A method and system for analyzing the performance of an acrylic sheet

Abstract

This invention discloses a method and system for performance analysis of acrylic sheets, relating to the field of material performance testing technology. The method includes: processing an acrylic sheet sample to generate a test sample based on a preset environmental stress time-series loading scheme; acquiring microscopic images and Fourier transform infrared spectra of the test sample to generate a state snapshot; determining the material degradation stage based on the state snapshot and a preset degradation judgment criterion; generating a stress adjustment command and modifying the scheme parameters when the sample is in the pre-damage stage; iteratively executing the aforementioned steps, recording the state snapshot and the updated scheme for each iteration; calculating the cumulative damage value between adjacent state snapshots; terminating the iteration when the cumulative damage value reaches a preset failure threshold, and calculating the predicted service life. This invention can reflect the chain reaction process of material degradation, accurately simulate the weakening of the resistance to subsequent stresses by initial environmental stress, and achieve reliable prediction of the service life of materials under complex interactive stress environments.

Description

Technical Field

[0001] This invention relates to the field of material performance testing technology, and in particular to a method and system for performance analysis of acrylic sheets. Background Technology

[0002] Hardened acrylic sheets are widely used in outdoor digital billboards, precision equipment protective screens, and other applications due to their excellent light transmittance, impact resistance, and surface hardness. The industry typically relies on a series of standardized accelerated aging tests for performance evaluation. These include using UV aging chambers to test weather resistance, salt spray chambers to assess corrosion resistance, and reciprocating friction devices to quantify scratch resistance. The degradation of optical performance is evaluated by measuring changes in light transmittance before and after the tests. Engineers compile data from these independent tests, attempting to establish mathematical relationships between various performance indicators to predict the overall service life of the sheet under general operating conditions. However, this analytical method based on independent environmental factor testing has a fundamental flaw. It treats environmental factors such as UV radiation, salt spray corrosion, and physical wear as independent variables, ignoring the objective fact that multiple stresses act on the material sequentially in a specific timeframe in real outdoor environments. Furthermore, it fails to consider how the material's resistance to a certain stress can change due to prior exposure to another stress.

[0003] Taking the protective screen of a self-service ticket machine in a coastal city's transportation hub as an example, the material is subjected to strong sunlight and high temperatures during the day, and at night it faces low temperatures, condensation of salty moisture, and physical abrasion from sand particles carried by sea breezes. Ultraviolet radiation and thermal stress first weaken the chemical bond structure within the hardened coating, making the material surface more sensitive to saline moisture at night. Moisture penetrates along the damaged areas and initiates microcracks. Subsequent wind and sand abrasion further expands these cracks, leading to coating peeling and material failure, forming a chain reaction. Traditional methods simply correlate individual stresses after testing them independently, completely failing to describe this sequential degradation process. This results in a significant discrepancy between laboratory-predicted lifespan and actual service performance, leading to numerous early failures. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method and system for analyzing the performance of acrylic sheets. It aims to solve the problem that existing methods cannot quantify the changes in material properties caused by initial environmental stress, especially how such changes reduce the material's resistance to subsequent different types of stress. It also overcomes the fundamental limitation that independent accelerated aging tests cannot reflect the interaction of multiple environmental stresses in a specific time sequence and that the accumulation of material damage is state-dependent.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for performance analysis of acrylic sheets, comprising the following steps: S1. Based on the preset environmental stress timing loading scheme, the acrylic sheet sample is sequentially subjected to ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spraying and reciprocating friction to generate the test sample. S2. Acquire microscopic images and Fourier transform infrared spectra of the sample to be tested, extract microcrack characteristic parameters and carbonyl index, and generate state snapshots; S3. Determine the material degradation stage based on the state snapshot and the preset degradation judgment criteria. The material degradation stage includes the initial integrity stage and the pre-damage stage. S4. Determine the updated environmental stress timing loading scheme based on the material deterioration stage: When the material is in the initial intact stage, use the current environmental stress timing loading scheme as the updated environmental stress timing loading scheme; when the material is in the pre-damage stage, generate stress adjustment instructions and modify the parameters in the current environmental stress timing loading scheme based on the stress adjustment instructions to obtain the updated environmental stress timing loading scheme. S5. Iterate through S1 to S4, record the state snapshot and environmental stress timing loading scheme generated in each iteration, and construct the deterioration state transition sequence. S6. Calculate the damage increment between any two adjacent state snapshots in the deteriorated state transition sequence, and sum up the damage increments to obtain the cumulative damage value. S7. When the cumulative damage value reaches the preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time of a single iteration. The equivalent service time of a single iteration represents the actual environmental action time simulated by a single complete execution of the environmental stress timing loading scheme.

[0006] Furthermore, the environmental stress sequential loading scheme includes first-stage stress parameters, second-stage stress parameters, and third-stage stress parameters. The first-stage stress parameters define the ultraviolet irradiation intensity and high-temperature holding time; the second-stage stress parameters define the low-temperature holding time, salt spray concentration, and salt spray duration; and the third-stage stress parameters define the friction load, friction stroke, and number of friction cycles. Based on the preset environmental stress sequential loading scheme, the acrylic sheet sample is sequentially subjected to ultraviolet irradiation coupled with high temperature, low-temperature coupled with salt spray, and reciprocating friction to generate the test sample, including: Acrylic sheet samples were irradiated with ultraviolet radiation intensity according to the first stage stress parameters in a xenon lamp aging chamber, and at the same time, high temperature environment was applied to the acrylic sheet samples in a high and low temperature damp heat test chamber according to the high temperature holding time in the first stage stress parameters, so as to obtain intermediate samples that have undergone the first stage stress action. The intermediate sample that has undergone the first stage of stress was subjected to a low-temperature environment by using a high and low temperature humidity test chamber according to the low temperature holding time in the second stage stress parameters. The intermediate sample was then subjected to salt spraying in a salt spray corrosion test chamber according to the salt spray concentration and salt spraying time in the second stage stress parameters during the low temperature holding period, thus obtaining an intermediate sample that has undergone the second stage of stress. By applying reciprocating friction to the intermediate sample that has undergone the second stage of stress using a reciprocating friction and wear testing machine according to the friction load, friction stroke and friction cycle number in the third stage stress parameters, a test sample that has withstood the superimposed effect of time is obtained.

[0007] Furthermore, the acquisition of microscopic images and Fourier transform infrared spectra of the sample to be tested, extraction of microcrack characteristic parameters and carbonyl index, and generation of state snapshots include: Microscopic images of the sample surface are acquired using an industrial camera, and an interferogram of the sample surface is acquired using a Fourier transform infrared spectrometer. The Fourier transform infrared spectrum is obtained by performing a Fourier transform on the interferogram. Edge detection is performed on the microscopic image to extract the edge segments of microcracks in the image. The number and maximum length of the edge segments of microcracks are counted. The number of edge segments of microcracks is used as the microcrack quantity parameter, and the maximum length of the edge segments of microcracks is used as the microcrack length parameter. The microcrack feature parameters are composed of the microcrack quantity parameter and the microcrack length parameter. Locate the wavenumber position corresponding to the carbonyl stretching vibration absorption peak in the Fourier transform infrared spectrum, and calculate the peak area of ​​the absorption peak. The carbonyl index is defined as the ratio of the peak area to the peak area of ​​the absorption peak at the same wavenumber position that was collected before environmental stress treatment. By combining microcrack characteristic parameters and carbonyl index, a snapshot of the state of the sample under test is generated.

[0008] Furthermore, the preset degradation judgment criteria include a preset microcrack number threshold, a preset microcrack length threshold, and a preset carbonyl index lower limit threshold. The preset microcrack number threshold defines the upper limit of the allowable number of surface microcracks, the preset microcrack length threshold defines the upper limit of the maximum length of a single microcrack, and the preset carbonyl index lower limit threshold defines the minimum allowable value of the carbonyl index. The material degradation stage is determined based on the state snapshot and the preset degradation judgment criteria. The material degradation stage includes an initial integrity stage and a pre-damage stage, including: Extract the microcrack number parameter, microcrack length parameter, and carbonyl index from the state snapshot. Compare the microcrack number parameter with a preset microcrack number threshold, compare the microcrack length parameter with a preset microcrack length threshold, and compare the carbonyl index with a preset carbonyl index lower limit threshold. When the number of microcracks is less than the preset threshold for the number of microcracks, the length of microcracks is less than the preset threshold for the length of microcracks, and the carbonyl index is greater than or equal to the preset lower limit threshold for the carbonyl index, the material deterioration stage is determined to be the initial intact stage. When the number of microcracks is greater than or equal to the preset threshold for the number of microcracks, or the length of microcracks is greater than or equal to the preset threshold for the length of microcracks, or the carbonyl index is less than the preset lower limit threshold for the carbonyl index, the material deterioration stage is determined to be the pre-damage stage.

[0009] Furthermore, the step of determining the updated environmental stress timing loading scheme based on the material deterioration stage includes: when in the initial integrity stage, using the current environmental stress timing loading scheme as the updated environmental stress timing loading scheme; when in the pre-damage stage, generating a stress adjustment command and modifying the parameters in the current environmental stress timing loading scheme based on the stress adjustment command to obtain the updated environmental stress timing loading scheme, including: When the material degradation stage is determined to be the initial intact stage, the current environmental stress time-series loading scheme is used as the updated environmental stress time-series loading scheme. After determining that the material degradation stage is the pre-damage stage, a stress adjustment strategy is determined based on the degradation index type corresponding to the pre-damage stage, and a stress adjustment command is generated. If the pre-damage stage is triggered by the carbonyl index falling below the lower threshold, the stress adjustment command includes an increase in salt spray concentration and an extension of salt spray duration. If the pre-damage stage is triggered by microcrack characteristic parameters, the stress adjustment command includes a reduction in friction load or an adjustment in the number of friction cycles. Identify parameter modification items included in the stress adjustment command; When the stress adjustment command includes an upward adjustment value for salt spray concentration and an extension value for salt spray duration, the salt spray concentration value of the second-stage stress parameter in the current environmental stress timing loading scheme is added to the upward adjustment value for salt spray concentration to obtain the updated salt spray concentration value. The salt spray duration value is added to the extension value for salt spray duration to obtain the updated salt spray duration value, and the corresponding parameters are replaced. When the stress adjustment command includes a decrease in friction load or an adjustment in the number of friction cycles, modify the friction load or the number of friction cycles in the third-stage stress parameters to generate an updated environmental stress timing loading scheme.

[0010] Furthermore, the iterative execution S1 to S4 records the state snapshot and environmental stress timing loading scheme generated in each iteration, constructing a deterioration state transition sequence, including: Establish an initial empty sequence of degraded state transitions and set the number of iterations to zero; Execute S1 to S4 to obtain the test sample subjected to time-series superposition generated in this iteration, the state snapshot generated in this iteration, and the updated environmental stress time-series loading scheme generated after adjustment in step S4 in this iteration. Increment the iteration number by one. The state snapshot generated in this iteration, the updated environmental stress timing loading scheme, and the current iteration number are combined into a state transition record. This state transition record is then appended to the end of the deteriorated state transition sequence to form the deteriorated state transition sequence.

[0011] Furthermore, the calculation of the damage increment between any two adjacent state snapshots in the deteriorated state transition sequence, and the summation of each damage increment to obtain the cumulative damage value, includes: Extract the state snapshot generated in the i-th iteration and the state snapshot generated in the (i+1)-th iteration from the deteriorated state transition sequence in sequence, where i is an integer greater than or equal to 1 and less than the total number of state transition records; Extract the first microcrack number parameter, the first microcrack length parameter, and the first carbonyl index from the state snapshot generated in the i-th iteration; extract the second microcrack number parameter, the second microcrack length parameter, and the second carbonyl index from the state snapshot generated in the (i+1)-th iteration. The difference between the second microcrack number parameter and the first microcrack number parameter is recorded as the microcrack number increment, the difference between the second microcrack length parameter and the first microcrack length parameter is recorded as the microcrack length increment, and the difference between the first carbonyl index and the second carbonyl index is recorded as the carbonyl index decay. The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by adding the increment of the number of microcracks, the increment of the microcrack length, and the decrease of the carbonyl index. The cumulative damage value is obtained by summing the damage increments between all adjacent iterations.

[0012] Furthermore, the increase in the number of microcracks, the increase in the length of microcracks, and the decrease in the carbonyl index are added together to obtain the damage increment between the i-th iteration and the (i+1)-th iteration, as follows: Divide the increment of the number of microcracks by the preset threshold for the number of microcracks to obtain the normalized increment of the number of microcracks. Divide the microcrack length increment by the preset microcrack length threshold to obtain the normalized microcrack length increment; Divide the carbonyl index decay by the preset maximum allowable carbonyl index decay value to obtain the normalized carbonyl index decay. Determine whether the normalized microcrack number increment is less than zero. If it is less than zero, set the normalized microcrack number increment to zero. Determine whether the normalized microcrack length increment is less than zero. If it is less than zero, set the normalized microcrack length increment to zero. Determine if the normalized carbonyl index decay is less than zero; if it is less than zero, set the normalized carbonyl index decay to zero. The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by summing the normalized microcrack number increment, the normalized microcrack length increment, and the normalized carbonyl index decay.

[0013] Furthermore, when the cumulative damage value reaches a preset failure threshold, the iteration is terminated, and the predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time per iteration. The equivalent service time per iteration represents the simulated real environmental action time of a single complete execution of the environmental stress timing loading scheme, as follows: The cumulative damage value is compared with a preset failure threshold. If the cumulative damage value is less than the preset failure threshold, the next iteration continues. When the cumulative damage value is greater than or equal to the preset failure threshold, the iteration is terminated and the current iteration number is obtained. The current iteration number is multiplied by the preset single-iteration equivalent service time to obtain the predicted service life of the acrylic sheet sample.

[0014] An acrylic sheet performance analysis system, comprising: Sample production module: Based on a preset environmental stress timing loading scheme, it sequentially performs ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spray and reciprocating friction on acrylic sheet samples to generate the test sample; State snapshot module: used to acquire microscopic images and Fourier transform infrared spectra of the sample to be tested, extract microcrack characteristic parameters and carbonyl index, and generate state snapshots; Adjustment instruction module: used to determine the material degradation stage based on the state snapshot and preset degradation judgment criteria, wherein the material degradation stage includes an initial intact stage and a pre-damage stage; Loading scheme module: used to determine the updated environmental stress time-series loading scheme according to the material deterioration stage: when it is in the initial integrity stage, the current environmental stress time-series loading scheme is used as the updated environmental stress time-series loading scheme; when it is in the pre-damage stage, stress adjustment instructions are generated, and the parameters in the current environmental stress time-series loading scheme are modified based on the stress adjustment instructions to obtain the updated environmental stress time-series loading scheme. Sequence Construction Module: Used to iteratively execute from the Sample Production Module to the Loading Scheme Module, record the state snapshot and environmental stress time-series loading scheme generated in each iteration, and construct the degradation state transition sequence; Damage calculation module: used to calculate the damage increment between any two adjacent state snapshots in the deterioration state transition sequence, and to accumulate the damage increments to obtain the cumulative damage value; Lifetime prediction module: When the cumulative damage value reaches the preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time of a single iteration. The equivalent service time of a single iteration represents the actual environmental action time simulated by a single complete execution of the environmental stress timing loading scheme.

[0015] The present invention provides a method and system for performance analysis of acrylic sheets, the beneficial effects of which are mainly reflected in the following aspects: 1. This technical solution can realistically reflect the chain reaction process of hardened acrylic sheets deterioration in complex outdoor environments. By applying ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spraying, and reciprocating friction in a preset sequence, it fully simulates the sequential action and interaction of multiple stresses in a real environment, overcoming the limitations of traditional methods that test each environmental factor independently. By acquiring microscopic images and infrared spectra of the material at each stress transition node, microcrack characteristic parameters and carbonyl index are extracted as state snapshots. Based on the deterioration judgment criteria, the current deterioration stage of the material is dynamically identified, realizing continuous tracking of the material's state transition. This allows the degree of weakening of material performance by the initial environmental stress to be quantified and recorded, thus providing a basis for assessing the decline in the material's resistance to subsequent stresses.

[0016] 2. This technical solution intelligently adjusts subsequent stress parameters based on the material degradation stage. When the material is detected to have entered the pre-damage stage, the salt spray or friction parameters are automatically adjusted, enabling the simulation process to realistically reflect the characteristics of damaged materials being more sensitive to subsequent stresses, ensuring the integrity and authenticity of the damage accumulation path. Based on the cumulative calculation of normalized damage increments between adjacent state snapshots, combined with a preset failure threshold and the equivalent service time per iteration, the predicted service life of acrylic sheets under complex interactive stress environments can be terminatedly derived. This effectively solves the technical problem of traditional methods failing to reproduce the chain-like degradation process of materials—"damage first, sensitivity later"—leading to a serious discrepancy between life predictions and actual conditions. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a method for analyzing the performance of acrylic sheets according to the present invention. Figure 2 This is a functional block diagram of an acrylic sheet performance analysis system according to the present invention. Detailed Implementation

[0018] 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.

[0019] Please see Figure 1 This invention provides a method for performance analysis of acrylic sheets, comprising the following steps: S1. Based on the preset environmental stress timing loading scheme, the acrylic sheet sample is sequentially subjected to ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spraying and reciprocating friction to generate the test sample. In this embodiment, the environmental stress timing loading scheme includes first-stage stress parameters, second-stage stress parameters, and third-stage stress parameters. The first-stage stress parameters define the ultraviolet irradiation intensity and high-temperature holding time; the second-stage stress parameters define the low-temperature holding time, salt spray concentration, and salt spray duration; and the third-stage stress parameters define the friction load, friction stroke, and number of friction cycles. Based on the preset environmental stress timing loading scheme, the acrylic sheet sample is sequentially subjected to ultraviolet irradiation coupled with high temperature, low-temperature coupled with salt spray, and reciprocating friction to generate a test sample, including: Acrylic sheet samples were irradiated with ultraviolet radiation intensity according to the first stage stress parameters in a xenon lamp aging chamber, and simultaneously subjected to a high-temperature environment according to the high-temperature holding time in the first stage stress parameters in a high-low temperature damp heat test chamber, thus obtaining intermediate samples that had undergone the first stage stress.

[0020] Specifically, the environmental stress timing loading scheme refers to a pre-programmed control program that defines the operating parameters and execution sequence of each environmental stress test unit. It divides a complete simulation cycle into three stages, each corresponding to a different time period within a day-night cycle in a coastal environment. The stress parameters in the first stage are used to simulate the daytime period. The ultraviolet radiation intensity refers to the ultraviolet radiation flux density of a specific band output from the xenon lamp aging chamber to the sample surface, and the high temperature holding time refers to the continuous operating time of the test chamber at the set high temperature value.

[0021] Ultraviolet radiation coupled with high temperature refers to the simultaneous application of ultraviolet radiation and high temperature in time to reproduce the working conditions of strong sunlight and high temperature during the daytime at the seaside. The intermediate sample that has undergone the first stage of stress refers to the transitional state of the sample after the combined action of ultraviolet radiation and high temperature. At this time, its chemical bond structure or microstructure may have undergone preliminary changes.

[0022] The intermediate sample that has undergone the first stage of stress was subjected to a low-temperature environment by using a high and low temperature humidity test chamber according to the low temperature holding time in the second stage stress parameters. Salt spray was then carried out in a salt spray corrosion test chamber according to the salt spray concentration and salt spray duration in the second stage stress parameters during the low temperature holding period to obtain the intermediate sample that has undergone the second stage of stress.

[0023] Specifically, the second-stage stress parameters are used to simulate the nighttime period at the seaside. The low-temperature holding time refers to the continuous operating time of the test chamber at the set low temperature value; the salt spray concentration refers to the mass percentage of the sprayed sodium chloride aqueous solution; and the salt spray duration refers to the actual duration of salt spraying during the low-temperature holding period. Low-temperature coupled salt spraying refers to the simultaneous application of low temperature and salt spraying in time to reproduce the condensation of salty moisture on the surface of the board during a drop in seaside nighttime temperatures. The intermediate sample undergoing the second-stage stress refers to the transitional state of the sample after undergoing the combined effects of low temperature and salt spray, based on the previous stress. At this point, further weakening of chemical bonds or the initiation of microcracks may occur.

[0024] By applying reciprocating friction to the intermediate sample that has undergone the second stage of stress using a reciprocating friction and wear testing machine according to the friction load, friction stroke and friction cycle number in the third stage stress parameters, a test sample that has withstood the superimposed effect of time is obtained.

[0025] Specifically, the third-stage stress parameters are used to simulate the abrasive effect of sand particles carried by sea breezes. Friction load refers to the normal pressure applied to the sample surface by the grinding head, friction stroke refers to the linear distance of a single reciprocating motion of the grinding head, and friction cycle number refers to the number of repetitions of the reciprocating motion. The temporal superposition effect refers to the sample sequentially experiencing the first stage of ultraviolet radiation coupled with high temperature, the second stage of low temperature coupled with salt spray, and the third stage of reciprocating friction. The stress of the subsequent stage is applied to the sample that has already undergone the previous stresses, thus realistically reproducing the process of gradual accumulation of material damage in an outdoor environment. The test sample subjected to the temporal superposition effect refers to the sample after completing all three stages of stress application; its state can reflect the actual deterioration of the material after multiple environmental factors act synergistically in a specific temporal sequence.

[0026] S2. Acquire microscopic images and Fourier transform infrared spectra of the sample to be tested, extract microcrack characteristic parameters and carbonyl index, and generate state snapshots; In this embodiment, the acquisition of microscopic images and Fourier transform infrared spectra of the sample to be tested, extraction of microcrack characteristic parameters and carbonyl index, and generation of state snapshots include: Microscopic images of the sample surface are acquired using an industrial camera, and an interference pattern of the sample surface is acquired using a Fourier transform infrared spectrometer. The Fourier transform infrared spectrum is obtained by performing a Fourier transform on the interference pattern.

[0027] Specifically, an industrial camera refers to an imaging device equipped with a high-resolution image sensor used to capture the microscopic morphology of a sample surface. A Fourier transform infrared spectrometer obtains the infrared spectrum by measuring the interferogram and performing a Fourier transform. The interferogram refers to the raw signal recorded by the detector showing the change in the intensity of the interfering light as a function of the optical path difference. The Fourier transform infrared spectrum is the spectrum obtained after Fourier transforming the interferogram, reflecting the absorption intensity of infrared light at different wavenumbers by the sample. Absorption peaks at specific wavenumbers correspond to vibrational modes of specific chemical bonds in the sample molecules. Microscopic images reflect the physical morphological characteristics of materials, while infrared spectroscopy reveals the chemical structural information of materials; together, they constitute the fundamental data for evaluating the current state of a sample.

[0028] Edge detection is performed on the microscopic image to extract the edge segments of microcracks in the image. The number and maximum length of the microcrack edge segments are counted. The number of microcrack edge segments is used as the microcrack quantity parameter, and the maximum length of the microcrack edge segments is used as the microcrack length parameter. The microcrack feature parameters are composed of the microcrack quantity parameter and the microcrack length parameter.

[0029] Specifically, edge detection refers to the technique of using image processing algorithms to identify the locations where pixel grayscale values ​​change abruptly in a microscopic image, thereby extracting the contour boundary. It is a well-known image processing method. Microcrack edge segments refer to the continuous or segmented lines corresponding to the microcrack contour on the sample surface, identified after edge detection.

[0030] The microcrack quantity parameter refers to the count value obtained by statistically analyzing the number of independent microcrack edge segments in the image, reflecting the density of microcrack distribution. The microcrack length parameter refers to the length value of the longest single segment extracted from all microcrack edge segments, reflecting the extension degree of the most severe single crack. The microcrack characteristic parameters are composed of the above two parameters, comprehensively characterizing the degree of physical damage to the sample surface from both quantity and scale dimensions.

[0031] Locate the wavenumber position corresponding to the carbonyl stretching vibration absorption peak in the Fourier transform infrared spectrum, and calculate the peak area of ​​the absorption peak; use the ratio of the peak area to the peak area of ​​the absorption peak at the same wavenumber position that was collected before environmental stress treatment as the carbonyl index.

[0032] Specifically, the carbonyl group refers to the functional group in which carbon and oxygen atoms are bonded by a double bond, and it is the hallmark chemical structural unit in the polymer molecular chain of acrylic sheets. The carbonyl stretching vibration absorption peak refers to the characteristic absorption signal produced in the infrared spectrum when the carbon-oxygen double bond in the carbonyl group undergoes stretching vibration, which usually appears around 1730 wavenumbers.

[0033] Peak area refers to the area obtained by integrating the absorption peak over a certain wavenumber range, and its size is positively correlated with the relative content of carbonyl groups in the sample. "Before environmental stress treatment" refers to the original initial state of the sample before any stress loading scheme is implemented; the peak area of ​​the absorption peak at the same wavenumber position collected at this time serves as a benchmark reference value for measuring subsequent changes in chemical structure. The formula is as follows:

[0034] In the formula, The carbonyl index is a dimensionless ratio. This represents the peak area of ​​the carbonyl stretching vibration absorption peak measured after the current stress cycle, reflecting the relative carbonyl content of the sample in the current state. This represents the peak area of ​​the carbonyl absorption peak at the same wavenumber position in the initial state of the sample before any environmental stress treatment, and is used as a baseline reference value. When the value decreases, it indicates a reduction in carbonyl content, breakage of polymer molecular chains, or oxidative degradation. The lower the value, the more severe the chemical degradation.

[0035] By combining microcrack characteristic parameters and carbonyl index, a snapshot of the state of the sample under test is generated.

[0036] Specifically, the "combination" refers to integrating the microcrack quantity parameter, microcrack length parameter, and carbonyl index into a unified data structure according to their corresponding relationships. This data structure comprehensively records the key state information of the sample under test in both physical morphology and chemical structure dimensions. The "state snapshot" refers to a comprehensive data record generated at a specific node in the environmental stress time-series loading scheme, describing the current degradation state of the sample under test. It is both an objective reflection of the stress effect in the previous stage and a direct input basis for subsequent degradation stage judgment and stress parameter adjustment. By incorporating physical damage indicators and chemical degradation indicators into the same state snapshot, the assessment of the degradation process is based on the synergistic analysis of surface morphology and internal chemical structure, improving the accuracy and reliability of degradation stage judgment.

[0037] S3. Determine the material degradation stage based on the state snapshot and the preset degradation judgment criteria. The material degradation stage includes the initial integrity stage and the pre-damage stage. In this embodiment, the preset degradation judgment criteria include a preset microcrack number threshold, a preset microcrack length threshold, and a preset carbonyl index lower limit threshold. The preset microcrack number threshold defines the upper limit of the allowable number of surface microcracks, the preset microcrack length threshold defines the upper limit of the maximum length of a single microcrack, and the preset carbonyl index lower limit threshold defines the minimum allowable value of the carbonyl index. The material degradation stage is determined based on the state snapshot and the preset degradation judgment criteria. The material degradation stage includes an initial integrity stage and a pre-damage stage, including: Extract the microcrack number parameter, microcrack length parameter, and carbonyl index from the state snapshot. Compare the microcrack number parameter with a preset microcrack number threshold, the microcrack length parameter with a preset microcrack length threshold, and the carbonyl index with a preset carbonyl index lower limit threshold.

[0038] Specifically, the degradation judgment criteria refer to a set of pre-defined rules used to determine the current degradation stage of a material based on quantitative indicators in the condition snapshot. The preset thresholds for the number of microcracks, the length of microcracks, and the lower limit of the carbonyl index are experimentally calibrated boundary values ​​based on the permissible damage level of the material's application scenario, corresponding to the maximum allowable degradation limits for the three indicators: number of microcracks, length of microcracks, and carbonyl index, respectively. Extraction refers to reading the specific values ​​of these three parameters from the condition snapshot. Comparison refers to comparing the three actual measured values ​​with their respective preset thresholds to determine whether each indicator is within the allowable range.

[0039] When the number of microcracks is less than the preset threshold for the number of microcracks, the length of microcracks is less than the preset threshold for the length of microcracks, and the carbonyl index is greater than or equal to the preset lower limit threshold for the carbonyl index, the material deterioration stage is determined to be the initial intact stage.

[0040] Specifically, the initial integrity stage refers to a state where the number of microcracks, the length of microcracks, and the carbonyl index of the material all do not exceed their respective preset thresholds, and the physical morphology and chemical structure remain at a healthy level. These three conditions are logically ANDed; all three must be met to be considered for this stage to be reached, indicating that no adjustments to subsequent stress parameters are currently necessary.

[0041] When the number of microcracks is greater than or equal to the preset threshold for the number of microcracks, or the length of microcracks is greater than or equal to the preset threshold for the length of microcracks, or the carbonyl index is less than the preset lower limit threshold for the carbonyl index, the material deterioration stage is determined to be the pre-damage stage.

[0042] Specifically, the pre-damage stage refers to a state where at least one of the material's indicators exceeds a preset threshold, indicating that non-negligible degradation has occurred but the material has not yet reached final failure. The above three conditions are logically ORed; the determination is triggered as soon as any one condition is met, making the degradation judgment highly sensitive. This ensures that when any dimension of physical damage or chemical degradation exceeds the standard, the subsequent stress parameter adjustment mechanism can be triggered in a timely manner to reflect the decrease in the material's resistance.

[0043] S4. Determine the updated environmental stress timing loading scheme based on the material deterioration stage: When the material is in the initial intact stage, use the current environmental stress timing loading scheme as the updated environmental stress timing loading scheme; when the material is in the pre-damage stage, generate stress adjustment instructions and modify the parameters in the current environmental stress timing loading scheme based on the stress adjustment instructions to obtain the updated environmental stress timing loading scheme. In this embodiment, determining the updated environmental stress timing loading scheme based on the material deterioration stage includes: when in the initial intact stage, using the current environmental stress timing loading scheme as the updated environmental stress timing loading scheme; when in the pre-damage stage, generating a stress adjustment command and modifying the parameters in the current environmental stress timing loading scheme based on the stress adjustment command to obtain the updated environmental stress timing loading scheme, including: When the material degradation stage is determined to be the initial intact stage, the current environmental stress time-series loading scheme is used as the updated environmental stress time-series loading scheme.

[0044] Specifically, the updated environmental stress timing loading scheme refers to the execution scheme output after this step, which will be used as the input for the next iteration. When it is determined to be in the initial intact stage, it means that the three degradation indicators of the sample have not exceeded their respective thresholds, and its ability to resist subsequent environmental stress has not decreased significantly. Therefore, the current scheme is directly used as the updated scheme to maintain the consistency of the simulation conditions.

[0045] After determining that the material degradation stage is the pre-damage stage, a stress adjustment strategy is determined based on the degradation index type corresponding to the pre-damage stage, and a stress adjustment command is generated. If the pre-damage stage is triggered by the carbonyl index falling below the lower limit threshold, the stress adjustment command includes an increase in salt spray concentration and an extension of salt spray duration. If the pre-damage stage is triggered by microcrack characteristic parameters, the stress adjustment command includes a decrease in friction load or an adjustment in the number of friction cycles.

[0046] Specifically, stress adjustment instructions are indications generated based on the degradation stage assessment results, used to modify specific parameters in the next round of the plan. Degradation index types are divided into two categories: carbonyl index triggering and microcrack characteristic parameter triggering. When triggered by a carbonyl index falling below the lower threshold, it indicates that the internal chemical bond structure of the material has been significantly weakened, reducing its resistance to salt spray corrosion. Therefore, the instructions include an upward adjustment value for salt spray concentration and an extension value for salt spray duration to simulate the real-world condition where damaged materials are more sensitive to saline moisture.

[0047] When triggered by microcrack characteristic parameters—that is, when the number or length of microcracks exceeds the corresponding threshold—it indicates that physical damage has occurred on the material surface, reducing its resistance to friction and wear. Therefore, the command includes a reduction in friction load or an adjustment value for the number of friction cycles to simulate the characteristic that a damaged surface is more susceptible to further damage under wind and sand. The stress adjustment strategy follows the principle of selecting the corresponding adjustment direction and parameter type based on the type of degradation index, so that the stress adjustment matches the nature of the damage.

[0048] Identify the parameter modification items included in the stress adjustment command; when the stress adjustment command includes an increase in salt spray concentration and an extension in salt spray duration, add the salt spray concentration value of the second-stage stress parameter in the current environmental stress timing loading scheme to the increase in salt spray concentration to obtain the updated salt spray concentration value, add the salt spray duration value to the extension in salt spray duration to obtain the updated salt spray duration value, and replace the corresponding parameters.

[0049] Specifically, the parameter modification items refer to the names of the parameters that need to be modified and their adjustment amounts as specified in the instruction. The salt spray concentration increase value refers to the concentration increment added to the current salt spray concentration, and the salt spray duration extension value refers to the duration increment added to the current spray duration. The updated salt spray concentration value and the updated salt spray duration value are generated using the following formula:

[0050]

[0051] In the formula, This indicates the updated salt spray concentration value. This indicates the salt spray concentration value of the current scheme. This indicates the upward adjustment value for salt spray concentration, which is preset based on the severity of pre-damage. This indicates the updated salt spray duration. This indicates the salt spray duration value of the current scheme. This represents the extension of salt spray duration, which is also preset based on the severity of pre-damage. By directly superimposing these values, the increase in the material's sensitivity to salt spray erosion is quantified as a quantitative increase in stress parameters.

[0052] When the stress adjustment command includes a decrease in friction load or an adjustment in the number of friction cycles, modify the friction load or the number of friction cycles in the third-stage stress parameters to generate an updated environmental stress timing loading scheme.

[0053] Specifically, the friction load reduction value refers to the downward adjustment of the current friction load. Its significance lies in the fact that when microcracks already exist on the material surface, even a small friction load can cause significant damage. Reducing the load can simulate the equivalent effect of a decrease in the material's resistance to wear. The friction cycle number adjustment value refers to the amount of adjustment to the current friction cycle number. In the pre-damage stage, this is usually an increase in the number of cycles to reflect the accelerated damage accumulation effect on the damaged surface under the same wear intensity. Modification refers to replacing the corresponding values ​​of the stress parameters in the third stage of the current scheme with the adjusted values, forming an updated scheme for use in the next iteration.

[0054] S5. Iterate through S1 to S4, record the state snapshot and environmental stress timing loading scheme generated in each iteration, and construct the deterioration state transition sequence. In this embodiment, the iterative execution of S1 to S4 records the state snapshot and environmental stress timing loading scheme generated in each iteration, and constructs a degradation state transition sequence, including: Establish an initial empty sequence of degraded state transitions and set the number of iterations to zero.

[0055] Specifically, the degradation state transition sequence refers to an ordered set of data arranged in iteration order, recording the complete trajectory of material degradation from its initial state to failure. "Initially empty" means creating an empty sequence without any records before the first iteration. The iteration number refers to the number of complete execution cycles of the current environmental stress timing loading scheme; setting it to zero indicates that no stress loading cycle has started yet.

[0056] Execute steps S1 to S4 to obtain the test sample subjected to time-series superposition generated in this iteration, the state snapshot generated in this iteration, and the updated environmental stress time-series loading scheme generated after adjustment in step S4. Increment the iteration number by one.

[0057] Specifically, executing S1 to S4 refers to sequentially running all steps of one round of stress loading, state acquisition, degradation judgment, and scheme update. The state snapshot and the updated environmental stress time-series loading scheme are generated by steps S2 and S4, respectively, and their meanings have been explained in the previous embodiments. Incrementing the iteration count by one means that the count value is increased by one after each complete round of iteration, which is used to mark the number of loops currently executed.

[0058] The state snapshot generated in this iteration, the updated environmental stress timing loading scheme, and the current iteration number are combined into a state transition record. This state transition record is then appended to the end of the deteriorated state transition sequence to form the deteriorated state transition sequence.

[0059] Specifically, a state transition record refers to an independent data unit encapsulated after a single iteration, consisting of a state snapshot, an updated solution, and the iteration count, all according to their corresponding relationships. It comprehensively records the input conditions, output results, and temporal position of that iteration. Appending refers to adding newly generated state transition records to the end of an existing sequence in chronological order to ensure that the sequential relationship between records in the sequence strictly matches the iteration execution order. As iterations continue, records gradually accumulate in the sequence, eventually forming a complete trajectory describing the continuous degradation evolution of the material from its initial intact state through multiple pre-damage adjustments until final failure.

[0060] S6. Calculate the damage increment between any two adjacent state snapshots in the deteriorated state transition sequence, and sum up the damage increments to obtain the cumulative damage value. In this embodiment, calculating the damage increment between any two adjacent state snapshots in the deteriorated state transition sequence and summing the damage increments to obtain the cumulative damage value includes: Extract the state snapshot generated in the i-th iteration and the state snapshot generated in the (i+1)-th iteration from the deteriorated state transition sequence in sequence, where i is an integer greater than or equal to 1 and less than the total number of state transition records.

[0061] Specifically, sequential extraction refers to taking out state snapshots of two adjacent rounds in the order recorded in the deterioration state transition sequence. i starts from 1, and i+1 is the next iteration that follows. The upper limit of i ensures that the i+1th state snapshot is valid.

[0062] Extract the first microcrack number parameter, the first microcrack length parameter, and the first carbonyl index from the state snapshot generated in the i-th iteration, and extract the second microcrack number parameter, the second microcrack length parameter, and the second carbonyl index from the state snapshot generated in the (i+1)-th iteration.

[0063] Specifically, the first parameter refers to the measurement value corresponding to the i-th iteration, and the second parameter refers to the measurement value corresponding to the (i+1)-th iteration. The difference between the two sets of parameters reflects the change in the degree of material degradation after a complete stress loading cycle.

[0064] The difference between the second microcrack number parameter and the first microcrack number parameter is recorded as the microcrack number increment, the difference between the second microcrack length parameter and the first microcrack length parameter is recorded as the microcrack length increment, and the difference between the first carbonyl index and the second carbonyl index is recorded as the carbonyl index decay.

[0065] Specifically, the increase in the number of microcracks refers to the change in the number of cracks between two adjacent cycles, the increase in the length of the longest single crack refers to the change in the length of the longest single crack, and the decrease in the carbonyl index refers to the decrease in the index caused by the deterioration of chemical bonds. These three metrics quantify the contribution of a single stress cycle to the material degradation from the three dimensions of crack initiation, crack propagation, and chemical degradation.

[0066] The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by adding the increment of the number of microcracks, the increment of the microcrack length, and the decrease of the carbonyl index.

[0067] Specifically, the damage increment refers to the quantitative value of the overall deterioration of the material caused by a single iteration. It is obtained by directly summing the three increments mentioned above and represents the sum of the material's deterioration progress in the physical and chemical dimensions within this iteration.

[0068] The cumulative damage value is obtained by summing the damage increments between all adjacent iterations.

[0069] Specifically, the accumulation refers to summing the damage increments of each pair of adjacent state snapshots from the first iteration to the last iteration. The accumulated damage value increases monotonically with the number of iterations, and triggers a lifespan termination determination when it reaches a preset failure threshold.

[0070] In this embodiment, the increase in the number of microcracks, the increase in the length of microcracks, and the decrease in the carbonyl index are added together to obtain the damage increment between the i-th iteration and the (i+1)-th iteration, as follows: The normalized microcrack number increment is obtained by dividing the microcrack number increment by a preset microcrack number threshold; the normalized microcrack length increment is obtained by dividing the microcrack length increment by a preset microcrack length threshold; and the normalized carbonyl index decay is obtained by dividing the carbonyl index decay by a preset maximum allowable decay value.

[0071] Specifically, the purpose of the above normalization process is to convert the dimensional original increments into dimensionless ratios relative to their respective allowable upper limits, making indices with different physical meanings comparable and cumulative on the same scale. The preset microcrack number threshold and preset microcrack length threshold are defined in the degradation judgment criteria. The preset maximum allowable decay value of the carbonyl index refers to the maximum allowable decrease in the carbonyl index between two adjacent iterations, experimentally calibrated based on the allowable rate of chemical degradation of the material. The core relationship formula for the normalization calculation is as follows:

[0072]

[0073]

[0074] In the formula, This represents the normalized increment of the number of microcracks. This indicates the increase in the number of microcracks. This indicates a preset threshold for the number of microcracks; This represents the normalized microcrack length increment. This represents the increment in microcrack length. This indicates a preset microcrack length threshold; This represents the normalized carbonyl index decay. This indicates the carbonyl index decay. This indicates the maximum allowable decay value of the preset carbonyl index.

[0075] Determine if the normalized microcrack number increment is less than zero; if so, set the normalized microcrack number increment to zero. Determine if the normalized microcrack length increment is less than zero; if so, set the normalized microcrack length increment to zero. Determine if the normalized carbonyl index decay is less than zero; if so, set the normalized carbonyl index decay to zero.

[0076] Specifically, a normalized increment less than zero indicates that the corresponding parameter in the subsequent iteration changes in the opposite direction to the previous iteration. Setting negative values ​​to zero ensures that the damage increment is always non-negative, making the cumulative damage value monotonically increase with the number of iterations, avoiding damage cancellation caused by measurement fluctuations, and ensuring the conservatism of the life assessment results.

[0077] The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by summing the normalized microcrack number increment, the normalized microcrack length increment, and the normalized carbonyl index decay.

[0078] Specifically, the three normalized increments, after being set to zero, are all non-negative dimensionless ratios. Their direct summation yields the damage increment for that iteration, comprehensively reflecting the relative progression of physical damage and chemical degradation within a single stress cycle relative to each failure threshold, thus providing a unified metric for calculating cumulative damage values.

[0079] S7. When the cumulative damage value reaches the preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time of a single iteration. The equivalent service time of a single iteration represents the actual environmental action time simulated by a single complete execution of the environmental stress timing loading scheme.

[0080] In this embodiment, when the cumulative damage value reaches a preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time per iteration. The equivalent service time per iteration represents the simulated real environmental action time of a single complete execution of the environmental stress timing loading scheme, as follows: The cumulative damage value is compared with a preset failure threshold. If the cumulative damage value is less than the preset failure threshold, the next iteration continues.

[0081] Specifically, the preset failure threshold refers to the pre-defined cumulative damage threshold corresponding to when the material reaches an unacceptable level of degradation. When the cumulative damage value is less than this threshold, it indicates that the material has not yet reached the functional failure limit, and the next iteration needs to be performed to allow the damage to accumulate further.

[0082] When the cumulative damage value is greater than or equal to the preset failure threshold, the iteration is terminated and the current iteration number is obtained. The current iteration number is multiplied by the preset single-iteration equivalent service time to obtain the predicted service life of the acrylic sheet sample.

[0083] Specifically, the current iteration number refers to the number of complete iterations completed when the cumulative damage value first reaches or exceeds the preset failure threshold. The calculation of the predicted service life is expressed by the following formula:

[0084] In the formula, This indicates the predicted service life of the acrylic sheet sample; This indicates the current iteration number when the cumulative damage value reaches the preset failure threshold; This represents the preset equivalent service time for a single iteration, which is the actual environmental impact time simulated by a single complete execution of the environmental stress timing loading scheme.

[0085] Please see Figure 2 This invention provides a performance analysis system for acrylic sheets, comprising: Sample production module: Based on a preset environmental stress timing loading scheme, it sequentially performs ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spray and reciprocating friction on acrylic sheet samples to generate the test sample; State snapshot module: used to acquire microscopic images and Fourier transform infrared spectra of the sample to be tested, extract microcrack characteristic parameters and carbonyl index, and generate state snapshots; Adjustment instruction module: used to determine the material degradation stage based on the state snapshot and preset degradation judgment criteria, wherein the material degradation stage includes an initial intact stage and a pre-damage stage; Loading scheme module: used to determine the updated environmental stress time-series loading scheme according to the material deterioration stage: when it is in the initial integrity stage, the current environmental stress time-series loading scheme is used as the updated environmental stress time-series loading scheme; when it is in the pre-damage stage, stress adjustment instructions are generated, and the parameters in the current environmental stress time-series loading scheme are modified based on the stress adjustment instructions to obtain the updated environmental stress time-series loading scheme. Sequence Construction Module: Used to iteratively execute from the Sample Production Module to the Loading Scheme Module, record the state snapshot and environmental stress time-series loading scheme generated in each iteration, and construct the degradation state transition sequence; Damage calculation module: used to calculate the damage increment between any two adjacent state snapshots in the deterioration state transition sequence, and to accumulate the damage increments to obtain the cumulative damage value; Lifetime prediction module: When the cumulative damage value reaches the preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time of a single iteration. The equivalent service time of a single iteration represents the actual environmental action time simulated by a single complete execution of the environmental stress timing loading scheme.

[0086] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units 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.

[0087] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0088] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes 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.

Claims

1. A method for performance analysis of acrylic sheets, characterized in that, Includes the following steps: S1. Based on the preset environmental stress timing loading scheme, the acrylic sheet sample is sequentially subjected to ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spraying and reciprocating friction to generate the test sample. S2. Acquire microscopic images and Fourier transform infrared spectra of the sample to be tested, extract microcrack characteristic parameters and carbonyl index, and generate state snapshots; S3. Determine the material degradation stage based on the state snapshot and the preset degradation judgment criteria. The material degradation stage includes the initial integrity stage and the pre-damage stage. S4. Determine the updated environmental stress timing loading scheme based on the material deterioration stage: When the material is in the initial intact stage, the current environmental stress timing loading scheme shall be used as the updated environmental stress timing loading scheme. When in the pre-damage stage, a stress adjustment command is generated, and the parameters in the current environmental stress timing loading scheme are modified based on the stress adjustment command to obtain the updated environmental stress timing loading scheme. S5. Iterate through S1 to S4, record the state snapshot and environmental stress timing loading scheme generated in each iteration, and construct the deterioration state transition sequence. S6. Calculate the damage increment between any two adjacent state snapshots in the deteriorated state transition sequence, and sum up the damage increments to obtain the cumulative damage value. S7. When the cumulative damage value reaches the preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time of a single iteration. The equivalent service time of a single iteration represents the actual environmental action time simulated by a single complete execution of the environmental stress timing loading scheme.

2. The method for performance analysis of acrylic sheets according to claim 1, characterized in that, The environmental stress sequential loading scheme includes first-stage stress parameters, second-stage stress parameters, and third-stage stress parameters. The first-stage stress parameters define the ultraviolet irradiation intensity and high-temperature holding time; the second-stage stress parameters define the low-temperature holding time, salt spray concentration, and salt spray duration; and the third-stage stress parameters define the friction load, friction stroke, and number of friction cycles. Based on the preset environmental stress sequential loading scheme, the acrylic sheet sample is subjected to a sequential process of ultraviolet irradiation coupled with high temperature, low-temperature coupled with salt spray, and reciprocating friction to generate a test sample, including: Acrylic sheet samples were irradiated with ultraviolet radiation intensity according to the first stage stress parameters in a xenon lamp aging chamber, and at the same time, high temperature environment was applied to the acrylic sheet samples in a high and low temperature damp heat test chamber according to the high temperature holding time in the first stage stress parameters, so as to obtain intermediate samples that have undergone the first stage stress action. The intermediate sample that has undergone the first stage of stress was subjected to a low-temperature environment by using a high and low temperature humidity test chamber according to the low temperature holding time in the second stage stress parameters. The intermediate sample was then subjected to salt spraying in a salt spray corrosion test chamber according to the salt spray concentration and salt spraying time in the second stage stress parameters during the low temperature holding period, thus obtaining an intermediate sample that has undergone the second stage of stress. By applying reciprocating friction to the intermediate sample that has undergone the second stage of stress using a reciprocating friction and wear testing machine according to the friction load, friction stroke and friction cycle number in the third stage stress parameters, a test sample that has withstood the superimposed effect of time is obtained.

3. The method for performance analysis of acrylic sheets according to claim 1, characterized in that, The process of acquiring microscopic images and Fourier transform infrared spectra of the sample to be tested, extracting microcrack characteristic parameters and carbonyl index, and generating a state snapshot includes: Microscopic images of the sample surface are acquired using an industrial camera, and an interferogram of the sample surface is acquired using a Fourier transform infrared spectrometer. The Fourier transform infrared spectrum is obtained by performing a Fourier transform on the interferogram. Edge detection is performed on the microscopic image to extract the edge segments of microcracks in the image. The number and maximum length of the edge segments of microcracks are counted. The number of edge segments of microcracks is used as the microcrack quantity parameter, and the maximum length of the edge segments of microcracks is used as the microcrack length parameter. The microcrack feature parameters are composed of the microcrack quantity parameter and the microcrack length parameter. Locate the wavenumber position corresponding to the carbonyl stretching vibration absorption peak in the Fourier transform infrared spectrum, and calculate the peak area of ​​the absorption peak. The carbonyl index is defined as the ratio of the peak area to the peak area of ​​the absorption peak at the same wavenumber position that was collected before environmental stress treatment. By combining microcrack characteristic parameters and carbonyl index, a snapshot of the state of the sample under test is generated.

4. The method for performance analysis of acrylic sheets according to claim 1, characterized in that, The preset degradation judgment criteria include a preset microcrack number threshold, a preset microcrack length threshold, and a preset carbonyl index lower limit threshold. The preset microcrack number threshold defines the upper limit of the allowable number of surface microcracks, the preset microcrack length threshold defines the upper limit of the maximum length of a single microcrack, and the preset carbonyl index lower limit threshold defines the minimum allowable value of the carbonyl index. The material degradation stage is determined based on the state snapshot and the preset degradation judgment criteria. The material degradation stage includes an initial integrity stage and a pre-damage stage, including: Extract the microcrack number parameter, microcrack length parameter, and carbonyl index from the state snapshot. Compare the microcrack number parameter with a preset microcrack number threshold, compare the microcrack length parameter with a preset microcrack length threshold, and compare the carbonyl index with a preset carbonyl index lower limit threshold. When the number of microcracks is less than the preset threshold for the number of microcracks, the length of microcracks is less than the preset threshold for the length of microcracks, and the carbonyl index is greater than or equal to the preset lower limit threshold for the carbonyl index, the material deterioration stage is determined to be the initial intact stage. When the number of microcracks is greater than or equal to the preset threshold for the number of microcracks, or the length of microcracks is greater than or equal to the preset threshold for the length of microcracks, or the carbonyl index is less than the preset lower limit threshold for the carbonyl index, the material degradation stage is determined to be the pre-damage stage.

5. The method for performance analysis of acrylic sheets according to claim 1, characterized in that, The updated environmental stress timing loading scheme is determined based on the material deterioration stage: when the material is in the initial intact stage, the current environmental stress timing loading scheme is used as the updated environmental stress timing loading scheme. When in the pre-damage stage, a stress adjustment command is generated, and the parameters in the current environmental stress timing loading scheme are modified based on the stress adjustment command to obtain an updated environmental stress timing loading scheme, including: When the material degradation stage is determined to be the initial intact stage, the current environmental stress time-series loading scheme is used as the updated environmental stress time-series loading scheme. After determining that the material degradation stage is the pre-damage stage, a stress adjustment strategy is determined based on the degradation index type corresponding to the pre-damage stage, and a stress adjustment command is generated. If the pre-damage stage is triggered by the carbonyl index falling below the lower threshold, the stress adjustment command includes an increase in salt spray concentration and an extension of salt spray duration. If the pre-damage stage is triggered by microcrack characteristic parameters, the stress adjustment command includes a reduction in friction load or an adjustment in the number of friction cycles. Identify parameter modification items included in the stress adjustment command; When the stress adjustment command includes an upward adjustment value for salt spray concentration and an extension value for salt spray duration, the salt spray concentration value of the second-stage stress parameter in the current environmental stress timing loading scheme is added to the upward adjustment value for salt spray concentration to obtain the updated salt spray concentration value. The salt spray duration value is added to the extension value for salt spray duration to obtain the updated salt spray duration value, and the corresponding parameters are replaced. When the stress adjustment command includes a decrease in friction load or an adjustment in the number of friction cycles, modify the friction load or the number of friction cycles in the third-stage stress parameters to generate an updated environmental stress timing loading scheme.

6. The method for performance analysis of acrylic sheets according to claim 1, characterized in that, The iterations S1 to S4 record the state snapshots and environmental stress timing loading schemes generated in each iteration, constructing a deterioration state transition sequence, including: Establish an initial empty sequence of degraded state transitions and set the number of iterations to zero; Execute S1 to S4 to obtain the test sample subjected to time-series superposition generated in this iteration, the state snapshot generated in this iteration, and the updated environmental stress time-series loading scheme generated after adjustment in step S4 in this iteration. Increment the iteration number by one. The state snapshot generated in this iteration, the updated environmental stress timing loading scheme, and the current iteration number are combined into a state transition record. This state transition record is then appended to the end of the deteriorated state transition sequence to form the deteriorated state transition sequence.

7. The method for performance analysis of acrylic sheets according to claim 1, characterized in that, The calculation of the damage increment between any two adjacent state snapshots in the deteriorated state transition sequence, and the summation of each damage increment to obtain the cumulative damage value, includes: Extract the state snapshot generated in the i-th iteration and the state snapshot generated in the (i+1)-th iteration from the deteriorated state transition sequence in sequence, where i is an integer greater than or equal to 1 and less than the total number of state transition records; Extract the first microcrack number parameter, the first microcrack length parameter, and the first carbonyl index from the state snapshot generated in the i-th iteration; extract the second microcrack number parameter, the second microcrack length parameter, and the second carbonyl index from the state snapshot generated in the (i+1)-th iteration. The difference between the second microcrack number parameter and the first microcrack number parameter is recorded as the microcrack number increment, the difference between the second microcrack length parameter and the first microcrack length parameter is recorded as the microcrack length increment, and the difference between the first carbonyl index and the second carbonyl index is recorded as the carbonyl index decay. The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by adding the increment of the number of microcracks, the increment of the microcrack length, and the decrease of the carbonyl index. The cumulative damage value is obtained by summing the damage increments between all adjacent iterations.

8. The method for performance analysis of acrylic sheets according to claim 7, characterized in that, The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by adding the increment of the number of microcracks, the increment of the microcrack length, and the decrease in the carbonyl index, as follows: Divide the increment of the number of microcracks by the preset threshold for the number of microcracks to obtain the normalized increment of the number of microcracks. Divide the microcrack length increment by the preset microcrack length threshold to obtain the normalized microcrack length increment; Divide the carbonyl index decay by the preset maximum allowable carbonyl index decay value to obtain the normalized carbonyl index decay. Determine whether the normalized microcrack number increment is less than zero. If it is less than zero, set the normalized microcrack number increment to zero. Determine whether the normalized microcrack length increment is less than zero. If it is less than zero, set the normalized microcrack length increment to zero. Determine if the normalized carbonyl index decay is less than zero; if it is less than zero, set the normalized carbonyl index decay to zero. The damage increment between the i-th iteration and the (i+1)-th iteration is obtained by summing the normalized microcrack number increment, the normalized microcrack length increment, and the normalized carbonyl index decay.

9. The method for performance analysis of acrylic sheets according to claim 8, characterized in that, When the cumulative damage value reaches a preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time per iteration. The equivalent service time per iteration represents the simulated real environmental action time of a single complete execution of the environmental stress timing loading scheme, as follows: The cumulative damage value is compared with a preset failure threshold. If the cumulative damage value is less than the preset failure threshold, the next iteration continues. When the cumulative damage value is greater than or equal to the preset failure threshold, the iteration is terminated and the current iteration number is obtained. The current iteration number is multiplied by the preset single-iteration equivalent service time to obtain the predicted service life of the acrylic sheet sample.

10. A performance analysis system for acrylic sheets, used with the performance analysis method for acrylic sheets as described in any one of claims 1 to 9, characterized in that, include: Sample production module: Based on a preset environmental stress timing loading scheme, it sequentially performs ultraviolet irradiation coupled with high temperature, low temperature coupled with salt spray and reciprocating friction on acrylic sheet samples to generate the test sample; State snapshot module: used to acquire microscopic images and Fourier transform infrared spectra of the sample to be tested, extract microcrack characteristic parameters and carbonyl index, and generate state snapshots; Adjustment instruction module: used to determine the material degradation stage based on the state snapshot and preset degradation judgment criteria, wherein the material degradation stage includes an initial intact stage and a pre-damage stage; Loading scheme module: used to determine the updated environmental stress time-series loading scheme according to the material deterioration stage: when it is in the initial integrity stage, the current environmental stress time-series loading scheme is used as the updated environmental stress time-series loading scheme; When in the pre-damage stage, a stress adjustment command is generated, and the parameters in the current environmental stress timing loading scheme are modified based on the stress adjustment command to obtain the updated environmental stress timing loading scheme. Sequence Construction Module: Used to iteratively execute from the Sample Production Module to the Loading Scheme Module, record the state snapshot and environmental stress time-series loading scheme generated in each iteration, and construct the degradation state transition sequence; Damage calculation module: used to calculate the damage increment between any two adjacent state snapshots in the deterioration state transition sequence, and to accumulate the damage increments to obtain the cumulative damage value; Lifetime prediction module: When the cumulative damage value reaches the preset failure threshold, the iteration is terminated. The predicted service life of the acrylic sheet sample is calculated based on the current iteration number and the preset equivalent service time of a single iteration. The equivalent service time of a single iteration represents the actual environmental action time simulated by a single complete execution of the environmental stress timing loading scheme.

Images