Design method of blue ice diamond drilling core drill reverse torsion mechanism plate spring and experimental platform thereof

Abstract

The application discloses a kind of blue ice diamond exploration coring drill reverse torsion mechanism plate spring design method and experimental platform, polar drilling equipment test technical field, establish benchmark finite element model, create the three-dimensional solid model of plate spring and well wall in ABAQUS software;Parametric modeling and experimental design, determine design variables include geometric factor, material factor, temperature factor and working condition factor, create several finite element models of different parameter combinations, extract the contact pressure result of each model;And record the result in data table;Using the data table using multiple linear regression method to fit power law relationship equation, the relationship between pressure and influencing factors is obtained.The application can significantly improve the reliability, safety and design efficiency of the reverse torsion mechanism in extreme environment, and has important engineering practical value and technical innovation.

Description

Technical Field

[0001] This invention relates to the field of polar drilling equipment testing technology, and more specifically to the design method and experimental platform of the anti-torsion mechanism leaf spring of the blue ice drilling core tool. Background Technology

[0002] In actual drilling, especially in the dense, hard blue ice of Antarctica, the interaction between the drill bit and the ice layer is extremely complex. It is highly susceptible to "stick-slip" effects, ice debris jamming, or encountering hard inclusions, causing a sharp increase in the drill bit's instantaneous resistance torque and generating sudden overtorque. Without effective protection, this peak torque will directly act on the vulnerable armored cable and its connector through the drill string's top sub, causing anything from minor cable torsion damage and signal transmission interruption to major accidents such as connection failure and drill string falling into the well.

[0003] To address this issue, the leaf spring anti-torque device is widely recognized as an ideal mechanical over-torque protection solution due to its compact structure, customizable torque characteristics, and lack of hydraulic leakage risk (suitable for ultra-low temperatures). Its core working principle is as follows: a set of pre-tensioned leaf springs generates an elastic reaction torque when subjected to torsion to balance the drill bit's working torque; when the torque abnormally increases, the leaf springs deform further, using their nonlinear mechanical properties to limit the peak torque transmitted upstream and absorb impact energy; after the torque is released, the leaf springs drive the drill bit to automatically reset.

[0004] However, the design of existing leaf spring-type anti-torsion devices, especially when applied to harsh polar environments, relies heavily on the selection of the core component—the leaf spring. Current technology exhibits significant empirical and unreliable limitations in this regard. The design of the leaf spring is influenced by many factors, such as thickness, a geometric factor. Thickness has the most significant impact on the bending stiffness of the leaf spring (proportional to the cube of the thickness) and directly determines its yield strength (maximum stress is inversely proportional to the square of the thickness). The design dilemma is that increasing thickness improves the device's stiffness and strength but makes it too rigid, losing its overload buffering capacity; decreasing thickness makes the device too flexible, resulting in poor stability during normal drilling and susceptibility to permanent deformation under initial impact. Width linearly affects the stiffness and load-bearing capacity of the leaf spring, and also relates to its lateral stability. The design dilemma is that increasing width improves stability and load-bearing capacity but is limited by the drill bit's internal diameter space; decreasing width may cause lateral instability of the leaf spring, leading to abnormal failure.

[0005] These parameters are intertwined and together shape the torque-rotation characteristic curve of the anti-torsion device. Designers need to strike a balance between "high initial stiffness to ensure drilling stability" and "low subsequent stiffness to achieve soft limit protection," as well as between "limited installation space" and "maximum energy absorption capacity." It is difficult to achieve global optimization by manually adjusting individual parameters based on experience.

[0006] Therefore, there is an urgent need for a parametric design method for leaf springs based on multidisciplinary optimization and low-temperature adaptability correction to overcome the above-mentioned defects and design a highly reliable and high-performance leaf spring anti-torsion device that can accurately match the extreme working conditions of Antarctic blue ice drilling. Summary of the Invention

[0007] In view of this, the present invention provides a design method for the anti-torsion mechanism leaf spring of a blue ice drilling core tool and its experimental platform to solve the problems in the background art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention discloses a design method for a leaf spring anti-torsion mechanism in a blue ice drilling core tool, comprising:

[0010] Establish a baseline finite element model, create a three-dimensional solid model of the leaf spring and well wall in ABAQUS software; set material properties, define a hard contact relationship between the outer surface of the leaf spring and the inner surface of the well wall, apply loads and boundary conditions, and set analysis steps and output variables;

[0011] Parametric modeling and experimental design: Determine design variables including geometric factors, material factors, temperature factors, and operating condition factors, and create several finite element models with different parameter combinations;

[0012] Run all finite element models sequentially or in parallel, extract the contact pressure results for each model, and record the results in a data table;

[0013] Using the data table, a power-law relationship equation was fitted using multiple linear regression to obtain the relationship between pressure and influencing factors.

[0014] Preferably, in the above-mentioned design method for the anti-torsion mechanism leaf spring of the blue ice drilling core tool, the relationship equation between pressure and influencing factors is as follows:

[0015] ;

[0016] in, Indicates the width of the leaf spring. Indicates the thickness of the leaf spring. Indicates the length of the leaf spring. Indicates the elastic modulus of the leaf spring; This represents the elastic modulus of ice; Indicates temperature; Indicates the well inclination angle; Indicates the coefficient of friction; A dimensionless constant. , , , , It is a power exponent; , This is the temperature coefficient.

[0017] Preferably, in the above-mentioned design method for the anti-torsion mechanism leaf spring of the blue ice drilling core tool, the specific steps for obtaining the relationship between pressure and influencing factors are as follows:

[0018] Establish the basic relationship between contact pressure and geometric / material parameters. Assuming that one end of the leaf spring is fixed and the other end is subjected to a concentrated force F perpendicular to the axis, causing bending, derive the relationship between beam end deflection and load, and establish the connection between contact pressure and bending force.

[0019] Considering material compatibility, an equivalent modulus ratio is introduced; the elastic modulus of leaf springs and ice varies with temperature;

[0020] Introduce a well inclination angle to geometrically correct the contact area;

[0021] The coefficient of friction affects the shear stress distribution in the contact area, and thus influences the pressure by changing the effective contact stiffness or the size of the slip zone;

[0022] The effects of each factor on stress are independent of each other and combine in a product form. = [Geometric Term] [Materials] [Temperature Item] [Well-inclined term] [Friction term]; Substituting each sub-term into the formula yields the relationship between pressure and influencing factors.

[0023] Preferably, in the above-mentioned design method for the anti-torsion mechanism leaf spring of the blue ice drilling core tool, the contact pressure calculation steps are as follows:

[0024] Establish a mechanical model of a leaf spring, with one end fixed and the other end subjected to a displacement load to cause it to bend. The moment of inertia of the rectangular cross-section is: Modulus of rectangular section ;

[0025] Deriving the relationship between beam end deflection and load: According to mechanics of materials, when a concentrated force F is applied to the free end of a cantilever beam: The maximum bending stress is ;

[0026] Load can be inversely derived from the deflection formula = (1)

[0027] Assuming the total pressure and bending force in the contact area are balanced, and the contact area... With leaf spring width and effective contact length Proportional:

[0028] ;

[0029] ;

[0030] Average contact pressure is Substituting into formula (1), we get:

[0031] Contact pressure and Proportional to, with Proportional to, with Proportional.

[0032] Preferably, in the above-mentioned design method for the anti-torsion mechanism leaf spring of the blue ice drilling core tool, the material matching introduces the equivalent modulus ratio, and the specific steps are as follows:

[0033] According to Hertz's contact theory, when two elastic bodies are in contact, the contact pressure is related to the equivalent elastic modulus. Related:

[0034] ;

[0035] Contact pressure and equivalent modulus Proportional to the power of 1:

[0036] ;

[0037] When the elastic modulus of the leaf spring That is, when the leaf spring is much stiffer than ice: ;

[0038] Considering a more general case, we introduce the material stiffness ratio:

[0039] = .

[0040] Preferably, in the above-mentioned design method for the anti-torsion mechanism leaf spring of the blue ice drilling core tool, the steps for determining the temperature term regarding the change of the elastic modulus of the leaf spring and ice with temperature are as follows:

[0041] Formulas for the change of elastic modulus of leaf springs and ice with temperature:

[0042] ;

[0043] ;

[0044] ;

[0045]

[0046] in, This is the initial elastic modulus of the leaf spring. Let be the initial elastic modulus of ice, and represent the functions of elastic modulus of leaf spring and ice as a function of temperature, respectively.

[0047] for ;

[0048] Considering the combined effects of temperature on the two materials and the contact state:

[0049] .

[0050] Preferably, in the above-mentioned design method for the anti-torsion mechanism leaf spring of the blue ice drilling core tool, the specific steps for introducing the geometric correction of the contact area by the well inclination angle are as follows:

[0051] Force decomposition when the well inclination angle is At that time, the directional friction force is ; Tangential friction force is ;

[0052] Well inclination leads to asymmetry in the contact area, reducing the effective contact area. Assume the area correction factor is:

[0053] ;

[0054] in, This is the well inclination sensitivity coefficient;

[0055] Pressure is inversely proportional to contact area: .

[0056] Preferably, in the above-mentioned design method for the leaf spring of the anti-torsion mechanism of the blue ice drilling core tool, the specific steps for the influence of the friction coefficient on the shear stress distribution in the contact area are as follows:

[0057] According to Coulomb's law of friction, frictional force Friction affects the stress distribution and slip conditions in the contact area;

[0058] The coefficient of friction affects the contact pressure distribution, exhibiting a power-law relationship: ;

[0059] in, The coefficient of friction; The friction index is determined by the contact conditions.

[0060] On the other hand, the present invention discloses an experimental platform for the anti-torsion mechanism of a blue ice drilling core drilling tool. The leaf spring obtained by the above method includes: a bracket, a well support, a telescopic assembly, a hand crank assembly, a leaf spring clamp, a strain gauge, and a simulated well.

[0061] The telescopic component is mounted on the bracket; the telescopic component drives the hand crank assembly to move up and down.

[0062] The output shaft end of the hand crank assembly and the bottom surface of the bracket are provided with leaf spring clamps; the leaf spring is clamped on the leaf spring clamps; the simulated well barrel is mounted on the bracket via the well barrel bracket; the strain gauge is mounted on the inner wall of the simulated well barrel;

[0063] The counter-torque generated by the leaf spring and the inner wall of the simulated well is balanced with the torque applied by the hand crank assembly; when the torque is manually increased, the maximum torque that the leaf spring can withstand is reached at the moment when relative rotation occurs between the leaf spring and the inner wall of the well; the torque value is obtained through a torque sensor, which is set on the output shaft, and the radial pressure is measured by strain gauges attached to the inner wall of the simulated well, transmitted to the computer and displayed in real time.

[0064] Preferably, in the above-mentioned experimental platform for the anti-torsion mechanism of a blue ice drilling core drilling tool, the wellbore support includes a fixed support, a fixed sleeve, and fastening bolts; the simulated wellbore is set inside the fixed sleeve; the fixed sleeve is hinged to the fixed support; the fixed sleeve is fixed by the fastening bolts to determine different well inclination angles.

[0065] As can be seen from the above technical solution, compared with the prior art, this invention discloses a design method and experimental platform for the anti-torsion mechanism leaf spring of a blue ice drilling core tool. This method significantly improves the reliability, safety, and design efficiency of the anti-torsion mechanism under extreme environments, possessing significant engineering practical value and technological innovation. Through parametric finite element modeling and multivariate regression analysis, an explicit power-law equation is established between the leaf spring contact pressure and multiple factors (geometry, material, temperature, and operating conditions). This breaks away from the traditional blind design approach that relies on experience and repeated trial and error, shifting leaf spring design from "empirical" to "theoretical and data-driven." This study considers the coupled effects of factors such as leaf spring thickness, width, length, material modulus ratio, temperature effect, well inclination angle, and friction coefficient, and comprehensively reflects the independent effects of each factor through a product-form equation. This supports multi-parameter synergistic optimization during the design phase, balancing the contradictions between stiffness, strength, stability, and buffering capacity. Introducing a temperature correction term (including linear and nonlinear temperature effects) accurately reflects the impact of material property changes on the mechanical behavior of leaf springs under ultra-low temperature environments, improving the environmental adaptability and reliability of leaf springs in polar blue ice drilling. By optimizing leaf spring parameters, the torque-rotation angle characteristic curve of the anti-torsion device can be precisely controlled. This method achieves an optimal balance between ensuring drilling stability with high initial stiffness and achieving soft limit protection with low subsequent stiffness, effectively suppressing the "stick-slip" effect and impact torque overload, and protecting the armored cable and connector. Based on the parametric modeling and batch simulation analysis of the ABAQUS platform, multiple design schemes can be quickly generated and key performance data can be extracted, significantly shortening the design cycle and reducing the cost and risk of physical testing. The proposed design method is not only applicable to blue ice drilling, but can also be extended to the design of elastic elements in other extreme environments (such as deep sea and space) or complex working conditions, and has strong method universality and engineering application value. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0067] Figure 1 A flowchart of the method provided by the present invention;

[0068] Figure 2 The model simulation diagram provided for this invention;

[0069] Figure 3 This is a schematic diagram of the experimental platform structure provided by the present invention. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] This invention discloses a design method for a leaf spring in the anti-torsion mechanism of a blue ice drilling core tool, such as... Figure 1 As shown, it includes:

[0072] Establish a baseline finite element model, create a three-dimensional solid model of the leaf spring and well wall in ABAQUS software; set material properties, define a hard contact relationship between the outer surface of the leaf spring and the inner surface of the well wall, apply loads and boundary conditions, and set analysis steps and output variables;

[0073] Parametric modeling and experimental design: Determine design variables including geometric factors, material factors, temperature factors, and operating condition factors, and create several finite element models with different parameter combinations;

[0074] Run all finite element models sequentially or in parallel, extract the contact pressure results for each model, and record the results in a data table;

[0075] Using the data table, a power-law relationship equation was fitted using multiple linear regression to obtain the relationship between pressure and influencing factors.

[0076] To further optimize the above technical solution, the relationship equation between pressure and influencing factors is as follows:

[0077] ;

[0078] in, Indicates the width of the leaf spring. Indicates the thickness of the leaf spring. Indicates the length of the leaf spring. Indicates the elastic modulus of the leaf spring; This represents the elastic modulus of ice; Indicates temperature; Indicates the well inclination angle; Indicates the coefficient of friction; For dimensionless constants, ... , ... It is a power exponent; , This is the temperature coefficient.

[0079] Furthermore, as shown in Table 1, the parameter ranges are as follows:

[0080]

[0081] Considering that the influencing factors are small or fixed, it can be simplified to:

[0082] The coefficients are fitted using the least squares method or machine learning methods to obtain... ;

[0083] Based on this, the design method of this embodiment can be used for design prediction: inputting design parameters, predicting whether the contact pressure meets the requirements. It can also be used for parameter back-calculation: given a target pressure Ptarget, calculating h. b These parameters are used for sensitivity analysis: calculating the elasticity coefficients of each factor and identifying key variables.

[0084] Furthermore, in another embodiment, the influence of leaf spring width and thickness on leaf spring design is emphasized, specifically:

[0085] S1. Establish the baseline finite element model:

[0086] ① Create a three-dimensional solid model of the leaf spring and well wall in ABAQUS software;

[0087] ② Set material properties: The leaf spring is made of 60Si2Mn spring steel, the well wall is made of Antarctic blue ice, and a quarter-circle arc model is used;

[0088] ③ Define the contact pair: The outer surface of the leaf spring establishes a hard contact relationship with the inner surface of the well wall;

[0089] ④ Apply load and boundary conditions: One end of the leaf spring is fixed, and a displacement load is applied to the other end to make it bend;

[0090] ⑤ Set the analysis step and output variables: including contact pressure CPRESS and contact force CFN.

[0091] S2. Parametric Modeling and Experimental Design:

[0092] ① Determine the design variables: leaf spring thickness h∈[2,4]mm, width b∈[30,50]mm;

[0093] ② Create 25 finite element models with different parameter combinations;

[0094] Create 25 models with the following parameter combinations:

[0095] Thickness: 2, 2.5, 3, 3.5, 4 mm;

[0096] Widths: 30, 35, 40, 45, 50 mm;

[0097] ③ Each model is saved as a separate file;

[0098] S3. Batch Simulation Calculation:

[0099] ① Run all finite element models sequentially or in parallel;

[0100] ② Extract the contact pressure results for each model;

[0101] ③ Record the results in a data table in the format (h, b, P).

[0102]

[0103] S4. Relationship equation fitting:

[0104] ① Perform logarithmic transformations on the data: ln(P), ln(h), ln(b);

[0105] ② Use multiple linear regression to fit the power-law relationship equation: ;

[0106] Model building as Figure 2 As shown, in Abaqus, a baseline model is built with the following parameters:

[0107] Leaf spring: thickness h mm, width b mm, length 955.15 mm;

[0108] Well wall: Inner diameter 196mm, quarter-circle arc;

[0109] Materials: Leaf spring E=206000MPa, Ice E=9500MPa;

[0110] Mesh: Leaf spring unit size 1.0mm, well wall 1.0mm;

[0111] S5. Equation Fitting:

[0112] After performing a logarithmic transformation and regression analysis on the data, we obtained:

[0113] .

[0114] To further optimize the above technical solution, the specific steps to obtain the relationship between pressure and influencing factors are as follows:

[0115] Establish the basic relationship between contact pressure and geometric / material parameters. Assuming that one end of the leaf spring is fixed and the other end is subjected to a concentrated force F perpendicular to the axis, causing bending, derive the relationship between beam end deflection and load, and establish the connection between contact pressure and bending force.

[0116] Considering material compatibility, an equivalent modulus ratio is introduced; the elastic modulus of leaf springs and ice varies with temperature;

[0117] Introduce a well inclination angle to geometrically correct the contact area;

[0118] The coefficient of friction affects the shear stress distribution in the contact area, and thus influences the pressure by changing the effective contact stiffness or the size of the slip zone;

[0119] The effects of each factor on stress are independent of each other and combine in a product form. = [Geometric Term] [Materials] [Temperature Item] [Well-inclined term] [Friction term]; Substituting each sub-term into the formula yields the relationship between pressure and influencing factors.

[0120] To further optimize the above technical solution, the contact pressure calculation steps are as follows:

[0121] Establish a mechanical model of a leaf spring, with one end fixed and the other end subjected to a displacement load to cause it to bend. The moment of inertia of the rectangular cross-section is: Modulus of rectangular section ;

[0122] Deriving the relationship between beam end deflection and load: According to mechanics of materials, when a concentrated force F is applied to the free end of a cantilever beam: The maximum bending stress is ;

[0123] Load can be inversely derived from the deflection formula = (1)

[0124] Assuming the total pressure and bending force in the contact area are balanced, and the contact area... With leaf spring width and effective contact length Proportional:

[0125] ;

[0126] ;

[0127] Average contact pressure is Substituting into formula (1), we get:

[0128] Contact pressure and Proportional to, with Proportional to, with Proportional.

[0129] To further optimize the above technical solution, the equivalent modulus ratio is introduced to improve material matching. The specific steps are as follows:

[0130] According to Hertz's contact theory, when two elastic bodies are in contact, the contact pressure is related to the equivalent elastic modulus. Related:

[0131] ;

[0132] Contact pressure and equivalent modulus Proportional to the power of 1:

[0133] ;

[0134] When the elastic modulus of the leaf spring That is, when the leaf spring is much stiffer than ice: ;

[0135] Considering a more general case, we introduce the material stiffness ratio:

[0136] = .

[0137] To further optimize the above technical solution, the temperature term for determining the elastic modulus of leaf springs and ice as a function of temperature is as follows:

[0138] Formulas for the change of elastic modulus of leaf springs and ice with temperature:

[0139] ;

[0140] ;

[0141] ;

[0142]

[0143] in, This is the initial elastic modulus of the leaf spring. Let be the initial elastic modulus of ice, and represent the functions of elastic modulus of leaf spring and ice as a function of temperature, respectively.

[0144] for ;

[0145] Considering the combined effects of temperature on the two materials and the contact state:

[0146] .

[0147] To further optimize the above technical solution, the geometric correction of the contact area by the well inclination angle is introduced. The specific steps are as follows:

[0148] Force decomposition when the well inclination angle is At that time, the directional friction force is ; Tangential friction force is ;

[0149] Well inclination leads to asymmetry in the contact area, reducing the effective contact area. Assume the area correction factor is:

[0150] ;

[0151] in, This is the well inclination sensitivity coefficient;

[0152] Pressure is inversely proportional to contact area: .

[0153] To further optimize the above technical solution, the specific steps regarding the influence of the friction coefficient on the shear stress distribution in the contact area are as follows:

[0154] According to Coulomb's law of friction, frictional force Friction affects the stress distribution and slip conditions in the contact area;

[0155] The coefficient of friction affects the contact pressure distribution, exhibiting a power-law relationship: ;

[0156] in, The coefficient of friction; The friction index is determined by the contact conditions.

[0157] Another embodiment of the present invention discloses an experimental platform for the anti-torsion mechanism of a blue ice drilling core drilling tool. The leaf spring obtained by applying the above design method includes: a support 1, a well support 2, a telescopic component 3, a hand crank component 4, a leaf spring clamp 5, a strain gauge, and a simulated well 6.

[0158] The telescopic component 3 is installed on the bracket 1; the telescopic component 3 drives the hand crank component 4 to move up and down;

[0159] The output shaft end of the hand crank assembly 4 and the bottom surface of the bracket 1 are provided with a leaf spring clamp 5; the leaf spring is clamped on the leaf spring clamp 5; the simulated well barrel 6 is mounted on the bracket 1 through the well barrel bracket 2; the strain gauge is mounted on the inner wall of the simulated well barrel 6;

[0160] The counter-torque generated by the leaf spring and the inner wall of the simulated well 6 is balanced with the torque applied by the hand crank assembly 4; when the torque is manually increased, the maximum torque that the leaf spring can withstand is reached at the moment when relative rotation occurs between the leaf spring and the inner wall of the well; the torque value is obtained through a torque sensor, which is set on the output shaft, and the radial pressure is measured by strain gauges attached to the inner wall of the simulated well 6, transmitted to the computer and displayed in real time.

[0161] To further optimize the above technical solution, the well support 2 includes a fixed support 21, a fixed sleeve 22, and a fastening bolt 23; the simulated well 6 is set inside the fixed sleeve 22; the fixed sleeve 22 is hinged to the fixed support 21; the fixed sleeve 22 is fixed by the fastening bolt 23 to determine different well inclination angles.

[0162] In another embodiment, the well inclination adjustment method is as follows: by manually adjusting the degree of inclination of the simulated well shaft through four fastening bolts surrounding the upper and lower parts, the effect of simulating well inclination is achieved.

[0163] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0164] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for designing a leaf spring anti-torsion mechanism in a blue ice drilling core sampler, characterized in that: include: Establish a baseline finite element model, and create three-dimensional solid models of the leaf spring and well wall in ABAQUS software; Set material properties, define a hard contact relationship between the outer surface of the leaf spring and the inner surface of the well wall, apply loads and boundary conditions, and set analysis steps and output variables; Parametric modeling and experimental design: Determine design variables including geometric factors, material factors, temperature factors, and operating condition factors, and create several finite element models with different parameter combinations; Run all finite element models sequentially or in parallel and extract the contact pressure results for each model; And record the results in the data table; Using the aforementioned data table, a power-law equation was fitted using multiple linear regression to obtain the relationship between stress and influencing factors; the equation relating stress and influencing factors is as follows: ； in, Indicates the width of the leaf spring. Indicates the thickness of the leaf spring. Indicates the length of the leaf spring. Indicates the elastic modulus of the leaf spring; This represents the elastic modulus of ice; Indicates temperature; Indicates the well inclination angle; Indicates the coefficient of friction; A dimensionless constant. , , , , It is a power exponent; , This is the temperature coefficient.

2. The design method of the leaf spring anti-torsion mechanism for the blue ice drilling core tool according to claim 1, characterized in that, The specific steps to determine the relationship between stress and influencing factors are as follows: Establish the basic relationship between contact pressure and geometric / material parameters. Assuming that one end of the leaf spring is fixed and the other end is subjected to a concentrated force F perpendicular to the axis, causing bending, derive the relationship between beam end deflection and load, and establish the connection between contact pressure and bending force. Considering material compatibility, an equivalent modulus ratio is introduced; the elastic modulus of leaf springs and ice varies with temperature; Introduce a well inclination angle to geometrically correct the contact area; The coefficient of friction affects the shear stress distribution in the contact area, and thus influences the pressure by changing the effective contact stiffness or the size of the slip zone; The effects of each factor on stress are independent of each other and combine in a product form. = [Geometric Term] [Materials] [Temperature Item] [Well-inclined term] [Friction term]; Substituting each sub-term into the formula yields the relationship between pressure and influencing factors.

3. The design method of the leaf spring anti-torsion mechanism for the blue ice drilling core drilling tool according to claim 2, characterized in that, The steps for calculating contact pressure are as follows: Establish a mechanical model of a leaf spring, with one end fixed and the other end subjected to a displacement load to cause it to bend. The moment of inertia of the rectangular cross-section is: Modulus of rectangular section ; Deriving the relationship between beam end deflection and load: According to mechanics of materials, when a concentrated force F is applied to the free end of a cantilever beam: The maximum bending stress is ; Load can be inversely derived from the deflection formula = (1) Assuming the total pressure and bending force in the contact area are balanced, and the contact area... With leaf spring width and effective contact length Proportional: ； ； Average contact pressure is Substituting into formula (1), we get: ; Contact pressure and Proportional to, with Proportional to, with Proportional.

4. The design method of the leaf spring anti-torsion mechanism for the blue ice drilling core drilling tool according to claim 2, characterized in that, Material compatibility is introduced by incorporating an equivalent modulus ratio. The specific steps are as follows: According to Hertz's contact theory, when two elastic bodies are in contact, the contact pressure is related to the equivalent elastic modulus. Related: ； Contact pressure and equivalent modulus Proportional to the power of 1: ； When the elastic modulus of the leaf spring That is, when the leaf spring is much stiffer than ice: ; Introducing material stiffness ratio: = .

5. The design method of the leaf spring anti-torsion mechanism for the blue ice drilling core extraction tool according to claim 2, characterized in that, The steps for determining the temperature term to account for the change in the elastic modulus of leaf springs and ice with temperature are as follows: Formulas for the change of elastic modulus of leaf springs and ice with temperature: ； ； ； ； in, This is the initial elastic modulus of the leaf spring. Let be the initial elastic modulus of ice, and represent the functions of elastic modulus of leaf spring and ice as a function of temperature, respectively. for ; Considering the combined effects of temperature on the two materials and the contact state: 。 6. The design method of the leaf spring anti-torsion mechanism for the blue ice drilling core drilling tool according to claim 2, characterized in that, The specific steps for introducing the well inclination angle to geometrically correct the contact area are as follows: Force decomposition when the well inclination angle is At that time, the directional friction force is ; Tangential friction force is ; Well inclination leads to asymmetry in the contact area, reducing the effective contact area. Assume the area correction factor is: ； in, This is the well inclination sensitivity coefficient; Pressure is inversely proportional to contact area: .

7. The design method of the leaf spring anti-torsion mechanism for the blue ice drilling core extraction tool according to claim 2, characterized in that, The specific steps to determine how the friction coefficient affects the shear stress distribution in the contact area are as follows: According to Coulomb's law of friction, frictional force Friction affects the stress distribution and slip conditions in the contact area; The coefficient of friction affects the contact pressure distribution, exhibiting a power-law relationship: ; in, The coefficient of friction; The friction index is determined by the contact conditions.

8. An experimental platform for the anti-torsion mechanism of a blue ice drilling core tool, comprising a leaf spring obtained by applying the leaf spring design method for the anti-torsion mechanism of a blue ice drilling core tool according to any one of claims 1-7, characterized in that... include: Support frame, well shaft support frame, telescopic assembly, hand crank assembly, leaf spring clamp, strain gauge and simulated well shaft; The telescopic component is mounted on the bracket; The telescopic component drives the hand crank component to move up and down; The output shaft end of the hand crank assembly and the bottom surface of the bracket are provided with leaf spring clamps; the leaf spring is clamped on the leaf spring clamps; the simulated well barrel is mounted on the bracket via the well barrel bracket; the strain gauge is mounted on the inner wall of the simulated well barrel; The counter-torque generated by the leaf spring and the inner wall of the simulated well is balanced with the torque applied by the hand crank assembly; when the torque is manually increased, the maximum torque that the leaf spring can withstand is reached at the moment when relative rotation occurs between the leaf spring and the inner wall of the well; the torque value is obtained through a torque sensor, which is set on the output shaft, and the radial pressure is measured by strain gauges attached to the inner wall of the simulated well, transmitted to the computer and displayed in real time.

9. The experimental platform for the anti-torsion mechanism of a blue ice drilling core extraction tool according to claim 8, characterized in that, The wellbore support includes a fixed bracket, a fixed sleeve, and fastening bolts; the simulated wellbore is set inside the fixed sleeve; the fixed sleeve is hinged to the fixed bracket; the fixed sleeve is fixed by the fastening bolts to determine different well inclination angles.

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