550 mm, maximum filling pressures up to about 35 MPa, pressure resistance test pressures up to about 60 MPa, and minimum burst pressures up to about 150 MPa.

[0089] While a detailed explanation is omitted, it has been confirmed that the following parameters can be appropriately calculated: volume up to approximately 110 liters, mass up to slightly less than 140 kg, diameter up to approximately 600 mm, length up to approximately 900 mm, maximum filling pressure up to approximately 87.5 MPa, pressure resistance test pressure up to approximately 105 MPa, minimum burst pressure up to approximately 160 MPa, and design burst pressure up to approximately 260 MPa.

[0090] For example, an analytical value of 23.3 liters was obtained for a volume of 23.3 liters, an analytical value of 27.2 kg was obtained for a mass of 26.2 kg, an analytical value of 254 mm was obtained for an external dimension of 258 mm, an analytical value of 3.7 mm was obtained for a wall thickness of 3.8 mm for the liner body 211, an analytical value of 12.1 mm was obtained for a wall thickness of 12.8 mm for the liner head 213, and an analytical value of 20.7 mm was obtained for a wall thickness of 21.0 mm for the CFRP layer.

[0091] Other examples include an analytical value of 122.2 liters for a volume of 113.2, an analytical value of 141.9 kg for a mass of 136.5 kg, an analytical value of 594 mm for an external dimension of 597 mm, an analytical value of 7.6 mm for the wall thickness of the liner body 211 of 7.6 mm, an analytical value of 18.5 mm for the wall thickness of the liner head 213 of 22.4 mm, and an analytical value of 51.9 mm for the wall thickness of the CFRP layer of 49.8 mm.

[0092] Figure 12 shows the relationship between the nominal value and the analytical value for the volume of the pressure vessel 200, that is, the relationship between the nominal value of the volume of the pressure vessel 200 and the analytical value for the volume of the pressure vessel 200. Figure 13 shows the relationship between the nominal value and the analytical value for the mass of the pressure vessel 200, that is, the relationship between the nominal value of the mass of the pressure vessel 200 and the analytical value for the mass of the pressure vessel 200. Figure 14 shows the relationship between the drawing value and the analytical value for the wall thickness of the CFRP of the pressure vessel 200, that is, the relationship between the drawing value of the wall thickness of the CFRP of the pressure vessel 200 and the analytical value for the wall thickness of the CFRP of the pressure vessel 200. Figure 15 shows the relationship between the drawing value and the analytical value for the wall thickness of the aluminum alloy liner 210 of the pressure vessel 200, that is, the relationship between the drawing value of the wall thickness of the aluminum alloy liner head 213 of the pressure vessel 200 and the analytical value for the wall thickness of the aluminum alloy liner head 213 of the pressure vessel 200.

[0093] Nominal values ​​are, for example, values ​​published by the manufacturer of the FRP pressure vessel model. Analytical values ​​are values ​​calculated by analysis using the design support system 1000. Drawing values ​​are, for example, values ​​in the drawings of the FRP pressure vessel model published by the manufacturer of the FRP pressure vessel model. Basically, drawing values ​​can be treated the same as nominal values. In Figures 12 and 13, the diagonal lines in the figures are lines connecting points where the nominal values ​​and analytical values ​​coincide. In Figures 14 and 15, the diagonal lines in the figures are lines connecting points where the drawing values ​​and analytical values ​​coincide. In all of Figures 12 to 15, a good agreement between the nominal values ​​or drawing values ​​and the analytical values ​​can be seen, indicating that each specification value can be calculated appropriately.

[0094] Next, (6) the calculation of the stress compression ratio will be explained. The stress compression ratio is the ratio of the stress on the pressure vessel 200 when the set pressure is applied to the stress at the time of fracture of the fiber-reinforced resin laminate. The fiber-reinforced resin laminate is formed by laminating fiber-reinforced resin at a specific fiber orientation angle. The stress at the time of fracture of the fiber-reinforced resin laminate is the stress generated in the laminate when the laminate fractures when pressure is actually applied to the laminate in a tensile strength test. The stress on the pressure vessel 200 when the set pressure is applied is the stress generated in the pressure vessel 200 when the set pressure is applied to the pressure vessel 200. The set pressure can be the minimum burst pressure, the pressure test pressure, etc. In this embodiment, the set pressure is the minimum burst pressure. The higher the stress compression ratio, the higher the probability that the pressure vessel 200 will fracture. Below, Young's modulus and stress, which are related to the calculation of the stress compression ratio, will be explained.

[0095] Figure 16 shows the axial Young's modulus (E1), circumferential Young's modulus (E2), axial stress (σ1), and circumferential stress (σ2) for the CFRP layers of six commercially available FRP pressure vessel models. These stress values ​​are calculated based on the stress values ​​at fracture obtained from tensile strength tests conducted on laminates stacked at various orientation angles, using Teijin carbon fiber "HTA40" (235.4 GPa) as the reinforcing fiber and a general-purpose epoxy resin as the matrix resin. The above calculated values ​​are for a volume fiber content of 67% and a mass resin content of 25%.

[0096] As a result, even with differences in wall thickness, all FRP pressure vessel models exhibited similar Young's modulus and stress values. This is considered to be the result of years of accumulated experience in the design, prototyping, development, and commercialization of FRP pressure vessels, and is one of the proven know-hows for commercializing FRP pressure vessels. This relationship also stems from the accumulated know-how of developing dozens of types of FRP pressure vessels that have been commercialized in the past, and it can be seen that, for a given pressure, the circumferential stress σ2 of pressure vessel 200 is approximately twice the axial stress σ1.

[0097] Figure 17 shows the composition ratio of each orientation angle of carbon fibers in the body 201 of the FRP pressure vessel model. This composition ratio is the ratio of the thickness of the layer formed at a certain orientation angle to the total thickness of the CFRP layer. The average value of the axial Young's modulus E1 is 58.0 GPa, and the average value of the circumferential Young's modulus E2 is 84.8 GPa.

[0098] Figure 18 shows the approximate composition ratios for each orientation angle. As mentioned above, these approximate composition ratios represent the ratio of the thickness of layers formed at a certain orientation angle to the total thickness of the CFRP layer, so that the axial Young's modulus E1 is an average of 58.0 GPa and the circumferential Young's modulus E2 is an average of 84.8 GPa. Figure 18 shows guidelines A and B. Guideline B indicates that approximately 30% of the layers have an orientation angle of around 15 degrees, approximately 10% have an orientation angle of around 25 degrees, approximately 5% have an orientation angle of around 35 degrees, approximately 10% have an orientation angle of around 70 degrees, and approximately 45% have an orientation angle of around 90 degrees. Note that an orientation angle of 90 degrees means that the carbon fibers were wound using the hoop winding method.

[0099] For the CFRP layer of the body 201 of the pressure vessel 200, which is formed with this orientation angle composition ratio, the axial Young's modulus E1 is 57.3 GPa, and the circumferential Young's modulus E2 is 86.4 GPa. Furthermore, when the stress values ​​at fracture obtained from the CFRP laminate that underwent tensile strength testing were calculated, the axial stress σ1 was 1051 MPa, and the circumferential stress σ2 was 1975 MPa. It can be seen that σ2 is approximately twice that of σ1.

[0100] Figure 19 shows the stress when the minimum burst pressure is applied. As shown in Figure 19, for the circumferential stress σ2 of the pressure vessel 200, E, G, H, and J all exceed 1000 MPa. Figure 20 shows the stress pressure ratio. As shown in Figure 20, the ratio of the circumferential stress σ2 is higher than the axial stress σ1, indicating that the failure of the FRP pressure vessel is predominantly circumferential.

[0101] Furthermore, the circumferential stress σ2 reaches nearly 60% to nearly 70% for E, G, and H. Therefore, it can be seen that the margin of safety against fracture stress for E, G, and H is only about 40% to 30%. For these vessels, minor defects during molding can affect various design verification items of FRP pressure vessels (pressure cycle testing, high humidity environment, high / low temperature environment, drop test, etc.). For this reason, it is effective to change the type of reinforcing fiber to one with high strength and high elasticity, or to change the type of matrix resin. Examples of minor defects during molding include the presence of large air bubbles, large meandering of reinforcing fibers, and large gaps between reinforcing fibers.

[0102] Next, with reference to Figure 21, the design support process executed by the design support system 1000 will be described. The design support method in this disclosure is realized by the design support system 1000 executing the design support process.

[0103] First, the control unit 11 of the information processing device 100 acquires the set pressure and the capacity corresponding value (step S101). After completing the process in step S101, the control unit 11 acquires the target value (step S102). The target value is considered in the design of the pressure vessel 200, just like the specification value, but it differs from the specification value in that it is merely a target and is not guaranteed to be achieved.

[0104] Possible target values ​​include the mass of the pressure vessel 200, the external dimensions of the pressure vessel 200, and the internal dimensions of the pressure vessel 200. The mass of the pressure vessel 200 is preferably set by referencing, for example, the mass of current market models. The external dimensions of the pressure vessel 200 are preferably set by referencing, for example, constraints based on the mounting location of the pressure vessel 200. For example, if the pressure vessel 200 is mounted in a hydrogen vehicle, it needs to be large enough not to come into contact with other parts of the hydrogen vehicle, such as the frame. The internal dimensions of the pressure vessel 200 are preferably set by referencing, for example, the capacity corresponding to the minimum required amount of each gas. Note that the more target values ​​set, the less freedom the design support system 1000 has in designing the pressure vessel 200, making the design of the pressure vessel 200 more difficult. Therefore, a reasonably wide tolerance range for the target values ​​is desirable. For example, it is preferable that a certain degree of error between the target values ​​and the analytical values ​​is acceptable. Alternatively, the target values ​​may be specified by upper and lower limits. In this embodiment, the target mass, which is the target value of the mass of the pressure vessel 200, and the target dimensions, which are the target values ​​of the dimensions of the pressure vessel 200, are obtained as target values.

[0105] After completing the process in step S102, the control unit 11 obtains the plate thickness (step S103). This plate thickness is the thickness of the aluminum alloy plate used to form the liner 210. After completing the process in step S103, the control unit 11 executes the liner design process (step S104). The liner design process will be described in detail with reference to Figure 22.

[0106] First, the control unit 11 calculates the dimensions of the liner bottom 212 (step S201). For example, the control unit 11 calculates the wall thickness of the liner bottom 212 from the plate thickness. After completing the process in step S201, the control unit 11 calculates the dimensions of the liner body 211 (step S202). For example, the control unit 11 calculates the wall thickness of the liner body 211 from the wall thickness of the liner bottom 212 and the inner diameter of the liner body 211.

[0107] After completing the process in step S202, the control unit 11 calculates the liner burst pressure (step S203). For example, the control unit 11 calculates the liner burst pressure from the dimensions of the liner body 211. After completing the process in step S203, the control unit 11 calculates the dimensions of the liner head 213 (step S204). For example, the control unit 11 calculates the thickness of the liner head 213 based on the set pressure, the liner burst pressure, and the thickness of the liner bottom 212.

[0108] After completing the process in step S204, the control unit 11 calculates the mass of the liner 210 (step S205). For example, the control unit 11 calculates the mass of the liner 210 from the dimensions of the liner body 211, the liner bottom 212, and the liner head 213. After completing the process in step S205, the control unit 11 completes the liner design process.

[0109] After completing the liner design process in step S104, the control unit 11 executes the reinforcement layer design process (step S105). For example, the control unit 11 calculates the wall thickness of the reinforcement layer 220 based on the outer diameter of the liner body 211, the set pressure, and the liner burst pressure. After completing the process in step S105, the control unit 11 outputs vessel information (step S106). The vessel information includes, for example, the specifications of the designed pressure vessel 200.

[0110] After completing the process in step S106, the control unit 11 determines whether the mass exceeds the target mass (step S107). The target mass is assumed to have been acquired as a target value. If the control unit 11 determines that the mass exceeds the target mass (step S107: YES), it returns to step S103. In step S103, the control unit 11 acquires, for example, a plate thickness that is thinner than the currently acquired plate thickness.

[0111] If the control unit 11 determines that the mass does not exceed the target mass (step S107: NO), it determines whether the dimensions differ significantly from the target dimensions (step S108). The target dimensions are assumed to have been acquired as target values. If the control unit 11 determines that the dimensions differ significantly from the target dimensions (step S108: YES), it returns to step S101. In step S101, the control unit 11 acquires a capacity-corresponding value that is different from the capacity-corresponding value currently acquired, for example.

[0112] When the control unit 11 determines that the dimensions do not differ significantly from the target dimensions (step S108: NO), it acquires fiber-reinforced resin information and the target ratio (step S109). The fiber-reinforced resin information is information indicating the composition of the materials contained in the fiber-reinforced resin and the configuration of the fiber orientation angle during the formation of the fiber-reinforced resin. The target ratio is the target value of the stress pressure ratio. The target ratio is specified, for example, within a range with a certain width. When the control unit 11 completes the process in step S109, it calculates the stress pressure ratio (step S110).

[0113] When the control unit 11 completes the processing in step S110, it outputs the stress saturation ratio (step S111). When the control unit 11 completes the processing in step S111, it determines whether the stress saturation ratio differs significantly from the target ratio (step S112). When the control unit 11 determines that the stress saturation ratio differs significantly from the target ratio (step S112: YES), it returns to step S101.

[0114] If the control unit 11 determines that the stress pressure ratio does not differ significantly from the target ratio (step S112: NO), it determines whether the stress pressure ratio differs from the target ratio (step S113). If the control unit 11 determines that the stress pressure ratio differs from the target ratio (step S113: YES), it returns to step S109. If the control unit 11 determines that the stress pressure ratio does not differ from the target ratio (step S113: NO), it completes the design support process.

[0115] As described above, in this embodiment, the liner 210 and the reinforcing layer 220 are automatically designed based on the set pressure and volume correspondence values. Therefore, this embodiment can appropriately support the design of the pressure vessel 200.

[0116] (modified version) Although embodiments of this disclosure have been described above, various forms of modification and application are possible.

[0117] The adoption of any part of the configuration, function, and operation described in the above embodiments is arbitrary. Furthermore, additional configurations, functions, and operations may be adopted in addition to those described above. The above embodiments can also be freely combined as appropriate. The number of components described in the above embodiments can also be adjusted as appropriate. Of course, the materials, sizes, electrical characteristics, etc., that can be used are not limited to those shown in the above embodiments.

[0118] In the embodiment described, an example was given in which the liner 210 is formed from an aluminum alloy. The liner 210 may also be formed from a resin material. A modified pressure vessel 200 will be described below.

[0119] The modified pressure vessel 200 uses nylon 11 (polyamide resin) (abbreviation: PA11) for the liner 210, and surrounds the liner 210 with Teijin carbon fiber "HTA40" (235.4 GPa) as reinforcing fibers and a general-purpose epoxy resin as the matrix resin. The volume fiber content is 67% and the mass resin content is 25%. The modified pressure vessel 200 has the following specifications. Nominal operating pressure (NWP): 70 MPa Maximum filling pressure (MFP): 87.5 MPa Pressure test pressure (TP): 105 MPa Minimum burst pressure: 157.5 MPa Volume: 177 liters (±10%) Mass: 106kg (±5kg) Length: 1,754 mm Dimensions Outer dimensions of the pressure vessel 200: φ445 Thickness of GFRP: 1 mm Outer dimensions of the pressure vessel 200 up to CFRP: φ443 Thickness of CFRP: 27.5 mm Outer dimensions of the pressure vessel 200 up to the liner 210 (resin liner): φ388

[0120] Also in this modified example, the rupture pressure estimation was carried out for the liner 210 using the analysis by N.L. Svensson according to the above reference. In nylon 11 (polyamide resin) (abbreviation: PA11), as the n-th power hardening characteristic, the equation (3) that represents the relationship between the true stress σ and the true strain ε up to the vicinity of the tensile yield stress σ y was calculated by the n-th power hardening formula. σ = 667.9·ε 0.7455 (MPa) ··· (3)

[0121] Also in this modified example, for the above-mentioned FRP pressure vessel model, using the analysis by N.L. Svensson and the n-th power hardening formula of equation (3), the rupture pressure P * was calculated by equation (1), and the length, pressure test pressure, and minimum rupture pressure of the entire pressure vessel 200 were input into the design support system 1000. Also, for the specifications of the liner 210, in order to realize the volume of the pressure vessel 200, the outer diameter, inner diameter, and thickness of the liner body 211, the outer shape and thickness of the liner bottom 212, and the outer shape and thickness of the liner head 213 were designed separately in advance and input into the design support system 1000. [[ID=...]] [[ID=...]]

[0122] [[ID=...]] Using the design support system 1000 as well, the analysis results when resin (PA11) is used for the liner 210 are shown. Note that the volume, mass, diameter of the entire pressure vessel 200, and the thickness of CFRP are the specification values calculated by the design support system 1000. From these results, it can be seen that the design support system 1000 is also applicable to the pressure vessel 200 in which the liner 210 is formed of a resin material. Volume: 177 liters (±10%) versus 176.5 liters Mass: 106 kg (±5 kg) versus 109.4 kg Length: 1,754 mm (as per input value) External dimensions of pressure vessel 200: φ445, compared to φ445.6 GFRP wall thickness: 1.0 mm, as per the input value. External dimensions of pressure vessel 200 up to the CFRP: φ443, compared to φ443.6 CFRP wall thickness: 27.5mm vs. 27.75mm Outer dimensions of Liner 210 up to the body: φ388, compared to φ388.1 Furthermore, the above volume (176.5 liters) can be achieved when the inner diameter of the liner 210 up to the body is φ384.5 (wall thickness of the liner 210 body: 1.81 mm).

[0123] Furthermore, for the pressure vessel 200 using resin (PA11) for the liner 210, the stress compression ratio at the time of minimum burst pressure application was investigated. The CFRP configuration specifications for the pressure vessel 200 followed guideline A for the composition ratio of each orientation angle, as shown in Figure 18. Guideline A is approximately 30% for orientation angles of around 15 degrees, approximately 10% for orientation angles of around 25 degrees, approximately 5% for orientation angles of around 35 degrees, approximately 5% for orientation angles of around 55 degrees, approximately 10% for orientation angles of around 70 degrees, and approximately 40% for orientation angles of around 90 degrees. Note that an orientation angle of 90 degrees means that the carbon fibers were wound by hoop winding. As a result, the stress compression ratio at the time of minimum burst pressure application was axial: 49.8% and circumferential: 57.0%, which is kept below 60%, indicating that there is a margin of over 40% against stress at the time of fracture.

[0124] In the above embodiment, the control unit 11 functioned as the respective components shown in Figure 4 by the CPU executing a program stored in the ROM or storage unit 12. However, in this disclosure, the control unit 11 may be dedicated hardware. Dedicated hardware includes, for example, a single circuit, a composite circuit, a programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. If the control unit 11 is dedicated hardware, each function of the respective components may be implemented by separate hardware, or the functions of each component may be implemented together by a single piece of hardware. Furthermore, some of the functions of each component may be implemented by dedicated hardware, while other parts may be implemented by software or firmware. In this way, the control unit 11 can implement the above-mentioned functions by hardware, software, firmware, or a combination thereof.

[0125] It is also possible to make an existing personal computer or information terminal or other computer function as the information processing device 100 described herein by applying an operating program that defines the operation of the information processing device 100 described herein to the computer. Furthermore, the method of distribution of such a program is arbitrary; for example, it may be distributed by storing it on a computer-readable recording medium such as a CD-ROM (Compact Disk ROM), DVD (Digital Versatile Disk), MO (Magneto Optical Disk), or memory card, or it may be distributed via a communication network such as the Internet.

[0126] This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of this disclosure. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of this disclosure. In other words, the scope of this disclosure is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of the disclosure are considered to be within the scope of this disclosure. [Explanation of symbols]

[0127] 11 Control unit, 12 Storage unit, 13 Display unit, 14 Operation reception unit, 15 Communication unit, 100 Information processing unit, 101 Designation reception unit, 102 Liner design unit, 103 Reinforcement layer design unit, 104 Container information output unit, 105 Ratio calculation unit, 200 Pressure vessel, 201 Body, 202 Bottom, 203 Head, 204 Storage space, 205 Plug member, 206 Nozzle, 207 Opening, 210 Liner, 211 Liner body, 212 Liner bottom, 213 Liner head, 220 Reinforcement layer, 221 Fiber, 250 Valve assembly, 1000 Design support system

Claims

1. A design support system for designing a pressure vessel comprising a hollow liner for containing a gas or liquid and a reinforcing layer made of fiber-reinforced resin formed on the outer surface of the liner, A specification receiving means for receiving a specified set pressure, which is the pressure set for the pressure vessel, and a volume corresponding value, which is the volume set for the pressure vessel. Liner design means for designing the liner based on the volume correspondence value and outputting liner information including the inner diameter of the liner, the wall thickness of the liner, and the liner burst pressure which is the pressure at which the liner bursts, A reinforcing layer design means that designs the reinforcing layer based on the set pressure and the liner information, and outputs reinforcing layer information including the thickness of the reinforcing layer, The system includes a container information output means that outputs container information, including the dimensions and mass of the pressure vessel, based on the liner information and the reinforcing layer information. Design support system.

2. The aforementioned set pressure is the minimum burst pressure, which is the pressure specified in the test of the pressure vessel. The designated receiving means receives a designation of fiber-reinforced resin information indicating the composition of the materials contained in the fiber-reinforced resin and the configuration of the fiber orientation angle during the formation of the fiber-reinforced resin. The system includes a ratio calculation means for calculating a stress pressure ratio, which is the ratio of the stress generated in the fiber-reinforced resin when pressure is applied to the fiber-reinforced resin and the fiber-reinforced resin is destroyed, to the stress generated in the pressure vessel when the minimum burst pressure is applied to the pressure vessel, based on the fiber-reinforced resin information. The container information output means outputs the container information including the stress pressure ratio calculated by the ratio calculation means. The design support system according to claim 1.

3. The aforementioned designation acceptance means accepts the designation of the plate thickness, which is the thickness of the aluminum alloy plate used to form the liner. The liner design means designs the liner based on the set pressure, the volume correspondence value, and the plate thickness. The design support system according to claim 1 or 2.

4. The liner comprises a cylindrical liner body, a dome-shaped liner bottom provided at one end of the liner body, and a dome-shaped liner head provided at the other end of the liner body, having a nozzle. The aforementioned designation receiving means accepts the designation of the length of the pressure vessel and the inner diameter of the liner as the volume corresponding values, The liner design means calculates the thickness of the bottom of the liner based on the plate thickness, calculates the thickness of the liner body based on the thickness of the bottom of the liner, calculates the liner burst pressure based on the inner diameter of the liner and the thickness of the liner body, and calculates the thickness of the liner head based on the set pressure, the liner burst pressure and the thickness of the bottom of the liner. The design support system according to claim 3.

5. The reinforcing layer design means calculates the thickness of the reinforcing layer based on the inner diameter of the liner, the thickness of the liner body, the outer diameter of the liner body, the set pressure, and the liner burst pressure. The design support system according to claim 4.

6. A design support method for designing a pressure vessel comprising a hollow liner for containing a gas or liquid and a reinforcing layer made of fiber-reinforced resin formed on the outer surface of the liner, The system accepts the specification of a set pressure, which is the pressure set for the pressure vessel, and a volume-corresponding value, which is the volume set for the pressure vessel. Based on the volume correspondence value, the liner is designed, and liner information is output including the inner diameter of the liner, the wall thickness of the liner, and the liner burst pressure, which is the pressure at which the liner bursts. Based on the set pressure and the liner information, the reinforcing layer is designed, and reinforcing layer information including the thickness of the reinforcing layer is output. Based on the liner information and the reinforcing layer information, container information including the dimensions of the pressure vessel and the mass of the pressure vessel is output. Design support method.

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