Design method for observation window of full-sea-depth manned submersible

Abstract

The invention relates to a design method for an observation window of a full-sea-depth manned submersible. The method comprises the following steps: carrying out size calculation according to a first observation window parameter and a preset observation window size formula to obtain an observation window target size; carrying out stress calculation according to the first observation window parameter, the observation window target size, the second observation window parameter and a preset stress formula, obtaining the theoretical stress of the observation window, and checking the design of the observation window target size; and performing numerical calculation according to the numerical calculation model, the third observation window parameters and a preset calculation scheme to obtain stress and displacement numerical calculation results of the observation window, and checking the observation window. The observation window checked by the application generally can pass the hydrostatic external pressure test, but in order to ensure the safety of the observation window, the hydrostatic external pressure test is suggested to be carried out to check that the displacement of the observation window does not exceed an allowable value and check that the observation window does not have stress damage. By adopting the method, the problem of accurate design of the core component of the full-sea-depth manned submersible is solved.

Description

Technical Field

[0001] The present application relates to the technical field of deep-sea manned submersibles, and in particular to a method for designing an observation window for a full-sea-depth manned submersible. Background Art

[0002] The hadal region refers to the area in the ocean with a depth greater than 6,000 meters. It is one of the most mysterious and extreme environments on Earth. Due to the extremely high pressure, active tectonic activities, frequent earthquakes and extremely unique ecosystem in this area, it has attracted great attention from scientists. In order to conduct in-depth research on the hadal environment, manned submersibles have become an important tool for scientific exploration, especially full-sea-depth manned submersibles, which can overcome huge water pressure and carry professionals to the abyss for direct observation and exploration. One of the core components of a manned submersible is the observation window, which plays a vital role in extreme deep-sea environments.

[0003] In the related technology, the design of the observation window mostly follows the ASME PVHO standard and is made of organic glass. The standard is divided into grades according to the design pressure and design temperature, and provides a method for selecting the size of the observation window under different grades. For example, the ASME PVHO standard recommends that when the design pressure exceeds 69MPa, frustum-shaped organic glass is used, and its basic dimensions such as thickness, large end diameter, small end diameter, etc. are calculated according to different combinations of pressure and temperature.

[0004] However, according to the ASME PVHO standard, the mechanical properties of the plexiglass material used in the design of the observation window are only required to be no less than the minimum value specified by the index. In fact, the mechanical properties of plexiglass materials from different sources, different thicknesses and different temperatures vary significantly. The mechanical properties of materials are necessary inputs for analyzing and judging structural designs. Therefore, the method of only limiting the minimum value of material properties will result in the observation window structure not being optimized. At the same time, the design is divided into pressure and temperature grades. If the design pressure or temperature changes slightly, which causes the design to cross into the adjacent grades, the design result will change dramatically, which will lose the rationality of the design and will also lead to the observation window structure not being optimized. At the same time, the ASME PVHO standard only provides four grades of 60°, 90°, 120°, and 150°. For other angles, such as 75° and 105°, the standard does not provide a method for determining the basic size of the observation window.

[0005] Using the ASME PVHO standard to design observation windows is a relatively simple method in engineering, but it is also impossible to perform post-design verification. The fundamental reason is that the design ideas of grading values ​​and experimental regression cannot establish a one-to-one mapping relationship between design parameters and design results. Summary of the invention

[0006] Based on this, it is necessary to provide a design method for a full-sea-depth manned submersible observation window in response to the above-mentioned technical problems, which has a relatively optimized design result and can be manufactured using a variety of glass materials (including plexiglass).

[0007] The present application provides a method for designing an observation window for a full-sea-depth manned submersible. The method comprises: Calculate the size of the observation window according to the first observation window parameter and the preset observation window size formula to obtain the target size of the observation window; Perform stress calculation according to the first observation window parameter, the observation window target size, the second observation window parameter and a preset stress formula to obtain the observation window theoretical stress; Numerical calculations are performed according to the numerical calculation model, the parameters of the third observation window and the preset calculation scheme to obtain numerical calculation results of the observation window stress and displacement, and the observation window is calibrated.

[0008] In one embodiment, performing size calculation according to the first observation window parameter and a preset observation window size formula to obtain the observation window target size includes: Determine the target small end diameter based on the light transmission diameter, the included angle, the maximum design pressure of the large end face and the preset small end formula; Determine the target observation window thickness based on the target small end diameter, the maximum design pressure of the large end face and a preset thickness formula; Determine the target large end diameter based on the target small end diameter, the target observation window thickness, the included angle and a preset large end formula; Set the target small end diameter, target viewing window thickness, and target large end diameter as the viewing window target size.

[0009] In one embodiment, force calculation is performed according to the first observation window parameter, the observation window target size, the second observation window parameter and a preset stress formula to obtain the observation window theoretical stress, including: Stress calculation is performed based on the included angle, the maximum design pressure of the large end face, the target size of the observation window, the parameters of the second observation window and the axial stress formula to obtain the axial stress at each location of the observation window along the thickness and radius directions; Stress calculation is performed according to the included angle, the parameters of the second observation window and the radial stress formula to obtain the radial stress at various locations along the radial direction of a certain axial section of the observation window; According to the calculated axial stress and radial stress, the compressive yield strength or tensile strength in the third observation window parameter is compared to perform a theoretical stress check on the observation window.

[0010] In one embodiment, stress calculation is performed based on the angle in the first observation window parameters and the maximum design pressure of the large end face, the target size of the observation window, the second observation window parameters and the axial stress formula to obtain the axial stress at each location of the observation window along the thickness and radius directions, including: Determine the axial deformation increment of the observation window at each location along the axial direction based on the target observation window thickness; Determine the first approximate radial strain at each location along the axial direction based on the axial deformation increment; determining an axial stress increment based on a first approximate radial strain, Poisson's ratio, and a compressive elastic modulus; Stress calculation is performed based on the target large end diameter, target small end diameter, included angle, maximum design pressure on the large end face, and axial stress formula to obtain the axial stress at each location of the observation window along the thickness and radius directions; In one embodiment, stress calculation is performed according to the included angle, the second observation window parameters and the radial stress formula to obtain radial stress at various locations along the radial direction of a certain axial section of the observation window, including: Based on the preset deformation formula, determine the axial deformation of a certain axial section at various radial locations; Determine the second approximate radial strain of a certain axial section at various radial locations based on the axial deformation and the included angle; Based on the second approximate radial strain, Poisson's ratio and compressive elastic modulus, the radial stress increment of a certain axial section at various radial locations is determined; Stress calculation is performed based on radial stress increment, angle, friction coefficient of the observation window and window seat support cone surface and radial stress formula to obtain radial stress at various locations along the radial direction of a certain axial section of the observation window; In one embodiment, numerical calculation is performed according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation results of the observation window stress and displacement, and the observation window is checked, including: A numerical calculation model is established based on the target size of the observation window, the parameters of the third observation window and the material parameters of the window seat; Based on the numerical calculation model, meshing, contact boundary setting, and load constraints are applied; Perform numerical calculations according to the numerical calculation model, the grid division, the contact boundary setting, and the load constraint application to obtain numerical calculation results of the observation window stress and displacement; According to the numerical calculation results, the observation window is displaced and the displacement value should not exceed 2 / 3 of the reserved displacement threshold; Based on the compressive yield strength or tensile strength in the third observation window parameter, the observation window is numerically calculated for stress verification. The stress in the main part of the observation window should not exceed its material strength, and the stress in the stress concentration part should not exceed 1.25 times of its material strength.

[0011] In one embodiment, meshing, contact boundary setting, and load constraint application are performed based on the numerical calculation model, including: Set the window as the target unit and the observation window as the contact unit; Set up contact pairs on the contact boundaries between the target unit and the contact unit; The friction coefficient between the target element and the contact element is determined experimentally.

[0012] In one embodiment, after performing numerical calculation according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation result, the method further includes: The observation window is tested according to the test plan. If the test displacement is not greater than the reserved displacement threshold, and there is no internal or external stress damage to the observation window after the test, the final design of the observation window is completed. Otherwise, the target size of the observation window needs to be readjusted until the theoretical stress calculation, numerical calculation and test are all passed simultaneously.

[0013] In one embodiment, before calculating the size of the observation window according to the first observation window parameter and the preset observation window size formula to obtain the target size of the observation window, the method further includes: The performance test of the observation window material is performed according to the preset specimen parameters and the preset performance test scheme to obtain the third observation window parameters.

[0014] In one embodiment, a performance test is performed on the observation window material according to preset specimen parameters and a preset performance test scheme to obtain a third observation window parameter, including: Test specimens of the observation window material are manufactured according to preset test specimen parameters to obtain multiple groups of test specimens; According to the performance test plan, performance tests are performed on multiple groups of test pieces to obtain the parameters of the third observation window.

[0015] In one embodiment, a performance test is performed on each group of test pieces according to a performance test scheme to obtain the third observation window parameters, including: Perform a tensile test on each group of tensile test pieces according to a preset tensile test plan to obtain tensile performance test results; A compression test is performed on each group of compression specimens according to a preset compression test scheme to obtain compression performance test results.

[0016] The above-mentioned full-sea-depth manned submersible observation window design method obtains the target size of the observation window through a preset size design formula, and then calculates the theoretical stress of the observation window in combination with the second observation window parameters and the preset stress formula, and compares the tensile strength or compressive yield strength obtained in advance to complete the theoretical stress verification of the observation window design; numerical calculations are performed in combination with the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation results of the observation window stress and displacement, and the numerical calculation verification of the observation window design is completed by comparing the allowable value of the displacement and the tensile strength or compressive yield strength obtained in advance; the observation window designed as above can generally pass the hydrostatic external pressure test, but in order to ensure the safety of the observation window, it is still recommended to carry out a hydrostatic external pressure test to verify that the displacement of the observation window does not exceed the allowable value and that the observation window does not suffer stress damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an observation window in the related art; Figure 2 The following is a table for selecting size ratio coefficients of observation windows in related technologies.

[0018] Figure 3 A schematic diagram of a flow chart of a method for designing an observation window for a full-sea-depth manned submersible in one embodiment; Figure 4 A schematic diagram of the dimensions of a tensile test piece in one embodiment; Figure 5 A schematic diagram of the dimensions of a compression test piece in one embodiment; Figure 6 is a schematic diagram of the structure of an observation window in an embodiment; Figure 7 A schematic diagram of the target size of the observation window, the stress calculation coordinate system, and the force in one embodiment; Figure 8 is a certain axial cross section (ordinate is z ) r =150mm, large end face pressure p Comparison curve of theoretical radial stress and experimentally measured radial stress from 0MPa to 115MPa; Fig. 9 In one embodiment, the center of the small end ( r=0,Z=h ), large end face pressure p From 0MPa to 115MPa, the numerically calculated displacement of the embodiment of the present invention (the figure is the compression constitutive simulation), the experimental measured displacement, and the numerically calculated displacement obtained by using the minimum index of the organic glass material specified in the ASME PVHO standard (the figure is the standard index simulation) are compared; Fig.10 In one embodiment, the center of the small end (r=0 ), large end sea water pressure p =30MPa, axial position ( Z From 0 to h ), comparison curve of axial stress calculated by existing theory (traditional theoretical calculation in the figure), axial stress calculated by the present invention (calculated by deformation correction formula), and axial stress calculated by numerical value of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] The applicant noted that the current design of submersible observation window glass mainly refers to the "Safety Standard for Pressure Vessels for Human Occupancy" (hereinafter referred to as ASME PVHO standard) formulated by the American Society of Mechanical Engineers. According to the provisions of the ASME PVHO standard, the design of the observation window glass is limited to 69MPa. When the design pressure exceeds 69MPa, the ASME PVHO standard recommends the use of a cone-shaped organic glass observation window, the structure of which is as follows: Figure 1 As shown, and a size ratio coefficient selection table is provided as follows Figure 2 As shown, it is used to calculate the basic dimensions of the observation window glass.

[0021] The above-mentioned ASME PVHO standard design is summarized as a method of selecting values ​​according to the design pressure and design temperature and performing experimental regression. The design results are relatively simple and rough. In the actual design using this standard, there are several major problems, such as a wide range of material properties, large differences in cross-grade design, and lack of design analysis and verification. The following are specific explanations: 1) Wide range of material properties According to the provisions of the ASME PVHO standard, the design of the observation window only requires that the mechanical properties of the material should not be lower than the minimum value specified by the index, but in fact, the mechanical properties of organic glass materials from different sources, different thicknesses and different temperatures are very different. According to relevant domestic literature, at 40°C, the tensile strength of domestic thick plate organic glass is 67.3% higher than that of thin plate (65.47MPa→39.14MPa), while the tensile strength of the same domestic thick plate organic glass at 40°C is 35.6% lower than that at 0°C (65.47MPa→101.64MPa). At the same time, the elastic modulus of organic glass materials under different conditions also has significant differences, and the elastic modulus and strength of the material are necessary inputs for analyzing and verifying the design of the observation window. Therefore, the method of only limiting the minimum value of material performance results in the failure to optimize the size design of the observation window.

[0022] 2) Large differences across grades Assuming that the light transmission diameter of a frustum-shaped observation window is 200 mm, the design temperature is ≤24°C, and the design cone angle is 150°, when its design pressure is 103.4 MPa, the minimum thickness of the observation window designed according to the ASME PVHO standard is 507 mm. When the design pressure increases by 0.1 MPa, the design thickness will increase by 286.6 mm, and the increase will reach 56.5%. The difference in design results brought about by the tiered values ​​obviously deviates from the reasonable range.

[0023] The results brought about by the design temperature classification are also quite different. Taking the full-sea-depth conical observation window as an example, if its design temperature is adjusted from ≤10°C to ≤24°C, the minimum thickness of the observation window will increase by 15.1mm. The design temperature of the observation window refers to the ambient temperature when the submersible reaches the design depth. Obviously, for the conical observation window for full-sea-depth submersibles, its design temperature should be within a relatively stable range. In addition, since the ASME PVHO standard design cone angle is divided into four levels of 60° / 90° / 120° / 150°, there is no applicable design guidance in the standard for some specific angles such as 75° or 105°.

[0024] 3) Analysis and verification of missing Using the ASME PVHO standard to design an observation window is a relatively simple method in engineering, but it is impossible to perform post-design verification. The fundamental reason is that the design ideas of grading values ​​and experimental regression cannot establish a one-to-one mapping relationship between design parameters and design results.

[0025] In one embodiment, Figure 3 As shown, the present application provides a method for designing an observation window for a full-sea-depth manned submersible. In this embodiment, the method includes the following steps: Step 302: Calculate the size of the observation window according to the first observation window parameter and a preset observation window size formula to obtain a target size of the observation window.

[0026] Specifically, by presetting the first observation window parameters, the first observation window parameters include the light transmission diameter, the angle, and the maximum design pressure of the large end face, the angle is the angle between the supporting cone and the central axis, and the maximum design pressure of the large end face is the maximum seawater pressure that the large end face bears and a certain safety factor. Then, the first observation window parameters are input into the pre-set observation window size formula to calculate and obtain the target size of the observation window.

[0027] Step 304 , performing force calculation according to the first observation window parameter, the observation window target size, the second observation window parameter and a preset stress formula to obtain the observation window theoretical stress.

[0028] Specifically, the second observation window parameters are obtained, and the second observation window parameters include a compressive elastic modulus, a Poisson's ratio, and a friction coefficient between the observation window and the window seat.

[0029] After the target size of the observation window is calculated, the axial stress and radial stress are calculated in combination with the preset stress formula (i.e., the axial stress formula and the radial stress formula), and then the stress of the observation window is theoretically calculated, and the calculated stress is used to check the strength of the observation window.

[0030] Step 306, performing numerical calculation according to the numerical calculation model, the third observation window parameters and the preset calculation scheme, obtaining numerical calculation results of the observation window stress and displacement, and checking the observation window.

[0031] Specifically, the third observation window parameters are obtained by testing in advance. The third observation window parameters include tensile strength, elongation at break, tensile elastic modulus, tensile load-deformation curve, compressive yield strength and compressive load-deformation curve in addition to the compressive elastic modulus and Poisson's ratio in the second observation window parameters. After determining the target size of the submersible observation window, a numerical calculation model including the window seat and the observation window is established. For example, a two-dimensional axisymmetric model can be used, and the model needs to take into account that if the deformation of the observation window is limited under pressure, the model should also include a limiting boundary.

[0032] The parameters of the third observation window are input into the numerical calculation model, and meshing, contact boundary setting and load constraint application are performed to obtain the numerical calculation results. Among them, in the contact boundary setting, the observation window is defined as a contact unit, the window seat is defined as a target unit, and a contact pair is set on the contact boundary of the two. The numerical calculation results include the stress and displacement of the observation window, where the displacement value should not exceed 2 / 3 of the reserved displacement threshold, the numerical calculation stress of the main part of the observation window should not exceed the compressive yield strength (when the observation window is only under pressure) or tensile strength (when the observation window is under tension) in the third observation window parameters, and the emergency concentrated part should not exceed 1.25 times the compressive yield strength (when the observation window is only under pressure) or tensile strength (when the observation window is under tension) in the third observation window parameters; in this way, the design of the target size of the observation window is verified.

[0033] The above-mentioned full-sea-depth manned submersible observation window design method obtains the target size of the observation window through a preset size design formula, and then calculates the theoretical stress of the observation window in combination with the second observation window parameters and the preset stress formula, and compares the tensile strength or compressive yield strength obtained in advance to complete the theoretical stress verification of the observation window design; numerical calculations are performed in combination with the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation results of the observation window stress and displacement, and the numerical calculation verification of the observation window design is completed by comparing the allowable value of the displacement and the tensile strength or compressive yield strength obtained in advance; the observation window designed as above can generally pass the hydrostatic external pressure test, but in order to ensure the safety of the observation window, it is still recommended to carry out a hydrostatic external pressure test to verify that the displacement of the observation window does not exceed the allowable value and that the observation window does not suffer stress damage.

[0034] In one embodiment, before calculating the size of the observation window according to the first observation window parameter and the preset observation window size formula to obtain the target size of the observation window, the method further includes: The performance test of the observation window material is performed according to the preset specimen parameters and the preset performance test scheme to obtain the third observation window parameters.

[0035] Among them, the preset specimen parameters include specimen size parameters for making tensile tests and dimensions for making compression specimens, and the preset performance test schemes include tensile test schemes and compression test schemes.

[0036] Specifically, multiple groups of test specimens for obtaining the parameters of the third observation window are made from a blank made using the same manufacturing process as the observation window. After determining the size parameters of the tensile specimen and the size parameters of the compression specimen, the blank is processed to obtain multiple groups of tensile specimens and multiple groups of compression specimens.

[0037] Then, each group of tensile test pieces and each group of compression test pieces are tested according to the tensile test scheme and the compression test scheme respectively to obtain the third observation window parameters.

[0038] In one embodiment, a performance test is performed on the observation window material according to preset specimen parameters and a preset performance test scheme to obtain a third observation window parameter, including: Test specimens of the observation window material are manufactured according to preset test specimen parameters to obtain multiple groups of test specimens; performance tests are performed on the multiple groups of test specimens according to a performance test plan to obtain third observation window parameters.

[0039] Specifically, the test piece is prepared from a blank prepared by the same process as that of the observation window. If the thickness of the blank is less than 150 mm, the sample is taken from the middle of the blank; otherwise, samples are taken from the surface and the middle of the blank respectively.

[0040] The sampled blanks are manufactured according to the size parameters of the specimens and the manufacturing plan, thereby obtaining multiple groups of specimens for testing material properties. Each group of specimens is then tested accordingly based on the performance test plan.

[0041] For example, the test specimens include tension test specimens and compression test specimens.

[0042] See also Figure 4 , Figure 4 The relevant manufacturing parameters of the tensile test piece are shown, based on which the blank is processed, specifically: During the specimen processing, the starting processing position should avoid the arc segment or the 50mm long gauge segment to avoid local defects caused by the tool staying too long; after processing, the specimen needs to be ground and polished to ensure a smooth surface without visible cracks, scratches or other defects; in addition, before conducting a tensile test, the specimen should be heat treated to eliminate residual stress.

[0043] See also Figure 5 , Figure 5 The relevant manufacturing parameters of the compression specimen are shown, based on which the blank is processed, specifically: The processed specimens need to be ground and polished to ensure a smooth surface without visible cracks, scratches or other defects, and at the same time ensure that the two end faces are flat and the edges are clear and sharp; before the compression test, the specimens should also be heat treated to effectively eliminate residual stress, thereby ensuring the stability and reliability of the specimens during the test and avoiding unnecessary deformation or damage caused by stress.

[0044] In one embodiment, a performance test is performed on each group of test pieces according to a performance test scheme to obtain the third observation window parameters, including: A tensile test is performed on each group of tensile specimens according to a preset tensile test scheme to obtain tensile performance test results; a compression test is performed on each group of compression specimens according to a preset compression test scheme to obtain compression performance test results; the tensile performance test results and the compression performance test constitute the third observation window parameters.

[0045] Among them, the multiple groups of specimens include multiple groups of tensile specimens and multiple groups of compression specimens, and the preset performance test schemes include preset tensile test schemes and preset compression test schemes.

[0046] For example, after the tensile specimen is made and before the tensile test, coarse sandpaper is pasted on both ends of the specimen to prevent breakage or slipping during the test. The specimen needs to be placed under standard environmental conditions (23℃±2℃, humidity 50%±5%) for more than 24 hours; the width and height at 20mm in the middle and on both sides of the gauge section are measured to calculate the cross-sectional area; when the specimen is clamped, the fixture design must ensure that there is no eccentricity during loading, and the clamping area is not less than 2 / 3 of the area of ​​the large end; stretching is performed at a loading rate of 5mm / min, and the strain is measured at a constant interval until the specimen breaks.

[0047] Before the compression test, place the specimen under standard environmental conditions (23℃±2℃, humidity 50%±5%) for more than 24 hours, measure the width and height of the specimen at different positions, and calculate the minimum cross-sectional area; place the specimen in the middle of the testing machine platen, ensure that the center line of the specimen coincides with the center of the platen, and the end faces are parallel; compress at a loading rate of 1.3mm / min, and measure the strain at constant time intervals during loading until the specimen yields.

[0048] In one embodiment, the size calculation is performed according to the first observation window parameter and a preset observation window size formula to obtain the observation window target size, including: Determine the target small end diameter based on the light transmission diameter, the included angle, the maximum design pressure of the large end face and the preset small end formula; determine the target observation window thickness based on the target small end diameter, the maximum design pressure of the large end face and the preset thickness formula; determine the target large end diameter based on the target small end diameter, the target observation window thickness, the included angle and the preset large end formula; set the target small end diameter, the target observation window thickness and the target large end diameter as the target size of the observation window.

[0049] The parameters of the first observation window include the light transmission diameter, the included angle and the maximum design pressure of the large end face.

[0050] Specifically, after determining the light transmission diameter of the observation window, the angle between the supporting cone and the central axis, and the maximum design pressure that the large end face can withstand, the size of the observation window is calculated. The size of the observation window includes the small end diameter, the observation window thickness, and the large end diameter.

[0051] The small end diameter is positively correlated with the maximum design pressure borne by the large end face, the angle between the supporting cone and the central axis, and the light transmission diameter. The formula for calculating the small end diameter is:

[0052] in, The maximum design pressure that the large end face can bear. is the angle between the supporting cone and the central axis, is the light transmission diameter.

[0053] The thickness of the observation window is positively correlated with the maximum design pressure of the large end surface and the diameter of the small end. The formula for calculating the thickness of the observation window is:

[0054] in, Small end diameter.

[0055] The large end diameter can be obtained by geometric calculation. The formula for calculating the large end diameter is:

[0056] in, is the observation window thickness, The large end diameter.

[0057] Based on the above formula, the target size of the observation window is calculated and determined. The sizes are shown as follows: Figure 7 As shown, and the structure of the observation window is as follows Figure 6 shown.

[0058] In one embodiment, force calculation is performed according to the angle in the first observation window parameters and the maximum design pressure of the large end face, the target size of the observation window, the second observation window parameters and the preset stress formula to obtain the theoretical stress of the observation window, including: The stress calculation is performed based on the angle in the first observation window parameters, the maximum design pressure of the large end face, the target size of the observation window, the parameters of the second observation window, and the axial stress formula to obtain the thickness of the observation window (i.e. Figure 7 Z direction) and radial direction (i.e. Figure 7 R direction) everywhere ( 0 - h,0-R ) axial stress; stress calculation is performed based on the angle in the first observation window parameters, the second observation window parameters and the radial stress formula to obtain a certain axial section of the observation window ( z ) along the radial direction ( r Department, Range 0-R ) of the radial stress; after the axial theoretical stress and the radial theoretical stress are calculated, the theoretical stress of the observation window is checked and judged according to the tensile strength or compressive yield strength in the third observation window parameters.

[0059] In one embodiment, stress calculation is performed based on the angle in the first observation window parameters and the maximum design pressure of the large end face, the target size of the observation window, the second observation window parameters and the axial stress formula to obtain the thickness of the observation window (i.e. Figure 7 Z direction) and radial direction (i.e. Figure 7 Axial stress at various locations (in the R direction), including: Based on the thickness of the observation window, determine the axial direction of the observation window. z Department ( z The range is 0 - h ) is the axial deformation increment, specifically:

[0060] in, is the axial distance from the large end face, is the observation window thickness;

[0061] Determine the axial direction based on the axial deformation increment z The first approximate radial strain at z It is negatively correlated with the diameter at the point and positively correlated with the axial deformation increment, specifically:

[0062] in, for z The cross-sectional diameter at can be obtained by geometric calculation, specifically: .

[0063] The axial stress increment is determined based on the first approximate radial strain, Poisson's ratio and compressive elastic modulus; the first approximate radial strain and compressive elastic modulus are positively correlated with the axial stress increment, specifically:

[0064] in, is the Poisson's ratio of the observation window material, E is the compression elastic modulus of the observation window material.

[0065] After calculating the axial stress increment, combined with z Diameter , Maximum design pressure of the large end surface p , Large end diameter and small end diameter , calculate and determine the radius r The specific calculation formula for the axial theoretical stress at is:

[0066] The first observation window parameters include the light transmission diameter, the included angle and the maximum design pressure of the large end face, and the second observation window parameters include the compressive elastic modulus, the Poisson's ratio and the friction coefficient between the observation window and the window seat.

[0067] In one embodiment, stress calculation is performed based on the angle in the first observation window parameter, the second observation window parameter and the radial stress formula to obtain a certain axial section of the observation window ( z ) along the radial direction ( r Department, Range 0-R ) of radial stress, including: Determine the axis z The cross section is in radial direction r Axial deformation at , the specific formula is:

[0068] In the formula, .

[0069] Determine the axial direction based on the axial deformation and the angle z The cross section is in radial direction r The second approximate radial strain at , axial deformation, radial coordinate r、 The angle between the support cone and the central axis is positively correlated with the second approximate radial strain. z The specific calculation formula is:

[0070] Determine the axial strain based on the second approximate radial strain, Poisson's ratio and compressive elastic modulus z The cross section is in radial direction r The radial stress increment at ; the second approximate radial strain and compressive elastic modulus are positively correlated with the radial stress increment, and the specific calculation formula is:

[0071] in, is the Poisson's ratio of the observation window material, E is the compression elastic modulus of the observation window material.

[0072] After the radial stress increment is calculated, the friction coefficient between the window seat and the observation window support cone, the angle between the support cone and the central axis, the axial theoretical stress and the radial stress increment are combined to determine the axial section of the observation window ( z ) along the radial direction ( r Department, Range 0-R ), the specific calculation formula is:

[0073] in, is the friction coefficient between the window seat and the observation window bearing cone, It is the angle between the supporting cone and the central axis.

[0074] In one embodiment, numerical calculation is performed according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation results of the observation window stress and displacement, and the observation window is checked, including: A numerical calculation model is established based on the target size of the observation window, the third observation window parameters and the window seat material parameters; based on the numerical calculation model, mesh division, contact boundary setting and load constraints are applied; numerical calculation is performed according to the numerical calculation model, the mesh division, contact boundary setting and load constraint application to obtain numerical calculation results of stress and displacement of the observation window; based on the numerical calculation results, the observation window is displaced and checked, and the displacement value should not exceed 2 / 3 of the reserved displacement threshold; based on the compressive yield strength in the third observation window parameters, the observation window is numerically calculated and stressed, and the stress of the main part of the observation window should not exceed its compressive yield strength, and the stress of the stress concentration part should not exceed 1.25 times of its compressive yield strength.

[0075] Exemplarily, the numerical calculation model of the observation window can adopt a two-dimensional axisymmetric model, and if the observation window has deformation restrictions under pressure, the calculation model should include corresponding restriction boundaries; the third observation window parameters are usually input into the numerical calculation model using a multilinear kinematic hardening (MKIN) or multilinear isotropic hardening (MISO) model.

[0076] In addition, when applying the restraining load, the maximum working pressure should be applied to the outside of the window seat and the large end face of the observation window; if there is a preload between the window seat and the observation window, the preload load should also be set in the relevant area.

[0077] After completing the above settings, the model is used for numerical calculation to obtain the numerical calculation results of the model, and the numerical calculation stress in the numerical calculation results is compared and analyzed with the compressive yield strength. Among them, due to the structural design of the observation window and the window seat in this embodiment, the observation window only bears pressure, and the compressive yield strength is used to judge the stress. The stress of the main part of the observation window should not exceed the compressive yield strength, and the ratio of the stress of the stress concentration part to the compressive yield strength shall not exceed 1.25.

[0078] In one embodiment, based on the numerical calculation model, meshing, contact boundary setting, and load constraint application are performed, including: Set the window as the target unit and the observation window as the contact unit; Set up contact pairs on the contact boundaries between the target unit and the contact unit; The friction coefficient between the target element and the contact element is determined experimentally.

[0079] In one embodiment, after performing numerical calculation according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation results, the method further includes: The observation window is tested according to a test plan to obtain test results; wherein the test plan includes a hydrostatic external pressure test.

[0080] In one embodiment, testing the observation window according to the test plan to obtain test results includes: According to the observation window design plan, prepare and install accessories to obtain a test observation window; perform a hydrostatic external pressure test on the test observation window to obtain a hydrostatic external pressure test result.

[0081] Specifically, before conducting the test, strain gauges need to be pasted on relevant positions on the inner and outer surfaces of the observation window, and displacement sensors need to be installed where the displacement needs to be measured; then, lubricant is evenly sprayed on the supporting surface of the window seat, and the observation window is installed in place on the window seat. During this process, the fasteners need to be tightened according to the specified torque, and an anti-collision frame is set on the outside of the observation window.

[0082] The installed observation window assembly is then subjected to a hydrostatic external pressure test. The test water temperature is controlled within the design water temperature, the maximum test pressure should be the maximum design pressure, the maximum design pressure takes into account the margin coefficient based on the maximum seawater pressure, and ensures that the pressure increase and decrease rate and the pressure holding time simulate the actual service conditions of the observation window as much as possible; wherein, the pressure holding time at the maximum test pressure is not less than 15 minutes. In one embodiment, when the maximum seawater pressure does not exceed 60MPa, the margin coefficient is not less than 1.25, and when the maximum seawater pressure exceeds 60MPa, the margin coefficient is not less than 1.1.

[0083] During the hydrostatic external pressure test, the displacement-pressure and strain-pressure curves need to be recorded synchronously, and the time and temperature information should be annotated. r =150mm, the test pressure increases from 0MPa to 115MPa, and the comparison curve between the theoretical radial stress and the radial stress measured by the test is as follows Figure 8 shown.

[0084] In one embodiment, after performing a hydrostatic external pressure test on the observation window and obtaining the hydrostatic external pressure test result, the method further includes: Inspect the observation window after the test and obtain the observation window inspection result.

[0085] Specifically, if the test displacement is not greater than the reserved displacement threshold, and if the observation window has no internal or external stress damage such as cracks or silver streaks after the test, the final design of the observation window is completed; Otherwise, the target size of the observation window needs to be readjusted until the theoretical stress calculation, numerical calculation and test are all passed simultaneously.

[0086] For example, remove the observation window from the window seat, place it on a dark blue background cloth, and carefully check the end face, cone surface and interior of the observation window from different angles with appropriate lighting to see if there are surface scratches, silver streaks or cracks. If there are none, it is judged that the stress verification test has passed.

[0087] In one embodiment, the center of the small end of the observation window ( r=0,Z=h ), the test pressure increases from 0MPa to 115MPa, and the comparison curves of numerically calculated displacement (compression constitutive simulation in the figure), experimental measured displacement, and numerically calculated displacement obtained by using the minimum index of organic glass material specified in the ASME PVHO standard (standard index simulation in the figure) are shown as follows Fig. 9 shown.

[0088] In one embodiment, the center of the small end of the observation window ( r=0 ), large end sea water pressure p =30MPa, axial position ( z From 0 to h ), the axial stress calculated by the existing theory (the traditional theoretical calculation in the figure), the axial stress calculated by the embodiment of the present invention (the deformation correction formula calculation), and the axial stress numerically calculated by the embodiment of the present invention are compared, as shown in FIG. Fig.10 shown.

[0089] In an exemplary embodiment, a method for designing an observation window of a full-sea-depth manned submersible is provided, the method comprising the following steps: Test specimens of the observation window material are manufactured according to preset test specimen parameters to obtain multiple groups of test specimens.

[0090] A tensile test is performed on each group of tensile specimens according to a preset tensile test scheme to obtain tensile performance test results.

[0091] A compression test is performed on each group of compression specimens according to a preset compression test scheme to obtain compression performance test results.

[0092] The compressive elastic modulus, Poisson's ratio, tensile strength, elongation at break, tensile elastic modulus, tensile load-deformation curve, compressive yield strength and compressive load-deformation curve are determined based on the tensile property test results and the compressive property test results.

[0093] The target small end diameter is determined based on the light transmission diameter, the included angle, the maximum design pressure of the large end face and the preset small end formula.

[0094] The target observation window thickness is determined based on the target small end diameter, the maximum design pressure of the large end face and a preset thickness formula.

[0095] The target big end diameter is determined based on the target small end diameter, the target observation window thickness, the included angle and a preset big end formula.

[0096] Set the target small end diameter, target viewing window thickness, and target large end diameter as the viewing window target size.

[0097] The axial deformation increment of the observation window at each location along the axial direction is determined based on the target observation window thickness.

[0098] The first approximate radial strain at each location along the axial direction is determined based on the axial deformation increment.

[0099] The axial stress increment is determined based on the first approximation radial strain, Poisson's ratio, and compressive elastic modulus.

[0100] Stress calculation is performed based on the target large end diameter, target small end diameter, included angle, maximum design pressure on the large end face, and axial stress formula to obtain the axial stress at various locations along the thickness and radius directions of the observation window.

[0101] Based on the preset formula, the axial deformation of a certain axial section at various radial locations is determined.

[0102] The second approximate radial strain of a certain axial section at various radial locations is determined based on the axial deformation and the included angle.

[0103] The radial stress increment of a certain axial section at various radial locations is determined based on the second approximate radial strain, Poisson's ratio and compressive elastic modulus.

[0104] Stress calculation is performed based on radial stress increment, angle, friction coefficient of the observation window and window seat supporting cone surface and radial stress formula to obtain radial stress at various locations along the radial direction of a certain axial section of the observation window.

[0105] According to the calculated axial stress and radial stress, the tensile strength and compressive yield strength are compared to perform stress check on the observation window.

[0106] A numerical calculation model was established based on the target size of the observation window, the compression elastic modulus, Poisson's ratio, compression load-deformation curve and material parameters of the window seat.

[0107] The numerical calculation model is meshed, and the mesh on the contact boundary between the window seat and the observation window is locally refined. The refined area is not less than the normal 2-layer mesh of the contact boundary.

[0108] Set the window as the target element and the viewer window as the contact element.

[0109] Set up contact pairs on the contact boundaries between the target element and the contact element.

[0110] The friction coefficient between the target element and the contact element is determined experimentally.

[0111] Apply the maximum working pressure to the outside of the window seat and the large end face of the observation window. The load application should include the position in contact with the sealing ring; if there is installation preload, the corresponding preload should be applied to the corresponding area of ​​the window seat and the observation window.

[0112] Based on the numerical calculation model and the above settings, numerical calculations are performed to obtain the numerical calculation results of the stress and displacement of the observation window.

[0113] According to the numerical calculation results, the displacement of the observation window is checked, and the displacement value should not exceed 2 / 3 of the reserved displacement threshold. At the same time, the compressive yield strength is compared, and the numerical calculation stress of the observation window is checked. The stress of the main part of the observation window should not exceed its compressive yield strength, and the stress of the stress concentration part should not exceed 1.25 times of its compressive yield strength.

[0114] When the theoretical calculated stress, numerical calculated stress and numerical calculated displacement all meet the requirements, accessories such as observation windows and test window seats are manufactured, and hydrostatic external pressure tests are carried out for experimental verification.

[0115] After the test, remove the observation window and carefully check whether there is stress damage on its surface and inside, such as silver streaks or cracks. If there is no damage, verify it through a stress verification test; at the same time, if the displacement measured in the test is not greater than the reserved displacement threshold, the observation window passes the test verification.

[0116] If the test verification fails, the target size of the observation window needs to be readjusted until the theoretical stress verification, numerical stress and displacement verification, and test verification are passed.

[0117] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0118] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for designing an observation window for a full-sea-depth manned submersible, characterized in that: The method comprises: Calculate the size of the observation window according to the first observation window parameters and the preset observation window size formula to obtain the target size of the observation window; wherein the first observation window parameters include the light transmission diameter, the angle and the maximum design pressure of the large end face; Perform stress calculation according to the first observation window parameter, the observation window target size, the second observation window parameter and a preset stress formula to obtain the observation window theoretical stress; Performing numerical calculations according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain numerical calculation results of the observation window stress and displacement, and verifying the observation window; The step of performing size calculation according to the first observation window parameter and a preset observation window size formula to obtain the observation window target size includes: Determine the target small end diameter based on the light transmission diameter, the included angle, the maximum design pressure of the large end face and the preset small end diameter formula; Determine the target observation window thickness based on the target small end diameter, the maximum design pressure of the large end face and a preset thickness formula; Determine the target large end diameter based on the target small end diameter, the target observation window thickness, the included angle and a preset large end formula; The target small end diameter, the target observation window thickness and the target large end diameter are set as the observation window target dimensions.

2. The method for designing an observation window for a full-sea-depth manned submersible according to claim 1, characterized in that: The first observation window parameters include a light transmission diameter, an angle, and a maximum design pressure of the large end face; the force calculation is performed according to the first observation window parameters, the observation window target size, the second observation window parameters, and a preset stress formula to obtain the observation window theoretical stress, including: Stress calculation is performed according to the included angle, the maximum design pressure of the large end face, the target size of the observation window, the parameters of the second observation window and the axial stress formula to obtain the axial stress at each location of the observation window along the thickness and radius directions; Stress calculation is performed according to the angle, the second observation window parameters, and the radial stress formula to obtain radial stress at various locations along the radial direction of a certain axial cross section of the observation window; According to the calculated axial stress and radial stress, the compressive yield strength or tensile strength in the third observation window parameter is compared to perform a theoretical stress check on the observation window.

3. The method for designing an observation window for a full-sea-depth manned submersible according to claim 2, characterized in that: The first observation window parameters also include the light transmission diameter; the second observation window parameters include the compressive elastic modulus, Poisson's ratio, and the friction coefficient of the observation window and the window seat support cone surface; the observation window target size includes the target small end diameter, the target observation window thickness, and the target large end diameter; Stress calculation is performed according to the included angle, the maximum design pressure of the large end face, the target size of the observation window, the parameters of the second observation window and the axial stress formula to obtain the axial stress at each location of the observation window along the thickness and radius directions, including: Determine the axial deformation increment of the observation window at each location along the axial direction based on the target observation window thickness; Determine a first approximate radial strain at each axial location based on the axial deformation increment; determining an axial stress increment based on the first approximate radial strain, Poisson's ratio, and compressive elastic modulus; Stress calculation is performed based on the target large end diameter, the target small end diameter, the included angle, the maximum design pressure of the large end face and the axial stress formula to obtain the axial stress at various locations along the thickness and radius directions of the observation window.

4. The method for designing an observation window for a full-sea-depth manned submersible according to claim 2, characterized in that: The second observation window parameters include compressive elastic modulus, Poisson's ratio, and friction coefficient between the observation window and the supporting cone surface of the window seat; Stress calculation is performed according to the angle, the second observation window parameter, and the radial stress formula to obtain radial stress at various locations along the radial direction of a certain axial section of the observation window, including: Based on the preset deformation formula, determine the axial deformation of a certain axial section at various radial locations; Determine a second approximate radial strain of a certain axial cross section at various radial locations based on the axial deformation and the included angle; Determine radial stress increments of a certain axial cross section at various locations in the radial direction based on the second approximate radial strain, Poisson's ratio and compressive elastic modulus; Stress calculation is performed based on the radial stress increment, the included angle, the friction coefficient of the observation window and the window seat supporting cone surface, and the radial stress formula to obtain the radial stress at various locations along the radial direction of a certain axial section of the observation window.

5. The method for designing an observation window for a full-sea-depth manned submersible according to claim 1, characterized in that: The third observation window parameters include, in addition to the compressive elastic modulus and Poisson's ratio in the second observation window parameters, tensile strength, elongation at break, tensile elastic modulus, tensile load-deformation curve, compressive yield strength and compressive load-deformation curve; The performing of numerical calculation according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation results of the observation window stress and displacement, and checking the observation window, includes: A numerical calculation model is established based on the target size of the observation window, the parameters of the third observation window and the material parameters of the window seat; Based on the numerical calculation model, meshing, contact boundary setting, and load constraints are applied; Perform numerical calculations according to the numerical calculation model, the mesh division, the contact boundary setting, and the load constraint application to obtain numerical calculation results of the observation window stress and displacement; According to the numerical calculation results, the observation window is displaced and the displacement value should not exceed 2 / 3 of the reserved displacement threshold; Based on the compressive yield strength or tensile strength in the third observation window parameter, the observation window is numerically calculated for stress verification. The stress in the main part of the observation window should not exceed its material strength, and the stress in the stress concentration part should not exceed 1.25 times of its material strength.

6. The method for designing an observation window for a full-sea-depth manned submersible according to claim 5, characterized in that: Based on the numerical calculation model, meshing, contact boundary setting, and load constraints are applied, including: Set the window seat as the target unit and the observation window as the contact unit; Setting a contact pair on a contact boundary between the target unit and the contact unit; The friction coefficient between the target unit and the contact unit is determined by experiments.

7. The method for designing an observation window for a full-sea-depth manned submersible according to claim 1, characterized in that: After performing numerical calculation according to the numerical calculation model, the third observation window parameters and the preset calculation scheme to obtain the numerical calculation result, the method further includes: The observation window is tested according to the test plan. If the test displacement is not greater than the reserved displacement threshold, and there is no internal or external stress damage to the observation window after the test, the final design of the observation window is completed. Otherwise, the target size of the observation window needs to be readjusted until the theoretical stress calculation, numerical calculation and test are all passed simultaneously.

8. The method for designing an observation window for a full-sea-depth manned submersible according to claim 1, characterized in that: Before calculating the size of the observation window according to the first observation window parameter and the preset observation window size formula to obtain the target size of the observation window, the method further includes: The performance test of the observation window material is performed according to the preset specimen parameters and the preset performance test scheme to obtain the third observation window parameters.

9. The method for designing an observation window for a full-sea-depth manned submersible according to claim 8, characterized in that: The method of performing a performance test on the observation window material according to the preset specimen parameters and the preset performance test scheme to obtain the third observation window parameters includes: Making specimens of the observation window material according to the preset specimen parameters to obtain multiple groups of specimens; According to the performance test scheme, performance tests are performed on multiple groups of the test pieces to obtain the third observation window parameters.

10. The method for designing an observation window for a full-sea-depth manned submersible according to claim 9, characterized in that: The plurality of groups of test specimens include a plurality of groups of tensile test specimens and a plurality of groups of compression test specimens; the preset performance test scheme includes a preset tensile test scheme and a preset compression test scheme; The step of performing a performance test on each group of the test pieces according to the performance test scheme to obtain the third observation window parameters includes: Perform a tensile test on each group of tensile test pieces according to a preset tensile test plan to obtain tensile performance test results; A compression test is performed on each group of compression specimens according to a preset compression test scheme to obtain compression performance test results.

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