A Deep-Sea Pressure-Resistant Cabin Made of Composite Materials and a Design Method for the Shell Thickness

Abstract

The present invention relates to the technical field of deep-sea pressure-resistant cabins, and in particular to a composite material deep-sea pressure-resistant cabin and a method for designing the thickness of the shell. The design method includes the following steps: 1) Adjust the ratio of the axial equivalent modulus to the circumferential equivalent modulus of the shell skin to 1:2, and calculate the axial equivalent elastic modulus and the circumferential equivalent elastic modulus of the shell; 2) Prepare flat specimens and conduct uniaxial compression tests in the axial and circumferential directions to obtain the strength and Poisson's ratio under axial and circumferential uniaxial compression; 3) Prepare cylindrical specimens and conduct external pressure failure tests to obtain the axial and circumferential strains corresponding to the failure; 4) Calculate the axial and circumferential stresses of the cylindrical specimens to obtain the biaxial compression parameters, substitute the biaxial compression parameters into the biaxial compression formula, and draw the biaxial compression strength prediction curve; 5) Adjust the shell thickness dimension so that the axial stress and the circumferential stress at each position fall on the biaxial compression strength prediction curve, and obtain the size of the pressure-resistant cabin shell with the highest structural efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of deep - sea pressure - resistant cabins, and particularly relates to a composite - material deep - sea pressure - resistant cabin and a method for designing the thickness of the shell. Background Art

[0002] There are rich biological and mineral resources in the deep sea, which provide important sources of minerals, food, etc. for humans. The ocean connects many countries and is an important channel for international trade, which is related to the national security of each country and is an important wealth for human development. In marine scientific research, the research on the deep - sea abyss area is a weak link. Currently, many countries have launched deep - sea scientific research plans, which is the forefront field of marine scientific research. In the field of deep - sea exploration, deep - sea submersibles are one of the most important means for humans to explore, develop and utilize the ocean. Submersibles can be divided into manned submersibles and unmanned submersibles, and unmanned submersibles can be divided into cabled submersibles, cable - less submersibles and underwater gliders.

[0003] Deep - sea submersibles operate in the deep sea and have high requirements for the pressure - resistant performance of their structures. The external structure of a deep - sea submersible consists of a light outer shell and a pressure - resistant shell structure. The pressure - resistant shell bears the hydrostatic pressure conditions in the deep sea, isolates seawater from the internal equipment of the shell, and avoids damage to the equipment caused by seawater pressure and corrosion. The mass of the pressure - resistant shell accounts for a high proportion of the total mass of the deep - sea submersible, providing most of the displacement volume. However, the heavier pressure - resistant shell will limit the battery - carrying capacity of the deep - sea submersible. Therefore, under the condition of ensuring its strength performance, stability performance and internal volume, optimizing the geometric parameters and ply design of the pressure - resistant shell, reducing the structural mass, thereby increasing its payload and reducing the power consumption of the power device, is of great significance for improving the performance of deep - sea unmanned submersibles and is an important factor determining the limit depth and performance of the submersible.

[0004] For the lightweight composite - material deep - sea pressure - resistant cabin structural cylinder section structure, there is still no standardized design and test method, which cannot provide support for the design of the lightweight deep - sea pressure - resistant cabin structure. The forces on the cylinder section structure of the deep - sea pressure - resistant cabin structure include the radial pressure of seawater, the axial pressure of the end cover, and the contact constraint at the end - cover boundary. Specifically, the force mode of the local structure of the cylinder section is a biaxial compression stress state, and the magnitudes and stress ratios of the axial and circumferential stresses of the local structures at different axial positions of the cylinder are different. For the traditional metal - structure deep - sea pressure - resistant cabin, the strength prediction methods for its cylinder section structure at different positions are the same, all using the mises stress to judge the structural strength and verifying it through experiments. However, the strength of the composite - material structure deep - sea pressure - resistant cabin is different under different axial and circumferential load ratios. For a relatively long cylinder section structure, strength failure usually occurs at the positions near the two end heads of the cylinder section. Due to the effect of the boundary at this position, there is an obvious additional bending moment, resulting in uneven axial stress distribution and premature strength failure.

[0005] The currently common composite material strength prediction models usually use the classical laminate theory to determine the external load borne by each layer, then analyze the response of a single ply until failure, and finally obtain the overall performance of the laminate. However, under biaxial combined loading, the failure of the laminate occurs layer by layer. The first failure is called the initial failure, and the corresponding load is called the initial failure strength of the laminate. It is predicted that the strength of the laminate under biaxial compressive loading does not decrease significantly compared with the unidirectional strength, and even the strength of the laminate under biaxial compressive loading is higher than the uniaxial compressive strength. There is a large difference between this kind of strength theory and the results of the external pressure cylinder test, and it cannot predict the strength failure under biaxial compressive stress state.

[0006] For the Max-stress strength theory shown below, this theory is for a single ply prepreg in a composite laminate, where, σ 11 is the stress in the fiber direction of the single ply material, σ 22 is the stress perpendicular to the fiber direction of the single ply material, τ 12 is the shear stress of the single ply prepreg, the X t is the tensile strength in the fiber direction of the single ply material, the X c is the compressive strength in the fiber direction of the single ply material, the Y t is the tensile strength perpendicular to the fiber direction of the single ply material, the Y c is the compressive strength perpendicular to the fiber direction of the single ply material, the S 12 is the shear strength of the single ply material, the σ 11 、σ 22 are positive in the tensile state and negative in the compressive state; the comparison between its strength prediction and the test results is as Figure 2 shown. According to the test results, the strength theory represented by the Max-stress strength theory with the formula exponent of "1" cannot predict the biaxial compressive strength. The exponent of the ratio of the stress to the allowable value is "1", and it cannot reflect the coupling effect of the composite material strength in biaxial compression.

[0007]

[0008] For the Tsai-Hill strength theory shown below, this theory is for a single ply prepreg in a composite laminate, where, the σ 11 is the stress in the fiber direction of the single ply material, σ 22 is the stress perpendicular to the fiber direction of the single ply material, τ 12 is the shear stress of the single ply prepreg, the X is the strength in the fiber direction of the single ply material, the Y is the strength perpendicular to the fiber direction of the single ply material, the S 12 is the shear strength of the single ply material; the comparison between its strength prediction and the test results is as Figure 2As shown, according to the test results, the strength theory with a formula exponent of "2" represented by the Tsai-Hill strength theory cannot predict the biaxial compression strength. The exponent of the ratio of stress to allowable value is "2", which cannot reflect the effect of the reduction of the unidirectional strength caused by biaxial compression of the composite material in biaxial compression.

[0009]

[0010] Therefore, in view of the above problems, the present invention urgently provides a composite material deep-sea pressure-resistant cabin and a method for designing the shell thickness. Summary of the Invention

[0011] The technical problem solved by the present invention is to provide a composite material deep-sea pressure-resistant cabin and a method for designing the shell thickness. By optimizing the Tsai-Hill strength theory and the Max-stress strength theory, and changing the research object of the strength theory from a single-layer plate to a laminated plate, the problems such as the large difference between the strength theory and the test results of the external pressure cylinder in the prior art can be solved, and better prediction of the strength of the composite material cylinder under external pressure load can be achieved.

[0012] The present invention provides a method for designing the shell thickness of a composite material deep-sea pressure-resistant cabin, including the following steps:

[0013] 1) Determine the lay-up scheme. Based on the classical laminated plate theory, adjust the ratio of the axial equivalent modulus to the circumferential equivalent modulus of the shell skin to 1:2, and calculate the axial equivalent elastic modulus and the circumferential equivalent elastic modulus of the shell;

[0014] 2) Prepare a flat specimen with the same material as the shell, and conduct uniaxial compression tests on the flat specimen in the axial direction and the circumferential direction corresponding to the shell respectively to obtain the strength and Poisson's ratio under axial and circumferential uniaxial compression;

[0015] 3) Prepare a cylindrical specimen with the same material as the shell, seal both ends of the cylindrical specimen, and conduct an external pressure failure test on the cylindrical specimen to obtain the axial strain and circumferential strain corresponding to the failure;

[0016] 4) Calculate the axial stress and circumferential stress of the cylindrical specimen through the linear elastic constitutive equation. Substitute the axial stress of the cylindrical specimen, the circumferential stress of the cylindrical specimen, the strength under axial compression of the flat specimen, and the strength under circumferential compression of the flat specimen into the biaxial compression formula to calculate the biaxial compression parameters. Substitute the biaxial compression parameters into the biaxial compression formula, and draw a biaxial compression strength prediction curve according to the biaxial compression formula;

[0017] 5) Adjust the thickness dimensions of each position of the shell so that the axial stress and circumferential stress at each position fall on the biaxial compression strength prediction curve, obtain the size of the pressure-resistant cabin shell with the highest structural efficiency, and complete the design of the composite material deep-sea pressure-resistant cabin shell.

[0018] Preferably, the biaxial compression formula is , where is the axial stress of the cylindrical specimen, is the circumferential stress of the cylindrical specimen, is the strength of the flat specimen under axial compression, is the strength of the flat specimen under circumferential compression, m is the axial compression parameter, and n is the circumferential compression parameter.

[0019] Preferably, the linear elastic constitutive equation includes the following formula: , ; where is the axial stress of the cylindrical specimen, is the circumferential stress of the cylindrical specimen, is the axial strain corresponding to the failure of the cylindrical specimen, is the circumferential strain corresponding to the failure of the cylindrical specimen, is the axial equivalent elastic modulus of the shell, is the circumferential equivalent elastic modulus of the shell, is the Poisson's ratio of the flat specimen under axial compression, is the Poisson's ratio of the flat specimen under circumferential compression.

[0020] Preferably, in step 3), when performing an external pressure failure test on the cylindrical specimen, strain gauges are pasted on the side wall of the cylindrical specimen to measure and obtain the axial strain corresponding to the failure of the cylindrical specimen and the circumferential strain corresponding to the failure.

[0021] Preferably, in step 3), cylindrical specimens of various different lengths are prepared, and step 3) is repeated to obtain multiple sets of data; in step 4), the calibrated axial compression parameter m and circumferential compression parameter n are calculated based on the multiple sets of data obtained in step 3).

[0022] Preferably, in step 1), the laying scheme of the wet winding process is to lay in the order of 20°, -20°, 90°, 90°, 90°.

[0023] Preferably, in step 2), when performing uniaxial compression tests on the flat specimen in the axial direction and circumferential direction corresponding to the shell respectively, the compression pressure is 700 MPa.

[0024] Preferably, in step 3), when performing an external pressure failure test on the cylindrical specimen with both ends sealed, the compression pressure is 370 MPa.

[0025] The present invention also provides a composite material deep-sea pressure-resistant cabin, and the deep-sea pressure-resistant cabin includes a shell, wherein the thickness at each position of the shell is obtained based on the design method for the thickness of the composite material deep-sea pressure-resistant cabin shell.

[0026] Preferably, the shell is prepared by wet winding or dry winding of prepreg materials.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a composite material deep-sea pressure-resistant cabin and a shell design method. The research object of the strength theory is changed from a single-layer prepreg in a composite material laminate to the laminate. Taking the laminate with a fixed ply scheme as the research object, by optimizing the Tsai-Hill strength theory and the Max-stress strength theory, and changing the research object of the strength theory from a single-layer plate to a laminate to adapt to the strength prediction under the biaxial compression stress state of the laminate. Through the uniaxial compression tests in the 0° and 90° directions of the laminate and the biaxial loading tests with two different load ratios, combined with formulas, the biaxial compression strength curve of the laminate is fitted, so as to predict the bearing capacity of different positions of the composite material pressure-resistant cabin, and further adjust the parameters of the pressure-resistant cabin to complete the structural design of the pressure-resistant cabin with qualified strength. Description of the Drawings

[0029] Figure 1 is a flow chart of the shell design method of the composite material deep-sea pressure-resistant cabin described in the embodiment of the present invention;

[0030] Figure 2 is a schematic diagram comparing the strength prediction and test results of the Tsai-Hill strength theory and the Max-stress strength theory described in the embodiment of the present invention;

[0031] Figure 3 is a schematic diagram comparing the strength prediction and test results of the biaxial compression strength prediction curve described in the embodiment of the present invention. Detailed Embodiments

[0032] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] As Figure 1 shown, this embodiment provides a composite material deep-sea pressure-resistant cabin shell design method, including the following steps:

[0034] 1) Determine the ply scheme. Based on the classical laminate theory, adjust the ratio of the axial equivalent modulus to the circumferential equivalent modulus of the shell skin to 1:2, and calculate the axial equivalent elastic modulus and the circumferential equivalent elastic modulus of the shell;

[0035] 2) Prepare flat specimens with the same material as the shell. Conduct uniaxial compression tests on the flat specimens in the axial and circumferential directions corresponding to the shell respectively to obtain the strength and Poisson's ratio under axial and circumferential uniaxial compression.

[0036] 3) Prepare cylindrical specimens with the same material as the shell. Seal both ends of the cylindrical specimens and conduct an external pressure failure test on the cylindrical specimens to obtain the axial strain and circumferential strain corresponding to failure.

[0037] 4) Calculate the axial stress and circumferential stress of the cylindrical specimen through the linear elastic constitutive equation. Substitute the axial stress of the cylindrical specimen, the circumferential stress of the cylindrical specimen, the strength under axial compression of the flat specimen, and the strength under circumferential compression of the flat specimen into the biaxial compression formula to calculate the biaxial compression parameters. Substitute the biaxial compression parameters into the biaxial compression formula, and draw the biaxial compression strength prediction curve according to the biaxial compression formula.

[0038] 5) Adjust the thickness dimensions of each position of the shell so that the axial stress and circumferential stress at each position fall on the biaxial compression strength prediction curve, obtain the size of the pressure-resistant cabin shell with the highest structural efficiency, and complete the design of the composite material deep-sea pressure-resistant cabin shell.

[0039] The present invention provides a design method for a composite material deep-sea pressure-resistant cabin shell. The research object of the strength theory is changed from a single-layer prepreg in a composite material laminate to a laminate. Taking the laminate with a fixed ply layup scheme as the research object, by optimizing the Tsai-Hill strength theory and the Max-stress strength theory, and changing the research object of the strength theory from a single-layer plate to a laminate to adapt to the strength prediction under the biaxial compression stress state of the laminate. Through uniaxial compression tests on the 0° and 90° directions of the laminate, and biaxial loading tests with two different load ratios, combined with formulas, fit the biaxial compression strength curve of the laminate, so as to predict the bearing capacity of different positions of the composite material pressure-resistant cabin, and further adjust the parameters of the pressure-resistant cabin to complete the design of the pressure-resistant cabin structure that meets the strength requirements.

[0040] In this embodiment, the biaxial compression formula is , where is the axial stress of the cylindrical specimen, is the circumferential stress of the cylindrical specimen, is the strength under axial compression of the flat specimen, is the strength under circumferential compression of the flat specimen, m is the axial compression parameter, and n is the circumferential compression parameter.

[0041] The biaxial compression formula of the present invention is further obtained based on the Tsai-Hill strength theory. The Tsai-Hill strength theory is for a single-layer prepreg with an exponent of 2, while the present invention is for a laminated plate of a deep-sea pressure-resistant cabin shell. During the biaxial compression process, the unidirectional strength will decrease. Therefore, the axial compression parameter m and the circumferential compression parameter n are proposed to correct the inaccurate prediction of the laminated plate strength by the Tsai-Hill strength theory.

[0042] In this embodiment, the linear elastic constitutive equation includes the following formula: , ; where is the axial stress of the cylindrical specimen, is the circumferential stress of the cylindrical specimen, is the axial strain corresponding to the failure of the cylindrical specimen, is the circumferential strain corresponding to the failure of the cylindrical specimen, is the axial equivalent elastic modulus of the shell, is the circumferential equivalent elastic modulus of the shell, is the Poisson's ratio of the flat specimen under axial compression, is the Poisson's ratio of the flat specimen under circumferential compression.

[0043] In this embodiment, in step 3), when performing an external pressure failure test on the cylindrical specimen, strain gauges are pasted on the side wall of the cylindrical specimen to measure the axial strain corresponding to the failure of the cylindrical specimen and the circumferential strain corresponding to the failure.

[0044] In this embodiment, in step 3), cylindrical specimens of various different lengths are prepared, and step 3) is repeated to obtain multiple groups of data; in step 4), the calibrated axial compression parameter m and the circumferential compression parameter n are calculated based on the multiple groups of data obtained in step 3).

[0045] In this embodiment, in step 1), the laying scheme of the wet winding process is to lay in the order of 20°, -20°, 90°, 90°, 90°.

[0046] In this embodiment, in step 2), when performing uniaxial compression tests on the flat specimen in the axial direction and circumferential direction corresponding to the shell respectively, the compression pressure is 700 MPa.

[0047] In this embodiment, in step 3), when performing an external pressure failure test on the cylindrical specimen with both ends sealed, the compression pressure is 370 MPa.

[0048] This embodiment also provides a composite material deep-sea pressure-resistant cabin. The deep-sea pressure-resistant cabin includes a shell, and the thickness of each position of the shell is obtained based on the design method for the thickness of the composite material deep-sea pressure-resistant cabin shell.

[0049] The present invention provides a deep - sea pressure - resistant cabin made of composite materials. The research object of the strength theory is changed from a single - layer prepreg in a composite laminate to the laminate. Taking the laminate with a fixed ply - laying scheme as the research object, by optimizing the Tsai - Hill strength theory and the Max - stress strength theory, and changing the research object of the strength theory from a single - layer plate to a laminate to adapt to the strength prediction under the biaxial compression stress state of the laminate. Through the uniaxial compression tests of the laminate in the 0° and 90° directions, as well as the biaxial loading tests with two different load ratios, combined with formulas, the biaxial compression strength curve of the laminate is fitted, so as to predict the bearing capacity of different positions of the composite - material pressure - resistant cabin, and further adjust the parameters of the pressure - resistant cabin to complete the structural design of the pressure - resistant cabin with qualified strength.

[0050] In this embodiment, the shell is prepared by wet winding or dry winding of prepreg.

[0051] The present invention also provides an embodiment. Among them, the design method of the shell of the deep - sea pressure - resistant cabin made of composite materials includes the following steps:

[0052] 1) Determine the ply - laying scheme. Based on the classical laminate theory, adjust the ratio of the axial equivalent modulus to the circumferential equivalent modulus of the shell skin to 1:2, and calculate the axial equivalent elastic modulus and the circumferential equivalent elastic modulus of the shell. Since the shell in this embodiment is prepared by wet winding of prepreg, the ply - laying scheme applicable to this embodiment is [20 / -20 / 90 / 90 / 90]. According to the classical laminate theory, calculate the axial equivalent elastic modulus and the circumferential equivalent elastic modulus of the laminate.

[0053] 2) Prepare flat specimens made of the same material as the shell, and conduct uniaxial compression tests on the flat specimens in the axial direction and the circumferential direction corresponding to the shell respectively to obtain the strength and Poisson's ratio under axial and circumferential uniaxial compression. Specifically, conduct an uniaxial compression test on the flat specimen in the axial direction corresponding to the shell until uniaxial compression failure. The measured strength of the flat specimen under axial compression is - 472 MPa, denoted as X C ; conduct an uniaxial compression test on the flat specimen in the circumferential direction corresponding to the shell until uniaxial compression failure. The measured strength of the flat specimen under circumferential compression is - 720 MPa, denoted as Y C ; at the same time, measure the Poisson's ratio of the flat specimen under axial compression and circumferential compression respectively.

[0054] 3) Prepare cylindrical specimens made of the same material as the shell. Seal both ends of the cylindrical specimens and conduct an external pressure failure test on the cylindrical specimens to obtain the axial strain and circumferential strain corresponding to the failure. Specifically, prepare two cylindrical specimens with different lengths. Install end caps at both ends of the cylindrical specimens. The distance between the two end caps of the same cylindrical specimen is the effective compression length of the cylindrical specimen. The effective compression lengths of the two prepared cylindrical specimens are 70 mm and 60 mm respectively. Paste strain gauges on the side walls of the cylindrical specimens to measure stress.

[0055] 4) Calculate the axial stress and circumferential stress of the cylindrical specimens through the linear elastic constitutive equation. Substitute the axial stress of the cylindrical specimen, the circumferential stress of the cylindrical specimen, the strength of the flat specimen under axial compression, and the strength of the flat specimen under circumferential compression into the biaxial compression formula to calculate the biaxial compression parameters. Substitute the biaxial compression parameters into the biaxial compression formula and draw the biaxial compression strength prediction curve according to the biaxial compression formula. For the cylindrical specimen with an effective compression length of 60 mm, after conducting an external pressure test on it until failure, measure the axial strain and circumferential strain corresponding to the failure. After substituting them into the linear elastic constitutive equation, calculate that the axial failure stress is 230 MPa and the circumferential failure stress is 300 MPa. For the cylindrical specimen with an effective compression length of 70 mm, after conducting an external pressure test on it until failure, measure the axial strain and circumferential strain corresponding to the failure. After substituting them into the linear elastic constitutive equation, calculate that the axial failure stress is 212 MPa and the circumferential failure stress is 320 MPa. Substitute the axial stress, the circumferential stress of the cylindrical specimen, the strength of the flat specimen under axial compression, and the strength of the flat specimen under circumferential compression data of the two groups of cylindrical specimens into the biaxial compression formula , where is the axial stress of the cylindrical specimen, is the circumferential stress of the cylindrical specimen, is the strength of the flat specimen under axial compression, is the strength of the flat specimen under circumferential compression, m is the axial compression parameter, and n is the circumferential compression parameter. Obtain m 60 = 0.855, n 60 = 0.865, m 70 = 0.855, n 70 = 0.865. Therefore, the biaxial compression formula is obtained as . Draw the biaxial compression strength prediction line as shown in Figure 3 ;

[0056] 5) Adjust the thickness dimensions of each position of the shell so that the axial stress and circumferential stress at each position fall on the biaxial compression strength prediction curve. Then, the strength of the shell at the thickness corresponding to the axial stress and circumferential stress falling on the biaxial compression strength prediction curve is higher, and the size of the pressure-resistant cabin shell with the highest structural efficiency is obtained, completing the design of the composite material deep-sea pressure-resistant cabin shell.

[0057] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for designing the thickness of a deep - sea pressure - resistant cabin shell of a composite material, characterized in that: It includes the following steps: 1) Determine the ply layup scheme. Based on the classical laminated plate theory, adjust the ratio of the axial equivalent modulus to the circumferential equivalent modulus of the shell skin to 1:2, and calculate the axial equivalent elastic modulus and the circumferential equivalent elastic modulus of the shell; 2) Prepare flat specimens with the same material as the shell, and conduct uniaxial compression tests on the flat specimens in the axial direction and the circumferential direction corresponding to the shell respectively to obtain the strength and Poisson's ratio under axial and circumferential uniaxial compression; 3) Prepare cylindrical specimens with the same material as the shell, seal both ends of the cylindrical specimens, and conduct an external pressure failure test on the cylindrical specimens to obtain the axial strain and circumferential strain corresponding to the failure; 4) Calculate the axial stress and circumferential stress of the cylindrical specimen through the linear elastic constitutive equation. Substitute the axial stress of the cylindrical specimen, the circumferential stress of the cylindrical specimen, the strength under axial compression of the flat specimen, and the strength under circumferential compression of the flat specimen into the biaxial compression formula to calculate the biaxial compression parameters. Substitute the biaxial compression parameters into the biaxial compression formula, and draw the biaxial compression strength prediction curve according to the biaxial compression formula; 5) Adjust the thickness dimensions of each position of the shell so that the axial stress and circumferential stress at each position fall on the biaxial compression strength prediction curve, obtain the size of the pressure-resistant cabin shell with the highest structural efficiency, and complete the design of the composite material deep-sea pressure-resistant cabin shell; The biaxial compression formula is , where is the axial stress of the cylindrical specimen, is the circumferential stress of the cylindrical specimen, is the strength of the flat specimen under axial compression, is the strength of the flat specimen under circumferential compression, m is the axial compression parameter, and n is the circumferential compression parameter; The linear elastic constitutive equation includes the following formula: , ; where is the axial stress of the tubular specimen, is the circumferential stress of the tubular specimen, is the axial strain corresponding to the failure of the tubular specimen, is the circumferential strain corresponding to the failure of the tubular specimen, is the axial equivalent elastic modulus of the shell, is the circumferential equivalent elastic modulus of the shell, is the Poisson's ratio of the flat specimen under axial compression, is the Poisson's ratio of the flat specimen under circumferential compression; In step 3), prepare cylindrical specimens with multiple different lengths, repeat step 3) to obtain multiple groups of data; in step 4), calculate and calibrate the axial compression parameter m and the circumferential compression parameter n based on the multiple groups of data obtained in step 3); In step 1), the ply layup scheme of the wet winding process is to lay in the order of 20°, -20°, 90°, 90°, 90°; 2. The method for designing the thickness of the deep-sea pressure-resistant cabin shell of the composite material according to claim 1, characterized in that: In step 3), when conducting the external pressure failure test on the cylindrical specimen, paste strain gauges on the side wall of the cylindrical specimen to measure and obtain the axial strain corresponding to the failure of the cylindrical specimen and the circumferential strain corresponding to the failure; 3. The method for designing the thickness of the deep-sea pressure-resistant cabin shell of the composite material according to claim 2, wherein: In step 2), when conducting the uniaxial compression tests on the flat specimens in the axial direction and the circumferential direction corresponding to the shell respectively, the compression pressure is 700 MPa; 4. The method for designing the thickness of the deep-sea pressure-resistant cabin shell of the composite material according to claim 3, characterized in that: In step 3), when conducting the external pressure failure test on the cylindrical specimen with both ends sealed, the compression pressure is 370 MPa; 5. A deep-sea pressure-resistant cabin made of composite materials, characterized in that: The deep-sea pressure-resistant cabin includes a shell, wherein the thickness of each position of the shell is obtained based on the composite material deep-sea pressure-resistant cabin shell thickness design method described in any one of claims 1-4; 6. The deep-sea pressure-resistant cabin made of composite material according to claim 5, characterized in that: The shell is prepared by a wet winding or dry winding process using prepreg.

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