An optimized preparation method and system for polypropylene cable outer shielding material

Abstract

This invention discloses an optimized preparation method and system for polypropylene cable outer shielding material, relating to the field of functionalized preparation and optimization technology of polypropylene cable outer shielding material. The method includes: acquiring performance data of the target material, generating a performance design constraint set, and screening conductive phase types; constructing a spatial distribution topology of the conductive phase in the polypropylene matrix according to the conductive phase type, forming a conductive network topology, and outputting the spatial distribution; determining the interface control method according to the conductive phase type and spatial distribution, and outputting interface control data; determining the spatial distribution characteristics of the flexible connection structure for dispersing stress according to the conductive network topology and interface control data, forming a stress buffer layout; performing electric field simulation based on the spatial distribution of the conductive phase, interface control data, and stress buffer layout, and dynamically correcting the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material. This application solves the problems of shielding material continuity and stress concentration through conductive network optimization and interface control.

Description

Technical Field

[0001] This invention relates to the field of functionalized preparation and optimization technology of polypropylene cable outer shielding material, and more specifically, to an optimized preparation method and system for polypropylene cable outer shielding material. Background Technology

[0002] In power and communication systems, the safe and reliable operation of high-voltage cables places stringent requirements on the performance of cable materials. Polypropylene, due to its excellent insulation properties, mechanical strength, and heat resistance, is widely used as an outer shielding material for cables. However, with the increase in rated voltage levels and the increasing complexity of operating conditions, traditional polypropylene outer shielding materials have revealed a series of performance limitations during service. As the demand for high-performance cables continues to grow, there is an urgent need for a method that can systematically optimize the preparation of polypropylene outer shielding materials. This method should achieve high reliability and long service life under various operating conditions through conductive phase selection, spatial distribution topology construction, interface control, stress buffering layout, and electric field functional gradient optimization.

[0003] For example, the invention patent with publication number CN109651694A discloses a semi-conductive outer shielding material for easily peelable silane cross-linked cables. Its raw materials include: 28% VA content ethylene-vinyl acetate resin, 40% VA content ethylene-vinyl acetate resin, polypropylene, nitrile rubber, conductive carbon black, microcrystalline wax, micron-sized activated montmorillonite, free radical release agent, and antioxidant 300#. The mass ratio of the 28% VA content ethylene-vinyl acetate resin, 40% VA content ethylene-vinyl acetate resin, nitrile rubber, and polypropylene is 18-20:20-25:9-10:6-7. This easily peelable semi-conductive outer shielding material for silane cross-linked cables solves the problem of polymer network interpenetration and adhesion at the interface of Nordic Chemicals' silane cross-linked insulation material, which prevents the cable from being peeled off during installation. Without changing the existing processing technology of silane cross-linked cables, it improves the uniformity of the electric field in silane cross-linked cables, thus extending the cable's service life.

[0004] For example, invention patent CN113930005B discloses a semi-conductive shielding material, its preparation method, and its application. The semi-conductive shielding material comprises the following components: ethylene-butyl acrylate copolymer, maleic anhydride-grafted polyethylene, ethylene-octene copolymer, conductive carbon black, pyrolytic PE wax, silicone, dispersant, and antioxidant; wherein the mass ratio of the ethylene-butyl acrylate copolymer, the maleic anhydride-grafted polyethylene, and the ethylene-octene copolymer is 1:0.1-1:2-6, preferably 1:0.2-0.6:3-5. This semi-conductive shielding material uses ethylene-octene copolymer as the matrix, and adds ethylene-butyl acrylate copolymer and maleic anhydride-grafted polyethylene, thereby making the extruded surface of the material smooth and flat, fundamentally solving the interfacial air gap problem between the insulation layer and the outer shielding layer, and simultaneously making the electric field distribution on the surface of the silane cross-linked cable more uniform.

[0005] The above-disclosed technical solutions have at least the following technical problems:

[0006] In traditional technologies, the interface between the polypropylene matrix and the conductive phase often lacks fine-tuning. The interfacial energy cannot adapt to stress and electric field changes under different service conditions, easily leading to local instability, resulting in reduced conductivity or deteriorated mechanical properties. Furthermore, existing shielding material preparation processes lack dynamic control over the functional gradient and electric field distribution along the thickness direction, potentially causing electric field concentration or uneven shielding in localized areas. To address these issues, this invention proposes a solution. Summary of the Invention

[0007] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide an optimized preparation method and system for polypropylene cable outer shielding material, which solves the problems of shielding material continuity and stress concentration through conductive network optimization and interface control.

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

[0009] An optimized preparation method for polypropylene cable outer shielding material includes: acquiring performance data of the target material, generating a performance design constraint set, and screening conductive phase types; constructing a spatial distribution topology of the conductive phase in a polypropylene matrix according to the conductive phase type, forming a conductive network topology, and outputting the spatial distribution of the conductive phase; matching the interfacial energy between the polypropylene matrix and the conductive phase according to the conductive phase type and spatial distribution, determining the interface control mode, and outputting interface control data; analyzing the stress concentration region between the conductive phase and the polypropylene matrix according to the conductive network topology and interface control data, and forming a stress buffer layout; performing electric field simulation based on the spatial distribution of the conductive phase, the interface control data, and the stress buffer layout, and dynamically correcting the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material.

[0010] In a preferred embodiment, the acquisition of performance data of the target material, generation of a performance design constraint set, and screening of conductive phase types are specifically as follows: Based on the rated voltage level, continuous operating temperature, and periodic bending conditions of the target cable, a multi-condition service performance window is constructed; within the multi-condition service performance window, the stable range of volume resistivity of the outer shielding material, the critical strain threshold for maintaining the continuity of the conductive network, and the allowable stress release range under low-temperature conditions are extracted to form electrical-mechanical coupling constraint data; based on the electrical-mechanical coupling constraint data, the threshold conditions required for different morphologies of conductive phases to form a continuous conductive network in the polypropylene matrix are inverted and analyzed to obtain the threshold-sensitive data of the conductive phase; using the multi-condition service performance window as the overall parameter space for the performance variation of the outer shielding material, the allowable performance of the outer shielding material under different service conditions is determined. The range of variation is initially defined to form a basic performance constraint range. Within this range, the continuity of the conductive network under deformation and thermal aging conditions is constrained based on electromechanical coupling constraint data, resulting in a feasible parameter subspace. Within this subspace, the characteristic range of conductive phases forming a continuous conductive network is screened based on threshold-sensitive data, generating a performance design constraint set. Based on this constraint set, the conductivity efficiency, morphological anisotropy, and interfacial interaction potential with the polypropylene matrix of candidate conductive phases are evaluated to obtain candidate conductive phase systems. Among these candidate systems, the conductive phase type that forms a continuous conductive network within the threshold-sensitive data range and satisfies the electromechanical coupling constraints and interface controllability requirements is selected as the basic input for the conductive phase in the design of the outer shielding material structure.

[0011] In a preferred embodiment, the construction of a multi-condition service performance window based on the target cable's rated voltage level, continuous operating temperature, and periodic bending conditions is as follows: Based on the target cable's rated voltage level, continuous operating temperature, and periodic bending conditions, the service status of the outer shielding material during cable operation is analyzed, and the service conditions are divided according to operating temperature range and service time characteristics to obtain normal temperature operating conditions, low temperature operating conditions, and long-term thermal aging conditions; according to the failure modes of the outer shielding material under each service condition, electrical performance data and mechanical performance data are selected for each service condition; through the operating limit conditions of the target cable under the corresponding service conditions, the performance data for each service condition are determined. The permissible variation range of performance data under service conditions without functional failure is defined. The permissible variation range of performance data under each service condition is normalized according to a unified performance data dimension, and a single-condition performance boundary is constructed for each service condition. Using the common performance data involved in each single-condition performance boundary as the mapping object, parameter space mapping is performed on the single-condition performance boundary to obtain multiple parameter space regions corresponding to different service conditions. Based on the superposition relationship of each service condition during the actual operation of the target cable, the intersection operation of the parameter space regions is performed to obtain a set of effective value boundaries. Based on the set of effective value boundaries, a multi-condition service performance window for the outer shielding material under normal temperature, low temperature, and thermal aging conditions is constructed.

[0012] In a preferred embodiment, the step of constructing a spatial distribution topology of conductive phases in a polypropylene matrix according to the conductive phase type, forming a conductive network topology, and outputting the spatial distribution of conductive phases is as follows: Based on the conductive phase type, conductive phase morphology characteristics, and conductive phase threshold sensitivity data, a mapping relationship between the local filling ratio and the probability of conductive network formation is established based on an occupancy probability model; using the initial conductive threshold as the target value of the network formation probability, the mapping relationship between the local filling ratio and the network formation probability is substituted, and the minimum local filling ratio that satisfies the target value is obtained through numerical inversion; the polypropylene matrix is ​​divided into three-dimensional grid cells, and the number of conductive phases placed in each cell is determined by the minimum local filling ratio; within each grid cell, three-dimensional coordinates are generated according to the conductive phase morphology characteristics; the distance between adjacent conductive phases is determined based on the three-dimensional coordinates, and nodes and edges that can form conductive contacts are marked to form an initial conductive network topology; the connectivity of the initial conductive network topology is verified to determine whether it meets the initial conductive threshold and continuity requirements; if not, the number of conductive phases is dynamically adjusted until the requirements are met, resulting in the final conductive network topology, and the spatial distribution of conductive phases is output.

[0013] In a preferred embodiment, the step of matching the interfacial energy between the polypropylene matrix and the conductive phase based on the type and spatial distribution of the conductive phase, determining the interfacial control method, and outputting interfacial control data specifically involves the following steps: Based on the spatial distribution of the conductive phase, the contact positions between the conductive phase and the polypropylene matrix are identified, and the actual contact area and contact method between the conductive phase and the polypropylene matrix are extracted; the interaction energy between the conductive phase and the polypropylene matrix in the contact area is calculated using molecular simulation methods to obtain the interfacial energy data corresponding to each contact area; the interfacial energy data is combined with the local stress distribution and electric field distribution of the outer shielding material under various service conditions to analyze the stability of the interface at the corresponding spatial location and screen out the interface instability regions; based on the morphological characteristics, local filling ratio, and spatial location of the conductive phase, the instability sources of the interface instability regions are analyzed; based on the instability sources of the instability regions, the interfacial control method is determined for different contact areas; based on the interface control method, the corresponding processing data and its application location are determined, so that the interface control method corresponds one-to-one with the spatial distribution of the conductive phase, forming interface control configuration data.

[0014] In a preferred embodiment, the step of combining interface energy data with the local stress distribution and electric field distribution of the outer shielding material under various service conditions to analyze the stability of the interface at corresponding spatial locations and screen out interface instability regions is as follows: The conductive network topology and material structure are simulated using the finite element method to obtain the local stress distribution and electric field distribution data of the outer shielding material under different service conditions; the interface energy data is mapped in three-dimensional space according to its corresponding coordinate distribution to the local stress field and electric field intensity data of the outer shielding material at the same location; and the conductive phase—polypropylene—in each contact area is analyzed using micromechanical simulation methods. A mechanical-electric field coupled model was established for the olefin interface unit, with local stress and electric field load as external inputs and interface energy as the initial potential energy term. The energy change of the mechanical-electric field coupled model was solved by the conjugate gradient method to obtain the variation trend of interface bonding energy in each interface contact region under service conditions. The interface energy data was spatially superimposed with the local stress and electric field data to perform stress-energy coupling analysis on each interface contact region, outputting the variation trend of interface bonding energy under service conditions. By judging whether the interface energy change exceeds the preset stability threshold of the conductive phase-polypropylene interface bonding, the interface instability region was identified.

[0015] In a preferred embodiment, the step of analyzing the stress concentration region between the conductive phase and the polypropylene matrix based on the conductive network topology and interface control data to form a stress buffer layout is as follows: The conductive phase nodes, edges, and their three-dimensional spatial coordinates in the conductive network topology are spatially mapped to the polypropylene matrix structure to obtain the spatial distribution of the conductive phase in the polypropylene matrix; the spatial distribution of the conductive network is spatially correlated with the interface control data to form a conductive network structure model; using the conductive network structure model as the calculation object, under simulated bending, stretching, or thermal shrinkage service conditions of the outer shielding material, the stress distribution at the interface between the conductive phase and the polypropylene matrix is ​​obtained through micromechanical simulation methods; the stress distribution is projected onto the interface position between the conductive phase and the polypropylene matrix; a local comparative analysis is performed on the stress distribution projected to the interface position to identify the stress concentration region between the conductive phase and the polypropylene matrix; using the spatial position of the stress concentration region as the arrangement basis, combined with the morphological characteristics of the corresponding conductive phase and its connection method in the conductive network, the setting position and distribution method of the flexible connection structure for dispersing stress are determined; based on the setting position and distribution method, the spatial distribution characteristics of the flexible connection structure are generated around the stress concentration region to obtain stress buffer layout data.

[0016] In a preferred embodiment, the step of determining the placement and distribution of the flexible connection structure for dispersing stress, based on the spatial location of the stress concentration region and combined with the morphological characteristics of the corresponding conductive phase and its connection method in the conductive network, is as follows: The three-dimensional spatial location of the identified stress concentration region is used as the starting point for arranging the flexible connection structure. The morphological characteristics of the conductive phase within the stress concentration region and its connection method in the conductive network are extracted. Based on the deformation characteristics corresponding to the morphology of the conductive phase and its connection method in the conductive network, the stress transmission path and concentration direction between the conductive phase and the polypropylene matrix are analyzed. The flexible connection structure is arranged according to the transmission path and concentration direction, thereby determining the specific placement of the flexible connection structure between the conductive phase and the polypropylene matrix and its distribution method in the conductive network.

[0017] In a preferred embodiment, the step of performing electric field simulation based on the spatial distribution of the conductive phase, interface control data, and stress buffer layout, and dynamically correcting the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material, specifically involves: performing a unified spatial mapping of the conductive phase spatial distribution data, interface control configuration data, and stress buffer layout data to construct a three-dimensional structural model of the outer shielding material; solving the three-dimensional structural model using the finite volume method to obtain the spatial distribution of the electric field intensity and electric field gradient at the stress buffer unit locations; performing spatial analysis on the electric field intensity and electric field gradient spatial distribution to identify non-uniform electric field regions; mapping the non-uniform electric field regions to the spatial distribution of the conductive phase, the distribution of the flexible connection structure, and the thickness direction position of the outer shielding material, and adjusting accordingly to obtain the corrected conductive phase spatial distribution and the functional gradient in the thickness direction; reintroducing the corrected conductive phase spatial distribution and the functional gradient in the thickness direction into the electric field simulation model, repeating the electric field solution and non-uniform electric field region identification process until preset conditions are met, and outputting the final conductive phase spatial distribution and the functional gradient in the thickness direction of the outer shielding material.

[0018] A system for optimizing the preparation of polypropylene cable outer shielding material is characterized by comprising a screening module, a topology module, a matching module, a stress buffering layout module, and an output module, with connections between the modules. The screening module acquires performance data of the target material, generates a performance design constraint set, and screens the conductive phase type. The topology module constructs a spatial distribution topology of the conductive phase in the polypropylene matrix based on the conductive phase type, forming a conductive network topology, and outputs the spatial distribution of the conductive phase. The matching module matches the interfacial energy between the polypropylene matrix and the conductive phase based on the conductive phase type and spatial distribution, determines the interface control method, and outputs interface control data. The stress buffering layout module analyzes the stress concentration region between the conductive phase and the polypropylene matrix based on the conductive network topology and interface control data, forming a stress buffering layout. The output module performs electric field simulation based on the spatial distribution of the conductive phase, interface control data, and stress buffering layout, dynamically correcting the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material.

[0019] The technical effects and advantages of the optimized preparation method and system for polypropylene cable outer shielding material of this invention are as follows:

[0020] 1. This invention achieves multi-condition performance optimization of external shielding materials through conductive phase selection and performance constraint design based on target material performance data. The method constructs a multi-condition service performance window by combining the cable's rated voltage level, continuous operating temperature, and periodic bending conditions. Within this window, the stable range of volume resistivity, the critical strain for conductive network continuity, and the allowable stress release range under low-temperature conditions are extracted and analyzed, achieving coupled constraint design of electrical and mechanical properties. Through conductive phase threshold sensitivity analysis and feasible parameter subspace screening, the conductive phase type that can form a continuous conductive network and meet the interface controllability requirements under actual operating conditions can be accurately selected, ensuring high reliability and stability of the external shielding material under complex service conditions.

[0021] 2. This invention achieves continuity and structural optimization of the conductive network by constructing a spatial distribution topology and conductive network model of the conductive phase. Utilizing an occupancy probability model, a mapping relationship between local filling ratio and network formation probability, and three-dimensional mesh generation and connectivity verification, the spatial distribution of the conductive phase in the polypropylene matrix can be accurately determined, enabling efficient formation of the conductive network. This method not only ensures the continuity and conductivity efficiency of the conductive network but also provides a reliable spatial basis for subsequent interface control and stress buffering layout. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of an optimized preparation method for a polypropylene cable outer shielding material according to the present invention.

[0023] Figure 2 This is a schematic diagram of the system structure of an optimized preparation method for a polypropylene cable outer shielding material according to the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1, Figure 1 An optimized preparation method for a polypropylene cable outer shielding material is provided according to the present invention, comprising:

[0026] S1. Obtain the performance data of the target material, generate a performance design constraint set, and filter the conductive phase type;

[0027] In this embodiment, the performance data of the target material is acquired, a performance design constraint set is generated, and the conductive phase type is filtered, as follows:

[0028] Acquire the performance data of the target cable, including electrical performance data and mechanical performance data. The electrical performance data includes volume resistivity stability, and the mechanical performance data includes elongation at break and flexural deformation retention.

[0029] Based on the rated voltage level, continuous operating temperature and periodic bending conditions of the target cable, a multi-condition service performance window for the outer shielding material under normal temperature, low temperature and thermal aging conditions is constructed. The multi-condition service performance window is used to define the performance variation boundary of the outer shielding material under different service conditions.

[0030] Within the multi-condition service performance window, the stable range of volume resistivity of the outer shielding material, the critical strain threshold for maintaining the continuity of the conductive network, and the allowable stress release range under low temperature conditions are extracted to form electrical-mechanical coupling constraint data.

[0031] Based on electromechanical coupling constraint data, the threshold conditions required for conductive phases with different morphologies to form a continuous conductive network in a polypropylene matrix are inverted and analyzed to obtain threshold sensitive data of the conductive phase. The threshold sensitive data of the conductive phase includes the initial conductivity threshold and the network stability threshold.

[0032] Using a multi-condition service performance window as the overall parameter space for the performance changes of the outer shielding material, the allowable performance variation range of the outer shielding material under different service conditions is initially defined to form a basic performance constraint range. Specifically, using a multi-condition service performance window as the overall parameter space for the performance changes of the outer shielding material, the allowable variation range of performance data under each service condition is uniformly represented according to the performance data dimension, and the intersection operation of the allowable range of each performance data under each service condition is performed to determine the initial allowable performance variation range of the outer shielding material under all service conditions. The initial allowable variation ranges of each performance data are integrated to form a basic performance constraint range.

[0033] Within the basic performance constraints, based on the electromechanical coupling constraint data, the continuity requirements of the conductive network under deformation and thermal aging conditions are constrained. Data combinations that cause the conductive network to fail under any constraint condition are eliminated, and a feasible parameter subspace that meets the conductivity continuity requirements is obtained.

[0034] Within the feasible parameter subspace, based on the threshold sensitivity data of the conductive phase, the characteristic range of the conductive phase that forms a continuous conductive network is screened to generate a performance design constraint set for the design of the outer shielding material. The performance design constraint set is used to limit the parameter boundaries of the selection of conductive phase type and subsequent structural design.

[0035] Based on the performance design constraint set, the conductivity efficiency, morphological anisotropy and interfacial interaction potential with the polypropylene matrix of the candidate conductive phases are evaluated, and conductive phases that cannot form a stable conductive network within the threshold range are eliminated to obtain the candidate conductive phase system.

[0036] In the candidate conductive phase system, the conductive phase type that forms a continuous conductive network within the threshold sensitive data range and meets the requirements of electromechanical coupling constraints and interface controllability is selected as the basic input of the conductive phase for the design of the outer shielding material structure.

[0037] In this embodiment, based on the rated voltage level, continuous operating temperature, and cyclic bending conditions of the target cable, a multi-condition service performance window for the outer shielding material under normal temperature, low temperature, and thermal aging conditions is constructed, as follows:

[0038] Based on the rated voltage level, continuous operating temperature, and periodic bending conditions of the target cable, the service status of the outer shielding material during cable operation is analyzed. The service conditions are then categorized according to operating temperature ranges and service time characteristics, resulting in normal temperature operating conditions, low temperature operating conditions, and long-term thermal aging conditions. Specifically: First, operating data of the target cable during actual operation is collected, including rated voltage level, continuous operating temperature curve, periodic bending frequency and amplitude, and long-term load conditions. Then, the operating temperature is divided into several ranges (e.g., normal temperature range, low temperature range, and high temperature range), and the service life is divided into short-term, long-term, and thermal aging stages based on the length of operating time. Next, the stress, thermal, and electrical conditions that the cable may experience in each temperature range and service life are combined with bending loads to form a set of typical service states. Finally, these typical service states are categorized into normal temperature operating conditions, low temperature operating conditions, and long-term thermal aging conditions.

[0039] Based on the failure modes of the outer shielding material under various service conditions, electrical performance data related to electric field control capability and mechanical performance data related to deformation adaptability were selected for each service condition.

[0040] By determining the operating limit conditions of the target cable under the corresponding service conditions, the allowable range of variation of each performance data is determined when no functional failure occurs under the service conditions.

[0041] The allowable variation range of performance data under each service condition is normalized according to a unified performance data dimension, and single-condition performance boundaries corresponding to normal temperature operation, low temperature operation and long-term thermal aging are constructed respectively.

[0042] Using the common performance data involved in the performance boundary of each single operating condition as the mapping object, the parameter space mapping of the single operating condition performance boundary is performed to obtain multiple parameter space regions corresponding to different service operating conditions.

[0043] Based on the superposition relationship of various service conditions of the target cable during actual operation, the intersection operation of the parameter space region is performed to limit the performance data range that must be met under all service conditions, and obtain the effective value boundary set of the performance data of the outer shielding material under multiple service conditions.

[0044] Based on the set of valid value boundaries, a multi-condition service performance window for the outer shielding material under normal temperature, low temperature and thermal aging conditions is constructed. The multi-condition service performance window is used to limit the performance variation boundary of the outer shielding material under different service conditions.

[0045] In this embodiment, based on electromechanical coupling constraint data, the threshold conditions required for different morphological conductive phases to form a continuous conductive network in a polypropylene matrix are inverted and analyzed to obtain threshold-sensitive data of the conductive phase. The threshold-sensitive data of the conductive phase includes the initial conductivity threshold and the network stability threshold, as follows:

[0046] Based on electromechanical coupling constraint data, the conditions required for conductive phases with different morphologies to form a continuous conductive network in a polypropylene matrix are analyzed. The morphological characteristics of the conductive phase are mapped to the micro-network forming capability. Combined with the volume resistivity stability range and the critical strain threshold for the conductive network to remain continuous under deformation or low temperature conditions, the minimum proportion of conductive phase required to form a conductive network is determined as the initial conductivity threshold. The range of conductive phase proportions that remain continuous under operating conditions is determined as the network stability threshold, thus obtaining threshold-sensitive data of the conductive phase.

[0047] In this embodiment, within the feasible parameter subspace, the characteristic range of the conductive phase forming a continuous conductive network is filtered based on the threshold-sensitive data of the conductive phase, generating a performance design constraint set for the design of the outer shielding material, as follows:

[0048] Determine whether the performance data of each conductive phase combination falls within the feasible parameter subspace, and determine whether the conductive phase ratio meets the initial conductivity threshold and network stability threshold. At the same time, evaluate whether the conductive phase combination can form a continuous conductive network and maintain mechanical properties under the electrical-mechanical coupling constraint conditions.

[0049] The conductive phase combinations that meet the above judgment conditions are retained, and their characteristic ranges are set to form the performance design constraint set for the external shielding material design.

[0050] In this embodiment, based on the performance design constraint set, the conductivity efficiency, morphological anisotropy, and interfacial interaction potential with the polypropylene matrix of the candidate conductive phases are evaluated. Conductive phases that cannot form a stable conductive network within the threshold range are eliminated, resulting in the following candidate conductive phase system:

[0051] Determine whether the proportion of conductive phase required for the formation of a conductive network in a polypropylene matrix meets the initial conductivity threshold and the network stability threshold.

[0052] To determine whether the morphological characteristics of the conductive phase can form a continuous conductive path in the polypropylene matrix, the morphological characteristics of the conductive phase include the size (e.g., particle size, fiber diameter, length), shape (e.g., spherical, flake, fibrous), aspect ratio, and spatial distribution characteristics (e.g., dispersion uniformity, degree of aggregation, and orientation distribution) of the conductive phase in the polypropylene matrix.

[0053] Determine whether the interfacial interaction potential between the conductive phase and the polypropylene matrix can guarantee the continuity and mechanical stability of the network under multiple operating conditions.

[0054] By eliminating conductive phases that do not meet any of the conditions, candidate conductive phase systems that can form stable conductive networks within the performance design constraint set are obtained.

[0055] S2, Based on the type of conductive phase, construct the spatial distribution topology of the conductive phase in the polypropylene matrix to form a conductive network topology, and output the spatial distribution of the conductive phase;

[0056] In this embodiment, based on the type of conductive phase, a spatial distribution topology of the conductive phase is constructed in the polypropylene matrix to form a conductive network topology, and the spatial distribution of the conductive phase is output, as detailed below:

[0057] Based on the conductive phase type, conductive phase morphology characteristics, and conductive phase threshold sensitivity data, a mapping relationship between the local filling ratio and the probability of conductive network formation is established based on the occupancy probability model.

[0058] Using the initial conductivity threshold as the target value for network formation probability, and substituting the mapping relationship between local fill ratio and network formation probability, the minimum local fill ratio that satisfies the target value is obtained through numerical inversion method.

[0059] The polypropylene matrix is ​​divided into three-dimensional mesh units, and the number of conductive phases placed in each unit is determined by the minimum local filling ratio.

[0060] Within each grid cell, three-dimensional coordinates are generated based on the morphological characteristics of the conductive phase. For fibrous or sheet-like conductive phases, random or partially oriented endpoint coordinates are generated and extended into line segments or surfaces. For granular conductive phases, random or uniformly distributed center coordinates are generated and local micro-aggregation is performed.

[0061] The distance between adjacent conductive phases is determined based on three-dimensional coordinates. Nodes and edges that can form conductive contact are marked to form an initial conductive network topology. Specifically, the center of each conductive phase is taken as a node. The shortest inter-surface distance is calculated for each pair of conductive phases (the inter-surface distance of spheres or ellipsoids is used for granular conductive phases, and the shortest distance of line segments or surfaces is used for fibrous or sheet-like conductive phases). When the shortest inter-surface distance is less than or equal to a preset conductive contact determination threshold, the conductive phases are marked as capable of forming conductive contact, and an edge is generated. The initial conductive network topology is formed by the set of nodes and edges.

[0062] The connectivity of the initial conductive network topology is verified to determine whether it meets the initial conductivity threshold and continuity requirements.

[0063] If the requirements are not met, the number or position of the conductive phases is dynamically adjusted to improve network connectivity until the requirements are met, the final conductive network topology is obtained, and the spatial distribution of the conductive phases is output.

[0064] In this embodiment, if the conditions are not met, the number or position of the conductive phases is dynamically adjusted to improve network connectivity, as follows:

[0065] In units with insufficient connectivity, the number of conductive phases is increased. The increase is calculated by multiplying the number of unconnected nodes by a safety factor and rounding down. The safety factor is a quantifiable proportional coefficient used to reserve redundant conductive phases to ensure local network connectivity when fine-tuning the number of conductive phases. It is used to amplify the number of unconnected node gaps obtained from theoretical calculations, so that the fine-tuned number can more reliably form a conductive network. The value range is 1.1 to 1.5, which can be adjusted according to the filling capacity of the polypropylene matrix. The safety factor is inversely proportional to the filling capacity. The filling capacity of the polypropylene matrix refers to the maximum volume fraction of conductive phase that can be borne per unit volume while ensuring the material's processability and mechanical properties.

[0066] Reduce the amount of conductive phase in areas with excessively high local conductive phase density to ensure that the local filling ratio does not exceed the upper limit.

[0067] For conductive phase nodes that are not connected, adjust their center or endpoint positions along the line connecting them to the nearest connectable node, with the adjustment range being 5% to 20% of the conductive phase particle size or aspect ratio;

[0068] After each fine-tuning, the network connectivity is recalculated and iterated until the network meets the initial conductivity threshold and continuity requirements.

[0069] S3, based on the type and spatial distribution of the conductive phase, match the interfacial energy between the polypropylene matrix and the conductive phase, determine the interface control method, and output the interface control data.

[0070] In this embodiment, the interfacial energy between the polypropylene matrix and the conductive phase is matched according to the type and spatial distribution of the conductive phase to determine the interface modulation method and output the interface modulation data, as follows:

[0071] Based on the spatial distribution of the conductive phase, the contact position between the conductive phase and the polypropylene matrix is ​​identified, and the actual contact area and contact mode between the conductive phase and the polypropylene matrix are extracted.

[0072] The interaction energy between the conductive phase and the polypropylene matrix in the contact region was calculated by molecular simulation method, and the interfacial energy data corresponding to each contact region was obtained.

[0073] By combining interface energy data with the local stress distribution and electric field distribution of the outer shielding material under thermal, electrical, and mechanical service conditions, the stability of the interface at the corresponding spatial location is analyzed, and contact areas with interface bonding failure risk during service are screened out as interface instability areas. The service conditions refer to the physical environment and mechanical load state borne by the outer shielding material during the actual operation of the target cable, as well as the local electric field distribution of the outer shielding material under the rated voltage of the cable.

[0074] Based on the morphological characteristics, local filling ratio, and spatial location of the conductive phase, the instability sources of the interface instability region are analyzed. The instability sources include insufficient wetting, insufficient interfacial bonding, or local stress concentration. Specifically, the morphological characteristics, local filling ratio, and spatial distribution coordinates of the conductive phase in the interface instability region are extracted as geometric and distribution information. Then, based on the interface energy data and the micromechanical coupling solution results, a local analysis is performed on each instability region: insufficient wetting regions are identified by comparing the interface energy with the contact area; regions with insufficient bonding are judged by the amplitude and total value of the interface bonding energy changing with the load; and regions with local stress concentration are identified by the peak value or gradient abrupt change of the local stress field. Finally, the instability source type of each interface instability region is labeled.

[0075] Based on the instability source of the instability region, interface control methods are determined for different contact regions. The control methods include surface modification of the conductive phase, introduction of interface additives, and construction of a locally enhanced or functionally graded interface layer around the conductive phase.

[0076] Based on the interface control method, the corresponding processing data and its position of action are determined, so that the interface control method corresponds one-to-one with the spatial distribution of the conductive phase, forming implementable interface control configuration data.

[0077] In this embodiment, the interaction energy between the conductive phase and the polypropylene matrix in the contact region is calculated using molecular simulation methods to obtain the interfacial energy data corresponding to each contact region, as follows:

[0078] Based on the identified actual contact area between the conductive phase and the polypropylene matrix, a surface structure model of the conductive phase and a polypropylene molecular chain model are established respectively. The surface structure model of the conductive phase is obtained by extracting the geometric units corresponding to the morphological features of the conductive phase and unfolding the surface. For granular conductive phases, spherical or near-spherical geometric units are used and atomic or basic unit arrangements are generated on their outer surfaces. For fibrous conductive phases, columnar or strip-shaped surface structures with finite length and cross-section are constructed along their long axis. For sheet-like conductive phases, planar or layered surface structures with finite thickness are constructed, and their surfaces are periodically or truncated to reflect the morphology of the actual contact area. The polypropylene molecular chain model is constructed by selecting repeating structural units of polypropylene and constructing molecular chain segments with a certain chain length according to the actual contact scale. The molecular chain segments are arranged in space in a random or partially oriented manner near the surface of the conductive phase, and their movement range is restricted by boundary conditions so that the constructed molecular chain model can reflect the true conformational state of the polypropylene matrix in the contact area.

[0079] The conductive phase surface model and the polypropylene molecular chain model are combined according to the actual contact mode. Polypropylene molecular chains are arranged near the conductive phase surface to form a conductive phase-polypropylene interface molecular model to reflect the interface state of the actual contact area.

[0080] The interface molecular model is subjected to energy minimization to achieve a stable configuration of the system and eliminate non-physical overlaps and high-energy structures present in the initial model.

[0081] Molecular dynamics simulation of the interface model was performed under preset temperature conditions to allow the polypropylene molecular chains to fully relax on the surface of the conductive phase and reach a thermodynamic equilibrium state.

[0082] Under thermodynamic equilibrium, the total energy of the overall interface system, the energy containing only the conductive phase, and the energy containing only the polypropylene matrix are calculated using a potential energy calculation algorithm. The interaction energy between the conductive phase and the polypropylene matrix in the corresponding contact area is obtained by differential calculation.

[0083] The interaction energies corresponding to different contact areas are organized and output to form the interface energy data for each contact area.

[0084] It should be noted that, under thermodynamic equilibrium, the total energy of the overall interface system, the energy containing only the conductive phase, and the energy containing only the polypropylene matrix are calculated using potential energy calculation algorithms. The total energy of each system consists of bond stretching energy, bond angle bending energy, dihedral angle torsion energy, and non-bonded interaction energy. The non-bonded interaction energy is calculated using the Coulomb interaction algorithm and the van der Waals interaction potential function. Under the premise of maintaining the consistency of the atomic configuration of each system, the total potential energy values ​​of the above systems are obtained, thus providing basic data for obtaining the interaction energy between the conductive phase and the polypropylene matrix through energy difference method.

[0085] In this embodiment, the interface energy data is combined with the local stress distribution and electric field distribution of the outer shielding material under thermal, electrical, and mechanical service conditions to analyze the stability of the interface at the corresponding spatial location. Contact areas with a risk of interface bonding failure during service are then identified as interface instability areas, as detailed below:

[0086] The topology and material structure of the conductive network were simulated using the finite element method, and the local stress distribution and electric field distribution data of the outer shielding material under different service conditions were obtained.

[0087] The interface energy data is mapped in three-dimensional space according to its corresponding coordinate distribution to the local stress field and electric field intensity data of the outer shielding material at the same location, so that each contact area has interface energy, local stress and electric field information at the same time.

[0088] Using micromechanical simulation methods, a mechanical-electric field coupled model is established for the conductive phase-polypropylene interface unit in each contact area. Local stress and electric field load are used as external inputs, and interface energy is used as the initial potential energy term.

[0089] The energy change of the mechanical-electric field coupling model was solved by the conjugate gradient method, and the trend of the interface bonding energy of each interface contact area under service conditions with load was obtained.

[0090] The interface energy data is spatially superimposed with the local stress and electric field data, and stress-energy coupling analysis is performed on each interface contact area to calculate the variation trend of interface bonding energy under service conditions.

[0091] By determining whether the change in interface energy exceeds the preset stability threshold of the conductive phase-polypropylene interface, regions with interface peeling, local instability, or insufficient wetting are identified, and these contact areas are marked as interface instability regions.

[0092] The method of establishing a mechanical-electric field coupling model for the conductive phase-polypropylene interface unit in each contact region using micromechanical simulation is as follows:

[0093] For each interface contact area, the conductive phase-polypropylene interface unit is first discretized into a finite number of unit nodes or unit volumes in three-dimensional space. Each unit node contains interface energy, position coordinates and conductive phase geometric feature information.

[0094] Then, based on the finite element theory of micromechanics, each element node is regarded as an independent mechanical element, and the material is given intrinsic mechanical properties (such as elastic modulus, Poisson's ratio, etc.) and electrical properties (such as local conductivity or dielectric constant).

[0095] In this model, local stress and electric field intensity are applied as external loads to each element node, while interface energy is used as the initial potential energy term, forming a mechanical-electric field coupled element model.

[0096] In this embodiment, based on the instability source of the unstable region, the interface control method is determined for different contact areas, as follows:

[0097] For areas with insufficient wetting, interfacial wettability can be increased by modifying the conductive phase surface (such as chemical grafting, plasma treatment, or coupling agent treatment).

[0098] For areas with insufficient interfacial bonding, interfacial additives or coupling agents are introduced to improve the interfacial bonding strength, and the type, concentration and distribution location of the additives are determined.

[0099] For regions of localized stress concentration, a localized reinforcement layer or functionally graded interface layer is constructed around the conductive phase to mitigate stress concentration, and the spatial distribution and thickness range of the reinforcement layer are determined.

[0100] By matching the instability source of each contact area with the corresponding control method, implementable interface control data is generated.

[0101] S4. Based on the conductive network topology and interface control data, analyze the stress concentration region between the conductive phase and the polypropylene matrix, determine the spatial distribution characteristics of the flexible connection structure for dispersing stress, and form a stress buffer layout.

[0102] In this embodiment, based on the conductive network topology and interface control data, the stress concentration region between the conductive phase and the polypropylene matrix is ​​analyzed, and the spatial distribution characteristics of the flexible connection structure for dispersing stress are determined, forming a stress buffer layout, as follows:

[0103] By spatially mapping the conductive phase nodes, edges and their three-dimensional spatial coordinates in the conductive network topology to the polypropylene matrix structure, the spatial distribution results of the continuous paths, intersection nodes and local high-fill regions of the conductive phase in the polypropylene matrix are obtained.

[0104] Spatial correspondence is established between the spatial distribution results of the conductive network and the interface control data. The contact areas that have been controlled and the uncontrolled areas are marked on the conductive paths, intersection nodes and turning points to form a conductive network structure model containing interface state information.

[0105] Using a conductive network structure model as the calculation object, under the conditions of simulating the bending, stretching or thermal shrinkage of the outer shielding material in service, the local stress field distributed along the conductive network path in the polypropylene matrix is ​​calculated by micromechanical simulation method. The stress distribution at the interface between the conductive phase and the polypropylene matrix is ​​obtained, and the stress distribution is projected to the interface position between the conductive phase and the polypropylene matrix.

[0106] Local comparative analysis of stress distribution projected to the interface position is performed to identify areas where stress peaks or stress gradient abrupt changes occur at conductive phase intersection nodes, conductive path turning points, or interface control transition regions, thereby determining the stress concentration area between the conductive phase and the polypropylene matrix.

[0107] Based on the spatial location of the stress concentration area, and combined with the morphological characteristics of the corresponding conductive phase and its connection method in the conductive network, the placement and distribution of the flexible connection structure for stress dispersion between the conductive phase and the polypropylene matrix are determined.

[0108] Based on the setting location and distribution method, the spatial distribution characteristics of the flexible connection structure are generated around the stress concentration area, so that the conductive network forms a deformable buffer while maintaining continuity. Finally, stress buffer layout data for subsequent electric field simulation and structural design are obtained. The spatial distribution characteristics of the flexible connection structure include the specific arrangement location of the flexible connection structure at the contact interface between the conductive phase and the polypropylene matrix, the cross node of the conductive phase or the turning area of ​​the conductive path, and the distribution pattern relative to the direction of the conductive network path.

[0109] In this embodiment, the spatial location of the stress concentration region is used as the basis for arrangement. Combined with the morphological characteristics of the corresponding conductive phase and its connection method in the conductive network, the placement position and distribution method of the flexible connection structure for dispersing stress between the conductive phase and the polypropylene matrix are determined, as follows:

[0110] Using the three-dimensional spatial location of the identified stress concentration region as the starting point for the arrangement of the flexible connection structure, the morphological features of the conductive phase in the stress concentration region and its connection mode in the conductive network are extracted. The connection mode includes whether the conductive phase is part of a continuous conductive path, part of an intersection node, or part of a path turning point, thereby clarifying the type of conductive structure corresponding to the stress concentration region.

[0111] Based on the deformation characteristics corresponding to the morphology of the conductive phase, and combined with its connection mode in the conductive network, the stress transmission path and concentration direction between the conductive phase and the polypropylene matrix are analyzed.

[0112] Based on the transmission path and concentration direction, the flexible connection structure is preferentially arranged at the position where the conductive phase and the polypropylene matrix are in direct contact on the stress transmission path, or at the connection node between the conductive phases. This allows the flexible connection structure to form a deformable connection relationship along the conductive network path or around the intersection node, thereby determining the specific placement of the flexible connection structure between the conductive phase and the polypropylene matrix and its distribution in the conductive network.

[0113] In this embodiment, based on the deformation characteristics corresponding to the morphology of the conductive phase and its connection mode in the conductive network, the stress transmission path and concentration direction between the conductive phase and the polypropylene matrix are analyzed, as follows:

[0114] After identifying the type of conductive structure corresponding to the stress concentration region, the deformation mode of the conductive phase under external force is analyzed based on the morphological characteristics of the conductive phase and its connection mode in the conductive network.

[0115] For particulate conductive phases, the contact interface between the phase and the polypropylene matrix is ​​taken as the main stress-bearing unit, and the stress transmission path from the matrix to the particle surface is analyzed.

[0116] For fibrous or sheet-like conductive phases, analyze the transmission of stress within the conductive phase and its tendency to concentrate towards the ends or edges along its long axis or planar direction.

[0117] Based on the connection method of the conductive phase in the conductive network as a continuous path, intersection node, or turning node, it can be determined whether the stress is continuously transmitted along the conductive path in the conductive network or is redistributed at the node or turning point.

[0118] Based on the analysis of the above deformation modes and connection relationships, the main transmission path and concentration direction of stress between the conductive phase and the polypropylene matrix are determined.

[0119] S5, based on the spatial distribution of the conductive phase, interface control data and stress buffer layout, performs electric field simulation and dynamically corrects the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material.

[0120] In this embodiment, electric field simulation is performed based on the spatial distribution of the conductive phase, interface control data, and stress buffer layout to dynamically correct the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material, as detailed below:

[0121] The conductive phase spatial distribution data, interface control configuration data, and stress buffer layout data are uniformly mapped to construct a three-dimensional structural model of the outer shielding material. In the three-dimensional structural model, the electric field boundary conditions are set according to the operating state of the target cable, so that the electric field is loaded along the thickness direction and radial direction of the outer shielding material, while keeping the conductive network topology and interface control state unchanged, so as to reflect the electric field environment of the outer shielding material under actual service conditions.

[0122] The potential distribution in each grid cell is obtained by solving the three-dimensional structural model using the finite volume method.

[0123] Based on the potential distribution, the electric field intensity in each grid cell is calculated through gradient calculation, and the electric field gradient is output, thereby obtaining the spatial distribution of electric field intensity and electric field gradient inside the outer shielding material along the conductive network path, intersection nodes and stress buffer unit positions.

[0124] Spatial analysis is performed on the spatial distribution of electric field intensity and electric field gradient to identify regions where the electric field locally accumulates in the conductive network, in the interface control transition region, or at the boundary of the stress buffer layout. These regions are then marked as non-uniform electric field regions. Specifically, for the calculated three-dimensional spatial distribution of electric field intensity and electric field gradient, the local average value and deviation are calculated in each grid cell and its neighborhood. By comparing these values ​​with preset thresholds, grid cells with local electric field concentration and gradient abrupt changes are identified. These grid cells are then combined with the spatial location of the conductive network topology, interface control units, and stress buffer units to determine whether they are located in the conductive network local accumulation, interface control transition region, or stress buffer layout boundary. The set of grid cells that meets the conditions is marked as a non-uniform electric field region.

[0125] The non-uniform electric field region is correlated with the spatial distribution of the conductive phase, the distribution of the flexible connection structure, and the position of the outer shielding material in the thickness direction. The correspondence between the non-uniform electric field and the local arrangement state, network connectivity structure, and thickness direction distribution of the conductive phase is analyzed and adjusted to obtain the corrected spatial distribution of the conductive phase and the functional gradient in the thickness direction.

[0126] For regions with non-uniform electric fields caused by local spatial distribution of conductive phases, while maintaining the overall connectivity of the conductive network, the local arrangement, relative spacing, or local filling state of the conductive phases in the corresponding region is adjusted to make the electric field distribution of the conductive network in that region more gradual.

[0127] For regions with non-uniform electric fields located in the thickness direction of the outer shielding material, the distribution density of conductive phases in layers of different thicknesses is adjusted to make the outer shielding material form a layer-by-layer structural distribution characteristic in the thickness direction, thereby reducing the tendency of electric field concentration along the thickness direction.

[0128] The corrected spatial distribution of the conductive phase and the functional gradient in the thickness direction are reintroduced into the electric field simulation model. The electric field solution and the process of identifying non-uniform regions of the electric field are repeated until the electric field distribution matches the topology of the conductive network, the interface control layout, and the stress buffer structure. The output is the spatial distribution data of the conductive phase and the functional gradient distribution data in the thickness direction of the outer shielding material after electric field simulation correction, which serve as the final input for the design and manufacturing implementation of the outer shielding material structure.

[0129] In this embodiment, the spatial distribution data of the conductive phase, the interface control configuration data, and the stress buffer layout data are uniformly spatially mapped to construct a three-dimensional structural model of the outer shielding material, as detailed below:

[0130] Based on the three-dimensional spatial coordinates of the conductive phase, each conductive phase node and its connectivity relationship are mapped into the three-dimensional model mesh, maintaining the integrity of the conductive network topology while preserving the morphological characteristics (particles, fibers, or sheets) and local arrangement information of each conductive phase.

[0131] The interface control configuration data is mapped to the contact area between the conductive phase and the polypropylene matrix. Based on the spatial coordinates and contact surface of each conductive phase, an interface control unit is generated, and the interface type, processing method and spatial range are defined.

[0132] The three-dimensional distribution of the flexible connection structure is superimposed on the model, and the starting point, extension path and coverage area of ​​the flexible connection structure are marked in the three-dimensional space so that they correspond to the conductive network nodes and interface control units in space.

[0133] The conductive phase, interface control unit, and flexible connection structure are divided into three-dimensional meshes within the overall volume of the outer shielding material. Various structural properties, including conductivity, dielectric, mechanical performance parameters, and interface state information, are assigned to each mesh unit to form a complete three-dimensional structural model that can be used for electric field simulation calculations.

[0134] It should be noted that the output conductive phase spatial distribution data and the functional gradient distribution data of the outer shielding material in the thickness direction after electric field simulation correction are used to guide the actual preparation of the outer shielding material, realize the three-dimensional arrangement and local filling ratio of the conductive phase in the polypropylene matrix, ensure the continuity and uniformity of the conductive network, and form a layer-by-layer functional gradient along the thickness direction to balance the electric field distribution and improve the interface reliability.

[0135] Example 2, Figure 2 The present invention provides a system for an optimized preparation method of polypropylene cable outer shielding material, comprising a screening module, a topology module, a matching module, a stress buffer layout module, and an output module, with connections between the modules;

[0136] The filtering module is used to acquire the performance data of the target material, generate a set of performance design constraints, and filter the conductive phase type;

[0137] The topology module is used to construct the spatial distribution topology of the conductive phase in the polypropylene matrix according to the type of conductive phase, form a conductive network topology, and output the spatial distribution of the conductive phase.

[0138] The matching module is used to match the interfacial energy between the polypropylene matrix and the conductive phase according to the type and spatial distribution of the conductive phase, determine the interface control method, and output the interface control data.

[0139] The stress buffer layout module is used to analyze the stress concentration area between the conductive phase and the polypropylene matrix based on the conductive network topology and interface control data, and to form a stress buffer layout.

[0140] The output module is used to perform electric field simulation based on the spatial distribution of the conductive phase, interface control data, and stress buffer layout, and to dynamically correct the spatial distribution of the conductive phase and the functional gradient in the thickness direction of the outer shielding material.

[0141] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0142] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0143] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0144] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0145] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0146] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for the optimized production of a polypropylene cable outer shield compound, characterized in that, The method comprises the following steps: obtaining performance data of the target material, generating a performance design constraint set, and screening the type of conductive phase; according to the type of conductive phase, constructing the spatial distribution topology of the conductive phase in the polypropylene matrix to form a conductive network topology, and outputting the spatial distribution of the conductive phase; according to the type and spatial distribution of the conductive phase, matching the interfacial energy between the polypropylene matrix and the conductive phase, determining the interface regulation mode and outputting the interface regulation data; according to the conductive network topology and the interface regulation data, analyzing the stress concentration area between the conductive phase and the polypropylene matrix to form a stress buffer layout; according to the spatial distribution of the conductive phase, the interface regulation data and the stress buffer layout, performing electric field simulation, and dynamically correcting the spatial distribution of the conductive phase and the thickness direction function gradient of the outer shielding material; The method for obtaining performance data of the target material, generating a performance design constraint set, and screening the type of conductive phase is as follows: based on the rated voltage level, continuous operation temperature and periodic bending working condition of the target cable, a multi-working condition service performance window is constructed; within the multi-working condition service performance window, the stable interval of the volume resistivity of the outer shielding material, the critical strain threshold for the continuity of the conductive network and the allowable stress release range under low temperature conditions are extracted to form electrical-mechanical coupling constraint data; based on the electrical-mechanical coupling constraint data, the threshold conditions required for different morphology conductive phases to form a continuous conductive network in the polypropylene matrix are inversely analyzed to obtain threshold sensitive data of the conductive phase; taking the multi-working condition service performance window as the overall parameter space of the performance change of the outer shielding material, the allowable performance change range of the outer shielding material under different service conditions is initially limited to form a basic performance constraint range; within the basic performance constraint range, according to the electrical-mechanical coupling constraint data, the continuity requirement of the conductive network under deformation and thermal aging conditions is constrained to obtain a feasible parameter subspace; within the feasible parameter subspace, according to the threshold sensitive data of the conductive phase, the conductive phase characteristic range for forming a continuous conductive network is screened to generate a performance design constraint set; according to the performance design constraint set, the conductive efficiency, morphology anisotropy and interface interaction potential of the candidate conductive phase with the polypropylene matrix are evaluated to obtain a conductive phase candidate system; in the conductive phase candidate system, the type of conductive phase that forms a continuous conductive network within the threshold sensitive data range and meets the electrical-mechanical coupling constraint and interface regulation requirements is selected as the basic input of the conductive phase for the structure design of the outer shielding material.

2. A process for the optimized preparation of a polypropylene cable outer shield material according to claim 1, characterized in that, The method for constructing a multi-working condition service performance window based on the rated voltage level, continuous operation temperature and periodic bending working condition of the target cable is as follows: based on the rated voltage level, continuous operation temperature and periodic bending working condition of the target cable, the service state of the outer shielding material during cable operation is analyzed, and the service working conditions are divided according to the operation temperature interval and service time characteristics to obtain normal temperature operation working condition, low temperature operation working condition and long-term thermal aging working condition; according to the failure mode of the outer shielding material under each service working condition, electrical performance data and mechanical performance data are selected for each service working condition; Determine the allowable variation interval of each performance data under the corresponding service condition when the target cable does not fail in function under the running limit condition of the corresponding service condition; Normalize the allowable variation interval of the performance data under each service condition according to a unified performance data dimension, and construct a single-condition performance boundary corresponding to each service condition respectively; Take the performance data commonly involved in each single-condition performance boundary as a mapping object to perform parameter space mapping on the single-condition performance boundary, and obtain a plurality of parameter space regions corresponding to different service conditions; According to the superposition relationship of each service condition of the target cable in the actual running process, perform intersection operation on the parameter space regions to obtain an effective value boundary set; According to the effective value boundary set, construct a multi-condition service performance window of the outer shielding material under normal temperature, low temperature and thermal aging conditions.

3. The process for the optimized preparation of polypropylene cable outer shield material according to claim 1, characterized in that, The space distribution topology of the conductive phase in the polypropylene matrix is constructed according to the type of the conductive phase, and the conductive network topology is formed, and the space distribution of the conductive phase is output, which is as follows: According to the type of the conductive phase, the morphology characteristics of the conductive phase and the threshold sensitive data of the conductive phase, a mapping relationship between the local filling ratio and the network formation probability is established based on the occupation probability model; Take the starting conductive threshold value as the target value of the network formation probability, substitute it into the mapping relationship between the local filling ratio and the network formation probability, and solve the minimum local filling ratio satisfying the target value by a numerical inversion method; Divide the polypropylene matrix into three-dimensional grid units, and the number of conductive phases placed in each unit is determined by the minimum local filling ratio; In each grid unit, three-dimensional coordinates are generated according to the morphology characteristics of the conductive phase; According to the three-dimensional coordinates, the distance between adjacent conductive phases is determined, the nodes and edges that can form conductive contact are marked, and the initial conductive network topology is formed; The initial conductive network topology is verified for connectivity to determine whether the starting conductive threshold value and the continuity requirement are met; If not, the number of conductive phases is dynamically adjusted until the requirements are met, the final conductive network topology is obtained, and the space distribution of the conductive phase is output.

4. The process for the optimized preparation of polypropylene cable outer shield material according to claim 1, characterized in that, According to the type and space distribution of the conductive phase, the interface energy between the polypropylene matrix and the conductive phase is matched, the interface regulation mode is determined, and the interface regulation data is output, which is as follows: According to the space distribution of the conductive phase, the contact position of the conductive phase and the polypropylene matrix is identified, the actual contact area and contact mode between the conductive phase and the polypropylene matrix are extracted; The interaction energy between the conductive phase and the polypropylene matrix in the contact area is calculated by a molecular simulation method to obtain interface energy data corresponding to each contact area; Combine the interface energy data with the local stress distribution and electric field distribution of the outer shielding material under each service condition to analyze the stability of the interface under the corresponding spatial position, and screen out the interface instability region; According to the morphology characteristics of the conductive phase, the local filling ratio and the spatial position, the instability source of the interface instability region is analyzed; According to the instability source of the instability region, the interface regulation mode is determined for different contact regions respectively; According to the interface regulation mode, the corresponding processing data and its action position are determined, so that the interface regulation mode and the space distribution of the conductive phase are one-to-one corresponding, and the interface regulation configuration data is formed.

5. The process for the optimized production of polypropylene cable outer shield material according to claim 4, characterized in that, The interface energy data is combined with the local stress distribution and electric field distribution of the outer shielding material under each service condition, the stability of the interface at the corresponding spatial position is analyzed, and the interface instability region is screened out, specifically as follows: The finite element simulation method is used to simulate the topological structure of the conductive network and the material structure, and the local stress distribution and electric field distribution data of the outer shielding material under different service conditions are obtained. The interface energy data is mapped with the local stress field and electric field intensity data of the outer shielding material at the same position in the three-dimensional space according to the corresponding coordinate distribution; A mechanical-electric field coupling model of the conductive phase-polypropylene interface unit in each contact area is established by the micro-mechanical simulation method, the local stress and electric field load are input as external action, and the interface energy is taken as the initial potential energy term; The energy change of the mechanical-electric field coupling model is solved by the conjugate gradient method, and the change trend of the interface bonding energy of each interface contact area under the service condition is obtained. The interface energy data is combined with the local stress and electric field data, and the stress-energy coupling analysis is performed on each interface contact area, and the change trend of the interface bonding energy of the interface under the service condition is output. The interface instability region is identified by judging whether the interface energy change exceeds the preset conductive phase-polypropylene interface bonding stability threshold.

6. The process for the optimized preparation of polypropylene cable outer shield material according to claim 1, characterized in that, According to the topological structure of the conductive network and the interface regulation data, the stress concentration region between the conductive phase and the polypropylene matrix is analyzed, and a stress buffer layout is formed, specifically as follows: The nodes, edges and three-dimensional space coordinates of the conductive phase in the conductive network topology are spatially mapped with the polypropylene matrix structure to obtain the spatial distribution result of the conductive phase in the polypropylene matrix; The spatial distribution result of the conductive network is correspondingly mapped with the interface regulation data to form a conductive network structure model; The stress distribution at the interface between the conductive phase and the polypropylene matrix is obtained by the micro-mechanical simulation method under the condition of simulating the bending, stretching or thermal shrinkage service state of the outer shielding material; The stress distribution is projected to the interface position of the conductive phase and the polypropylene matrix; The stress distribution projected to the interface position is locally compared and analyzed to identify the stress concentration region between the conductive phase and the polypropylene matrix; The spatial position of the stress concentration region is taken as the arrangement basis, and the setting position and distribution mode of the flexible connection structure for dispersing stress are determined in combination with the topographic features of the corresponding conductive phase and the connection mode in the conductive network; According to the setting position and distribution mode, the spatial distribution characteristics of the flexible connection structure are generated around the stress concentration region to obtain stress buffer layout data.

7. The process for the optimized production of a polypropylene cable outer shield material according to claim 6, characterized in that, The spatial position of the stress concentration region is taken as the arrangement basis, and the setting position and distribution mode of the flexible connection structure for dispersing stress are determined in combination with the topographic features of the corresponding conductive phase and the connection mode in the conductive network, specifically as follows: The three-dimensional spatial position of the identified stress concentration region is taken as the arrangement starting point of the flexible connection structure, and the topographic features of the conductive phase in the stress concentration region and the connection mode in the conductive network are extracted. According to the deformation characteristics corresponding to the morphology of the conductive phase, combined with the connection mode of the conductive network, the transmission path and the concentration direction of the stress between the conductive phase and the polypropylene matrix are analyzed; According to the transmission path and the concentration direction, the flexible connection structure is arranged, so as to determine the specific setting position of the flexible connection structure between the conductive phase and the polypropylene matrix and the distribution mode of the flexible connection structure in the conductive network.

8. The process for the optimized production of polypropylene cable outer shield material according to claim 1, characterized in that, The electric field simulation is performed according to the spatial distribution of the conductive phase, the interface regulation data and the stress buffer layout, and the spatial distribution of the conductive phase and the thickness direction functional gradient of the outer shielding material are dynamically corrected, which are as follows: The spatial distribution data of the conductive phase, the interface regulation configuration data and the stress buffer layout data are uniformly mapped in space to construct a three-dimensional structure model of the outer shielding material; The electric field intensity and the electric field gradient spatial distribution of the stress buffer unit position are obtained by solving the three-dimensional structure model through the finite volume method; The spatial analysis is performed on the electric field intensity and the electric field gradient spatial distribution, and the non-uniform region of the electric field is identified; The non-uniform region of the electric field is corresponded to the spatial distribution of the conductive phase, the distribution of the flexible connection structure and the thickness direction position of the outer shielding material, and is adjusted to obtain the corrected spatial distribution of the conductive phase and the thickness direction functional gradient; The corrected spatial distribution of the conductive phase and the thickness direction functional gradient are re-introduced into the electric field simulation model, and the electric field solving and the electric field non-uniform region identification process are repeated until the preset condition is met, and the final spatial distribution of the conductive phase and the thickness direction functional gradient of the outer shielding material are output.

9. A system for optimized production of a polypropylene cable outer shield material according to any one of claims 1 to 8, characterized in that The method comprises a screening module, a topology module, a matching module, a stress buffer layout module and an output module, and there is a connection between the modules; The screening module is used for obtaining the performance data of the target material, generating a performance design constraint set, and screening the conductive phase type; The topology module is used for constructing the spatial distribution topology of the conductive phase in the polypropylene matrix according to the conductive phase type, forming the conductive network topology, and outputting the spatial distribution of the conductive phase; The matching module is used for matching the interface energy between the polypropylene matrix and the conductive phase according to the conductive phase type and the spatial distribution, determining the interface regulation mode and outputting the interface regulation data; The stress buffer layout module is used for analyzing the stress concentration area between the conductive phase and the polypropylene matrix according to the conductive network topology and the interface regulation data, and forming the stress buffer layout; The output module is used for performing electric field simulation according to the spatial distribution of the conductive phase, the interface regulation data and the stress buffer layout, and dynamically correcting the spatial distribution of the conductive phase and the thickness direction functional gradient of the outer shielding material.

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