Coating performance analogue simulation method based on high and low temperature circulation and prestress loading

Abstract

The invention relates to the technical field of material testing, and discloses a coating performance simulation method based on high and low temperature circulation and prestress loading. The method comprises the following steps: constructing a coating matrix composite geometric model containing a microporous structure by acquiring actually measured working condition data of a pipeline or a part, and quantifying surface roughness and interface curvature characteristics in combination with reverse engineering; a dynamic temperature-pressure coupling equation is generated based on the thermal expansion effect of a high-pressure medium, a micropore optical load is converted into equivalent heat flux density through a ray tracing algorithm, transient boundary conditions of a temperature field and a stress field are associated, a crack initiation path is simulated through an extended finite element method, and a life attenuation curve is predicted in combination with a Paris formula. And material parameters are dynamically corrected based on experimental data, and a multi-parameter collaborative optimization model is generated. According to the method, the problems of interface stress evaluation distortion and life prediction deviation under the combined load are solved, and multi-physics field co-simulation support is provided for coating compression resistance optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of material testing for applying repetitive or complex forces, and particularly to a simulation method for coating performance based on high and low temperature cycling and prestress loading. Background Art

[0002] The research on coating performance under high and low temperature cycling and prestress loading focuses on simulating the service environment of coatings in fields such as pipelines and aerospace under the alternating action of high-pressure medium pressure and extreme temperatures. By establishing a multi-physical field coupling model of the coating-substrate system, considering the effects of thermal expansion, interfacial stress distribution, and microporous structure, prestress and temperature alternating loads are applied synchronously to reveal the crack initiation, propagation mechanism, and fatigue failure law of the coating under the combined thermal and mechanical effects, providing theoretical support and optimization paths for improving the compressive performance and thermal cycle life of the coating under complex working conditions.

[0003] Existing coating performance testing methods mostly use single environmental load simulation, which cannot effectively reproduce the combined working conditions of coatings under medium pressure and temperature alternation in high-pressure pipeline applications, resulting in distorted evaluation of mechanical responses. Existing test devices and simulation models do not fully couple the synergistic effects of prestress loading and wide-temperature range cycling. Especially in the stress concentration areas caused by the microporous structure of the coating, it is difficult to quantify the risk of interfacial delamination caused by differences in thermal expansion coefficients. In addition, the lack of a multi-physical field coupling failure analysis model leads to significant deviations in the fatigue damage mechanism and life prediction of coatings under high-pressure-temperature cycling composite loads, restricting the reliability setting and optimization of coating materials under harsh working conditions. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the present invention provides a simulation method for coating performance based on high and low temperature cycling and prestress loading, and solves the problem of the defect of the existing technology in accurately evaluating the mechanical properties and failure behavior of coatings under the combined conditions of high-pressure medium pressure and high and low temperature cycling.

[0005] To solve the above technical problems, the specific technical solutions of the present invention are as follows: The simulation method for coating performance based on high and low temperature cycling and prestress loading provided by the present invention includes: Step 1, obtaining the measured working condition data of a pipeline or component, where the measured working condition data includes internal pressure distribution, temperature gradient, high-pressure medium material parameters, and surface topography scan data, and constructing a coating-substrate composite geometric model according to the measured working condition data; Step 2: Convert the micropore structure in the surface topography scan data of the measured working condition data into a digital model, calculate the optical load distribution based on the geometric characteristics of the micropore structure, and import the digital model and the optical load distribution into the coating-substrate composite geometric model to obtain the mechanical property parameters and thermal physical property parameters of the coating and substrate materials; Step 3: Import the mechanical property parameters and thermal physical property parameters of the coating and substrate materials into a preset finite element simulation platform, and generate a dynamic temperature-pressure coupling equation according to the thermal expansion characteristics of the high-pressure medium; Step 4: Perform thermo-mechanical coupling analysis in the finite element simulation platform, set the prestress and temperature cycle range, correlate the temperature field and the stress field based on the dynamic temperature-pressure coupling equation, and convert the optical load distribution into an equivalent heat flux density through a ray tracing algorithm and superimpose it on the coating surface thermal boundary condition; Step 5: Perform non-uniform mesh division on the coating-substrate composite interface region and the micropore region of the coating-substrate composite geometric model. The coating-substrate composite interface region uses a hexahedron-dominated encrypted mesh, and the micropore edge uses a tetrahedron transition mesh; Step 6: Stepwise load the temperature cycle and prestress in the finite element simulation platform, calculate the superimposed value of the thermal stress and mechanical stress at each time step through a transient solver, and extract the stress peak value and distribution data of the coating-substrate composite interface region; Step 7: Input the stress peak value and distribution data into a fracture mechanics analysis module, determine the crack propagation direction based on the stress intensity factor, and calculate the damage index and remaining life under cyclic loading in combination with the fatigue cumulative damage model.

[0006] Further, for the coating performance simulation method based on high and low temperature cycles and prestress loading of the present invention, the steps of constructing the coating-substrate composite geometric model include: Generate a parametric model that matches the pipeline or component in the measured working condition data through a preset three-dimensional modeling platform. The coating thickness and substrate size of the parametric model are consistent with the measured data; Use reverse engineering methods to convert the micropore diameter and distribution density in the surface topography scan data into the topological structure of the coating-substrate composite geometric model; Based on the curvature characteristics of the surface topography scan data, mark the curvature characteristics of the coating-substrate composite interface region in the coating-substrate composite geometric model and generate surface roughness parameters; Automatically encrypt the high stress gradient region in the coating-substrate composite geometric model through an adaptive mesh division tool, and verify the mesh convergence based on the surface roughness parameters to control the iteration residual threshold.

[0007] Further, for the coating performance simulation method based on high and low temperature cycles and prestress loading according to the present invention, the steps of generating the dynamic temperature-pressure coupling equation include: Call the high-pressure medium material parameters in the measured working condition data, where the high-pressure medium material parameters include the coefficient of thermal expansion and the pressure-temperature correlation characteristics; Calculate the pressure fluctuation curve caused by the thermal expansion of the high-pressure medium under the temperature cycle condition through fluid mechanics simulation; Correlate the pressure fluctuation curve with the thermal physical property parameters of the coating and the substrate, and establish a dynamic coupling relationship equation between the temperature field and the stress field; Input the dynamic coupling relationship equation into the thermal-mechanical coupling analysis of the finite element simulation platform as the boundary condition for transient loading.

[0008] Further, for the coating performance simulation method based on high and low temperature cycles and prestress loading according to the present invention, the steps of setting the prestress and temperature cycle range include: Define the medium pressure as the initial prestress loading value in the thermal-mechanical coupling analysis of the finite element simulation platform, and the medium pressure matches the characteristics of the high-pressure medium; Quantify the influence of the microporous structure of the coating-substrate composite geometric model on the local heat distribution through the ray tracing algorithm, and generate a non-uniform heat flux load distribution map; Input the heat flux load distribution map into the optical heat transfer interface of the finite element simulation platform, and calculate the temperature gradient change on the coating surface based on the dynamic temperature-pressure coupling equation; Perform transient coupling on the temperature gradient change and the mechanical stress field in the thermal-mechanical coupling analysis, and output the stress superposition result in the time domain.

[0009] Further, for the coating performance simulation method based on high and low temperature cycles and prestress loading according to the present invention, the steps of non-uniform mesh division include: According to the stress gradient distribution in the coating-substrate composite interface region of the coating-substrate composite geometric model, divide a hexahedron-dominated encrypted mesh, and set tetrahedral transition elements at the edges of the micropores based on the generated surface roughness parameters; Solve the established dynamic temperature-pressure coupling equation using an implicit time integration algorithm, and set an adaptive time step to balance the calculation accuracy and efficiency; Automatically extract the stress-strain curve in the heating and cooling stages in the finite element simulation platform through a script, and identify the critical turning point of the peeling stress in the coating-substrate composite interface region; Compare the critical turning point with the mesh convergence analysis result, and dynamically adjust the mesh density of the coating-substrate composite geometric model to optimize the calculation stability.

[0010] Furthermore, for the coating performance simulation method based on high and low temperature cycling and prestress loading according to the present invention, the steps of calculating the damage index and remaining life under cyclic loading by combining with the fatigue cumulative damage model include: using the extended finite element method to simulate the interfacial delamination crack initiation path of the coating matrix composite geometric model, and obtaining the correlation data between crack propagation rate and stress distribution based on the extracted stress peak and distribution data; establishing a fatigue crack propagation model based on the Paris formula to predict the life decay curve under different temperature cycles; Generating the stress nephogram and interfacial peeling stress distribution map in the finite element simulation platform through a preset post-processing platform, and locating the optimized high stress concentration area according to the stress nephogram; Reverse-adjusting the component ratio of the coating material according to the distribution data of the high stress concentration area to generate a multi-parameter collaborative optimization model corresponding to the life decay curve.

[0011] Furthermore, the coating performance simulation method based on high and low temperature cycling and prestress loading according to the present invention further includes: Performing a residual comparison between the interfacial peeling strength output by the fracture mechanics analysis module and the actual high and low temperature-pressure combined test data; Fitting the deviation between the simulation and experimental results by the least squares method, and dynamically updating the thermal expansion coefficient of the coating material and the interfacial strength parameters generated therein; Setting an accelerated life test to collect the failure mode data under combined loads, and correcting the fracture toughness parameter of the material constitutive model in the dynamic temperature-pressure coupling equation; Recalculating the remaining life according to the corrected model parameters, and outputting the calibrated coating compressive performance optimization path corresponding to the multi-parameter collaborative optimization model.

[0012] Advantages of the present invention; The present invention constructs a coating matrix composite geometric model containing microporous structures through measured working condition data, combines reverse engineering to quantify the interface curvature characteristics and surface roughness parameters, and solves the problem of stress evaluation deviation caused by geometric distortion in existing modeling; generates a dynamic temperature-pressure coupling equation based on the thermal expansion effect of high-pressure media, converts the microporous optical load into an equivalent heat flux density through a ray tracing algorithm, correlates the transient boundary conditions of the temperature field and the stress field, and accurately characterizes the synergistic action mechanism of temperature cycling and pressure fluctuation; adopts a non-uniform mesh division strategy of hexahedron encrypted grids and tetrahedron transition elements, combines an implicit time integration algorithm to solve the thermo-mechanical coupling equation, and improves the calculation accuracy of the interface stress peak; simulates the crack propagation path and life attenuation trend through the extended finite element method and the Paris formula, combines experimental data for closed-loop verification and dynamically corrects material parameters to generate a multi-parameter collaborative optimization model, provides high-precision multi-physics field simulation support for the compressive performance optimization and life prediction of coatings under high-pressure, high-low temperature alternating working conditions, and significantly improves the systematicness of the reliability design of coatings in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the drawings.

[0014] Figure 1 It is a flowchart of a coating performance simulation method based on high-low temperature cycling and prestress loading provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The technical solutions provided by each embodiment of the present invention will be described in detail below with reference to the drawings. To better understand the objectives of the present invention, the present invention will be further described in detail below.

[0016] Please refer to Figure 1 , the coating performance simulation method based on high-low temperature cycling and prestress loading provided by the present invention includes: Step 1, obtain the measured working condition data of the pipeline or component, where the measured working condition data includes internal pressure distribution, temperature gradient, high-pressure medium material parameters, and surface topography scan data, and construct a coating matrix composite geometric model according to the measured working condition data; The specific implementation process of Step 1 is as follows: Collect the surface topography scan data of the pipeline or component through a 3D laser scanner, obtain the internal pressure distribution and temperature gradient parameters by combining a pressure sensor and a thermocouple, and at the same time extract the thermal expansion coefficient and the pressure-temperature correlation curve from the material property database of the high-pressure medium. The measured working condition data is imported into the 3D modeling software through the data interface module. Based on the reverse engineering algorithm, the point cloud of the surface topography scan data is denoised, the geometric contours of the coating and the substrate are reconstructed, and a parametric model with the same coating thickness, substrate size as the actual component is generated. For the microporous structure, the topological mapping technology is used to convert the pore size and distribution density in the scan data into the hole features of the geometric model, forming a composite structure including the surface roughness parameters.

[0017] During the model construction process, the geometric undulation characteristics of the coating-substrate composite interface region are quantified through the curvature analysis tool, the curvature extreme points are marked and the surface roughness parameters are generated. This parameter is used as the input condition for mesh generation, guiding the subsequent local refinement strategy of the adaptive mesh tool for the high stress gradient region. Through the dynamic calibration module of the measured data and the model parameters, the dimensional deviation of the geometric model is adjusted to make the model match the physical structure of the actual working condition, providing a high-fidelity geometric basis for the thermo-mechanical coupling simulation.

[0018] The above steps realize the high-precision construction of the coating-substrate composite geometric model through the acquisition of measured data, reverse engineering reconstruction and parametric modeling, laying the data and model foundation for the simulation analysis of the interface stress distribution under the composite load, and solving the problem of stress evaluation deviation caused by geometric feature distortion in the existing methods.

[0019] Step 2: Convert the microporous structure in the surface topography scan data of the measured working condition data into a digital model, calculate the optical load distribution based on the geometric features of the microporous structure, and import the digital model and the optical load distribution into the coating-substrate composite geometric model to obtain the mechanical property parameters and thermal property parameters of the coating and substrate materials; The specific implementation process of Step 2 is as follows: Perform 3D point cloud processing on the microporous structure in the surface topography scan data through reverse engineering software, use the denoising algorithm to remove the scan noise and retain the hole geometric features, and generate a digital model including the micropore diameter, depth and distribution density. Based on the geometric features of the microporous structure, call the optical load calculation module, simulate the scattering, reflection and absorption effects of the micropores on the incident light through the ray tracing algorithm, quantify the local light intensity distribution difference, and generate a non-uniform optical load distribution map. This distribution map is imported into the coating-substrate composite geometric model through the data interface module and associated with the coating surface boundary conditions to characterize the heat flux density difference caused by the micropores.

[0020] After superimposing the digital model and the optical load distribution, elastic modulus, Poisson's ratio, and thermal conductivity parameters of the coating and matrix materials are called through the material property database. Combining with the pressure-temperature correlation curve of the high-pressure medium, a set of mechanical property parameters and thermophysical property parameters required for thermomechanical coupling analysis are generated. The parameter set is mapped to the corresponding area of the geometric model through the material assignment module of the finite element simulation platform, forming the input conditions for multi-physics field simulation that match the measured working conditions. The above steps realize the accurate modeling of the non-uniform thermal and mechanical loads on the coating surface through the digital reconstruction of the microporous structure and the quantification of the optical load, providing key input parameters for the establishment of the dynamic temperature-pressure coupling equation.

[0021] Through the above process, the microporous geometric features and optical load distribution in the measured data are systematically integrated into the coating matrix composite model, solving the problem of distorted temperature field evaluation caused by ignoring the microporous heat flow disturbance in the existing methods, and providing a high-fidelity material parameter basis for the interface stress analysis under composite loads.

[0022] Step 3: Import the mechanical property parameters and thermophysical property parameters of the coating and matrix materials into the preset finite element simulation platform, and generate a dynamic temperature-pressure coupling equation according to the thermal expansion characteristics of the high-pressure medium; The specific implementation process of Step 3 is as follows: Through the data import module of the finite element simulation platform, input the elastic modulus, Poisson's ratio, and thermal conductivity parameters of the coating and matrix materials, as well as the thermal expansion coefficient and pressure-temperature correlation curve of the high-pressure medium into the material property library. Based on the dynamic thermal expansion characteristics of the high-pressure medium, call the fluid mechanics simulation module to calculate the volume change of the thermal expansion of the medium under temperature cycle conditions, and generate a pressure fluctuation curve that changes with time. This curve is correlated with the thermophysical property parameters of the coating and matrix through the multi-physics field coupling interface, establishing a mathematical relationship between the temperature field gradient and the dynamic response of the stress field, and forming a dynamic temperature-pressure coupling equation.

[0023] During the equation generation process, superimpose the heat flux density distribution on the coating surface and the medium pressure fluctuation data through the thermomechanical coupling analysis module, and define the transient boundary conditions of temperature cycle and prestress loading. Use the heat conduction equation and elastic mechanics equation in the finite element solver to superimpose the thermal strain caused by the temperature field change and the mechanical stress field, and construct an iterative calculation model of temperature-stress biaxial coupling. Synchronously solve the interaction between the temperature field and the stress field through the implicit algorithm to realize the thermomechanical coupling transient simulation of the coating interface area.

[0024] The above steps accurately quantify the temperature-stress synergy mechanism at the coating interface under composite loads through the dynamic correlation between the high-pressure medium thermal expansion effect and material parameters, solve the problem of stress evaluation deviation caused by ignoring thermo-pressure coupling in existing single-physics field simulations, and provide a high-precision multi-physics field analysis basis for subsequent crack propagation simulation and life prediction.

[0025] Step 4: Perform thermo-mechanical coupling analysis in the finite element simulation platform. Set the prestress and temperature cycle range, correlate the temperature field and stress field based on the dynamic temperature-pressure coupling equation, and convert the optical load distribution into equivalent heat flux density through the ray tracing algorithm and superimpose it on the thermal boundary condition of the coating surface; The specific implementation process of Step 4 is as follows: Through the thermo-mechanical coupling analysis module of the finite element simulation platform, call the pressure-temperature correlation curve of the high-pressure medium, define the medium pressure as the initial prestress loading value, and its value matches the characteristic parameters of the high-pressure medium in the actual working condition. The temperature cycle range is set based on the temperature gradient in the measured data, and the heating and cooling rates and the number of cycles are input through the transient boundary condition loading interface to form a temperature alternating load spectrum consistent with the service environment. Based on the dynamic temperature-pressure coupling equation, correlate the gradient change of the temperature field with the elastic response of the stress field, and synchronously solve the heat conduction equation and the elastic mechanics equation through the matrix iteration algorithm to establish a transient calculation model of temperature-stress biaxial coupling.

[0026] Perform secondary quantization on the optical load distribution of the microporous structure through the ray tracing algorithm, simulate the scattering path and energy absorption characteristics of light in the micropores, and generate an equivalent heat flux density distribution map. This distribution map is superimposed on the coating surface through the thermal boundary condition mapping module and fused with the temperature field data output by the dynamic temperature-pressure coupling equation to form a composite boundary condition of non-uniform heat flux-pressure synergistic action. During the solution process, use the implicit time integration algorithm to perform step-by-step iterative calculation on the thermo-mechanical coupling equation, update the stress distribution state after superimposing the temperature gradient and prestress in real time, and output the transient stress field data at each time step.

[0027] The above steps realize the dynamic correlation analysis of the temperature field and stress field under the composite load through the initial loading of prestress, the transient definition of temperature cycle, and the boundary superposition of heat flux density, solve the problem of distorted interface stress evaluation caused by the simplification of heat flux distribution or load separation in the existing methods, and provide the boundary condition support of multi-physical field collaboration for the accurate simulation of the coating interface peeling behavior.

[0028] Step 5: Perform non-uniform grid division on the coating matrix composite interface region and the microporous region of the coating matrix composite geometric model. The coating matrix composite interface region uses a hexahedron-dominated encrypted grid, and the microporous edge uses a tetrahedron transition grid; The specific implementation process of Step 5 is as follows: Use an adaptive mesh generation tool to perform stress gradient analysis on the coated substrate composite geometry model to identify high stress concentration regions in the interface area. Based on the geometric feature data generated from surface roughness parameters, adopt a hexahedron-dominated refined mesh generation strategy in the coated substrate composite interface area, use regularly arranged mesh elements to improve the calculation accuracy of stress distribution, and at the same time control the mesh size gradient to reduce computational resource consumption. For the micro-hole edge area, due to complex geometric curvature and high surface roughness, use tetrahedral transition elements to connect the refined area and the regular mesh area to adapt to the geometric morphology of the hole edge and maintain mesh continuity.

[0029] After mesh generation is completed, use the mesh convergence verification module to perform residual analysis on the mesh density of the interface area and the micro-hole edge. Based on the preset iterative residual threshold, compare the stress calculation results under different mesh densities, and dynamically adjust the refinement level of the local mesh. Automatically extract the stress-strain curves during the heating and cooling stages through scripts, identify the critical turning points of interface peeling stress, and optimize the mesh distribution in combination with the convergence analysis results to make the calculation results meet the stability requirements.

[0030] The above steps solve the computational stability problem under complex geometry and transient loads through stress gradient-driven non-uniform mesh generation, geometric adaptation of tetrahedral transition elements, and dynamic mesh optimization, providing a reliable numerical analysis basis for the high-precision extraction of stress peak values at the coating interface and crack propagation simulation, and supporting the accurate construction of subsequent fatigue damage models.

[0031] Step 6: Apply temperature cycles and prestress step by step in the finite element simulation platform, calculate the superposition value of thermal stress and mechanical stress at each time step through the transient solver, and extract the stress peak value and distribution data of the coated substrate composite interface area; The specific implementation process of Step 6 is as follows: Through the load application module of the finite element simulation platform, apply temperature cycle loads and prestress step by step, define the temperature change rate and the number of cycles during the heating and cooling stages, and form an alternating temperature spectrum consistent with the measured working conditions. The initial prestress is set according to the pressure characteristics of the high-pressure medium and mapped to the boundary surface of the coated substrate composite model through the pressure application interface. The transient solver calls the implicit time integration algorithm, dynamically adjusts the calculation step size based on adaptive time step control, shortens the step size during the stage of rapid temperature change to improve calculation accuracy, and extends the step size during the stable stage to improve efficiency, and simultaneously solves the heat conduction equation and the elastic mechanics equation.

[0032] After each time step calculation is completed, the thermal stress caused by thermal expansion and the mechanical prestress are vectorially superimposed through the stress superposition module to generate the transient stress field distribution data under the combined load. The post-processing tool is used to extract the stress peak value and its spatial coordinates in the coating-substrate composite interface region, and the high-stress concentration positions where the interface peeling risk is analyzed by combining with the distribution cloud map. The stress extreme values at key time points are automatically screened through scripts to generate the stress-time change curve and the peak value statistical table, providing input parameters for the crack propagation simulation.

[0033] Through step-by-step loading, transient solution and stress superposition calculation, the above steps accurately quantify the dynamic response of the interface stress under the combined action of temperature cycle and prestress, solve the problem of stress evaluation distortion caused by load separation or static assumption in the existing methods, and provide a high-precision stress data basis for the subsequent fatigue damage model and life prediction.

[0034] Step 7: Input the stress peak value and distribution data into the fracture mechanics analysis module, determine the crack propagation direction based on the stress intensity factor, and calculate the damage index and remaining life under cyclic load in combination with the fatigue cumulative damage model.

[0035] The specific implementation process of step 7 is as follows: The stress peak value and distribution data in the coating-substrate composite interface region are input into the fracture mechanics analysis module through the data interface module, and the extended finite element method (XFEM) is called to simulate the initiation path of the interface delamination crack. Based on the calculation results of the stress intensity factor at the crack tip, the tendency of the crack to propagate along the interface or the substrate is identified through the direction determination algorithm to generate the crack propagation direction map. Combining the stress distribution data and the crack propagation path, the correlation between the crack propagation rate and the local stress peak value is established, providing input parameters for the fatigue cumulative damage model.

[0036] In the fatigue cumulative damage model, the growth relationship of the crack length with the number of temperature cycles is constructed based on the Paris formula, and the influence of the thermal expansion difference between the coating and the substrate on the crack propagation is introduced through the temperature-stress biaxial correction module to predict the life decay curve under different temperature cycle conditions. The damage index is calculated by the cumulative damage integral algorithm, and the stress amplitude of each cycle is compared with the fatigue limit of the material to generate the change curve of the damage index with the number of cycles, and the service life evaluation result of the coating is output in combination with the remaining life prediction module.

[0037] A three-dimensional visualization atlas of the interface peeling stress distribution map and the crack propagation path is generated through a post-processing platform to locate high-damage-risk areas. Based on the damage index and remaining life data, the component ratio of the coating material and the interface structure parameters are reversely optimized to generate a multi-parameter collaborative optimization scheme. The above steps solve the problem of life assessment deviation caused by ignoring the synergistic effect of composite loads in the existing methods through the closed-loop iteration of crack propagation simulation, damage accumulation quantification, and life prediction models, providing high-precision simulation support for the compressive performance optimization of the coating.

[0038] The simulation method for coating performance based on high and low temperature cycles and prestress loading provided by the present invention has the following specific implementation process: First, the measured working condition data of the pipeline or component are collected through a three-dimensional laser scanner and a pressure sensor, including the internal pressure distribution, temperature gradient, high-pressure medium material parameters, and surface topography scan data. Based on the measured data, a composite geometric model of the coating matrix is reconstructed in three-dimensional modeling software to ensure that the coating thickness and matrix size of the model are consistent with the actual component. The point cloud processing of the microporous structure in the surface topography scan data is carried out using reverse engineering algorithms, and its topological structure is mapped to the geometric model, and the roughness characteristics of the interface region are quantified through a curvature analysis tool.

[0039] Secondly, the digital model of the microporous structure is imported into the finite element simulation platform, and combined with the optical load calculation module, a local optical load distribution is generated according to the microporous geometric characteristics. The scattering and absorption effects of the micropores on light are simulated through the ray tracing algorithm, and the optical load is converted into an equivalent heat flux density distribution. This heat flux density distribution serves as the thermal boundary condition on the coating surface and acts together with the thermal expansion characteristics of the high-pressure medium to establish a dynamic temperature-pressure coupling equation.

[0040] Subsequently, the material parameters of the high-pressure medium are called, including the thermal expansion coefficient and the pressure-temperature correlation curve, and the dynamic pressure fluctuation caused by the thermal expansion of the medium under temperature cycling is calculated through fluid mechanics simulation. The pressure fluctuation is correlated with the thermal physical properties of the coating and the matrix, and the dynamic coupling equation of the temperature field and the stress field is derived. The initial value of the prestress is set to the medium pressure in the finite element simulation platform, and the temperature gradient change and the mechanical stress field are coupled through transient boundary conditions.

[0041] Aiming at the high stress gradient characteristics of the coating matrix composite interface region, hexahedron meshes are used to improve the calculation accuracy of the stress distribution; due to the high geometric complexity at the edges of the micropores, tetrahedron transition elements are used to balance the mesh quality and calculation efficiency. Through the convergence verification module of the adaptive mesh generation tool, the mesh density is iteratively adjusted based on the surface roughness parameters until the residual threshold meets the preset conditions.

[0042] During the loading stage, the temperature cycle load and prestress are applied step by step, and the transient thermo-mechanical coupling equation is solved using the implicit time integration algorithm. The superposition results of thermal stress and mechanical stress at each time step are calculated through the transient solver, and the peak stress and spatial distribution data in the interface region are extracted. Based on the stress distribution data, the extended finite element method is used to simulate the initiation path of interface delamination cracks, and the crack propagation rate and life decay trend are predicted by combining the stress intensity factor and the Paris formula.

[0043] Furthermore, the interfacial debonding strength output by the simulation is compared with the data of the combined high and low temperature-pressure test in terms of residuals. The thermal expansion coefficient and interfacial strength parameters of the coating material are fitted and dynamically corrected by the least squares method. Based on the corrected parameters, the remaining life is recalculated iteratively, and the high stress concentration areas are located by combining the stress nephogram generated by the post-processing platform, and the component ratio of the coating material is inversely optimized to form a path for improving the compressive performance with multi-parameter collaborative optimization.

[0044] Through the above steps, driven by measured data for model construction, multi-physical field coupling analysis and dynamic parameter correction, high-precision simulation of the stress distribution at the coating interface under complex loads and life prediction are realized, providing systematic multi-scale simulation support for the optimization of the coating compressive performance.

[0045] Specifically, for the coating performance simulation method based on high and low temperature cycles and prestress loading described in the present invention, the steps of constructing the composite geometric model of the coating substrate include: Generate a parametric model that matches the pipeline or component in the measured working condition data through a preset three-dimensional modeling platform, and the coating thickness and substrate size of the parametric model are consistent with the measured data; Adopt the reverse engineering method to convert the micropore aperture and distribution density in the surface topography scan data into the topological structure of the composite geometric model of the coating substrate; Based on the curvature characteristics of the surface topography scan data, mark the curvature characteristics of the composite interface region of the coating substrate in the composite geometric model of the coating substrate, and generate surface roughness parameters; Automatically encrypt the high stress gradient region in the composite geometric model of the coating substrate through an adaptive mesh generation tool, and verify the mesh convergence based on the surface roughness parameters to control the iteration residual threshold.

[0046] The specific steps of constructing the composite geometric model of the coating substrate include the following: Through a preset three-dimensional modeling platform, call the measured working condition data of pipelines or components, including internal pressure distribution, temperature gradient, and surface topography scanning data, to generate a parametric model. The coating thickness and matrix size of the parametric model are defined based on the measured data, and the geometric features of the model are strictly corresponding to the actual components. During the modeling process, a calibration module based on the measured data is used to dynamically adjust the model size to match the physical structure under the actual working conditions.

[0047] Based on the surface topography scanning data, extract the micropore aperture and distribution density information through reverse engineering methods. Use three-dimensional point cloud processing technology to denoise and reconstruct the scanning data, and convert the discrete micropore geometric features into a continuous topological structure. Through a parametric mapping algorithm, associate the micropore distribution density with local regions in the geometric model to form a composite geometric model containing micropore structures.

[0048] In the geometric model, based on the curvature characteristics of the surface topography scanning data, use a curvature analysis tool to label the characteristics of the coating matrix composite interface region. Through curvature gradient calculation, identify the local curvature extreme points in the interface region and associate them with the surface roughness parameters. The surface roughness parameters are generated by quantifying the geometric undulation degree of the interface region, providing geometric feature input for subsequent mesh generation and stress analysis.

[0049] For high stress gradient regions, use an adaptive mesh generation tool to locally refine the geometric model. In the coating matrix composite interface region, preferentially use a hexahedron-dominated mesh type to improve the calculation accuracy of stress distribution. Due to the high geometric complexity at the micropore edges, use tetrahedral transition elements to connect the refined region and the conventional mesh region. Through a mesh convergence verification module, control the iterative process based on the surface roughness parameters and residual thresholds until the mesh generation result meets the preset convergence conditions.

[0050] The above steps establish a coating matrix composite geometric model matching the actual working conditions through measured data-driven parametric modeling, reverse engineering feature reconstruction, and adaptive mesh generation, providing a high-precision geometric basis for subsequent multi-physics field coupling analysis.

[0051] Specifically, for the coating performance simulation method based on high and low temperature cycles and prestress loading described in the present invention, the steps of generating the dynamic temperature-pressure coupling equation include: Call the high-pressure medium material parameters in the measured working condition data, and the high-pressure medium material parameters include the coefficient of thermal expansion and the pressure-temperature correlation characteristics; Through fluid mechanics simulation, calculate the pressure fluctuation curve caused by the thermal expansion of the high-pressure medium under the temperature cycle condition; Associate the pressure fluctuation curve with the thermal physical properties parameters of the coating and the matrix to establish a dynamic coupling relationship equation between the temperature field and the stress field; Input the dynamic coupling relationship equation into the thermo-mechanical coupling analysis of the finite element simulation platform as the boundary condition for transient loading.

[0052] The specific steps for generating the dynamic temperature-pressure coupling equation include the following: When calling the high-pressure medium material parameters in the measured working condition data, extract the thermal expansion coefficient and the data of the correlation characteristics between pressure and temperature through a preset material database interface. The material parameters are loaded into the fluid mechanics simulation platform through a parametric input module to form a set of medium thermodynamic properties. Based on the physical properties of the high-pressure medium, establish a correlation model between its thermal expansion effect and temperature change to provide input conditions for subsequent pressure fluctuation calculations.

[0053] Through the fluid mechanics simulation platform, set the temperature cycle boundary conditions to simulate the dynamic thermal expansion behavior of the high-pressure medium during the heating and cooling process. Use the finite volume method to perform transient solutions for the flow and heat transfer processes of the medium, and output the fluctuation curve of the medium pressure changing with time under the temperature cycle. This curve characterizes the dynamic response characteristics of the pressure caused by thermal expansion and provides an input load for thermo-mechanical coupling analysis.

[0054] When correlating the pressure fluctuation curve with the thermal physical properties of the coating and the substrate, construct the coupling relationship between the temperature field and the stress field based on the heat conduction equation and the elastic mechanics equation. Map the pressure fluctuation data of the medium to the surface nodes of the coating-substrate composite model through a multi-physics field interface, and combine the thermal conductivity of the coating material and the elastic modulus of the substrate to establish a dynamic transfer equation for the temperature gradient and the thermal stress. This equation describes the transient influence mechanism of the temperature field change on the local stress in matrix form.

[0055] After inputting the dynamic coupling relationship equation into the thermo-mechanical coupling analysis module of the finite element simulation platform, define the time-varying laws of temperature and pressure through the transient boundary condition loading interface. In the thermo-mechanical coupling solver, apply the pressure fluctuation curve as a time-varying load to the coating surface, and at the same time correlate the temperature cycle range to the thermal expansion constitutive model of the material. Synchronously solve the mutual influence of the temperature field and the stress field through an implicit iterative algorithm to achieve multi-field collaborative simulation under dynamic temperature-pressure coupling conditions.

[0056] The above steps accurately quantify the dynamic influence of the thermal expansion of the high-pressure medium on the coating interface stress through fluid mechanics simulation and multi-physics field coupling modeling, and provide physically driven boundary condition inputs for the stress distribution analysis under composite loads.

[0057] Specifically, the coating performance simulation method based on high and low temperature cycles and prestress loading according to the present invention is characterized in that the steps of setting the prestress and the temperature cycle range include: Define the medium pressure as the initial prestress loading value in the thermo-mechanical coupling analysis of the finite element simulation platform, and the medium pressure matches the characteristics of the high-pressure medium; Quantify the influence of the microporous structure of the coating-substrate composite geometric model on the local heat distribution through the ray tracing algorithm, and generate a non-uniform heat flux load distribution map; Input the non-uniform heat flux load distribution map into the optical heat transfer interface of the finite element simulation platform, and calculate the temperature gradient change on the coating surface based on the dynamic temperature-pressure coupling equation; Perform transient coupling on the temperature gradient change and the mechanical stress field in the thermo-mechanical coupling analysis, and output the stress superposition result in the time domain.

[0058] The specific steps for setting the prestress and temperature cycle range include the following: In the thermo-mechanical coupling analysis module of the finite element simulation platform, call the characteristic parameters of the high-pressure medium through the preset material property library, and define the medium pressure as the initial prestress loading value. The initial prestress is applied to the boundary surface of the coating-substrate composite model through the pressure loading interface, and its value matches the thermal expansion coefficient and working pressure of the high-pressure medium, forming an initial stress state consistent with the actual service environment.

[0059] Based on the microporous structure data of the coating-substrate composite geometric model, use the ray tracing algorithm to simulate the scattering, reflection, and absorption behaviors of micropores on incident light. Quantify the influence of the micropore aperture and distribution density on the local heat flux transfer path through the geometric optical model, and generate a non-uniform heat flux load distribution map. This distribution map is associated with the coating surface through the heat flux density mapping module, characterizing the heat distribution difference caused by the micropore geometric characteristics.

[0060] Input the non-uniform heat flux load distribution map into the optical heat transfer interface of the finite element simulation platform, and calculate the transient temperature gradient change on the coating surface in combination with the temperature field boundary conditions in the dynamic temperature-pressure coupling equation. The temperature gradient is correlated with the thermal conductivity parameter of the coating material through the heat conduction equation, generating the temperature field distribution data that changes with time as the input load for the thermo-mechanical coupling analysis.

[0061] In the transient coupling solution process, superimpose the thermal strain caused by the temperature gradient change and the elastic strain of the mechanical stress field. Establish a dynamic correlation between the temperature field and the stress field through the multi-field coupling matrix, and use the implicit time integration algorithm to synchronously solve the superimposed values of thermal stress and prestress at each time step. Finally, output the stress distribution nephogram in the time domain and the stress-time curve of the key nodes, reflecting the transient response characteristics of the interface stress under the combined load.

[0062] Through the above steps of initial prestress definition, micro-hole heat flux distribution modeling, and multi-field transient coupling analysis, the simulation of the dynamic stress response under the combined action of temperature cycle and mechanical load is realized, providing a high-precision multi-physics simulation basis for the quantitative evaluation of the coating interface peeling behavior.

[0063] Specifically, for the coating performance simulation method based on high and low temperature cycles and prestress loading according to the present invention, the non-uniform mesh division step includes: According to the stress gradient distribution in the coating matrix composite interface region of the coating matrix composite geometric model, a hexahedron-dominated encrypted mesh is divided, and tetrahedron transition elements are set at the edges of the micro-holes based on the generated surface roughness parameters; An implicit time integration algorithm is used to solve the established dynamic temperature-pressure coupling equation, and an adaptive time step is set to balance the calculation accuracy and efficiency; Automatically extract the stress-strain curves in the heating and cooling stages in the finite element simulation platform through scripts, and identify the critical turning point of the peeling stress in the coating matrix composite interface region; Compare the critical turning point with the mesh convergence analysis result, and dynamically adjust the mesh density of the coating matrix composite geometric model to optimize the calculation stability.

[0064] The specific steps of non-uniform mesh division include the following: According to the stress gradient distribution data in the coating matrix composite interface region, high stress concentration regions are identified through stress analysis tools, and a hexahedron-dominated encrypted mesh division strategy is preferentially adopted. The regular arrangement of hexahedron meshes in the interface region improves the calculation accuracy of stress distribution, and at the same time reduces the consumption of calculation resources through the control of the mesh size gradient. Due to the complex geometric shape and high surface roughness parameters in the micro-hole edge region, tetrahedron transition elements are used to connect the encrypted region and the conventional mesh region to adapt to the curvature change of the micro-holes and maintain mesh continuity. [[ID=A]]''

[0065] During the solution process of the dynamic temperature-pressure coupling equation, an implicit time integration algorithm is used to handle the non-linear thermo-mechanical coupling problem. Through the adaptive time step control module, the time step is dynamically adjusted based on the transient change rates of the temperature field and the stress field. When the temperature or stress gradient changes violently, the time step is automatically shortened to improve the calculation accuracy; in the stage of gentle change, the step length is extended to improve the solution efficiency, realizing the balanced optimization of accuracy and efficiency.

[0066] Automatically call the post-processing data interface of the finite element simulation platform through scripts to extract the stress-strain curves in the heating and cooling stages of the coating matrix composite interface region. The peak detection algorithm is used to identify the stress mutation points in the curve, and the critical turning point of the peeling stress is located by combining the curvature change analysis. This turning point characterizes the starting position of the interface delamination risk and provides key input parameters for subsequent life analysis.

[0067] Compare the stress value corresponding to the critical turning point with the result of mesh convergence analysis to evaluate the calculation stability at the current mesh density. If the stress deviation at the critical turning point exceeds the preset threshold, locally refine or sparsely adjust the interface area through the mesh redivision module. The adjusted mesh density is re-verified based on the surface roughness parameter and the residual convergence criterion until the calculation result meets the stability requirement.

[0068] The above steps effectively solve the calculation stability problem under complex geometries and transient loads through the stress gradient-driven mesh generation strategy, adaptive time step control, and dynamic mesh optimization, providing a reliable numerical analysis basis for the accurate simulation of the coating interface peeling behavior.

[0069] Specifically, for the coating performance simulation method based on high and low temperature cycling and prestress loading described in the present invention, the steps of calculating the damage index and remaining life under cyclic loading by combining the fatigue cumulative damage model include: using the extended finite element method to simulate the interface delamination crack initiation path of the coating matrix composite geometry model, and obtaining the correlation data between the crack propagation rate and the stress distribution based on the extracted stress peak and distribution data; establishing a fatigue crack propagation model based on the Paris formula to predict the life decay curve under different temperature cycles; Generate the stress nephogram and interface peeling stress distribution map in the finite element simulation platform through a preset post-processing platform, and locate the optimized high stress concentration area according to the stress nephogram; Reverse adjust the component ratio of the coating material according to the distribution data of the high stress concentration area to generate a multi-parameter collaborative optimization model corresponding to the life decay curve.

[0070] The specific steps of calculating the damage index and remaining life under cyclic loading by combining the fatigue cumulative damage model include the following: Under the framework of the extended finite element method, based on the interface stress distribution data of the coating matrix composite geometry model, simulate the initiation path of the interface delamination crack. Through the crack tip stress intensity factor extraction module, obtain the crack propagation rate data at different temperature cycle stages, and establish its correlation with the local stress peak. The simulation result of the crack propagation path is mapped to the geometry model through the path tracking algorithm to form a dynamic evolution map of the interface delamination risk.

[0071] The fatigue crack growth model based on the Paris formula correlates the crack growth rate with the stress intensity factor amplitude, and constructs a quantitative relationship between the number of temperature cycles and the crack length growth. Through the temperature and stress biaxial correction module, the influence of the thermal expansion difference of the coating material on crack growth is introduced to generate the life decay curve under different temperature cycle conditions. This curve characterizes the remaining life trend of the coating under the combined load and provides input parameters for the calculation of the damage index.

[0072] The output data of the finite element simulation platform is called through the preset post-processing platform to generate the interface peeling stress distribution map and the three-dimensional stress nephogram. Using the stress peak clustering algorithm, the spatial coordinates and amplitude characteristics of the high stress concentration area are located in the nephogram. The distribution data of the high stress area is superimposed with the crack growth atlas through the thermo-mechanical coupling analysis module to identify the key positions of the interface peeling risk.

[0073] Based on the distribution characteristics of the high stress concentration area, the component ratio parameters of the coating material are adjusted reversely. Through the material parameter optimization interface, a response surface model of the coating component ratio and the interface stress amplitude is established, and a multi-parameter collaborative optimization scheme is generated in combination with the life decay curve. This scheme verifies the suppression effect of the component adjustment on the interface peeling stress through iterative calculation, and finally outputs the optimized configuration path of the coating material matching the target life.

[0074] The above steps realize the damage quantitative evaluation and anti-peeling performance improvement of the coating under the combined load through crack growth simulation, life decay modeling and material reverse optimization, and provide a closed-loop simulation verification system for the multi-physical field collaborative design of the coating material.

[0075] Specifically, the coating performance simulation method based on high and low temperature cycles and prestress loading described in the present invention further includes: Comparing the residual of the interface peeling strength output by the fracture mechanics analysis module with the actual high and low temperature-pressure combined test data; Fitting the deviation between the simulation and experimental results by the least squares method, and dynamically updating the thermal expansion coefficient of the coating material and the interface strength parameters generated therein; Setting up an accelerated life test to collect the failure mode data under the combined load, and correcting the fracture toughness parameters of the material constitutive model in the dynamic temperature and pressure coupling equation; Recalculating the remaining life according to the corrected model parameters, and outputting the calibrated coating compressive performance optimization path corresponding to the multi-parameter collaborative optimization model.

[0076] The coating performance simulation method based on high and low temperature cycles and prestress loading described in the present invention further includes the following specific steps: Synchronously call the interfacial peel strength data output by the fracture mechanics analysis module and the actual high and low temperature-pressure combined test data through the data interface module, and use the residual calculation module to compare and analyze the simulation and experimental results. By defining the residual threshold range, screen out the regions with significant deviation in interfacial peel strength, and generate a residual distribution map. This distribution map is used to locate the sensitive regions of parameter mismatch in the simulation model and provide data input for parameter calibration.

[0077] Based on the deviation data of the residual distribution map, establish a linear correlation model between the simulation and experimental results through the least squares fitting algorithm. Use the parameter optimization engine to dynamically adjust the thermal expansion coefficient and interfacial strength parameters of the coating material, so that the simulation results gradually converge to the experimental data. The parameter update process is realized through iterative calculation, and the residual threshold is re-verified after each iteration until the deviation value meets the preset convergence standard.

[0078] Set up an accelerated life test platform to simulate the coating failure mode under combined load conditions. Apply the synergistic effect of high and low temperature cycles and mechanical prestress through a multi-axis loading device, and use strain sensors and infrared thermal imagers to collect data on interfacial delamination, crack propagation, and thermal distribution. Input the failure mode data into the material constitutive model correction module, and based on the sensitivity analysis of fracture toughness parameters, adjust the fracture toughness parameters in the dynamic temperature-pressure coupling equation to match the experimentally observed failure evolution law.

[0079] According to the corrected thermal expansion coefficient, interfacial strength parameter, and fracture toughness parameter, re-execute the thermo-mechanical coupling simulation process to calculate the remaining life of the coating under combined load. Through the multi-parameter collaborative optimization model, cross-validate the life prediction results with the experimental life data, and generate a calibrated compressive performance optimization path. This path outputs a coating performance improvement plan that matches the target service conditions through the combined optimization of material components, interfacial structure, and process parameters.

[0080] The above steps construct a high-precision coating performance prediction and optimization system through experimental-simulation data closed-loop verification, parameter dynamic update, and failure mode-driven model correction, providing an iteratively verifiable solution for the reliable design of coating compressive performance under complex working conditions.

[0081] The following is an explanatory description of the technical feature terms in the technical solution of the present invention: Coating-substrate composite geometric model: refers to a digital model constructed through 3D modeling tools, including the geometric structures and dimensional parameters of the coating and the substrate. Its coating thickness and substrate shape are consistent with the actual components, and the topological features of the microporous structure (such as pore size and distribution density) are integrated. The surface topography scan data is converted into a geometric entity that can be simulated through reverse engineering.

[0082] Dynamic temperature-pressure coupling equation: A mathematical model that describes the synergistic effect of the thermal expansion effect of high-pressure media and temperature cycling. By performing hydrodynamic simulation calculations on the fluctuation curve of the medium pressure with temperature changes, and combining the thermal conductivity and elastic modulus parameters of the coating and the substrate, a transient correlation relationship between the temperature field and the stress field is established, which is used to simulate the interactive effects of thermal-mechanical loads.

[0083] Ray tracing algorithm: A calculation method based on the principles of geometric optics, used to quantify the scattering, reflection, and absorption effects of microporous structures on light, generate a non-uniform heat flux density distribution map, and map the heat flux density to the coating surface boundary conditions to characterize the local thermal distribution differences caused by micropores.

[0084] Hexahedral encrypted grid and tetrahedral transition element: For the high stress gradient characteristics of the coating-substrate composite interface region, regularly arranged hexahedral grids are used to improve the calculation accuracy; due to the high geometric complexity at the edges of micropores, tetrahedral grids are used to adapt to the curvature changes, and the calculation efficiency and convergence are balanced through adaptive mesh division.

[0085] Implicit time integration algorithm: A numerical method for solving non-linear thermo-mechanical coupling equations. By controlling the dynamic adjustment of the calculation step size through adaptive time step control, the step size is shortened when the temperature or stress changes violently to improve the accuracy, and the step size is extended during the flat stage to enhance the solution efficiency.

[0086] Extended finite element method (XFEM): A numerical method for simulating crack propagation. Based on the interface stress distribution data, the crack initiation path is traced without re-meshing, the crack propagation rate is calculated through the stress intensity factor, and the fatigue cumulative damage model is combined to predict the life decay trend.

[0087] Paris formula: A mathematical model that characterizes the fatigue crack propagation law, correlates the crack propagation rate with the amplitude of the stress intensity factor, and introduces the influence of thermal expansion differences through the temperature and stress biaxial correction module to generate life prediction curves under different temperature cycles.

[0088] Residual contrast and parameter dynamic update: Compare the interface debonding strength output by the simulation with the experimental data, fit the deviation through the least squares method, and iteratively correct the thermal expansion coefficient and interface strength parameters of the coating material to make the simulation results converge to the experimental values and improve the model prediction accuracy.

[0089] Accelerated life test: Apply the synergistic load of high and low temperature cycles and mechanical prestress through a multi-axis loading device, and collect data on interface delamination, crack propagation, and thermal distribution, which are used to correct the fracture toughness parameters of the material constitutive model and optimize the adaptability of the dynamic temperature-pressure coupling equation to actual working conditions.

[0090] Multi-parameter collaborative optimization model: Based on the high stress concentration area distribution data and the life attenuation curve, the coating component ratio and interface structure parameters are adjusted reversely, and the optimization scheme is verified through the response surface model, and the compressive performance improvement path matching the target service conditions is output.

[0091] The present invention constructs a composite geometric model of a coating matrix containing a microporous structure to solve the problem that a single load simulation in the prior art cannot reproduce a composite working condition. Based on the measured working condition data, a reverse engineering method is used to quantify the micropore diameter, distribution density and interface curvature characteristics in the surface topography scan data, and a parametric model consistent with the real component is generated. The micropore optical load is converted into an equivalent heat flux density through a ray tracing algorithm, and a dynamic temperature-pressure coupling equation is established in combination with the thermal expansion effect of the high-pressure medium to accurately characterize the synergistic effect of temperature cycle and pressure fluctuation on the coating surface, and provide multi-physical field boundary condition input for the transient analysis of the interface stress distribution.

[0092] The present invention overcomes the defect of inaccurate evaluation of the coupling effect of prestress and temperature alternation through non-uniform grid division and multi-field collaborative simulation. A hexahedron encrypted grid is adopted in the coating matrix composite interface area, and a tetrahedron transition unit is divided at the micropore edge in combination with the surface roughness parameter to improve the calculation accuracy of the stress gradient. An implicit time integration algorithm is used to synchronously solve the thermo-mechanical coupling equation, and the interface stress peak value and distribution data are extracted through a transient solver, and the crack propagation path and life attenuation trend are simulated by associating the extended finite element method with the Paris formula to realize the dynamic evaluation of the damage index under the composite load.

[0093] The present invention optimizes the coating performance prediction model through closed-loop verification of experimental and simulation data. The interface peeling strength output by the fracture mechanics analysis is compared with the high and low temperature-pressure combined test data for residuals, and the material thermal expansion coefficient and interface strength parameters are dynamically corrected by the least square method. The fracture toughness parameters of the material constitutive model are corrected based on the failure mode data of the accelerated life test, and a calibrated multi-parameter collaborative optimization path is generated to form a coating compressive performance improvement scheme matching the target service conditions, solving the limitation of the existing model in life prediction deviation under complex working conditions.

[0094] The specific implementation manner of the present invention is as follows: A coating performance simulation method based on high and low temperature cycles and prestress loading. First, the surface topography scan data of the pipeline or component is collected by a three-dimensional laser scanner, and the internal pressure distribution, temperature gradient and high-pressure medium material parameters are obtained in combination with a pressure sensor and a thermocouple. Based on the measured data, a composite geometric model of the coating matrix is reconstructed in a three-dimensional modeling software, and a reverse engineering algorithm is used to denoise and topologically reconstruct the point cloud data of the microporous structure to generate a parametric model including pore diameter, distribution density and interface curvature characteristics. The surface roughness parameters of the interface area are extracted through a curvature analysis tool to provide geometric feature input for subsequent grid division.

[0095] In the finite element simulation platform, the thermal expansion coefficient of the high-pressure medium and the data of the correlation characteristics between pressure and temperature are called, and the pressure fluctuation curve caused by the thermal expansion of the medium under temperature cycling is calculated through fluid mechanics simulation. Based on the heat conduction equation and the elastic mechanics equation, the pressure fluctuation is correlated with the thermal conductivity and elastic modulus parameters of the coating and the substrate, and a dynamic temperature-pressure coupling equation is established. The scattering effect of the microporous structure on the local heat flux distribution is quantified by the ray tracing algorithm, and a non-uniform heat flux load distribution map is generated, which is used as the transient thermal boundary condition and input into the simulation platform. In the coating-substrate composite interface region, hexahedron meshes are encrypted, and tetrahedral transition elements are divided at the edges of the micropores in combination with the surface roughness parameters. The calculation efficiency and accuracy are balanced through the adaptive time step control module.

[0096] The thermo-mechanical coupling equation is solved by the implicit time integration algorithm, the temperature cycle and the prestress are applied step by step, and the peak value and distribution data of the interface stress are extracted. Based on the extended finite element method, the crack initiation path is simulated, and the life decay curve under different temperature cycles is predicted in combination with the Paris formula. The residual comparison is made between the interface peeling strength output by the simulation and the data of the high and low temperature-pressure combined test, and the thermal expansion coefficient and interface strength parameters of the coating material are dynamically corrected by the least square method. The failure mode data are collected through the accelerated life test, the fracture toughness parameters of the material constitutive model are optimized, a calibrated multi-parameter collaborative optimization path is generated, and a coating compressive performance improvement plan matching the service conditions of the high-pressure pipeline is output, realizing high-precision simulation of the interface stress distribution and life prediction under complex working conditions.

Claims

1. A simulation method for coating performance based on high and low temperature cycling and prestress loading, characterized in that, Including: Obtain the measured working condition data of the pipeline or component, where the measured working condition data includes internal pressure distribution, temperature gradient, high-pressure medium material parameters, and surface topography scanning data, and construct a coating-substrate composite geometric model based on the measured working condition data; Convert the micropore structure in the surface topography scanning data of the measured working condition data into a digital model, calculate the optical load distribution based on the geometric characteristics of the micropore structure, and import the digital model and the optical load distribution into the coating-substrate composite geometric model to obtain the mechanical property parameters and thermal physical property parameters of the coating and substrate materials; Import the mechanical property parameters and thermal physical property parameters of the coating and substrate materials into a preset finite element simulation platform, and generate a dynamic temperature-pressure coupling equation according to the thermal expansion characteristics of the high-pressure medium; Perform thermo-mechanical coupling analysis in the finite element simulation platform, set the prestress and temperature cycle range, correlate the temperature field and stress field based on the dynamic temperature-pressure coupling equation, and convert the optical load distribution into an equivalent heat flux density through a ray tracing algorithm and superimpose it on the coating surface thermal boundary condition; Perform non-uniform mesh division on the coating-substrate composite interface region and micropore region of the coating-substrate composite geometric model. The coating-substrate composite interface region uses a hexahedron-dominated encrypted mesh, and the micropore edge uses a tetrahedron transition mesh; Stepwise load the temperature cycle and prestress in the finite element simulation platform, calculate the superimposed value of thermal stress and mechanical stress at each time step through a transient solver, and extract the stress peak value and distribution data of the coating-substrate composite interface region; Input the stress peak value and distribution data into a fracture mechanics analysis module, determine the crack propagation direction based on the stress intensity factor, and calculate the damage index and remaining life under cyclic loading in combination with the fatigue cumulative damage model.

2. The simulation method for coating performance based on high and low temperature cycling and prestress loading according to claim 1, characterized in that, The steps of constructing the coating-substrate composite geometric model include: Generate a parametric model that matches the pipeline or component in the measured working condition data through a preset three-dimensional modeling platform. The coating thickness and substrate size of the parametric model are consistent with the measured data; Use reverse engineering methods to convert the micropore diameter and distribution density in the surface topography scanning data into the topological structure of the coating-substrate composite geometric model; Based on the curvature characteristics of the surface topography scanning data, mark the curvature characteristics of the coating-substrate composite interface region in the coating-substrate composite geometric model and generate surface roughness parameters; Automatically encrypt the high stress gradient region in the coating-substrate composite geometric model through an adaptive mesh division tool, and verify the mesh convergence based on the surface roughness parameters to control the iteration residual threshold.

3. The simulation method for coating performance based on high and low temperature cycling and prestress loading according to claim 2, wherein The steps of generating the dynamic temperature-pressure coupling equation include: Call the high-pressure medium material parameters in the measured working condition data, where the high-pressure medium material parameters include the thermal expansion coefficient and the pressure-temperature correlation characteristics; Calculate the pressure fluctuation curve caused by the thermal expansion of the high-pressure medium under the temperature cycle condition through fluid mechanics simulation; Correlate the pressure fluctuation curve with the thermal physical property parameters of the coating and substrate, and establish a dynamic coupling relationship equation between the temperature field and the stress field. Input the dynamic coupling relationship equation into the thermo-mechanical coupling analysis of the finite element simulation platform as the boundary condition of transient loading.

4. The simulation method for coating performance based on high and low temperature cycles and prestress loading according to claim 3, wherein The steps of setting the prestress and temperature cycle range include: Define the medium pressure as the initial prestress loading value in the thermo-mechanical coupling analysis of the finite element simulation platform, and the medium pressure matches the characteristics of the high-pressure medium; Quantify the influence of the microporous structure of the coating matrix composite geometric model on the local heat distribution through the ray tracing algorithm to generate a non-uniform heat flux load distribution map; Input the heat flux load distribution map into the optical heat transfer interface of the finite element simulation platform, and calculate the temperature gradient change on the coating surface based on the dynamic temperature-pressure coupling equation; Perform transient coupling on the temperature gradient change and the mechanical stress field in the thermo-mechanical coupling analysis, and output the stress superposition result in the time domain.

5. The simulation method for coating properties based on high and low temperature cycles and prestress loading according to claim 4, characterized in that, The steps of the non-uniform mesh division include: According to the stress gradient distribution in the coating matrix composite interface region of the coating matrix composite geometric model, divide the encrypted mesh dominated by hexahedrons, and set tetrahedral transition elements at the edges of the micropores based on the generated surface roughness parameters; Use the implicit time integration algorithm to solve the established dynamic temperature-pressure coupling equation, and set the adaptive time step to balance the calculation accuracy and efficiency; Automatically extract the stress-strain curve in the heating and cooling stages in the finite element simulation platform through a script, and identify the critical turning point of the peeling stress in the coating matrix composite interface region; Compare the critical turning point with the mesh convergence analysis result, and dynamically adjust the mesh density of the coating matrix composite geometric model to optimize the calculation stability.

6. The simulation method for coating performance based on high and low temperature cycles and prestress loading according to claim 5, characterized in that, The steps of calculating the damage index and remaining life under cyclic loads by combining the fatigue cumulative damage model include: using the extended finite element method to simulate the interface delamination crack initiation path of the coating matrix composite geometric model, and obtaining the correlation data between the crack propagation rate and the stress distribution based on the extracted stress peak and distribution data; establishing a fatigue crack propagation model based on the Paris formula to predict the life decay curve under different temperature cycles; Generate the stress nephogram and interface peeling stress distribution map in the finite element simulation platform through a preset post-processing platform, and locate the optimized high stress concentration area according to the stress nephogram; Reverse-adjust the component ratio of the coating material according to the distribution data of the high stress concentration area to generate a multi-parameter collaborative optimization model corresponding to the life decay curve.

7. The simulation method for coating performance based on high and low temperature cycles and prestress loading according to claim 6, wherein It also includes: Perform a residual comparison between the interface peeling strength output by the fracture mechanics analysis module and the actual high and low temperature-pressure combined test data; Fit the deviation between the simulation and experimental results by the least squares method, and dynamically update the thermal expansion coefficient of the coating material and the interface strength parameters generated therein; Set an accelerated life test to collect the failure mode data under combined loads, and correct the fracture toughness parameter of the material constitutive model in the dynamic temperature-pressure coupling equation; Recalculate the remaining life according to the corrected model parameters, and output the calibrated coating compressive performance optimization path corresponding to the multi-parameter collaborative optimization model.

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