A method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments

Abstract

This invention discloses a method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments, belonging to the field of materials testing technology. The method includes: constructing a drift baseline and registering drift mutation markers based on a maintained sequence record and the original load sequence; performing zero-point drift subtraction and mutation segment removal to generate a load-displacement synchronization sequence; inserting a micro-amplitude stress disturbance segment into the load-maintaining segment based on the load-displacement synchronization sequence; acquiring high-frequency mechanical signals and marking the segment type; simultaneously setting mutation thresholds and persistence thresholds to identify brittle fracture precursor events; extracting the elastic modulus and strength correlation intervals from the load-displacement synchronization sequence; combining the brittle fracture precursor events to identify the brittle fracture initiation load interval; performing solidification registration; and generating a mechanical property evaluation report. This invention achieves the active excitation and effective identification of brittle fracture precursor events, improving the reliability of ultra-low temperature mechanical testing data and the ability to quantitatively evaluate the failure process.

Description

Technical Field

[0001] This invention relates to the field of materials testing technology, and in particular to a method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments. Background Technology

[0002] Resin-based composite materials, with their high specific strength, low coefficient of thermal expansion, and excellent structural designability, have been widely applied in cryogenic engineering fields such as cryogenic load-bearing structures for deep space probes, liquid hydrogen and liquid oxygen propellant tanks, and liquefied natural gas transportation equipment. Continuous advancements in testing technology, including the synergistic integration of advanced measurement methods such as multi-parameter sensing systems and digital image correlation, have enhanced the ability to refine the characterization of the mechanical response of materials under cryogenic conditions, providing a solid technical foundation for the structural design, reliability verification, and new material-related services for equipment operating in extreme environments.

[0003] However, existing methods for evaluating the mechanical properties of cryogenic materials still have two shortcomings: First, the sensor is affected by thermal stress, resulting in nonlinear zero-point drift and lack of dynamic correction mechanism, which leads to distortion of load displacement data. Second, the micro-damage precursor events of brittle fracture of resin-based composite materials are transient and have weak signal characteristics, lacking active excitation and high-sensitivity identification capabilities, making it difficult to accurately determine the fracture initiation load, thus limiting the reliability and engineering applicability of the evaluation results. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments, addressing the problems of insufficient zero-point drift dynamic correction capability of sensors and the lack of a real-time identification mechanism for brittle fracture precursor events.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] This invention provides a method for evaluating the mechanical properties of resin-based composite materials in an ultra-low temperature environment. The method includes: pre-treating the resin-based composite material sample, initializing the mechanical parameter acquisition configuration, and performing segmented cooling and stabilization on the sample in an ultra-low temperature environment, while simultaneously acquiring mechanical sensor data alternately in no-load and load-holding segments to generate a holding sequence record and an original load sequence; based on the holding sequence record and the original load sequence, constructing a drift baseline and registering drift mutation markers, performing zero-point drift subtraction and mutation segment removal to generate a load-displacement synchronization sequence; based on the load-displacement synchronization sequence, inserting a micro-amplitude stress disturbance segment in the load-holding segment, acquiring high-frequency mechanical signals and marking the segment type, and simultaneously setting mutation thresholds and persistence thresholds to identify brittle fracture precursor events; extracting the elastic modulus and strength correlation interval from the load-displacement synchronization sequence, and combining the brittle fracture precursor events to identify the brittle fracture initiation load interval, performing solidification registration, and generating a mechanical property evaluation report.

[0008] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the specific steps for initializing the mechanical parameter acquisition and configuration are as follows:

[0009] The coaxiality of the sensitive axis and the loading axis of the mechanical sensor is checked and finely adjusted for alignment. The initial zero point value is recorded, and a coaxial zero point record set is obtained.

[0010] Based on the coaxial zero-point record set, a high sampling frequency is configured, and timestamp synchronization verification and background noise registration are performed to generate a high sampling configuration record;

[0011] The zero-point saturation warning threshold is verified for the high sampling configuration record, and the zero-point saturation warning status is recorded. At the same time, the range boundary is calibrated to obtain the mechanical parameter acquisition configuration.

[0012] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in an ultra-low temperature environment according to the present invention, the specific steps for performing segmented cooling and stabilization on the resin-based composite material sample in an ultra-low temperature environment are as follows.

[0013] According to the mechanical parameters collected and configured, the signal line connection, synchronous verification and segmented cooling were performed in the ultra-low temperature environment. The cooling switching timestamp was recorded, the stability of the clamping body was monitored and the gas circulation status was checked, and a segmented cooling process record was generated.

[0014] Based on the segmented cooling process sheet, target temperature stability constraints are applied, and the stability holding window is locked to register the no-load holding segment interval, generating a stability holding window list.

[0015] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the specific steps for generating and maintaining the sequence record and the original load sequence are as follows:

[0016] Based on the stable holding window list, the system is divided into no-load holding segment and load holding segment. Mechanical sensor data is collected alternately, and the sampling integrity is verified to generate a holding sequence record.

[0017] Perform segmental seam verification and jump point labeling on the mechanical sensor data in the retained sequence record to generate the original load sequence.

[0018] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the specific steps for constructing a drift baseline and registering drift mutation markers based on the maintained sequence record and the original load sequence are as follows.

[0019] Based on the preserved sequence record and the original load sequence, the start and end timestamps of the unloaded preserved segment are locked, and the static intervals at the beginning and end of the segment are extracted, spliced ​​and smoothed to generate the drift baseline.

[0020] Perform zero-point stability checks on the drift baseline, locate sudden rises and falls, register drift mutation markers, and generate a drift marker list.

[0021] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the specific steps for generating the load-displacement synchronization sequence are as follows:

[0022] Based on the drift marker list, the drift baseline is mapped to the original payload sequence, and zero-point drift subtraction and abrupt window annotation are performed to generate abrupt window annotation list;

[0023] Based on the mutation window annotation list, mutation segment removal is performed, displacement sampling data is extracted, and timestamp bidirectional interpolation alignment and residual verification are performed to generate a load displacement synchronization sequence.

[0024] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the step of inserting a micro-amplitude stress disturbance segment into the load holding segment based on the load displacement synchronization sequence, acquiring high-frequency mechanical signals and marking the segment type is as follows.

[0025] Based on the load-displacement synchronization sequence, the load holding segment is locked and a micro-amplitude stress disturbance segment is inserted. The load holding steady-state verification is performed, and a disturbance segment arrangement list is generated.

[0026] Based on the disturbance segment arrangement list, high-frequency mechanical signals are collected and segment types are marked. At the same time, abnormal noise segments are removed to generate a high-frequency acquisition segment set.

[0027] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the specific steps for setting abrupt change threshold and a persistence threshold to identify brittle fracture precursor events are as follows.

[0028] Extract the undisturbed stable interval from the high-frequency acquisition segments, register the background noise amplitude band and set the sudden change threshold and the continuous threshold, and at the same time perform the verification of the micro-amplitude stress disturbance segment to generate a threshold configuration sheet;

[0029] Based on the threshold configuration list, high-frequency mutation fragments are screened, and echo suppression segment rearrangement is performed to obtain brittle fracture precursor events.

[0030] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the specific steps for generating the mechanical property evaluation report are as follows:

[0031] By combining brittle fracture precursor events with load-displacement synchronization sequences, fracture surface elimination and curve monotonic segment merging are performed to construct load-displacement curves, and load peak point location is performed to generate load-displacement curve records.

[0032] Extract monotonically increasing segments from the load-displacement curve record and remove abnormal displacement segments. Extract the intervals related to elastic modulus and strength, perform linear window progressive trimming, and generate an interval extraction list.

[0033] Based on the interval extraction list, brittle fracture precursor events are mapped to load-displacement curves, and inter-segment repetitive events are merged to identify the brittle fracture initiation load interval, perform solidification registration, and generate a mechanical performance evaluation report.

[0034] As a preferred embodiment of the method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments according to the present invention, the pretreatment includes end face cleaning, parallelism verification, and graded pre-tightening clamping calibration.

[0035] The beneficial effects of this invention are as follows: by constructing a drift baseline and eliminating abrupt change segments, thermally induced zero-point drift dynamic correction is achieved, enabling the load displacement data to have intrinsic accuracy and laying a reliable test data foundation for new material-related services; by embedding micro-amplitude stress disturbances and setting a dual-threshold recognition mechanism during the load holding stage, the active excitation and effective identification of brittle fracture precursor events are achieved, improving the reliability of cryogenic mechanical test data and the ability to quantitatively evaluate the failure process. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of a method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments.

[0038] Figure 2 A flowchart for generating a load-displacement synchronization sequence.

[0039] Figure 3 This is a flowchart for detecting micro-stress disturbances and precursory events of brittle fracture.

[0040] Figure 4 A flowchart for generating a mechanical performance evaluation report. Detailed Implementation

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0042] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0043] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0044] Reference Figures 1-4 As one embodiment of the present invention, this embodiment provides a method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments, comprising the following steps:

[0045] S1: Pre-treat the resin-based composite material sample, initialize the mechanical parameter acquisition configuration, and perform segmented cooling and stabilization in an ultra-low temperature environment. At the same time, mechanical sensor data are collected alternately in the no-load holding segment and the load holding segment to generate the holding sequence record and the original load sequence.

[0046] S1.1: Pre-treatment includes end face cleaning, parallelism verification, and graded pre-tightening clamping calibration;

[0047] Specifically, during pretreatment, the end faces of the resin-based composite material sample are exposed, and oil and particles are wiped away using non-woven fabric and volatile cleaning agent. After blowing away the edge gaps of the end faces with compressed gas, the sample is allowed to dry. During parallelism verification, the resin-based composite material sample is placed on a plane reference platform, and the height difference of the end faces is measured at multiple points along the end faces using measuring tools. The sample is then rotated around the axis for remeasurement to confirm the tilt direction and maximum deviation position of the end faces relative to the reference platform. If the parallelism exceeds the allowable deviation, the end faces are slightly modified, and the parallelism verification is repeated until the requirements are met. During the graded pre-tightening clamping calibration, the resin-based composite material sample is placed into the clamping body, and the end face of the resin-based composite material sample is made to be completely in contact with the contact surface of the clamping body. Pre-tightening loads are applied in stages, and each stage of pre-tightening load is held for a fixed duration. During the holding period, the clamping position of the clamping body and the offset of the resin-based composite material sample axis are observed, and the clamping position is finely adjusted. After the graded pre-tightening is completed, the sample is released to no load, and the load is applied again to verify the consistency of the clamping position, thus completing the graded pre-tightening clamping calibration.

[0048] S1.2: Perform coaxiality verification and fine-tuning of the sensitive axis and loading axis of the mechanical sensor, record the initial zero point value, and obtain the coaxial zero point record set;

[0049] Specifically, read the initial calibration record of the clamping body and keep the clamping state unchanged. Place the loading shaft at the center line position of the clamping body and lock the loading shaft position. Simultaneously align the coaxiality measuring fixture with the reference surface of the sensitive shaft of the mechanical sensor and the reference surface of the loading shaft. Read the radial offset and angular deviation and write them into the coaxiality verification record. Based on the radial offset and angular deviation, perform radial displacement compensation and angular compensation on the fine-tuning adjustment component of the mechanical sensor mounting position. After performing one fine-tuning adjustment, re-measure the radial offset and angular deviation and update the coaxiality verification record. Repeat the fine-tuning adjustment and re-measurement until the coaxiality verification criteria are met (e.g., radial offset less than 0.02 mm and angular deviation less than 0.05 degrees) and tighten all fasteners. Keep the loading shaft locked and the mechanical sensor unloaded. Continuously collect the mechanical sensor output and average it to obtain the initial zero point value (e.g., the collection time is 2 seconds). Write the coaxiality verification record and the initial zero point value into the coaxial zero point record set.

[0050] It should be noted that the sensitive axis reference plane refers to the plane on the mechanical sensor that is strictly bound to the geometric direction of the sensitive axis and serves as the reference for coaxiality measurement. It is used to align the reference direction of the coaxiality measurement fixture with the sensitive axis of the mechanical sensor.

[0051] The loading axis reference plane refers to the plane on the loading axis that is concentric with the center line of the loading axis and serves as the reference for coaxiality measurement. It is used to align the reference direction of the coaxiality measurement fixture with the geometric direction of the loading axis.

[0052] S1.3: Based on the coaxial zero-point record set, configure the high sampling frequency, perform timestamp synchronization verification and background noise registration, and generate a high sampling configuration record;

[0053] Specifically, the process involves reading the initial zero-point value from the coaxial zero-point record set and verifying the coaxiality record entries; registering the output range and acquisition channel number of the mechanical sensor while maintaining the loading axis locked and the mechanical sensor in an unloaded state; setting the sampling frequency and writing an effective timestamp (e.g., setting the sampling frequency to 20000 Hz); triggering a unified time-stamp pulse and simultaneously writing the same time-stamp event into the mechanical sensor acquisition channel and the displacement sampling channel; extracting the timestamps of the corresponding timestamp events from the two channels and obtaining the time deviation; compensating for the timestamp offset of the acquisition channel according to the time deviation and repeatedly writing the timestamp event until the time deviation meets the timestamp synchronization verification criteria; registering the time deviation and timestamp offset compensation amount as a timestamp synchronization verification record; maintaining the unloaded state and continuously acquiring the mechanical sensor output; statistically analyzing the noise amplitude band and noise power level according to the background noise registration set and registering the acquisition period marker; and generating a high-sampling configuration record.

[0054] It should be noted that the timestamp synchronization verification criterion is used to specify the allowable range of timestamp differences written by the mechanical sensor acquisition channel and the displacement sampling channel for the same time-scaled event, and to determine whether timestamp offset compensation is completed (e.g., timestamp difference is less than 1 millisecond).

[0055] S1.4: Perform zero-point saturation warning threshold verification on the high sampling configuration record, record the zero-point saturation warning status, and perform range boundary calibration to obtain the mechanical parameter acquisition configuration;

[0056] Furthermore, the sampling frequency, timestamp synchronization verification record, and background noise registration set in the high sampling configuration record are read. The resin-based composite material sample clamping state remains unchanged, and the mechanical sensor remains unloaded. The mechanical sensor output is continuously acquired according to the high sampling configuration record, and the average value of the sampling window is taken as the zero-point output value. The zero-point output value is compared with the upper boundary of the mechanical sensor output range to obtain the upper boundary distance. The zero-point output value is compared with the lower boundary of the mechanical sensor output range to obtain the lower boundary distance. The smaller value between the upper and lower boundary distances is taken as the minimum usable distance from the zero-point output value to the boundary of the mechanical sensor output range. The background noise amplitude band registered in the background noise registration set is taken as the background noise amplitude range and amplified and subtracted using a background noise amplification factor. The zero-point output value is compared with the coaxial zero point... The absolute difference between the zero-point initial value index number in the record set is used as the zero-point deviation, which is amplified and subtracted by the zero-point deviation amplification factor to obtain the remaining margin. The remaining margin is compared with the zero-point saturation warning threshold and written into the zero-point saturation warning status. The low-end calibration load and the high-end calibration load are loaded according to the calibration load set of the range boundary calibration and kept for a fixed duration. The average value and peak value of the output platform segment of the mechanical sensor are recorded respectively, and the output waveform is checked for saturation shearing or boundary truncation. After unloading the calibration load, the zero-point output value is collected again and compared with the zero-point initial value registered in the coaxial zero-point record set and written into the regression deviation record (for example, the allowable deviation is 1% of the range). The zero-point saturation warning status, the range boundary calibration record and the regression deviation record are encapsulated into a mechanical parameter acquisition configuration.

[0057] The formula for calculating the remaining margin is:

[0058] ;

[0059] in, Indicates the remaining margin. Indicates the upper boundary of the measurement range. Indicates the zero-point output value. Indicates the lower boundary of the measurement range. Indicates the background noise amplification factor. Indicates the background noise amplitude band. Indicates the zero-point deviation amplification factor. This represents the initial zero value registered in the coaxial zero-point record set. This indicates the initial value index number at the zero point.

[0060] It should be noted that the zero-point saturation warning threshold is based on the definition of the output range boundary of the mechanical sensor and the remaining margin between the zero-point output value and the range boundary. It is used to determine when the zero-point output value is close to the range boundary and trigger the zero-point saturation warning state (example range: the remaining margin is less than 3% to 10% of the range).

[0061] The background noise amplification factor is defined based on the safety margin requirements of the background noise amplitude band registered in the background noise registration set and the zero-point saturation warning threshold. It is used to amplify the background noise amplitude band proportionally and then use it as a deduction item for the remaining margin (example range: 1 to 3).

[0062] The zero-point deviation amplification factor is defined based on the allowable deviation range of the initial zero-point value and the zero-point output value registered in the coaxial zero-point record set, as well as the safety margin requirement of the zero-point saturation warning threshold. It is used to amplify the zero-point deviation proportionally and then use it as a deduction item for the remaining margin (example range: 0.5 to 2).

[0063] S1.5: According to the mechanical parameters collected and configured, perform signal line connection, synchronous verification and segmented cooling in the ultra-low temperature environment, and record the cooling switching timestamp, monitor the stability of the clamping body and check the gas circulation status, and generate a segmented cooling process sheet;

[0064] Specifically, in an ultra-low temperature environment, according to the mechanical parameter acquisition configuration, the mechanical sensor signal line and the displacement sampling signal line are connected to the low-temperature wiring port, and terminal tightness checks and shielding continuity checks are performed. A unified time stamp is triggered, and after writing the same time stamp into the mechanical sensor acquisition channel and the displacement sampling channel, the timestamp difference between the two channels is read to complete the synchronization verification. If the timestamp difference exceeds the limit, the timestamp offset of the acquisition channel is adjusted (using the positive or negative direction of the timestamp difference as the adjustment direction and increasing or decreasing in fixed steps; after each adjustment, the timestamp difference is re-measured until the timestamp difference returns to the allowable range and remains stable within multiple consecutive acquisition windows as the convergence criterion). Cooling is initiated according to the mechanical parameter acquisition configuration, and segmented processing is performed according to the segment number. During segmented cooling, the start time stamp, end time stamp, and target temperature arrival time stamp of each segment are recorded. When the cooling mode switches, the cooling switching time stamp is recorded and the cooling mode flag before and after the switch is written. During segmented cooling, the displacement sampling signal and the no-load output of the mechanical sensor are continuously read and the displacement drift band and no-load output drift band are recorded as stability entries of the clamping body. During segmented cooling, the gas circulation indicator is read and the gas circulation status is checked to ensure that the continuous circulation condition and the fluctuation limitation condition are met. The gas circulation status entry is then recorded. The segment number, segmented cooling time stamp entry, cooling switching time stamp, clamping body stability entry, and gas circulation status entry are summarized and written into the segmented cooling process sheet.

[0065] It should be noted that ultra-low temperature environments typically refer to temperature environments where the temperature drops to levels far below conventional low temperatures and can be maintained stably, such as temperatures below -150 degrees Celsius or close to the liquid nitrogen temperature range of -196 degrees Celsius.

[0066] Continuous circulation condition refers to the gas circulation indicator being continuously in the "circulation on" state during the segmented cooling period, with no interruption or jump in the circulation direction and circulation path markings, and the circulation status record remaining continuous and consistent between adjacent acquisition windows.

[0067] The fluctuation limitation condition refers to the instantaneous value of the gas circulation indicator during the segmented cooling period remaining within the allowable range around the baseline value of the corresponding segment, and the variation between adjacent acquisition windows not exceeding the allowable step size, while the circulation status record does not show frequent back-and-forth switching.

[0068] S1.6: Based on the segmented cooling process sheet, perform target temperature stability constraints, lock the stability holding window, register the no-load holding segment interval, and generate a stability holding window list;

[0069] Specifically, the process reads the segment number, temperature fluctuation band within the segment, and cooling switching timestamp from the segmented cooling process sheet. It selects the target temperature for the current segment by segment number and maintains constant cooling output in the ultra-low temperature environment. It continuously reads the ultra-low temperature environment temperature readings and calculates the temperature fluctuation band within a sliding time window. When the temperature fluctuation band meets the stability holding criteria, it registers the start timestamp of the stability holding window. When the temperature fluctuation band continuously meets the stability holding criteria and the duration reaches the stability holding duration, it registers the end timestamp of the stability holding window. During the period from the start timestamp to the end timestamp of the stability holding window, it keeps the mechanical sensor unloaded and the loading shaft locked. It binds the stability holding window to the segment number and registers the no-load holding segment interval number and the start and end timestamps of the no-load holding segment. Simultaneously, it writes the coverage of the cooling switching timestamp falling within the stability holding window into the no-load holding segment interval registration entry. Finally, it summarizes the segment number, the start and end timestamps of the stability holding window, and the no-load holding segment interval registration entries into a stability holding window list.

[0070] It should be noted that the stability holding criterion is used to determine that the target temperature has entered a stable holding state when the temperature fluctuation band and duration of the ultra-low temperature ambient temperature reading within the sliding time window meet the specified range (e.g., the temperature fluctuation band is less than 0.2℃ and the duration is greater than 300 seconds).

[0071] The target temperature stability constraint is used to determine that the target temperature enters the stability holding window when the temperature fluctuation band of the ultra-low temperature ambient temperature reading is continuously within the allowable range of the stability holding criterion within the sliding time window and the duration reaches the stability holding time.

[0072] S1.7: Based on the stable holding window list, divide the no-load holding segment and the load holding segment, alternately collect mechanical sensor data, and perform sampling integrity verification to generate holding sequence records;

[0073] Specifically, the system reads the stability holding window list and expands the start and end timestamps of the stability holding window and the registration entries for the no-load holding segment interval according to the segment number. It locks the no-load holding segment interval registration entries within each stability holding window as no-load holding segments, and locks the period from the end timestamp of the no-load holding segment to the end timestamp of the stability holding window as load holding segments, registering the corresponding segment type and segment number (e.g., no-load holding segment and load holding segment). During the no-load holding segment, the loading shaft is locked and the mechanical sensor is unloaded. Mechanical sensor data is continuously acquired at the sampling frequency recorded by the high sampling configuration and written to the timestamp and segment type marker. The load holding segment raises the loading axis to the target load according to the target value set of the load holding segment and keeps it unchanged. It continuously collects mechanical sensor data at the sampling frequency recorded by the high sampling configuration and writes it to the timestamp and segment type mark. The sampling integrity verification is performed on the collection segments of the no-load holding segment and the load holding segment. The sampling integrity verification includes timestamp monotonicity check, sample sequence number continuity check, segment start and end timestamp coverage check, and comparison check of the number of samples that should be obtained according to the sampling frequency. When the sampling integrity verification finds missing or duplicate, a missing mark or duplicate mark is written to the corresponding collection segment, and a holding sequence record is generated.

[0074] S1.8: Perform segmental seam verification and jump point labeling on the mechanical sensor data in the retained sequence record to generate the original load sequence.

[0075] Specifically, the adjacent boundaries of the unloaded and loaded segments are located by segment type. For each adjacent boundary, the sampling segments before and after the boundary are extracted. Inter-segment seam verification is performed and written to the seam marker. Inter-segment seam verification includes timestamp continuity verification, sample sequence number continuity verification, and boundary amplitude consistency verification. Boundary amplitude consistency verification involves calculating the mean band for the sampling segments before and after the boundary, calculating the difference between the two mean bands, and comparing it with the seam verification parameter set. If the difference exceeds the limit, a boundary time... Write a seam anomaly marker at the stamp (e.g., boundary difference greater than 0.5% of the range); within the mechanical sensor data entries that maintain the sequence record, calculate the difference between adjacent samples at a fixed sampling step size and form a difference sequence; perform jump point labeling on the difference sequence, which includes writing jump type markers for single-point abrupt changes and continuous abrupt changes respectively, and binding the timestamp and segment type marker corresponding to the jump point to the mechanical sensor data entries; encapsulate the mechanical sensor data entries with seam markers and jump point labels in timestamp order to generate the original load sequence.

[0076] It should be noted that the mechanical sensor data represents a sequence of load measurement values ​​continuously output by the mechanical sensor at the sampling frequency during the no-load holding segment and the load holding segment, and is marked with timestamps and sample sequence numbers. The data includes timestamps, sample sequence numbers, segment type markers, load measurement values, joint markers, joint anomaly markers, and jump type markers.

[0077] S2: Based on the preserved sequence record and the original load sequence, construct the drift baseline and register the drift mutation marker, perform zero-point drift subtraction and mutation segment removal, and generate a load displacement synchronization sequence;

[0078] S2.1: Based on the preserved sequence record and the original load sequence, lock the start and end timestamps of the unloaded preserved segment, and extract the static interval at the beginning and end of the segment, perform splicing and smoothing processing, and generate the drift baseline;

[0079] Specifically, the start and end timestamps of the unloaded holding segment are locked based on the start and end timestamps of the segment, and the corresponding sampling segments of the unloaded holding segment are located in the original load sequence according to the timestamps. Based on the parameter set of the static interval, the first and last static intervals are extracted from the sampling segments of the unloaded holding segment. The first static interval extracts a fixed-duration sampling segment starting from the start timestamp of the unloaded holding segment, and the last static interval extracts a sampling segment backwards from the end timestamp of the unloaded holding segment for a fixed duration (e.g., a fixed duration of 2 seconds). Jump point labeling and avoidance processing are performed on the first and last static intervals, and sampling points containing jump type markers are removed. Continuous valid sampling points are retained and the static interval numbers are registered. The static intervals are spliced ​​in the order of timestamps. The splicing position is weighted and fused using the boundary transition zone, and the splicing gaps are linearly filled according to the timestamps. The spliced ​​sequence is subjected to sliding time window mean smoothing and boundary slope transition processing, and the smoothing processing range is registered to generate the drift baseline.

[0080] S2.2: Perform zero-point stability check on the drift baseline, locate sudden rise and fall segments, register drift mutation markers, and generate a drift marker list;

[0081] Furthermore, the drift baseline is read and sliding time windows are divided according to timestamps. Within each sliding time window, the load mean and load fluctuation band are calculated. The difference between the load mean and the initial zero value registered in the coaxial zero-point record set is used to obtain the zero-point offset. When the zero-point offset exceeds the allowable offset band or the load fluctuation band exceeds the allowable fluctuation band, a zero-point stability anomaly mark is written (e.g., the allowable offset band is 0.3% of the range, and the allowable fluctuation band is 0.2% of the range). The difference between adjacent load sampling points is calculated point by point along the timestamps, and the continuous over-limit intervals in the same direction are located. The continuous over-limit intervals in the same direction are merged into sudden rise and fall segments, and the start and end timestamps, duration, and peak difference of the sudden rise and fall segments are registered (e.g., duration greater than 0.05 seconds). The overlapping part of the sudden rise and fall segments and the zero-point stability anomaly mark coverage area is merged and registered as a drift change mark, generating a drift mark list.

[0082] S2.3: Based on the drift marker list, map the drift baseline to the original load sequence, and perform zero-point drift subtraction and abrupt window annotation to generate abrupt window annotation list;

[0083] Specifically, sampling points are located and their sequence numbers are registered in the original load sequence according to the start and end timestamps. The drift baseline is aligned point by point with the original load sequence according to the timestamp. When the timestamps of the drift baseline and the original load sequence do not coincide, bidirectional interpolation is used to obtain the drift baseline value. When there is a gap in the drift baseline, the most recent valid drift baseline value is used and a gap mark is written in the gap interval. For each sampling point in the original load sequence, the difference between the load value of the original load sequence and the drift baseline value is calculated to form the zero-point drift deduction load value, while keeping the timestamp and segment type mark of the original load sequence unchanged. The start and end timestamps of the drift mutation mark entries are registered as the mutation window boundary and the mutation window range is obtained by expanding forward and backward according to the window expansion duration (e.g., expanding by 0.1 seconds). The mutation window range is bound to the sampling point sequence number range and registered as a mutation window label entry. When the coverage area of ​​the zero-point stability anomaly mark entry overlaps with the mutation window range, boundary merging is performed and the mutation window range is updated. All mutation window label entries are summarized in the order of timestamps to generate a mutation window label list.

[0084] It should be noted that the effective drift baseline value refers to the drift baseline value corresponding to the timestamp that is not covered by the gap marker and does not fall within the coverage area of ​​the zero-point stability anomaly marker entry.

[0085] S2.4: Based on the mutation window annotation list, perform mutation segment removal, extract displacement sampling data, perform bidirectional timestamp interpolation alignment and residual verification, and generate load displacement synchronization sequence.

[0086] Specifically, the corresponding timestamp interval is located in the original load sequence according to the abrupt change window range. Load sampling points falling within the abrupt change window range are marked for removal and removed from the original load sequence. Adjacent load sampling points on both sides of the abrupt change window range are retained as alignment boundaries. Displacement sampling data is exported from the acquisition channel, and the timestamp sequence of the displacement sampling data is retained. The timestamp sequence of the retained sampling points in the original load sequence is aligned with the timestamp sequence of the displacement sampling data through bidirectional timestamp interpolation. The bidirectional timestamp interpolation alignment includes interpolating the displacement sampling data based on the timestamps of the original load sequence to obtain the displacement alignment value. The process involves interpolating the original load sequence using the displacement sampling data timestamp as a reference to obtain load alignment values; calculating the difference between the load alignment values ​​and the load values ​​of the original load sequence at the overlapping timestamps to form residual entries; calculating the difference between the displacement alignment values ​​and the displacement values ​​of the displacement sampling data to form residual entries; performing residual verification on the residual entries according to the allowable residual band; writing alignment anomaly markers on sampling points corresponding to timestamps where the residuals exceed the allowable residual bands and removing them from the alignment output; and encapsulating the load sampling points that pass the residual verification with the corresponding displacement alignment values ​​in the order of timestamps to generate a load-displacement synchronization sequence.

[0087] The allowable residual band refers to the residual tolerance range determined by the range boundary calibration results in the acquisition preparation package and the background noise amplitude band recorded in the high sampling configuration. It is used to determine whether the residual item exceeds the limit (example range: displacement residual band is 0.2% to 1.0% of the range boundary, load residual band is 0.2% to 1.0% of the range boundary).

[0088] S3: Based on the load-displacement synchronization sequence, a micro-amplitude stress disturbance segment is inserted into the load holding segment. High-frequency mechanical signals are collected and the segment type is marked. At the same time, abrupt change threshold and a duration threshold are set to identify brittle fracture precursor events.

[0089] S3.1: Based on the load-displacement synchronization sequence, lock the load holding segment and insert a micro-stress disturbance segment, perform load holding steady-state verification, and generate a disturbance segment arrangement list;

[0090] Specifically, the load displacement synchronization sequence is read, and the load mean and load fluctuation band are calculated within the sliding time window. The continuous interval of the load fluctuation band that satisfies the load holding steady-state verification criterion is locked as the load holding segment, and the start and end timestamps of the load holding segment are recorded. Within the load holding segment, disturbance insertion times are selected at fixed intervals, and a steady-state buffer zone is reserved (referring to the reserved load holding timestamp interval before and after the micro-stress disturbance segment, used to re-verify the load holding steady-state verification criterion). The load mean corresponding to the disturbance insertion time is recorded as the load holding reference value. Micro-load upward and downward swings are performed around the load holding reference value, and the load holding steady-state verification criterion is maintained. A small-amplitude stress disturbance segment is formed by maintaining the duration of the disturbance. The start and end timestamps of the small-amplitude stress disturbance segment and the disturbance amplitude mark are recorded (for example, the disturbance amplitude is 0.5% to 2% of the load holding reference value, and the disturbance duration is 0.2 seconds to 1 second). The load holding steady-state verification criteria are re-verified between the steady-state buffer zones before and after the small-amplitude stress disturbance segment and written into the steady-state verification mark. If the steady-state verification mark is not met, the small-amplitude stress disturbance segment is written into the elimination mark and the next disturbance insertion time is used. The start and end timestamps of the load holding segment, the start and end timestamps of the small-amplitude stress disturbance segment, the disturbance amplitude mark and the steady-state verification mark are written into the disturbance segment arrangement list.

[0091] It should be noted that the load holding steady state verification criterion is used to determine that the load holding segment is in steady state when the load fluctuation band and load change amplitude of the load displacement synchronization sequence within the sliding time window are within a limited range (for example, the load fluctuation band is less than 0.2% of the load holding reference value and the load change amplitude is less than 0.1% of the load holding reference value).

[0092] S3.2: Based on the disturbance segment arrangement list, collect high-frequency mechanical signals and mark the segment types, while performing abnormal noise segment removal to generate a high-frequency acquisition segment set;

[0093] Specifically, high-frequency acquisition segment numbers are established based on the start and end timestamps of the load holding segment and the micro-stress disturbance segment, and these high-frequency acquisition segment numbers are bound to segment type and disturbance amplitude markers. Within the timestamp interval corresponding to each high-frequency acquisition segment number, the mechanical sensor output is acquired according to the sampling frequency recorded by the high-sampling configuration and written to the high-frequency acquisition timestamp. Simultaneously, the high-frequency acquisition segment number and segment type marker are written to each sampling point. For the high-frequency mechanical signal corresponding to each high-frequency acquisition segment number, the upper and lower amplitude limits are statistically analyzed within a sliding time window to form a noise amplitude band. This noise amplitude band is then compared with the background noise amplitude band recorded by the high-sampling configuration. An abnormal noise marker is written for the interval that exceeds the control multiple and the continuous duration of the excess reaches the set duration, and it is removed from the high-frequency acquisition segment number output (for example, the control multiple is 3 times and the set duration is 0.02 seconds). The high-frequency mechanical signal after removal is subjected to timestamp monotonicity check and sample sequence number continuity check and an integrity marker is written. The high-frequency mechanical signal with integrity marker is encapsulated according to the high-frequency acquisition segment number to generate a high-frequency acquisition segment set (referring to the set of traceable signal segments formed by encapsulating the high-frequency mechanical signal that has passed the abnormal noise removal and integrity check, together with the high-frequency acquisition timestamp, segment type marker and disturbance amplitude marker, according to the high-frequency acquisition segment number as the index).

[0094] S3.3: Extract the undisturbed stable interval from the high-frequency acquisition segments, register the background noise amplitude band and set the sudden change threshold and the continuous threshold, and at the same time perform the verification of the micro-amplitude stress disturbance segment to generate the threshold configuration sheet;

[0095] Furthermore, the high-frequency acquisition segment set is read and segment type markings are expanded according to the high-frequency acquisition segment number. Sampling segments marked as load-holding segments are extracted as candidate undisturbed stable intervals. Within these candidate undisturbed stable intervals, the upper and lower amplitude limits are statistically analyzed using a sliding time window to form noise amplitude bands. Time windows where the noise amplitude band exceeds the allowable fluctuation band are removed, and continuous valid time windows are retained and their start and end timestamps are recorded. Noise amplitude bands are summarized and statistically analyzed for all undisturbed stable intervals, and background noise amplitude bands are recorded. Abrupt change threshold and a persistence threshold are set based on the background noise amplitude bands. The abrupt change threshold is written as a multiple of the background noise amplitude band, and the persistence threshold is written as a continuous multiple. Continue writing the over-limit duration (e.g., the mutation threshold is 3 times the background noise amplitude band and the duration threshold is 0.02 seconds); read the sampling segments marked as micro-stress disturbance segments in the high-frequency acquisition segment concentration and compare them with the disturbance amplitude markings, calculate the peak-valley difference within the micro-stress disturbance segment and verify that the peak-valley difference falls within the coverage range of the disturbance amplitude markings, and at the same time verify that the adjacent undisturbed stable intervals before and after the micro-stress disturbance segment maintain a continuous and effective time window. Micro-stress disturbance segments that fail the verification are marked for removal and removed from the threshold setting basis. The background noise amplitude band, mutation threshold, duration threshold, undisturbed stable interval number and micro-stress disturbance segment verification mark are summarized into a threshold configuration sheet.

[0096] It should be noted that the verification of the micro-amplitude stress disturbance section is recorded as passing if the peak-to-valley difference falls within the coverage range of the disturbance amplitude mark and the adjacent undisturbed stable intervals before and after are continuously effective; otherwise, it is recorded as failing (for example, if the coverage range is 0.5% to 2%, a peak-to-valley difference of 0.3% is failing, while a peak-to-valley difference of 1.2% is passing).

[0097] S3.4: Based on the threshold configuration list, high-frequency mutation fragments are screened, and echo suppression segment rearrangement is performed to obtain brittle fracture precursor events.

[0098] Specifically, the abrupt change threshold and the duration threshold in the threshold configuration sheet are read. The high-frequency acquisition segment set is expanded according to the high-frequency acquisition segment number, and the high-frequency acquisition timestamp and segment type label are retained. Within the sliding time window, the difference amplitude between adjacent sampling points is calculated and compared with the abrupt change threshold. The interval where the difference amplitude continuously exceeds the abrupt change threshold and the continuous duration reaches the duration threshold is marked as a high-frequency abrupt change segment (for example, in the micro-stress disturbance segment, there is a timestamp interval lasting about 0.02 seconds, in which the difference amplitude between adjacent sampling points continuously exceeds the abrupt change threshold and forms a spike with the peak amplitude higher than the background noise amplitude). The event segment is recorded with the start and end timestamps and peak amplitude of the high-frequency mutation segment. The echo detection interval is extracted from the end of the high-frequency mutation segment, and the peak-valley alternation segment and amplitude decay trend are statistically analyzed. The end segment that satisfies the existence of the peak-valley alternation segment and the amplitude decaying over time is marked as the echo segment. The high-frequency mutation segment is divided into the main peak segment and the echo segment and rearranged according to the timestamp order. The main peak segment is retained, and the echo segment is subjected to segmented weighted decay and endpoint smoothing. The event number, event start and end timestamps, peak amplitude, high-frequency acquisition segment number and echo suppression mark are written into the brittle precursor event.

[0099] It should be noted that brittle fracture precursor events refer to failure precursor timestamp events that are screened by the abrupt change characteristics of high-frequency mechanical signals and confirmed by echo suppression within the load holding period or the micro-stress disturbance period. These events are used to mark the brittle fracture initiation risk window in advance and to provide a basis for solidifying and registering the brittle fracture initiation load range.

[0100] S4: Extract the elastic modulus and strength correlation interval from the load displacement synchronization sequence, and identify the brittle fracture initiation load interval by combining the brittle fracture precursor events, perform solidification registration, and generate a mechanical performance evaluation report.

[0101] S4.1: Combine brittle fracture precursor events with load-displacement synchronization sequences, perform fracture surface elimination and curve monotonic segment merging, construct load-displacement curves, and perform load peak point location to generate load-displacement curve records.

[0102] Specifically, the start and end timestamps and event numbers of the brittle fracture precursor events are read. These timestamps are mapped to the load-displacement synchronization sequence, and fracture labels are written into the corresponding timestamp intervals. Load sampling points and displacement sampling points with fracture labels are removed from the load-displacement synchronization sequence, while adjacent sampling points are retained as connection points at the removal boundaries. The removed load-displacement synchronization sequence is segmented according to the increasing direction of displacement sampling points. Intervals where displacement sampling points regress or stagnate are marked with non-monotonic markers and removed from the load-displacement synchronization sequence, retaining continuously increasing intervals of displacement sampling points as monotonic segments. The connection points of adjacent monotonic segments are then processed. Displacement continuity is checked against load continuity. When the displacement difference and load difference fall within the allowable connection zone, adjacent monotonic segments are merged into the same monotonic segment and a merge number is written. If the allowable connection zone is not met, a breakpoint mark is written at the connection point. The merged monotonic segments are spliced ​​together in the order of timestamps to form a load-displacement curve. Transition zone weighted fusion and endpoint smoothing are performed at the splicing point. The load sampling points are traversed along the load-displacement curve, and the timestamp and displacement sampling point corresponding to the maximum load value are located as the load peak point. The breakpoint label coverage area, monotonic segment merge number, breakpoint mark, and load peak point are written together into the load-displacement curve record.

[0103] S4.2: Extract monotonically increasing segments from the load-displacement curve record and remove abnormal displacement segments, extract the intervals related to elastic modulus and strength, perform linear window progressive trimming, and generate an interval extraction list;

[0104] Specifically, the load-displacement curve records are read and the differences between adjacent displacements and loads are checked point by point along the timestamps. Continuous intervals with positive displacement and load differences are grouped into monotonically increasing segments and their start and end timestamps are recorded. Within the monotonically increasing segments, continuous intervals with displacement regression, displacement stagnation, or displacement jumps are marked as abnormal displacement segments and removed (e.g., a displacement jump is marked when the difference between adjacent displacements is greater than 0.2 mm), retaining continuous valid intervals. Within the continuous valid intervals, the intervals related to elastic modulus and strength are extracted. These intervals include the elastic segment near the displacement start point and the strength segment near the load peak point. For the strength segment, a linear window progressive clipping is performed. The linear window progressive clipping involves fixing the linear window length and moving the window boundary by a fixed step size. Within each linear window, a linear relationship between load and displacement is established, and the deviation amplitude band is statistically analyzed. The linear window with the smallest deviation amplitude band is retained as the elastic modulus interval (e.g., the linear window length is 0.5 seconds and the step size is 0.05 seconds). For the strength segment, the strength-related interval is truncated by moving backward from the load peak point and avoiding abnormal displacement segments. The start and end timestamps of the monotonically rising segments, the start and end timestamps of the abnormal displacement segments, the start and end timestamps of the elastic modulus interval, and the start and end timestamps of the strength-related interval are written into the interval extraction list.

[0105] It should be noted that the linear window progressive pruning converts the window length and step size into the number of window points and step size based on the sampling frequency in the high sampling configuration record, and fixes the rounding rule as "the number of window points is the number of points corresponding to the sampling frequency and the window length, and the number of step size is the number of points corresponding to the sampling frequency and the step size".

[0106] S4.3: Based on the interval extraction list, the brittle fracture precursor events are mapped to the load-displacement curve, and the inter-segment repetitive events are merged to identify the brittle fracture initiation load interval, perform solidification registration, and generate a mechanical performance evaluation report.

[0107] Specifically, the event start and end timestamps are mapped to the timestamp index of the load-displacement curve, and the covered load sampling points and displacement sampling points are located. Event number markers are written in the coverage area. The event number markers are sorted by timestamp, and event number markers with overlapping timestamp intervals or timestamp intervals smaller than the merging interval are merged and the merged event start and end timestamps are updated (e.g., the merging interval is 0.01 seconds). The merged event start and end timestamps are superimposed with the start and end timestamps of the strength-related interval to locate the load sampling points in the common coverage area. The starting timestamp where the load changes from rising to falling is located along the common coverage area from the starting timestamp and is used as the termination boundary of the brittle fracture initiation load area. The load value range corresponding to the starting timestamp and termination boundary of the common coverage area is registered as the brittle fracture initiation load area. The timestamp boundary, load value range, and corresponding displacement value range of the brittle fracture initiation load area are written into the solidified registration, and the interval extraction list, brittle fracture precursor events, load-displacement curves, and solidified registration are summarized into a mechanical performance evaluation report.

[0108] In summary, this invention achieves dynamic correction of thermally induced zero-point drift by constructing a drift baseline and eliminating abrupt changes, thus ensuring the intrinsic accuracy of load displacement data and laying a reliable test data foundation for new material-related services. By embedding micro-amplitude stress disturbances and setting a dual-threshold recognition mechanism during the load holding phase, it achieves the active excitation and effective identification of brittle fracture precursor events, thereby improving the reliability of cryogenic mechanical test data and the ability to quantitatively assess the failure process.

[0109] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments, characterized in that: include, The resin-based composite material sample was pretreated, the mechanical parameter acquisition configuration was initialized, and the resin-based composite material sample was subjected to segmented cooling and stable holding in an ultra-low temperature environment. At the same time, mechanical sensor data was collected alternately in the no-load holding segment and the load holding segment to generate holding sequence records and original load sequences. Based on the preserved sequence record and the original load sequence, a drift baseline is constructed and drift mutation markers are registered. Zero-point drift deduction and mutation segment removal are performed to generate a load displacement synchronization sequence. Based on the load-displacement synchronization sequence, a micro-amplitude stress disturbance segment is inserted into the load holding segment. High-frequency mechanical signals are collected and the segment type is marked. At the same time, abrupt change threshold and a duration threshold are set to identify brittle fracture precursor events. The elastic modulus and strength correlation intervals are extracted from the load-displacement synchronization sequence, and the brittle fracture initiation load interval is identified by combining the brittle fracture precursor events. The solidification registration is carried out, and a mechanical performance evaluation report is generated.

2. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 1, characterized in that: The specific steps for initializing the mechanical parameter acquisition and configuration are as follows. The coaxiality of the sensitive axis and the loading axis of the mechanical sensor is checked and finely adjusted for alignment. The initial zero point value is recorded, and a coaxial zero point record set is obtained. Based on the coaxial zero-point record set, a high sampling frequency is configured, and timestamp synchronization verification and background noise registration are performed to generate a high sampling configuration record; The zero-point saturation warning threshold is verified for the high sampling configuration record, and the zero-point saturation warning status is recorded. At the same time, the range boundary is calibrated to obtain the mechanical parameter acquisition configuration.

3. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 2, characterized in that: The specific steps for performing segmented cooling and stabilization on resin-based composite material samples in an ultra-low temperature environment are as follows. According to the mechanical parameters collected and configured, the signal line connection, synchronous verification and segmented cooling were performed in the ultra-low temperature environment. The cooling switching timestamp was recorded, the stability of the clamping body was monitored and the gas circulation status was checked, and a segmented cooling process record was generated. Based on the segmented cooling process sheet, target temperature stability constraints are applied, and the stability holding window is locked to register the no-load holding segment interval, generating a stability holding window list.

4. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 3, characterized in that: The specific steps for generating the preserved sequence record and the original payload sequence are as follows. Based on the stable holding window list, the system is divided into no-load holding segment and load holding segment. Mechanical sensor data is collected alternately, and the sampling integrity is verified to generate a holding sequence record. Perform segmental seam verification and jump point labeling on the mechanical sensor data in the retained sequence record to generate the original load sequence.

5. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 4, characterized in that: The specific steps for constructing a drift baseline and registering drift mutation markers based on the preserved sequence records and the original payload sequences are as follows. Based on the preserved sequence record and the original load sequence, the start and end timestamps of the unloaded preserved segment are locked, and the static intervals at the beginning and end of the segment are extracted, spliced ​​and smoothed to generate the drift baseline. Perform zero-point stability checks on the drift baseline, locate sudden rises and falls, register drift mutation markers, and generate a drift marker list.

6. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 5, characterized in that: The specific steps for generating the load-displacement synchronization sequence are as follows. Based on the drift marker list, the drift baseline is mapped to the original payload sequence, and zero-point drift subtraction and abrupt window annotation are performed to generate abrupt window annotation list; Based on the mutation window annotation list, mutation segment removal is performed, displacement sampling data is extracted, and timestamp bidirectional interpolation alignment and residual verification are performed to generate a load displacement synchronization sequence.

7. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 6, characterized in that: The method based on load-displacement synchronization sequence involves inserting a micro-amplitude stress disturbance segment into the load holding segment, acquiring high-frequency mechanical signals, and labeling the segment type. The specific steps are as follows: Based on the load-displacement synchronization sequence, the load holding segment is locked and a micro-amplitude stress disturbance segment is inserted. The load holding steady-state verification is performed, and a disturbance segment arrangement list is generated. Based on the disturbance segment arrangement list, high-frequency mechanical signals are collected and segment types are marked. At the same time, abnormal noise segments are removed to generate a high-frequency acquisition segment set.

8. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 7, characterized in that: The specific steps for setting mutation and persistence thresholds to identify brittle fracture precursor events are as follows. Extract the undisturbed stable interval from the high-frequency acquisition segments, register the background noise amplitude band and set the sudden change threshold and the continuous threshold, and at the same time perform the verification of the micro-amplitude stress disturbance segment to generate a threshold configuration sheet; Based on the threshold configuration list, high-frequency mutation fragments are screened, and echo suppression segment rearrangement is performed to obtain brittle fracture precursor events.

9. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 8, characterized in that: The specific steps for generating the mechanical performance evaluation report are as follows. By combining brittle fracture precursor events with load-displacement synchronization sequences, fracture surface elimination and curve monotonic segment merging are performed to construct load-displacement curves, and load peak point location is performed to generate load-displacement curve records. Extract monotonically increasing segments from the load-displacement curve record and remove abnormal displacement segments. Extract the intervals related to elastic modulus and strength, perform linear window progressive trimming, and generate an interval extraction list. Based on the interval extraction list, brittle fracture precursor events are mapped to load-displacement curves, and inter-segment repetitive events are merged to identify the brittle fracture initiation load interval, perform solidification registration, and generate a mechanical performance evaluation report.

10. The method for evaluating the mechanical properties of resin-based composite materials in ultra-low temperature environments as described in claim 1, characterized in that: The pretreatment includes end face cleaning, parallelism verification, and graded pre-tightening clamping calibration.

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