CN-121983195-A - Method for predicting and evaluating hardness change trend of silk-covered wire

CN121983195ACN 121983195 ACN121983195 ACN 121983195ACN-121983195-A

Abstract

A wire wrapping wire hardness change trend prediction and assessment method belongs to the technical field of material performance assessment, and comprises the steps of obtaining a surface layer strain value and a core strain value of a wire wrapping wire in a bending process, calculating a strain difference value, synchronously obtaining bending radius, grain boundary migration distance and microcrack germination distribution data, constructing a comprehensive damage data set, establishing a dislocation density accumulation mapping relation according to the strain difference value, determining a hardening degree grade, calculating surface layer damage depth by combining the grain boundary migration distance and the microcrack germination distribution data, determining microcrack germination probability, carrying out correlation analysis on the microcrack germination probability and the bending radius, determining a softening turning point position, dynamically adjusting the soft hardness prediction range, carrying out bending life simulation, and outputting a residual life assessment result. The full-chain analysis from microscopic damage to macroscopic life prediction is realized, the reliability evaluation precision of the wire covered wire in a high-stress environment is remarkably improved, and a scientific basis is provided for preventive maintenance.

Inventors

CHEN MINGHAI
MAI JUN
XIAO SONGTAO

Assignees

广东松田科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260110

Claims (10)

1. The method for predicting and evaluating the variation trend of the hardness of the silk-covered wire is characterized by comprising the following steps of: step S1, obtaining a surface strain value and a core strain value of a wire covered wire in a bending process, calculating a strain difference value between the surface strain value and the core strain value, synchronously obtaining current bending radius, grain boundary migration distance and microcrack initiation distribution data, and constructing a comprehensive damage data set; Step S2, establishing a mapping relation between dislocation density accumulation amount and the strain difference value according to the strain difference value, extracting dislocation density accumulation amount, comparing the dislocation density accumulation amount with a preset hardening threshold value, and determining the current hardening degree grade of the wire wrapping wire according to the comparison result; Step S3, calculating the surface damage depth according to the grain boundary migration distance and the microcrack initiation distribution data and combining the hardening degree grade, and determining the microcrack initiation probability based on the spatial distribution characteristics of the surface damage depth and the microcrack initiation distribution data; S4, performing correlation analysis on the crack initiation probability and the current bending radius, determining the corresponding bending radius position as a softening turning point position when the crack initiation probability exceeds a preset softening threshold value, dynamically adjusting a soft hardness prediction range according to the softening turning point position and the surface layer damage depth, and generating a softening evolution curve by fusing a strain difference value and a grain boundary migration distance; and S5, based on the softening evolution curve, integrating the hardening degree grade and the softening turning point position to perform bending life simulation, determining the residual bending life cycle number, and outputting a life evaluation result.
2. The method for predicting and evaluating the hardness variation trend of a wire-covered wire according to claim 1, wherein in the step S2, the current hardness level of the wire-covered wire is determined according to the comparison result, and the method comprises the following steps: acquiring a historical damage record of the silk-covered wire, and extracting a dislocation density reference value in an initial hardening stage from the historical damage record; calculating the deviation ratio between the current dislocation density accumulation amount and the dislocation density reference value; Matching is carried out according to the deviation proportion and a preset grading interval, wherein the low hardening grade is determined when the deviation proportion is smaller than a first threshold value, the medium hardening grade is determined when the deviation proportion is between the first threshold value and a second threshold value, and the high hardening grade is determined when the deviation proportion is larger than the second threshold value; And determining the hardening degree grade according to the matching result, and establishing a correlation parameter between the hardening degree grade and the fatigue life.
3. The method for predicting and evaluating the hardness change trend of a wire-covered wire according to claim 2, wherein the establishing the correlation parameter between the hardness level and the fatigue life comprises: Calculating a grain boundary strengthening parameter according to the dislocation density accumulation amount, wherein the grain boundary strengthening parameter is obtained by multiplying the dislocation density accumulation amount by a preset material coefficient; Acquiring a life attenuation coefficient corresponding to the hardening degree grade; carrying out fusion calculation on the grain boundary strengthening parameters and the life attenuation coefficient to obtain hardening influence factors; The hardening influencing factor is used as an input parameter of the subsequent bending life simulation.
4. The method for predicting and evaluating the trend of soft hardness change of a wire-covered wire according to claim 1, wherein in the step S3, the determining the probability of microcrack initiation based on the spatial distribution characteristics of the surface layer damage depth and the microcrack initiation distribution data comprises: Performing space grid division on the microcrack initiation distribution data, counting the number of microcrack initiation points in each grid unit, and generating a microcrack density distribution map; Determining a damage depth weight coefficient according to the damage depth of the surface layer, wherein the larger the damage depth is, the higher the corresponding weight coefficient is; carrying out weighted calculation on the microcrack density distribution map and the damage depth weight coefficient to obtain a weighted damage value of each grid unit; and carrying out normalization processing on the weighted damage value, and determining the microcrack initiation probability according to a normalization result and a preset probability mapping function.
5. The method for predicting and evaluating the variation trend of hardness of a wire-wrapped wire according to claim 4, wherein the determining the microcrack initiation probability according to the normalization result and the preset probability mapping function further comprises: Acquiring the change rate of the grain boundary migration distance, and judging whether the change rate exceeds a preset migration threshold value; When the change rate exceeds a preset migration threshold, a migration correction coefficient is applied to the normalization result, wherein the migration correction coefficient is positively correlated with the grain boundary migration distance; and recalculating the initiation probability of the microcracks according to the corrected normalization result, and taking the corrected initiation probability of the microcracks as a final output result.
6. The method for predicting and evaluating the trend of soft hardness change of a wire-covered wire according to claim 1, wherein in the step S4, the correlation analysis is performed between the probability of initiation of the microcracks and the current bending radius, and when the probability of initiation of the microcracks exceeds a preset softening threshold, determining the corresponding bending radius position as the softening turning point position comprises: establishing a two-dimensional coordinate system of the crack initiation probability and the bending radius, and drawing the crack initiation probability under different bending radii into a probability distribution curve; performing first derivative calculation on the probability distribution curve, and identifying position points where sign change or amplitude mutation occurs to the derivative value; Comparing the crack initiation probability corresponding to the position points with a preset softening threshold value, and screening position points of which the crack initiation probability exceeds the preset softening threshold value for the first time; and determining the bending radius corresponding to the screened position point as the softening turning point position.
7. The method for predicting and evaluating the hardness variation trend of a silk covered wire according to claim 6, wherein the dynamically adjusting the hardness prediction range according to the softening turning point position and the surface layer damage depth, fusing the strain difference and the grain boundary migration distance to generate a softening evolution curve comprises: obtaining a bending radius value and a surface layer damage depth value corresponding to the softening turning point position; calculating an upper limit value and a lower limit value of a soft hardness prediction range according to the bending radius value and the surface layer damage depth value, wherein the upper limit value is determined based on the hardening degree grade, and the lower limit value is determined based on the microcrack initiation probability; in the soft and hard prediction range, a softening evolution curve is constructed by taking the bending radius as a horizontal axis and taking a weighted fusion value of a strain difference value and a grain boundary migration distance as a vertical axis; And performing piecewise fitting on the softening evolution curve to determine evolution characteristic parameters of a hardening stage, a turning stage and a softening stage.
8. The method according to claim 1, wherein in the step S5, based on the softening evolution curve, the bending life simulation is performed by integrating the hardness level and the softening transition point position, and determining the remaining bending life cycle number includes: extracting curve slope change characteristics according to the softening evolution curve, and determining a softening evolution rate; Establishing a finite element analysis model of the silk-covered wire, converting the hardening degree grade into a material constitutive parameter, and inputting the material constitutive parameter into the finite element analysis model; applying a cyclic bending load in the finite element analysis model, and setting a damage accumulation starting point based on the softening turning point position; And calculating the damage increment of each bending period according to the softening evolution rate and the damage accumulation model, accumulating the damage increment until reaching a failure threshold value, and determining the residual bending life cycle number.
9. The method for predicting and evaluating a trend of hardness change in a silk covered wire according to claim 8, wherein the calculating the damage increment per bending cycle according to the softening evolution rate and damage accumulation model further comprises: Obtaining a bending radius value corresponding to a current bending period, and judging whether the bending radius value is smaller than a bending radius value corresponding to a softening turning point position; when the bending radius value is smaller than the bending radius value corresponding to the softening turning point position, introducing a softening acceleration coefficient to correct the damage increment, wherein the softening acceleration coefficient is inversely proportional to the bending radius value; and updating the accumulated damage value according to the corrected damage increment, and dynamically adjusting damage increment calculation parameters of the subsequent bending period according to the difference value between the accumulated damage value and the failure threshold.
10. The method for predicting and evaluating the hardness variation trend of a wire-wrapped wire according to claim 8, further comprising, after determining the number of remaining bending life cycles: extracting risk nodes with cycle numbers lower than a preset safety threshold value from the residual bending life cycle numbers; Verifying whether the evolution trend of the crack initiation distribution is consistent with a bending life simulation result or not according to the bending radius position and the crack initiation distribution data corresponding to the risk nodes; when the evolution trend is consistent, integrating the residual bending life cycle number with risk node information to generate a life assessment report; and when the evolution trend is inconsistent, the bending life simulation is conducted again after the damage accumulation model parameters are adjusted until the evolution trend is consistent, and a life evaluation report is output.

Description

Method for predicting and evaluating hardness change trend of silk-covered wire Technical Field The invention belongs to the technical field of material performance evaluation, and particularly relates to a silk-covered wire hardness change trend prediction and evaluation method. Background The hardness change research of the wire-covered wire is an important direction in the field of material processing and performance evaluation, and is directly related to the reliability and service life of the wire and cable under a complex use environment, and particularly has non-negligible key value in power transmission and mechanical equipment. The silk-covered wire can undergo complex mechanical and microstructure changes in the bending process, the soft and hard evolution trend of the silk-covered wire is accurately predicted, the product quality can be improved, and the potential safety hazard caused by material failure can be effectively reduced. However, current research and detection methods often have difficulty capturing the cooperative changes of the interior and surface of the material in its entirety in the face of dynamic changes during wire-wrap bending. Many methods focus more on the mechanical performance of a single link, ignoring the interaction effect of internal structure adjustment and surface damage of materials under different bending degrees. Such neglect results in an insufficiently accurate determination of the trend of the material properties, especially in the critical phase of the transition of the material from hardening to softening, lacking in an in-depth analysis of the multifactorial coupling effect. The more central technical difficulty is that the key factor of reconstructing the grain boundary migration path in the bending process is not fully known and solved. Grain boundary migration refers to the phenomenon that the boundary of the internal crystal structure of a material is adjusted when being stressed, and the adjustment can directly influence the mechanical property of the material. When the bending degree is gradually increased, the migration path of the grain boundary in the material is changed in a complex manner, so that the stress of the surface layer and the stress of the core are distributed unevenly, and the surface layer may be subjected to fine cracks preferentially, while the core is still relatively stable. Such inconsistent changes in the interior and exterior make predictions of the overall properties of the material extremely complex. Further, the reconstruction of the grain boundary migration path also shows nonlinear variation along with the reduction of the bending radius, and the difficulty of judging the hardening or softening turning point of the material is increased. For example, in an installation scenario where the wire wrap is repeatedly bent to fit a narrow space, the material may become gradually stiff due to the internal structural adjustment in the initial stage, but when the bending radius is reduced to a certain extent, the appearance of surface microcracks may cause the overall load-bearing capacity to decrease, which may be manifested as an unexpected softening phenomenon. The inconsistency of the internal and external changes makes the traditional detection means difficult to accurately judge the critical point of the material performance and also can not effectively predict the service life of the material. Therefore, how to capture the influence of the reconstruction of the migration path of the grain boundary on the change of the hardness of the material in real time in the bending process, and accurately identify the turning critical point from hardening to softening becomes a key problem for improving the performance evaluation reliability of the wire covered wire. Disclosure of Invention In order to solve the technical problems, the invention provides a silk-covered wire softness and hardness change trend prediction and evaluation method, which comprises the following steps: step S1, obtaining a surface strain value and a core strain value of a wire covered wire in a bending process, calculating a strain difference value between the surface strain value and the core strain value, synchronously obtaining current bending radius, grain boundary migration distance and microcrack initiation distribution data, and constructing a comprehensive damage data set; Step S2, establishing a mapping relation between dislocation density accumulation amount and the strain difference value according to the strain difference value, extracting dislocation density accumulation amount, comparing the dislocation density accumulation amount with a preset hardening threshold value, and determining the current hardening degree grade of the wire wrapping wire according to the comparison result; Step S3, calculating the surface damage depth according to the grain boundary migration distance and the microcrack initiation distribution data and combining the harde