Telescope athermalization design and manufacturing method suitable for south pole end station site environment

Abstract

The invention belongs to the technical field of optical-mechanical structure design and manufacturing, and discloses a telescope athermalization design and manufacturing method suitable for the Antarctic extreme station site environment, and the method comprises the following steps: 1, building a thermal response model according to a temperature range; 2, establishing a thermal expansion characteristic curve according to thermal environment characteristics, matching thermal performances of the primary mirror, the secondary mirror, the lens cone and the support structure through a material database and a prediction model, and selecting corresponding materials; 3, according to a thermal analysis result, topological optimization and parametric modeling are carried out on a primary mirror support, a secondary mirror support and a lens cone connection node, an optimal support position, a stress path and an error chain under different temperature loads are obtained, and a reserved assembly compensation amount is obtained; and 4, according to the material and the reserved assembly compensation amount, carrying out partition modular 3D printing and assembly on the telescope. According to the design and manufacturing method provided by the invention, through collaborative optimization of materials, structures and manufacturing, low-heat deformation of the telescope in an extreme environment can be realized.

Description

Technical Field

[0001] This invention relates to the field of optomechanical structure design and manufacturing technology, and in particular to a method for the calorimetric design and fabrication of a telescope suitable for the extreme environment of Antarctica. Background Technology

[0002] In extreme environments such as Dome A in Antarctica, temperatures can drop as low as -80 degrees Celsius, with significant diurnal temperature variations. Under these conditions, giant, precision instruments like telescopes are prone to problems such as mismatched thermal expansion coefficients between structures, thermal deformation of mirrors, and optical axis misalignment, severely impacting image quality and optical stability.

[0003] Traditional methods often employ low-expansion designs using single materials or simple passive insulation measures, but they cannot achieve complete heatlessness from the perspective of integrating material design, structural design, and manufacturing processes. Especially in systems with multiple components such as the primary mirror, secondary mirror, and supporting truss of a dual-reflection telescope, differences in thermal expansion between parts can lead to thermal stress concentration and the accumulation of assembly errors, resulting in optical axis drift and a decline in optical performance.

[0004] Therefore, there is an urgent need for a thermal design method that can work together on materials, structure and manufacturing to achieve structural and optical stability of the telescope in extreme low-temperature environments. Summary of the Invention

[0005] To address the problem in existing technologies where thermal expansion differences in various parts of a telescope under extreme environments lead to thermal stress concentration and assembly error accumulation, resulting in optical axis drift and decreased optical performance, this invention proposes a heatless design and manufacturing method for a telescope suitable for the extreme environment of Antarctica. Through reasonable material selection, structural matching, error chain compensation, and 3D printing manufacturing technology, the key structures of the telescope achieve low thermal deformation and high stability in a wide temperature range environment.

[0006] This invention is achieved through the following technical solution, including the following steps:

[0007] Step 1: Based on the measured temperature of the extreme site area and the ambient temperature range of the assembly site, establish a thermal response model of the telescope in a cross-temperature range environment. Analyze the linear expansion, thermal stress distribution deformation mode and optical axis offset trend of the primary mirror, secondary mirror and support structure, identify the heat-sensitive area and obtain the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the telescope tube and the optical axis drift.

[0008] Step 2: Based on the thermal environment characteristics, select a low thermal expansion material with a thermal expansion coefficient close to zero, establish the thermal expansion characteristic curve of the low thermal expansion material within the measured temperature range of the extreme site area determined in Step 1, and match the thermal performance of the primary mirror, secondary mirror, mirror tube and support structure through the material database and prediction model to select the corresponding material.

[0009] Step 3: Based on the thermal analysis results obtained in Step 1, perform topology optimization and parametric modeling on the primary mirror support, secondary mirror bracket and mirror tube connection nodes to obtain the optimal support position and force path under different temperature loads. Using the finite element analysis method, calculate the thermal stress, node deformation and optical axis deviation caused by temperature changes, identify high stress concentration areas and thermal deformation sensitive points, and calculate the error chain at this point to obtain the reserved assembly compensation amount.

[0010] Step 4: Based on the materials matched in Step 2 and the optimal support position and force path, high stress concentration area and heat deformation sensitive point obtained in Step 3, as well as the reserved assembly compensation amount, the telescope is 3D printed and assembled in a modular manner.

[0011] As a further preferred option, the specific steps of step 1 are as follows:

[0012] Step 1.1: Construct cross-temperature range heat input, including the measured temperature range of extreme site areas, assembly site temperature, temperature change rate and gradient, and material thermal properties;

[0013] Step 1.2: Solve the temperature field using Fourier thermal conductivity variance to obtain the steady-state and transient temperature distributions of the mirror, mirror tube, and support nodes. The formulas are as follows:

[0014] ;

[0015] In the formula, k represents the thermal conductivity of the material; T represents the temperature field function; q represents the internal heat source term; ρ represents the material density; and c represents the specific heat capacity of the material. Represents the Laplace operator;

[0016] Step 1.3: Solve for the thermal stress field using the thermal strain and Hooke's law to obtain the thermal stress contour maps for each part. The formula is as follows:

[0017] ;

[0018] ;

[0019] In the formula, ε t α(T) represents thermal strain; α(T) represents the coefficient of linear expansion of the material; ΔT represents the temperature difference; σ represents thermal stress; E represents the elastic modulus of the material; ε represents the total strain.

[0020] Step 1.4: Use the finite element method to solve the thermal deformation mode and obtain the nodal displacements, thereby obtaining the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the mirror tube, and the optical axis drift.

[0021] Step 1.5: Use threshold screening and sensitivity analysis to identify heat-sensitive areas and obtain the heat-sensitive areas.

[0022] As a further preferred option, the specific steps of step 2 are as follows:

[0023] Step 2.1: Predict the temperature-dependent coefficient of linear expansion (CTE) of the material using the CALPHAD prediction method, construct the thermal expansion curve of the material, and obtain the thermal expansion curve of each material within the measured temperature range of the extreme site region. The formula is as follows:

[0024] ;

[0025] In the formula, α(T) represents the linear expansion coefficient of the material; a0, a1, and a2 represent the constant coefficients of the polynomial fitting, respectively.

[0026] Step 2.2: By solving for the strain difference of different materials, the thermal strain of different components is matched. The formula is as follows:

[0027] ;

[0028] In the formula, α1(T) represents the strain difference of the material; α2(T) and α1(T) represent the coefficients of linear expansion of material 1 and material 2 at the instantaneous temperature T, respectively.

[0029] The constraints are as follows:

[0030] ;

[0031] In the formula, This indicates the upper limit of the allowable relative thermal strain difference, i.e., the engineering allowable value;

[0032] Step 2.3: Use a thermal compensation structure between the various parts of the telescope.

[0033] As a further preferred embodiment, the specific steps of step 3 are as follows:

[0034] Step 3.1: Using the minimum compliance objective function in the finite element analysis method, topology optimization is performed to find the optimal support layout, obtaining the optimal support point positions and force paths for the primary and secondary mirrors, as shown in the following formula:

[0035] ;

[0036] In the formula, C represents structural flexibility; F represents the nodal load vector; and U represents the displacement vector.

[0037] Step 3.2: Construct the error chain to obtain the reserved assembly compensation amount, as shown in the following formula:

[0038] ;

[0039] ;

[0040] ;

[0041] In the formula, Indicates the amount reserved for assembly compensation; k i δ represents the transfer coefficient of the i-th error source to the final optomechanical reference; i This represents the i-th assembly error term; Indicates the cumulative amount of heat deformation chain; m i ε represents the structural transfer coefficient of the i-th heat deformation source; i This represents the thermal strain of the i-th component.

[0042] As a further preferred option, the specific steps of step 4 are as follows:

[0043] Step 4.1: Divide the telescope into several functional modules, including the primary mirror assembly, secondary mirror assembly, telescope tube connection module, and support base module. 3D print each module according to the thermal properties and materials matched in Step 2.

[0044] Step 4.2: Based on the optimal support position and force path obtained in Step 3, 3D hybrid printing is adopted, combined with metal-ceramic-composite material gradient printing, and the printing path and material ratio are adjusted.

[0045] Step 4.3: Based on the reserved assembly compensation amount obtained in Step 3, assemble the modules using a thermal compensation structure.

[0046] As a further preferred embodiment, the thermal compensation structure in step 2.3 includes a thermal compensation ring, a thermal isolation layer, and a flexible transition interface.

[0047] As a further preferred option, a controllable elastic connection structure is adopted at the flexible transition interface, which is composed of an elastic leaf spring or a flexible diaphragm.

[0048] As a further preferred option, in step 4.1, cordierite is used to integrally print the primary mirror assembly, secondary mirror assembly, mirror barrel connection module, and support base module.

[0049] As a further preferred option, in step 4.2, a high-stiffness material is used in the central region of the module, and a low-expansion material is used in the edge region.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] 1. The design and manufacturing method proposed in this invention achieves low thermal deformation of the telescope in an environment of -80℃ to +20℃ through the synergistic optimization of materials, structure and manufacturing.

[0052] 2. The design and manufacturing method proposed in this invention utilizes CALPHAD and machine learning to predict the thermal properties of novel composite materials, ensuring thermal expansion matching of multiple components.

[0053] 3. The design and fabrication method proposed in this invention adopts partitioned printing and functionally graded materials technology to achieve integrated topology optimization and thermal matching.

[0054] 4. The design and manufacturing method proposed in this invention achieves long-term stability of optical axis accuracy under extreme environments through error chains and flexible assembly.

[0055] 5. The design and manufacturing method proposed in this invention has a wide range of applications and can be widely used in fields such as large double-reflection telescopes and lightweight space optical systems at Antarctic and plateau astronomical observatories. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the overall structure of the telescope.

[0057] The image shows:

[0058] 1. Secondary mirror holder; 2. Secondary mirror; 3. Mirror tube; 4. Primary mirror; 5. Primary mirror support; 6. Base. Detailed Implementation

[0059] The advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings.

[0060] like Figure 1 As shown, a large telescope generally consists of a primary mirror 4, a primary mirror support 5, a base 6, a secondary mirror 2, a telescope tube 3, and a secondary mirror holder 1. The purpose of this invention is to achieve low thermal deformation and high stability of the telescope's key structures in a wide temperature range environment through reasonable material selection, structural matching, error chain compensation, and 3D printing manufacturing technology.

[0061] This invention provides a method for the design and fabrication of a telescope without heat, suitable for the extreme environment of Antarctica, comprising the following steps:

[0062] Step 1: Based on the measured temperature of the extreme site area and the ambient temperature range of the assembly site, establish a thermal response model of the telescope in a cross-temperature range environment. Analyze the linear expansion, thermal stress distribution deformation mode and optical axis offset trend of the primary mirror, secondary mirror and support structure, identify the thermally sensitive areas and obtain the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the telescope tube and the optical axis drift.

[0063] The extreme test sites mentioned are mainly located in regions with extreme temperatures and large diurnal temperature variations, such as Antarctica and high-altitude areas. For example, the measured temperature range in Antarctica is -80℃ to +20℃. In contrast, the assembly and testing sites are primarily located in China, with temperatures around 20℃, significantly different from the operating environment. The telescope is typically designed, manufactured, and assembled at room temperature, but when put into use, it must withstand extremely low temperatures and wide temperature range cycling for extended periods, leading to significant changes in material properties, structural clearances, and assembly prestress.

[0064] Therefore, in this invention, it is first necessary to establish a temperature cross-domain model of the telescope from the domestic assembly environment (approximately 20°C) to the Antarctic operating environment (minimum -80°C) to perform thermal response analysis on key components, including changes in the coefficient of linear expansion, thermal stress distribution, deformation modes, and optical axis offset trends. Simultaneously, thermally sensitive areas in the system, such as the primary mirror support point, truss connection nodes, and mirror fixing structure, are identified to provide input conditions for subsequent material matching, structural optimization, and compensation design. The thermal response model construction process of this invention is as follows:

[0065] Step 1.1: Construct cross-temperature range heat input, including the measured temperature range of extreme site areas, assembly site temperature, temperature change rate and gradient, and material thermal properties, including CTE, specific heat and thermal conductivity.

[0066] Step 1.2: Solve the temperature field using Fourier thermal conductivity variance to obtain the steady-state and transient temperature distributions of the mirror, mirror tube, and support nodes. The formulas are as follows:

[0067] ;

[0068] In the formula, k represents the thermal conductivity of the material, which characterizes the material's ability to conduct heat under a unit temperature gradient, with units of W / (m·K); T represents the temperature field function, which describes the temperature distribution at any location in the structure over time, with units of K; q represents the internal heat source term, including the intensity of the volumetric heat source generated by environmental radiation, absorbed heat flow, or internal heat dissipation, with units of W / m³; ρ represents the material density, which measures the mass per unit volume of the material, with units of kg / m³; and c represents the specific heat capacity of the material, which describes the amount of heat absorbed by the material to increase its mass by 1 K, with units of J / (kg·K). This represents the Laplace operator, used to describe the sum of the second-order partial derivatives of temperature in three spatial directions, i.e., the spatial diffusion characteristics of the temperature field.

[0069] Step 1.3: Solve for the thermal stress field using the thermal strain and Hooke's law to obtain the thermal stress contour maps for each part. The formula is as follows:

[0070] ;

[0071] ;

[0072] In the formula, ε t The following parameters represent the thermal strain, used to describe the free expansion or contraction of a material due to temperature changes; T represents the temperature field function, used to describe the temperature distribution at any location in the structure over time, in Kelvin; α(T) represents the linear expansion coefficient of the material, which varies with temperature T and describes the expansion per unit length of the material with temperature changes; ΔT represents the temperature difference, the temperature change between the structure's operating temperature and the assembly reference temperature; σ represents thermal stress, i.e., the equivalent mechanical stress caused by the restricted thermal expansion within the structure, in Pa; E represents the elastic modulus (Young's modulus), used to describe the linear elastic response of the material under tensile or compressive conditions, in Pa; ε represents the total strain, including the thermal strain and the elastic strain component caused by force.

[0073] Step 1.4: Use the finite element method to solve the thermal deformation mode and obtain the nodal displacements, thereby obtaining the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the mirror tube, and the optical axis drift.

[0074] Step 1.5: Use threshold screening and sensitivity analysis to identify heat-sensitive areas and obtain the heat-sensitive areas.

[0075] Based on experience, the heat-sensitive areas in the structure of large telescopes are generally the main mirror support points, the telescope tube nodes, and the mirror fixing structures. These will serve as the core inputs for subsequent material matching and compensation design.

[0076] Step 2: Based on the characteristics of the thermal environment, select a low thermal expansion material with a thermal expansion coefficient close to zero, establish the thermal expansion characteristic curve of the low thermal expansion material within the measured temperature range of the extreme site area determined in Step 1, and match the thermal performance of the primary mirror, secondary mirror, mirror tube and support structure through the material database and prediction model to achieve overall thermal strain coordination and avoid thermal stress concentration.

[0077] After completing the thermal environment characteristic analysis, this invention addresses the thermal deformation problem under the extreme temperature difference conditions in Antarctica by using material selection and structural co-design to achieve the athermal characteristics of the telescope.

[0078] First, based on the functional differences of key components such as the primary mirror, secondary mirror, mirror tube, and support structure, the coefficient of linear expansion (CTE) of different components is systematically matched. Low thermal expansion materials such as cordierite, Invar alloy, and carbon fiber reinforced polymer (CFRP) are used. These low thermal expansion materials have a near-zero coefficient of thermal expansion. Using a material thermal performance database and the phase diagram calculation prediction method (CALculation of PHAse Diagrams, or CALPHAD prediction method), their thermal expansion characteristic curves within the range of -80℃ to +20℃ are established, achieving precise control of thermal strain across the temperature range.

[0079] Secondly, regarding the overall structure of the telescope, this invention adopts a 3D printing modular manufacturing strategy, dividing the entire device into main modules such as the primary mirror assembly, secondary mirror assembly, telescope tube connecting section, and support base. Each module can be integrally printed using the same type of material with a near-zero coefficient of thermal expansion (such as cordierite), achieving consistency in material thermal properties, avoiding thermal stress concentration at the interface of heterogeneous materials, and thus achieving thermal matching and heatless operation of the overall structure.

[0080] In addition, flexible transition interfaces or interfaces with the same expansion ratio are set at the structural connection points, so that different functional modules can maintain mechanical continuity and optical alignment stability when the temperature changes drastically, thereby effectively suppressing optical axis shift and imaging distortion caused by temperature changes.

[0081] Through the above-mentioned material matching and structural optimization design, the present invention can maintain the stability of the optical system under extreme temperature change conditions and achieve the adaptive anechoic structure performance of the telescope.

[0082] The specific process for matching the thermal properties of the materials with the various components of the telescope is as follows:

[0083] Step 2.1: Predict the temperature-dependent coefficient of linear expansion (CTE) of the material using the CALPHAD prediction method, construct the thermal expansion curve of the material, and obtain the thermal expansion curve of each material within the measured temperature range of the extreme site region. The formula is as follows:

[0084] ;

[0085] In the formula, α(T) represents the linear expansion coefficient of the material, which varies with temperature T and is used to describe the expansion per unit length of the material with temperature changes; a0, a1, and a2 represent the constant coefficients of the polynomial fitting: a0: constant term, characterizing the baseline CTE value (unit K) near T=0. -1 a1: Linear coefficient, describing the degree to which CTE changes linearly with temperature (unit: K). -2 a2: Quadratic coefficient, describing the quadratic nonlinear component of CTE with temperature (unit: K). -3The specific values ​​of coefficients a0, a1, and a2 are obtained by regression fitting of CALPHAD predicted data and experimental measurement data, and their confidence intervals or fitting errors should be reported.

[0086] Step 2.2: By solving for the strain difference of different materials, the thermal strain of different components is matched. The formula is as follows:

[0087] ;

[0088] In the formula, The strain difference of the material is represented by Δε; Δε represents the temperature difference between the reference temperature and the actual temperature. Change to operating temperature The difference in cumulative thermal strain between material 1 and material 2 during the process (dimensionless, or expressed in m / m); α1(T) and α2(T) represent the linear expansion coefficients of material 1 and material 2 at instantaneous temperature T, respectively; here α1(T) and α2(T) have the same meaning as the previous α(T), and are both temperature-dependent CTE functions.

[0089] The constraints are as follows:

[0090]

[0091] In the formula, This indicates the upper limit of the allowable relative thermal strain difference (engineering tolerance), used to determine whether the thermal matching between two materials meets the system's optical / mechanical tolerances;

[0092] By solving for the strain difference of different materials and matching the thermal strain of different components, thermal consistency between the primary mirror, secondary mirror, and mirror tube can be achieved.

[0093] Step 2.3: A thermal compensation structure is used between the various parts of the telescope to achieve thermal strain coordination. The thermal compensation structure includes a thermal compensation ring, a thermal isolation layer and a controllable flexible transition interface, which is used to reduce thermal stress concentration between different parts and maintain structural continuity, so that local expansion differences are absorbed and thermal stress concentration is avoided.

[0094] A controllable elastic connection structure, consisting of elastic leaf springs or flexible diaphragms, is used at the flexible transition interface to maintain the stability of the optical axis direction when the temperature changes.

[0095] Step 3: Based on the thermal analysis results obtained in Step 1, namely the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the mirror tube, and the optical axis drift, perform topology optimization and parametric modeling on the primary mirror support, secondary mirror bracket, and mirror tube connection nodes to obtain the optimal support position and force path under different temperature loads. Using the finite element analysis (FEA) method, calculate the thermal stress, node deformation, and optical axis deviation caused by temperature changes, identify high stress concentration areas and thermal deformation sensitive points, and calculate the error chain at these points to obtain the reserved assembly compensation amount.

[0096] After determining the material system and thermal expansion matching scheme, the present invention further carried out structural optimization and thermal compensation design for the key load-bearing components of the telescope to achieve low thermal deformation and optical axis stability of the overall structure under extreme environments.

[0097] First, based on the preliminary thermal analysis results, topology optimization and parametric modeling were performed on the primary mirror support, secondary mirror bracket, and truss connection nodes to determine the optimal support positions and force paths under different temperature loads. Then, using finite element analysis (FEA), the thermal stress, node deformation, and optical axis deviation caused by temperature changes were calculated, identifying high stress concentration areas and thermal deformation sensitive points.

[0098] Secondly, a thermal compensation structure and a flexible support mechanism are introduced at the key connection points of the telescope structure. The thermal compensation structure includes a thermal compensation ring, a thermal insulation layer, and a controllable flexible transition interface, which are used to absorb the slight expansion differences between different components and reduce stress concentration at the interface; the flexible support mechanism achieves flexible decoupling between the primary mirror and the support through adjustable elastic elements (such as thin film supports, elastic leaf springs, etc.), so that the system maintains the stability of the optical axis direction when the system contracts at low temperatures or expands at high temperatures.

[0099] Meanwhile, this invention systematically analyzes structural assembly tolerances based on the "error chain theory," reserving assembly compensation amounts during the design phase. By adjusting the preload and assembly sequence, assembly errors and thermal deformation errors cancel each other out, achieving consistency between the assembled state and the service state. The specific steps are as follows:

[0100] Step 3.1: Using the minimum compliance objective function in the finite element analysis (FEA) method, perform topology optimization to find the optimal support layout, and obtain the optimal support point positions and force paths for the primary and secondary mirrors, as shown in the following formula:

[0101]

[0102] In the formula, C represents structural compliance, a measure of the total deformation energy of the structure under external loads, measured in work (J). A smaller C indicates higher overall structural stiffness and a more optimal force path. Topology optimization aims to minimize C to find the optimal material distribution and support layout. F represents the external nodal force vector, representing the external forces applied to the structure, including gravity, primary mirror self-weight, installation and adjustment forces, or equivalent wind loads, typically measured in N; F is the input to the finite element model. U represents the nodal displacement vector, the nodal displacement response obtained from the finite element solution, measured in meters; U is the deformation result of the structure under load F.

[0103] Step 3.2: Construct the error chain to obtain the reserved assembly compensation amount, as shown in the following formula:

[0104]

[0105]

[0106]

[0107] In the formula, Indicates the allowance for assembly compensation; indicates the amount that needs to be pre-adjusted during assembly to offset various assembly error items, in meters or μm; k i δ represents the transfer coefficient of the i-th error source to the final optomechanical reference, dimensionless; it describes the proportion of the influence of this error on the final optical axis / mirror position; i This represents the i-th assembly error term, which may include machining errors, positioning errors, fixture errors, installation deviations, etc., in meters (m); Δx t This represents the cumulative amount of thermal deformation chain, in meters (m); it also represents the final positional deviation caused by changes in ambient temperature and inconsistent thermal expansion of the structure; in meters (m). i ε represents the structural transfer coefficient of the i-th thermal deformation source, dimensionless; it describes the amplification or attenuation effect of the thermal strain of this component on the final reference point or optical axis position; i Let represent the thermal strain of the i-th component, which is dimensionless.

[0108] Error chain compensation, achieved by adjusting preload, assembly sequence, and interface gaps during assembly, allows thermal deformation errors to cancel out assembly errors. Through these thermal compensation and structural optimization methods, the telescope of this invention maintains structural stability and optical performance across a wide temperature range of -80℃ to +20℃, achieving the goal of a thermal-free, integrated optomechanical structure design.

[0109] Step 4: Based on the materials matched in Step 2 and the optimal support position and force path, high stress concentration area and heat deformation sensitive point obtained in Step 3, as well as the reserved assembly compensation amount, the telescope is 3D printed and assembled in a modular manner.

[0110] After completing the thermal performance matching and structural optimization design, this invention proposes a heatless manufacturing and assembly method for telescopes based on 3D hybrid printing technology, realizing an integrated process from material design to whole-machine forming.

[0111] First, based on the functional requirements and stress characteristics of each module, materials with a coefficient of thermal expansion close to zero (such as cordierite, Invar alloy, or composite ceramic materials) are selected for printing to ensure the consistency of thermal performance between modules. For core structures such as the primary mirror, secondary mirror, and truss, the same material can be used for integral printing, thereby achieving thermal matching at the source and avoiding thermal stress concentration at heterogeneous interfaces.

[0112] Secondly, this invention employs 3D hybrid printing technology, combining metal, ceramic, and composite material gradient printing processes to achieve integrated manufacturing of multiple materials. Through zoned printing path planning and functionally graded material design, a balance between mechanical strength and thermal performance can be achieved in different regions, ensuring structural rigidity while reducing thermal deformation. After printing, the modules are assembled through high-precision interface positioning and flexible connections, achieving high dimensional consistency and assembly compensation capabilities.

[0113] The assembly process employs a "regional overall printing + modular assembly compensation" strategy. This means achieving high precision in localized areas during the printing stage and compensating for assembly errors and thermal strain differences during the assembly stage through fine-tuning interfaces. By combining error chain theory and preload control methods, optical axis consistency and structural stability can be maintained during low-temperature shrinkage and high-temperature expansion cycles.

[0114] The specific steps are as follows:

[0115] Step 4.1: Divide the telescope into several functional modules, including the primary mirror assembly, secondary mirror assembly, telescope tube connection module, and support base module. 3D print each module according to the thermal performance and materials matched in Step 2 to ensure that the thermal performance between modules is consistent.

[0116] Step 4.2: Based on the optimal support position and force path obtained in Step 3, 3D hybrid printing is adopted, combined with metal-ceramic-composite material gradient printing, and the printing path and material ratio are adjusted to achieve continuous transition of mechanical and thermal properties in different regions.

[0117] High-rigidity materials can be used in the central area of ​​the module, while low-expansion materials can be used in the edge areas, thereby achieving a continuous transition in thermal performance, enhanced mechanical properties, and reduced thermal stress.

[0118] Step 4.3: Based on the reserved assembly compensation amount obtained in Step 3, a thermal compensation structure is used to assemble the modules to achieve optical axis consistency.

[0119] Through the above process, this invention achieves full-process thermal stability control of the telescope from material selection and printing manufacturing to structural assembly, significantly improving the morphological stability and optical performance reliability of the entire instrument in the extreme Antarctic environment.

[0120] To verify the effectiveness and engineering feasibility of the calorimetric design method for the telescope of this invention, multi-stage engineering prototype manufacturing and environmental simulation testing were carried out.

[0121] First, based on the above design scheme, typical structural units (including the primary mirror support unit, truss connection unit, and secondary mirror assembly) were selected for 3D printing and assembly of engineering verification prototypes. Using the same material system as the actual telescope (e.g., cordierite or low-expansion Invar alloy), representative prototypes were manufactured through partitioned printing, modular connection, and assembly compensation processes.

[0122] Secondly, thermal vacuum testing and low-temperature deformation measurement experiments were conducted in a laboratory environment. The sample was subjected to a temperature cycle from 20°C to -80°C in a temperature-controlled chamber, and structural deformation, optical axis misalignment, and nodal stress were monitored in real time using a laser interferometer and a three-dimensional displacement sensing system. Experimental results show that the thermal matching design, flexible support structure, and error chain compensation mechanism proposed in this invention can effectively suppress thermal deformation. The optical axis drift between the primary and secondary mirrors is less than the design tolerance range, verifying the stability of the anechoic design.

[0123] Finally, the method of the present invention was verified by comparing the results with the experimental results through finite element analysis (FEA), which confirmed that the method of the present invention can significantly reduce the thermal stress and overall deformation of the structure under extreme temperature differences, thereby improving the structural reliability and optical imaging stability of the telescope system.

[0124] Based on the above engineering verification and test results, this invention demonstrates that the proposed calorimetric design method for telescopes has good feasibility and stable technical effects in the extreme environment of Antarctica, providing a feasible engineering path for the design and manufacturing of subsequent large-scale precision optical and mechanical equipment in polar regions.

[0125] The calorimetric design and fabrication method for telescopes suitable for the extreme environment of Antarctica described in this invention can be extended to the calorimetric structural design of large-scale precision optomechanical equipment in other extreme temperature difference environments.

[0126] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A method for the calorimetric design and fabrication of a telescope suitable for the extreme environment of Antarctica, characterized in that: Includes the following steps: Step 1: Based on the measured temperature of the extreme site area and the ambient temperature range of the assembly site, establish a thermal response model of the telescope in a cross-temperature range environment. Analyze the linear expansion, thermal stress distribution deformation mode and optical axis offset trend of the primary mirror, secondary mirror and support structure, identify the heat-sensitive area and obtain the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the telescope tube and the optical axis drift. Step 2: Based on the thermal environment characteristics, select a low thermal expansion material with a thermal expansion coefficient close to zero, establish the thermal expansion characteristic curve of the low thermal expansion material within the measured temperature range of the extreme site area determined in Step 1, and match the thermal performance of the primary mirror, secondary mirror, mirror tube and support structure through the material database and prediction model to select the corresponding material. Step 3: Based on the thermal analysis results obtained in Step 1, perform topology optimization and parametric modeling on the primary mirror support, secondary mirror bracket and mirror tube connection nodes to obtain the optimal support position and force path under different temperature loads. Using the finite element analysis method, calculate the thermal stress, node deformation and optical axis deviation caused by temperature changes, identify high stress concentration areas and thermal deformation sensitive points, and calculate the error chain at this point to obtain the reserved assembly compensation amount. Step 4: Based on the materials matched in Step 2 and the optimal support position and force path, high stress concentration area and heat deformation sensitive point obtained in Step 3, as well as the reserved assembly compensation amount, the telescope is 3D printed and assembled in a modular manner.

2. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 1, is characterized in that: The specific steps of step 1 are as follows: Step 1.1: Construct cross-temperature range heat input, including the measured temperature range of extreme site areas, assembly site temperature, temperature change rate and gradient, and material thermal properties; Step 1.2: Solve the temperature field using Fourier thermal conductivity variance to obtain the steady-state and transient temperature distributions of the mirror, mirror tube, and support nodes. The formulas are as follows: ； In the formula, k represents the thermal conductivity of the material; T represents the temperature field function; q represents the internal heat source term; ρ represents the material density; and c represents the specific heat capacity of the material. Represents the Laplace operator; Step 1.3: Solve for the thermal stress field using the thermal strain and Hooke's law to obtain the thermal stress contour maps for each part. The formula is as follows: ； ； In the formula, ε t α(T) represents thermal strain; α(T) represents the coefficient of linear expansion of the material; ΔT represents the temperature difference; σ represents thermal stress; E represents the elastic modulus of the material; ε represents the total strain. Step 1.4: Use the finite element method to solve the thermal deformation mode and obtain the nodal displacements, thereby obtaining the thermal deformation of the primary mirror surface, the displacement and tilt angle of the secondary mirror, the axial and radial shrinkage of the mirror tube, and the optical axis drift. Step 1.5: Use threshold screening and sensitivity analysis to identify heat-sensitive areas and obtain the heat-sensitive areas.

3. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 2, is characterized in that: The specific steps of step 2 are as follows: Step 2.1: Predict the temperature-dependent coefficient of linear expansion (CTE) of the material using the CALPHAD prediction method, construct the thermal expansion curve of the material, and obtain the thermal expansion curve of each material within the measured temperature range of the extreme site region. The formula is as follows: ； In the formula, α(T) represents the linear expansion coefficient of the material; a0, a1, and a2 represent the constant coefficients of the polynomial fitting, respectively. Step 2.2: By solving for the strain difference of different materials, the thermal strain of different components is matched. The formula is as follows: ； In the formula, α1(T) represents the strain difference of the material; α2(T) and α1(T) represent the coefficients of linear expansion of material 1 and material 2 at the instantaneous temperature T, respectively. The constraints are as follows: ； In the formula, This indicates the upper limit of the allowable relative thermal strain difference, i.e., the engineering allowable value; Step 2.3: Use a thermal compensation structure between the various parts of the telescope.

4. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 3, is characterized in that: The specific steps of step 3 are as follows: Step 3.1: Using the minimum compliance objective function in the finite element analysis method, topology optimization is performed to find the optimal support layout, obtaining the optimal support point positions and force paths for the primary and secondary mirrors, as shown in the following formula: ； In the formula, C represents structural flexibility; F represents the nodal load vector; and U represents the displacement vector. Step 3.2: Construct the error chain to obtain the reserved assembly compensation amount, as shown in the following formula: ； ； ； In the formula, Indicates the amount reserved for assembly compensation; k i This represents the transfer coefficient of the i-th error source to the final optomechanical reference; δ i This represents the i-th assembly error term; Indicates the cumulative amount of heat deformation chain; m i ε represents the structural transfer coefficient of the i-th heat deformation source; i This represents the thermal strain of the i-th component.

5. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 4, is characterized in that: The specific steps of step 4 are as follows: Step 4.1: Divide the telescope into several functional modules, including the primary mirror assembly, secondary mirror assembly, telescope tube connection module, and support base module. 3D print each module according to the thermal properties and materials matched in Step 2. Step 4.2: Based on the optimal support position and force path obtained in Step 3, 3D hybrid printing is adopted, combined with metal-ceramic-composite material gradient printing, and the printing path and material ratio are adjusted. Step 4.3: Based on the reserved assembly compensation amount obtained in Step 3, assemble the modules using a thermal compensation structure.

6. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 5, is characterized in that: The thermal compensation structure in step 2.3 includes a thermal compensation ring, a thermal isolation layer, and a flexible transition interface.

7. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 6, is characterized in that: A controllable elastic connection structure is adopted at the flexible transition interface, which is composed of elastic leaf springs or flexible diaphragms.

8. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 5, is characterized in that: In step 4.1, cordierite is used to integrally print the primary mirror assembly, secondary mirror assembly, mirror barrel connection module, and support base module.

9. The method for designing and fabricating a telescope without heat in the extreme environment of Antarctica, as described in claim 5, is characterized in that: In step 4.2, a high-stiffness material is used in the central region of the module, and a low-expansion material is used in the edge region.

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