Test system and method for testing the combustion and mechanical coupling properties of a textile

Abstract

The present application relates to a test system and method for textile combustion and mechanical coupling performance test, and belongs to the technical field of fabric test, the system comprises: a test box body, a test space is formed in the inside, and an observation window is arranged; a visible light measuring unit is arranged outside the observation window and is used for collecting visible light images of the combustion process of a test sample; an infrared thermal imaging unit is arranged outside the observation window and is used for collecting infrared temperature field information of the combustion process of the test sample; a endoscopic observation unit is arranged in the observation window and is used for acquiring image information of a local area of the test sample; a top servo drive clamping system comprises a test sample clamping assembly, a locking assembly, a driving assembly, an angle encoder and a torque sensor; a data analysis and control unit is used for synchronously fusing and analyzing the data collected by each unit. The present application combines visible light measurement, infrared thermal imaging and endoscopic observation, and realizes multi-modal synchronous monitoring of flame propagation, temperature field distribution and local damage evolution in the combustion process.

Description

Technical Field

[0001] This invention relates to the field of fabric testing technology, specifically to a test system and method for testing the combustion and mechanical coupling properties of textiles. Background Technology

[0002] Afterflame time, smoldering time, and damage length are core indicators for evaluating the flame retardant performance of fabrics. Currently, in practice, these parameters are mainly obtained through manual testing, often using manual readings or single video analysis. However, this traditional testing method is highly subjective, and the results are easily influenced by the operator's subjective judgment. Furthermore, it cannot simultaneously analyze the mechanical failure behavior of the material after combustion, resulting in low measurement accuracy, poor repeatability, and the inability to obtain thermal state information during combustion. Flame retardant performance testing is particularly crucial for protective textiles such as fire suits and forest fireproof clothing, directly impacting the life, health, and safety of users. Human observation errors can lead to misjudgments of protective performance, resulting in significant safety hazards.

[0003] Therefore, there is an urgent need for a multi-parameter fusion testing system that can simultaneously monitor combustion behavior and test mechanical failure, enabling correlation analysis between combustion behavior and mechanical failure behavior, thereby improving testing efficiency, result accuracy, and data consistency and traceability. Summary of the Invention

[0004] The purpose of this invention is to provide a test system and method for testing the combustion and mechanical coupling properties of textiles, which can solve the technical problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides a test system for testing the combustion and mechanical coupling properties of textiles, comprising: a test chamber, a visible light measurement unit, an infrared thermal imaging unit, an endoscopic observation unit, a top servo-driven clamping system, and a data analysis and control unit; the test chamber forms a closed test space, and the test chamber is provided with an observation window; the visible light measurement unit is disposed outside the observation window for acquiring visible light image information of the sample combustion process; the infrared thermal imaging unit is disposed outside the observation window for acquiring infrared temperature field information of the sample combustion process; the endoscopic observation unit is disposed inside the observation window, with its probe facing the sample, for acquiring image information of a local area of ​​the sample; and a top servo-driven clamping system... The holding system is connected inside the test chamber and includes a sample clamping assembly, a locking assembly, a driving assembly, an angle encoder, and a torque sensor. The sample clamping assembly includes a left clamping arm and a right clamping arm. The locking assembly is used to lock or unlock the sample clamping assembly. The driving assembly is used to drive the left and right clamping arms to rotate in opposite directions around a set axis. The angle encoder is used to detect the rotation angle and angular velocity, and the torque sensor is used to detect the torque. The data analysis and control unit is electrically connected to the visible light measurement unit, the infrared thermal imaging unit, the endoscopic observation unit, and the top servo drive clamping system, respectively, for synchronously fusing and analyzing the data collected by each unit.

[0006] In a preferred embodiment, the optical axis of the visible light measurement unit passes through the central region of the sample and forms an angle with the sample normal direction, and the optical axis of the infrared thermal imaging unit passes through the central region of the sample and forms an angle with the sample normal direction. The visible light measurement unit and the infrared thermal imaging unit are respectively disposed on both sides of the central projection region of the sample.

[0007] In a preferred embodiment, the endoscopic observation unit includes a high-temperature resistant industrial endoscope probe, which is arranged laterally or at an angle inside the test chamber, and there is a gap between the endoscope probe and the sample surface.

[0008] In a preferred embodiment, the data analysis and control unit uses a unified time reference to synchronously control the visible light measurement unit, infrared thermal imaging unit, endoscopic observation unit, angle encoder, and torque sensor, thereby achieving synchronous acquisition and timestamp marking of visible light images, infrared thermal images, endoscopic images, temperature signals, torque signals, and angle signals.

[0009] In a preferred embodiment, the visible light measurement unit includes an industrial camera, a low-distortion lens, an illumination assembly, and a calibration reference structure, wherein the calibration reference structure is located near the sample and is on the same observation plane as the sample.

[0010] A second aspect of the present invention provides a testing method based on the aforementioned testing system, comprising the following steps: S1, fix the sample in the sample clamping assembly of the top servo drive clamping system, activate the locking assembly to make the clamping structure in a rigid locking state, and simultaneously activate the visible light measurement unit, infrared thermal imaging unit and endoscopic observation unit. S2, Perform a combustion test. The visible light measurement unit acquires visible light image information of the sample combustion process, the infrared thermal imaging unit acquires infrared temperature field information of the sample combustion process, and the endoscopic observation unit acquires image information of a local area of ​​the sample. The data analysis and control unit calculates the afterflame time, smoldering time, damage length, and melting dripping behavior based on the acquired data. S3, after the combustion stage ends, the data analysis and control unit sends an unlocking command to the locking component to release the clamping structure constraint; S4, the drive assembly is activated, driving the left and right clamping arms of the sample clamping assembly to rotate in opposite directions around a set axis, applying a tearing load to the burned sample; the data analysis and control unit adjusts the output of the drive assembly according to the feedback signals of the angle encoder and the torque sensor to achieve closed-loop control; S5, the data analysis and control unit performs synchronous fusion analysis on the visible light image, infrared temperature field information, endoscopic observation image, rotation angle and torque data to generate test results.

[0011] In a preferred embodiment, in S1, a calibration reference structure is set at a position near the sample, and the visible light measurement unit acquires a calibration image. The data analysis and control unit establishes a length conversion coefficient based on the actual size of the calibration structure and the corresponding pixel size in the image.

[0012] In a preferred embodiment, in S2, flame outline, flame area, flame height, flame propagation path, and carbonization boundary feature information are extracted using an image recognition algorithm; molten dripping behavior is detected using a moving target recognition algorithm and dripping time, number of drips, and dripping trajectory are recorded; ablation boundary, carbonization boundary, or tearing boundary is extracted using an edge recognition algorithm and converted into actual damage length according to the length conversion coefficient.

[0013] In a preferred embodiment, in S2, after the ignition source is removed, the data analysis and control unit identifies the flame region features based on the visible light image, records the time of ignition source removal, records the time of complete flame extinguishing when the flame features completely disappear, and calculates the afterflame time based on the ignition source removal time and the time of complete flame extinguishing; when no flame features are detected in the visible light image and the temperature of the monitored area in the infrared temperature field is higher than a set threshold, the sample is determined to be in a smoldering state; when the temperature remains below the set threshold, the smoldering is determined to end, and the smoldering duration is calculated based on the smoldering start time and smoldering end time; the crack initiation location and propagation path are identified through image difference algorithm, edge recognition algorithm, and feature point tracking algorithm, and the crack propagation rate is calculated based on the crack length and corresponding time at different times.

[0014] In a preferred embodiment, in S4, the data analysis and control unit adjusts the output power of the drive component according to the real-time feedback torque signal to keep the angular velocity within a set range; the data analysis and control unit establishes an equivalent conversion model between heavy hammer loading, manual loading and rotational loading, calculates the standard loading energy according to the heavy hammer mass, gravitational acceleration and heavy hammer release height specified in the standard test method, and determines the target rotational angular velocity and target output torque of the clamping arm according to the target loading energy and target loading rate.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention combines visible light measurement, infrared thermal imaging, and endoscopic observation to achieve multimodal synchronous monitoring of flame propagation, temperature field distribution, and local damage evolution during combustion. Through the locking and counter-rotating tearing mechanism of the top servo-driven clamping system, continuous automatic switching between combustion testing and mechanical tearing testing at the same station is achieved, avoiding errors caused by sample transfer. Real-time feedback and closed-loop control of the angle encoder and torque sensor enable adaptive and precise control of the tearing loading process. Synchronous fusion of multi-source data along a unified time axis establishes a direct correlation between combustion behavior and mechanical failure behavior, enabling automated calculation of afterflame time, smoldering time, damage length, number of melt drips, and crack propagation parameters. This significantly improves the repeatability of test results, data consistency, and the reliability of coupled analysis. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the experimental system in an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the test system in an embodiment of the present invention.

[0017] The meanings of the labels in the diagram are as follows: 1. Test chamber; 2. Visible light measurement unit; 3. Infrared thermal imaging unit; 4. Endoscopic observation unit; 5. Top servo-driven clamping system; 51. Left clamping arm; 52. Right clamping arm. 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] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] See Figures 1-2 This embodiment discloses a test system for testing the combustion and mechanical coupling properties of textiles. The system includes a test chamber 1, a visible light measurement unit 2, an infrared thermal imaging unit 3, an endoscopic observation unit 4, a top servo drive clamping system 5, and a data analysis and control unit.

[0021] The test chamber 1 serves as the main load-bearing structure of the entire system, integrating various functional modules and providing a closed test environment for combustion and mechanical failure testing. Test chamber 1 effectively isolates external airflow, temperature, humidity, and light interference, thereby ensuring the stability and repeatability of the combustion process and thermal field distribution test results. The data analysis and control unit is electrically connected to the visible light measurement unit 2, the infrared thermal imaging unit 3, the endoscopic observation unit 4, and the top servo drive clamping system 5, respectively. Through interlocking control, it automates the test process, performing sequential control and data acquisition for the entire process of combustion testing, state switching, and tear testing.

[0022] Specifically, the test chamber 1 is constructed as a rectangular box structure, forming an independent and enclosed test space to facilitate the installation and arrangement of various measuring equipment. Openable transparent observation doors are provided on both sides of the test chamber 1, preferably made of heat-resistant and smoke-resistant tempered glass, allowing operators to observe the internal test status in real time and perform equipment maintenance, while ensuring the light transmission requirements for visible light and infrared measurements. Multiple equipment mounting interfaces are provided on the side walls and top of the test chamber 1 for fixing the visible light measurement unit 2, the infrared thermal imaging unit 3, and the endoscopic observation unit 4. A sealed wiring structure is also provided for the transmission of control signals and data. The test chamber 1 also contains a sample mounting rack to support the top servo-driven clamping system 5 and the test sample.

[0023] The visible light measurement unit 2 is located outside the observation window on the front of the test chamber 1, and on one side of the central projection area of ​​the sample. Its optical axis passes through the central area of ​​the sample and forms an angle of 10° to 45° with the normal direction of the sample, preferably 20° to 35°. The distance between the visible light measurement unit 2 and the observation window is preferably 50 to 200 mm, more preferably 80 to 150 mm; the distance between it and the center of the sample is preferably 200 to 350 mm, more preferably 235 to 305 mm. To form the above observation angle, the visible light measurement unit 2 is laterally offset along the plane of the observation window relative to the central projection position of the sample. The offset distance is preferably 80 to 220 mm, more preferably 100 to 180 mm. This setting makes the optical axis obliquely point towards the central area of ​​the sample, thereby taking into account the overall flame morphology acquisition, edge recognition, and avoiding the obstruction of the image by the bright areas of the flame. The visible light measurement unit 2 includes an industrial camera, a low-distortion lens, an illumination component, an image acquisition module, and a calibration reference structure. The optical axis of the aforementioned visible light measurement unit 2 is the optical central axis of the industrial camera lens, which is formed by extending from the optical center of the lens along the center of the lens's field of view. A high-resolution industrial camera ensures clear capture of rapid dynamic changes during combustion. A low-distortion lens is used to reduce the impact of image edge distortion on measurement accuracy, and the illumination assembly provides uniform and stable visible light illumination conditions inside the test chamber 1, ensuring consistent brightness in image acquisition.

[0024] The infrared thermal imaging unit 3 is also located outside the observation window on the front of the test chamber 1, on the other side of the central projection area of ​​the sample. Its optical axis passes through the central area of ​​the sample. The optical axis of the infrared thermal imaging unit 3 is the optical central axis of the infrared lens, forming an angle of 20° to 45° with the normal direction of the sample, preferably 25° to 40°. The distance between the infrared thermal imaging unit 3 and the observation window is preferably 50 to 300 mm, more preferably 100 to 200 mm; the distance between it and the center of the sample is preferably 250 to 400 mm, more preferably 280 to 350 mm. To form the above observation angle, the infrared thermal imaging unit 3 is laterally offset along the plane of the observation window relative to the central projection position of the sample. The offset distance is preferably 100 to 250 mm, more preferably 120 to 220 mm. The infrared thermal imaging unit 3 is preferably an industrial-grade infrared thermal imager to capture the dynamic changes in the temperature field during the combustion process in real time.

[0025] The infrared thermal imaging unit 3 and the visible light measurement unit 2 are arranged with different observation angles to reduce field-of-view interference between the devices and the impact of flame thermal radiation reflection on the temperature measurement results, while ensuring a high degree of overlap between the temperature field measurement area and the visible light observation area. The oblique observation method ensures clear imaging of the overall sample outline while also taking into account the observation of sample edge areas and localized damaged areas, reducing the impact of flame obstruction, smoke interference, and observation window reflection on image quality, and improving the accuracy of identifying damage length, crack propagation, and melt dripping behavior. The visible light measurement unit 2, as the main observation unit of the system, establishes an image coordinate system that also serves as a reference coordinate system for multi-source data fusion analysis, providing a unified benchmark for subsequent correlation analysis of temperature field data, crack propagation data, and mechanical response data.

[0026] The endoscopic observation unit 4 is located inside the observation window on the front of the test chamber 1, with its probe facing the center of the sample. The optical axis of the endoscope forms an angle of 0° to 30° with the normal direction of the sample, preferably 10° to 20°, and the optical axis of the endoscope is the optical central axis of the industrial endoscope objective. The distance between the tip of the endoscope probe and the sample surface is preferably 20 to 100 mm, more preferably 30 to 60 mm. To form a close-range oblique observation angle, the endoscope probe is laterally offset along the observation window plane relative to the center projection position of the sample, with an offset distance preferably 5 to 25 mm, more preferably 10 to 20 mm. The endoscopic observation unit 4 includes a high-temperature resistant industrial endoscope probe and a light source system, wherein the high-temperature resistant industrial endoscope probe is arranged inside the test chamber 1 by side or tilting insertion to monitor a local area of ​​the sample in real time. The endoscopic observation unit 4 employs a close-range, high-magnification observation method, enabling it to obtain localized microscopic damage information that is difficult to identify with ordinary industrial cameras. This includes processes such as fiber breakage, crack initiation, localized carbonization, material softening, melt shrinkage, and carbonized layer peeling. The images acquired by the endoscope can be synchronously correlated and analyzed with visible light images and infrared thermographic data, achieving refined observation of the evolution of localized damage during combustion and providing high-resolution data support for identifying key failure events and studying material failure mechanisms. Specifically, the data analysis and control unit performs synchronous correlation analysis on visible light images, infrared thermographic data, and endoscopic images based on a unified time reference. More specifically, the system first establishes a one-to-one correspondence between the three types of image data based on a unified timestamp, forming corresponding data sets from visible light images, infrared thermographic images, and endoscopic images acquired at the same time. Subsequently, according to pre-established spatial calibration parameters, the three types of imaging data are uniformly mapped to the same sample coordinate system, achieving positional correspondence between images from different perspectives. Based on this, the image processing module of the data analysis and control unit extracts the flame outline, flame propagation path, combustion boundary, and molten dripping target from the visible light image, extracts the temperature distribution, hot spot area, and temperature gradient information from the infrared thermogram, and extracts local damage features such as fiber breakage, crack initiation, local charring, melting shrinkage, and char layer peeling from the endoscopic image. The data analysis and control unit further fuses and analyzes the flame state, temperature changes, and local damage features acquired at the same location and time based on temporal and spatial correspondences. For example, when the visible light image identifies the flame front propagating to a certain area, the infrared temperature change of the corresponding area is simultaneously read, and combined with the endoscopic image analysis, it is determined whether crack initiation, fiber breakage, or char layer peeling has occurred in that area, thereby establishing a correspondence between combustion behavior, thermal response, and material damage evolution. Finally, the system generates flame propagation curves, temperature change curves, local damage evolution curves, and time series of key failure events based on the time-varying patterns of various features, providing multimodal data support for the analysis of material combustion failure mechanisms.

[0027] The top servo-driven clamping system 5 is connected to the sample mounting rack inside the test chamber 1. It is used to fix the sample during the combustion test and to apply a controlled counter-rotating tearing load to the sample after combustion. Specifically, the top servo-driven clamping system 5 includes a servo motor, a reduction mechanism, an electromagnetic brake assembly, an angle encoder, a torque sensor, a sample clamping assembly, and a motion control module. The servo motor provides rotational power; the reduction mechanism converts high-speed, low-torque output to low-speed, high-torque output; the electromagnetic brake assembly rigidly locks the clamping structure during the combustion test; the angle encoder detects the rotation angle and angular velocity of the clamping arms in real time; the torque sensor monitors the resistance changes generated during the sample tearing process; and the motion control module implements motion control and feedback adjustment. The sample clamping assembly includes a left clamping arm 51 and a right clamping arm 52, which can rotate counter-rotate around a set axis under the drive of the servo motor, thereby applying a tearing force to the sample. During the combustion test, the electromagnetic brake assembly is locked, keeping the sample clamping assembly fixed and providing stable boundary conditions for the sample. During combustion, the sample may experience thermal shrinkage, curling, bulging, or localized warping due to heat. The electromagnetic brake assembly effectively suppresses displacement of the clamping structure, ensuring consistent combustion conditions. Once the system determines the combustion stage is complete, the data analysis and control unit sends an unlocking command to the electromagnetic brake assembly, releasing the clamping structure constraints and allowing the sample clamping assembly to gain rotational freedom and enter the subsequent mechanical testing stage. In this embodiment, the electromagnetic brake assembly can be an existing industrial electromagnetic brake or electromagnetic de-energizer; the specific model is not limited, as long as it can lock and unlock the clamping assembly. The sample clamping assembly can use existing mechanical clamping structures, including clamping plates, clamping blocks, clamping screws, or elastic clamping mechanisms; the specific structure is not limited, as long as it can stably clamp the sample.

[0028] After combustion, the system drives the left clamping arm 51 and right clamping arm 52 of the sample clamping assembly to rotate in opposite directions around a set axis, thereby applying a tearing load to the burned sample. The angle encoder provides real-time feedback of the rotation angle θ and angular velocity ω, and the torque sensor provides real-time feedback of the output torque M. The motion control module compares the real-time feedback values ​​with the set target values ​​and automatically adjusts the servo motor output to achieve closed-loop control of angular velocity and torque.

[0029] The relationship between torque and tearing force is as follows: M = F × r; Where M is the output torque, F is the tearing force acting on the sample, and r is the vertical distance between the line of force action of the sample and the rotation center axis of the clamping arm, i.e., the torque arm.

[0030] The data analysis and control unit automatically adjusts the output power based on real-time torque detection to maintain the angular velocity within a set range, thereby achieving stable loading. By setting different angular velocities, torque thresholds, and loading curves, it can simulate standard hammer loading, manual tearing, and other specified loading conditions. During the test, the system simultaneously records rotation angle, angular velocity, torque changes, and time data, and generates angle-time curves, torque-time curves, and damage evolution curves, thereby enabling a quantitative evaluation of the structural integrity of the material after combustion.

[0031] The data analysis and control unit is located outside the test chamber 1 and includes a data acquisition module, a clock synchronization module, an image processing module, a signal analysis module, an event determination module, a parameter calculation module, a result output module, and a safety control module. The data acquisition module is responsible for acquiring data from industrial cameras, infrared thermal imagers, endoscopes, angle encoders, and torque sensors, and for buffering and unified management of this data. The clock synchronization module provides a unified time reference, synchronizes the triggering of each imaging device and sensor, and adds a unified timestamp to the acquired data. The image processing module is responsible for image preprocessing, noise reduction, image enhancement, edge recognition, target detection, flame recognition, charred area recognition, and crack recognition. The signal analysis module is responsible for filtering, curve fitting, feature extraction, and trend analysis of temperature, angle, and torque signals. The event determination module automatically determines key events such as ignition start, flame extinguishing, smoldering start, smoldering end, droplet formation, and crack initiation based on image features and temperature changes. The parameter calculation module calculates test parameters such as afterflame time, smoldering time, damage length, crack propagation rate, flame propagation speed, maximum temperature, and maximum torque based on the collected data. The result output module generates test reports, image records, data curves, and test results, and supports data storage and export. The safety control module is linked to each execution unit, including the ventilation system, emergency stop device, and overload protection device, to achieve safety control during the test. The data analysis and control unit is connected to the visible light measurement unit 2, the infrared thermal imaging unit 3, the endoscopic observation unit 4, and the top servo drive clamping system 5, respectively. During the test, the data analysis and control unit uses a unified time base to synchronously control each sensor and imaging device, realizing the synchronous acquisition and timestamp marking of visible light images, infrared thermal images, endoscopic images, temperature signals, torque signals, and angle signals, thereby establishing a correspondence between multi-source data. The system can ensure that image information, temperature information, and mechanical information are matched at any given time, realizing synchronous analysis of combustion behavior and structural failure behavior.

[0032] Based on the test system provided in the foregoing embodiments, this embodiment also provides a method for testing the combustion and mechanical coupling properties of textiles, including the following steps: S1, fix the sample in the sample clamping assembly of the top servo drive clamping system 5, activate the electromagnetic brake assembly to put the clamping structure in a rigid locking state, and simultaneously activate the visible light measurement unit 2, infrared thermal imaging unit 3 and endoscopic observation unit 4 to monitor the sample combustion process in real time.

[0033] Specifically, before the test begins, the operator cuts the sample to be tested to the specified size and clamps both ends of the sample using the left clamping arm 51 and the right clamping arm 52 of the sample clamping assembly, ensuring that the sample is flat and wrinkle-free in the width direction. After the sample is clamped, the data analysis and control unit sends a locking command to the electromagnetic brake assembly, which is then energized and engages, placing the clamping structure in a rigid locked state. Simultaneously, the visible light measurement unit 2, the infrared thermal imaging unit 3, and the endoscopic observation unit 4 are activated to monitor the sample combustion process in real time. Before the test begins, a calibration reference structure is set up near the sample. The calibration reference structure is preferably a graduated scale, grid calibration plate, or feature mark plate with known dimensions. The calibration reference structure is located on the same or approximately the same observation plane as the sample to reduce the influence of perspective error on the measurement results.

[0034] The visible light measurement unit 2 first acquires a calibration image. The data analysis and control unit identifies the pixel length P corresponding to the calibration structure and establishes a length conversion coefficient K=L / P based on its actual length L, where K is the length conversion coefficient (mm / pixel). In a preferred embodiment, the system can also combine camera intrinsic parameter calibration, lens distortion correction, and perspective compensation algorithms to correct the measurement results, establish a precise mapping relationship between image space and actual physical space, and realize the automatic calculation of parameters such as damage length, crack length, and carbonization length, thereby improving the accuracy, repeatability, and traceability of the test results.

[0035] S2, perform combustion test, collect visible light image information of the sample combustion process through visible light measurement unit 2, collect infrared temperature field information of the sample through infrared thermal imaging unit 3, and obtain local image information of local crack propagation and material softening process of the sample through endoscopic observation unit 4. The data analysis and control unit automatically calculates afterflame time, smoldering time, damage length and melt dripping behavior based on the collected data.

[0036] Specifically, the ignition source exposes the sample to flame for the duration specified in the standard. During the combustion test, the visible light measurement unit 2, the infrared thermal imaging unit 3, and the endoscopic observation unit 4 are activated simultaneously to monitor the combustion process in real time.

[0037] The visible light measurement unit 2 continuously acquires visible light image data during the sample combustion process and transmits it in real time to the data analysis and control unit for processing. The data analysis and control unit extracts feature information such as flame outline, flame area, flame height, flame propagation path, and charring boundary using image recognition algorithms; identifies crack initiation locations and propagation processes using edge detection and feature tracking algorithms; and detects molten dripping behavior and records dripping time, number of drips, and dripping trajectory using moving target recognition algorithms. Simultaneously, it automatically calculates the damaged length and damaged area based on calibration results.

[0038] For identifying molten dripping behavior, the system continuously detects moving targets in the area below the sample using visible light images. When a bright target or molten material detaches from the sample and moves downwards, the system automatically records the time, location, and number of drips. The drip trajectory is analyzed using a continuous frame target tracking algorithm, and the drip size parameters are calculated based on changes in the target area. When multiple independent detached targets are detected per unit time, the system automatically accumulates the total number of drips N, expressed as: N= Where N is the total number of drips. Simultaneously, the system can determine whether special phenomena such as igniting the filter paper or continuous burning and dripping occur, and automatically generate corresponding event records.

[0039] Infrared thermal imaging unit 3 acquires temperature field distribution information in real time during the sample combustion process and transmits the temperature data to the data analysis and control unit. The data analysis and control unit calculates the temperature distribution of the monitored area in real time based on the temperature field data.

[0040] The visible light image data and the temperature field data acquired by the infrared thermal imaging unit 3 are synchronized and correlated using a unified timestamp to establish a correspondence between flame propagation, temperature change, crack propagation and structural damage, thereby realizing automated recording, visual analysis and historical data tracing of the entire combustion process.

[0041] Endoscopic observation unit 4 continuously acquires high-resolution images of local areas of the sample during the combustion test. The system identifies the crack initiation location and propagation path through image difference algorithms, edge recognition algorithms, and feature point tracking algorithms.

[0042] After the ignition source is removed from the sample within the time specified in the standard, the system automatically enters the combustion state monitoring mode. For the calculation of afterflame time, the data analysis and control unit identifies flame region characteristics based on visible light images. When the ignition source is removed, the system automatically records the time t of ignition source departure. b The system continuously monitors changes in the flame area. When the flame features in the image completely disappear and this continues for a preset time, the moment t when the flame is completely extinguished is recorded. e The afterburning time is calculated according to the following formula, and the system automatically generates the afterburning process curve and key node records: t f = t e – t b； Where: t f For afterburning time, t b To remove the ignition source time, t e This refers to the time required for the open flame to be completely extinguished.

[0043] For calculating smoldering time, the system combines visible light images and infrared temperature field information for joint determination, effectively avoiding errors caused by single temperature determination or manual observation. When the visible light measurement unit 2 detects the disappearance of open flame on the sample surface, the system automatically enters smoldering monitoring mode. The data analysis and control unit sets the smoldering determination temperature threshold T0; when the highest temperature T in the monitoring area... max Satisfy T max When T > 0, and no flame features are detected in the visible light image, the system determines that the sample is in a smoldering state; when T < 0, the system determines that the sample is in a smoldering state. max If the temperature remains below the set threshold for a preset time, the smoldering is considered to have ended.

[0044] The duration of smoldering is calculated using the following formula: t s = t e2 - t b2； Where: t s t represents the duration of smoldering. b2 t is the smoldering start time. e 2 represents the end time of smoldering.

[0045] For calculating the damage length, the data analysis and control unit performs image calibration based on the calibration reference structure image acquired by the visible light measurement unit, establishing a correspondence between pixel size and actual size. It then automatically extracts ablation boundaries, carbonization boundaries, or tear boundaries using an edge recognition algorithm. After obtaining the pixel length D of the damaged area, it is automatically converted to the actual damage length based on the calibration coefficient K. L d = D × K; Where L d Let D be the length of the damaged area in the image, and K be the length calibration coefficient. The system simultaneously saves the boundary recognition results and the measurement process images, enabling traceability of the results.

[0046] Throughout the combustion test, the endoscopic observation unit 4 continuously monitors the damage evolution of local areas of the sample. When new crack features appear in two adjacent frames, the system automatically records the coordinates of the crack initiation location. It continuously tracks the changes in the position of the crack front, forming the crack propagation trajectory. The crack propagation rate can be expressed as: Where Vc is the crack propagation rate, These represent the crack lengths at different times. , These correspond to specific time points. When the crack length exceeds a preset value, the crack propagation rate exceeds a set threshold, or the local damage area reaches a set proportion, the system automatically triggers a critical damage event determination and automatically saves the images, videos, and temperature information at the corresponding time points.

[0047] S3, when the system determines that the combustion stage has ended, the data analysis and control unit sends an unlocking command to the top servo drive clamping system 5, so that the electromagnetic brake assembly switches from the locked state to the released state. While keeping the sample clamping state unchanged, the rotation lock of the clamping assembly is released, so that the clamping assembly obtains the degree of freedom to rotate around the set axis and enters the test conversion stage.

[0048] Specifically, after the system determines the end of the combustion stage based on the combined judgment of the visible light measurement unit and the infrared thermal imaging unit, the data analysis and control unit sends an unlocking command to the top servo drive clamping system 5, causing the electromagnetic brake assembly to switch from the locked state to the released state. Throughout the unlocking process, the sample remains firmly clamped and fixed by the left and right clamping arms, without loosening or re-clamping. Only the locking constraint of the clamping assembly around the rotation axis is released, restoring its rotational freedom.

[0049] Subsequently, the control system initializes the top servo-driven clamping system 5 to zero, adjusting the clamping components to the preset initial position and completing the zero-position calibration of the angle encoder. After zeroing, the system automatically enters the tear test phase, providing a uniform initial state for subsequent controlled rotation loading.

[0050] S4, the top servo drive clamping system 5 is started, driving the sample clamping assembly to rotate in opposite directions around a set axis, applying a controlled tearing load to the burned sample, and realizing the mechanical failure test of the material after combustion; according to the rotation angle and angular velocity signals fed back by the encoder, and the torque signal fed back by the torque sensor, the output of the servo motor is adjusted in real time to realize closed-loop control of the rotation speed and loading process.

[0051] Specifically, after combustion, the data analysis and control unit sends a start command to the top servo drive clamping system 5, driving the movable clamp to rotate in opposite directions around a set axis, applying a controlled tearing load to the burned sample. The servo drive system drives the left clamping arm 51 and the right clamping arm 52 to rotate in opposite directions around their respective rotation axes, thus subjecting the sample to tearing between the two clamping arms. During the tear test, the angle encoder provides real-time feedback of the rotation angle θ and angular velocity ω, and the torque sensor provides real-time feedback of the output torque M. The motion control module compares the real-time feedback values ​​with the set target values ​​and automatically adjusts the servo motor output to achieve closed-loop control of angular velocity and torque. The control system automatically adjusts the output power based on the real-time detected torque to keep the angular velocity within the set range, thereby achieving stable loading. By setting different angular velocities, torque thresholds, and loading curves, standard hammer loading, manual tearing, and other specified loading conditions can be simulated.

[0052] To ensure comparability between automated test results and those obtained using the traditional hammer method and manual tearing tests, an equivalent conversion model is established between hammer loading, manual loading, and rotational loading. First, the actual mass characteristics of the sample are calculated based on the sample size, mass per unit area, and weight parameters. Then, the hammer mass specified in the standard test method (GB / T5455-2014) is considered. Calculate the standard loading energy based on gravitational acceleration g and the release height H of the weight. Subsequently, the target loading rate is determined according to the application time and loading process specified in the standard test, and corrected by combining the average tensile speed and force characteristics obtained during the artificial tear test. The control system calculates the target rotational angular velocity ω, angular acceleration α, and target output torque T of the clamping arm based on the target loading energy, target loading rate, and actual parameters of the sample, and inputs them as servo control parameters into the motion control module.

[0053] During the tear test, the endoscopic observation unit 4 continuously acquires high-resolution local images of the crack propagation area, the visible light measurement unit 2 simultaneously acquires macroscopic images of the overall tearing process of the sample, and the infrared thermal imaging unit 3 records the temperature changes of the sample during the tearing process. The system simultaneously records the changes in rotation angle, angular velocity, torque, and crack propagation process, and generates angle-time curves, torque-time curves, and damage evolution curves.

[0054] The S5 data analysis and control unit synchronously acquires and fuses visible light images, infrared temperature fields, endoscopic observation images, rotation angles, and torque data. It automatically calculates afterflame time, smoldering time, damage length, number of melt drips, torque changes, and crack propagation parameters, and generates test results and original records.

[0055] Specifically, after the test, the data analysis and control unit automatically processes the multi-source data collected during the test. The data analysis and control unit uses a unified time base to synchronously control all sensors and imaging devices, achieving synchronous acquisition and timestamping of visible light images, infrared thermograms, endoscopic images, temperature signals, torque signals, and angle signals. Image information at any given time in the system is matched with temperature and mechanical information, enabling synchronous analysis of combustion behavior and structural failure behavior.

[0056] The visible light unit is used to acquire structural changes, damage length, melt dripping, and afterflame behavior during the combustion process of the sample, and to obtain a video record of the entire combustion process; the infrared thermal imaging unit 3 is used to monitor the temperature distribution of the sample and determine the smoldering state and duration; the endoscopic observation unit 4 is used to identify local crack propagation and key damage events for in-depth review and confirmation; the data analysis unit synchronously fuses multi-source data and realizes automatic calculation. During the test, the top servo-driven clamping system 5 is locked in the combustion test phase to rigidly fix the sample; after the combustion test, the control system releases the locking state and drives the clamping structure to rotate in opposite directions at a preset angular velocity to apply a controlled tearing load to the burned sample. During the test, the system automatically adjusts the rotation speed according to real-time torque feedback to achieve closed-loop control of the tearing process, and synchronously records the rotation angle, torque changes, and crack propagation process, thereby realizing automated testing and quantitative evaluation of the structural damage and mechanical failure behavior of textiles after combustion. This invention realizes the synchronous observation and quantitative analysis of combustion behavior and mechanical tearing behavior, improves test repeatability and data consistency, and is suitable for the field of coupled research on combustion performance and structural failure. This invention enables automated testing and multi-source data fusion analysis of combustion behavior, smoldering / afterflame, and mechanical damage, thereby improving testing accuracy and safety.

[0057] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A test system for testing the combustion and mechanical coupling properties of textiles, characterized in that, include: The test chamber forms a closed test space inside, and the test chamber is equipped with an observation window; A visible light measurement unit is located outside the observation window and is used to acquire visible light image information of the sample combustion process; An infrared thermal imaging unit is located outside the observation window and is used to collect infrared temperature field information during the combustion process of the sample. An endoscopic observation unit is located inside the observation window, with its probe facing the sample, and is used to acquire image information of a local area of ​​the sample. The top servo-driven clamping system, connected inside the test chamber, includes a sample clamping assembly, a locking assembly, a driving assembly, an angle encoder, and a torque sensor. The sample clamping assembly includes a left clamping arm and a right clamping arm. The locking assembly is used to lock or unlock the sample clamping assembly. The driving assembly is used to drive the left and right clamping arms to rotate in opposite directions around a set axis. The angle encoder is used to detect the rotation angle and angular velocity, and the torque sensor is used to detect the torque. The data analysis and control unit is electrically connected to the visible light measurement unit, the infrared thermal imaging unit, the endoscopic observation unit, and the top servo drive clamping system, respectively, and is used to synchronously fuse and analyze the data collected by each unit.

2. The testing system according to claim 1, characterized in that, The optical axis of the visible light measurement unit passes through the central region of the sample and forms an angle with the normal direction of the sample. The optical axis of the infrared thermal imaging unit passes through the central region of the sample and forms an angle with the normal direction of the sample. The visible light measurement unit and the infrared thermal imaging unit are respectively located on both sides of the central projection region of the sample.

3. The testing system according to claim 1, characterized in that, The endoscopic observation unit includes a high-temperature resistant industrial endoscope probe, which is arranged inside the test chamber in a lateral or inclined manner, and there is a gap between the endoscope probe and the sample surface.

4. The testing system according to claim 1, characterized in that, The data analysis and control unit uses a unified time reference to synchronously control the visible light measurement unit, infrared thermal imaging unit, endoscopic observation unit, angle encoder, and torque sensor, thereby achieving synchronous acquisition and timestamp marking of visible light images, infrared thermal images, endoscopic images, temperature signals, torque signals, and angle signals.

5. The testing system according to claim 1, characterized in that, The visible light measurement unit includes an industrial camera, a low-distortion lens, an illumination assembly, and a calibration reference structure. The calibration reference structure is located near the sample and is on the same observation plane as the sample.

6. A test method based on the test system according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1, fix the sample in the sample clamping assembly of the top servo drive clamping system, activate the locking assembly to make the clamping structure in a rigid locking state, and simultaneously activate the visible light measurement unit, infrared thermal imaging unit and endoscopic observation unit. S2, Perform a combustion test. The visible light measurement unit acquires visible light image information of the sample combustion process, the infrared thermal imaging unit acquires infrared temperature field information of the sample combustion process, and the endoscopic observation unit acquires image information of a local area of ​​the sample. The data analysis and control unit calculates the afterflame time, smoldering time, damage length, and melting dripping behavior based on the acquired data. S3, after the combustion stage ends, the data analysis and control unit sends an unlocking command to the locking component to release the clamping structure constraint; S4, the drive assembly is activated, driving the left and right clamping arms of the sample clamping assembly to rotate in opposite directions around a set axis, applying a tearing load to the burned sample; the data analysis and control unit adjusts the output of the drive assembly according to the feedback signals of the angle encoder and the torque sensor to achieve closed-loop control; S5, the data analysis and control unit performs synchronous fusion analysis on the visible light image, infrared temperature field information, endoscopic observation image, rotation angle and torque data to generate test results.

7. The test method according to claim 6, characterized in that, In S1, a calibration reference structure is set up near the sample, and the visible light measurement unit acquires the calibration image. The data analysis and control unit establishes a length conversion coefficient based on the actual size of the calibration structure and the corresponding pixel size in the image.

8. The test method according to claim 7, characterized in that, In S2, the flame outline, flame area, flame height, flame propagation path, and carbonization boundary feature information are extracted by image recognition algorithm; the molten dripping behavior is detected by moving target recognition algorithm and the dripping time, dripping number, and dripping trajectory are recorded; the ablation boundary, carbonization boundary, or tearing boundary is extracted by edge recognition algorithm and converted into the actual damage length according to the length conversion coefficient.

9. The test method according to claim 6, characterized in that, In S2, after the ignition source is removed, the data analysis and control unit identifies the flame area features based on the visible light image, records the time of ignition source removal, and records the time of complete flame extinguishing when the flame features completely disappear. The afterflame time is calculated based on the ignition source removal time and the time of complete flame extinguishing. When no flame features are detected in the visible light image and the temperature of the monitored area in the infrared temperature field is higher than a set threshold, the sample is determined to be in a smoldering state. When the temperature continues to be lower than the set threshold, the smoldering is determined to end. The smoldering duration is calculated based on the smoldering start time and the smoldering end time. The crack initiation location and propagation path are identified by image difference algorithm, edge recognition algorithm and feature point tracking algorithm, and the crack propagation speed is calculated based on the crack length and corresponding time at different times.

10. The method according to claim 6, characterized in that, In S4, the data analysis and control unit adjusts the output power of the drive component according to the real-time feedback torque signal to keep the angular velocity within the set range; the data analysis and control unit establishes an equivalent conversion model between heavy hammer loading, manual loading and rotational loading, calculates the standard loading energy according to the heavy hammer mass, gravitational acceleration and heavy hammer release height specified in the standard test method, and determines the target rotational angular velocity and target output torque of the clamping arm according to the target loading energy and target loading rate.

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