A film bulging mechanical property testing system and method supporting multi-rate loading and multi-sample parallel testing

Abstract

The application provides a film bulging mechanical property testing system and method supporting multi-rate loading and multi-sample parallel testing. The system comprises a gas source integrated gas path control module, a visual measurement module, a multi-channel selection valve, a relay, a central control module and a testing module; the hardware platform and the software platform in the central controller are controlled synchronously to ensure microsecond-level data correspondence precision, so that the variable rate control of the high-speed proportional valve can provide more real working condition simulation. The multi-channel selection valve is arranged between the shared gas source and each testing component, and cooperates with the central control module to realize multi-sample parallel testing, and the single experiment data volume is improved by N times, which is particularly suitable for production line quality control and material consistency screening. In each component, a four-way valve is added to connect each part in the component, instead of the traditional multi-valve group and multiple independent system mode. The application reduces the hardware cost and simplifies the system structure.

Description

Technical Field

[0001] This invention relates to the field of materials mechanical property testing technology, specifically a thin film bulging mechanical property testing system and method that supports multi-rate loading and parallel testing of multiple samples. Background Technology

[0002] Current thin film mechanical testing methods mostly employ uniaxial tensile testing, which struggles to simulate the biaxial stress state under pressure differentials. Furthermore, existing bulging methods still present the following problems:

[0003] 1. Limited testing throughput: Existing devices mostly adopt a single-sample testing structure, which can only test one sample at a time. In high-throughput material screening or quality control scenarios that require statistical testing results, a large number of samples need to be tested one by one, resulting in a long overall testing cycle.

[0004] 2. Limited Loading Control Methods: Most conventional devices employ manual adjustment or simple electric control, making it difficult to achieve precise and programmable multiple loading rates. Thin film materials typically exhibit rate-dependent mechanical behavior, requiring testing at different strain rates to fully characterize their properties, a capability that current equipment lacks.

[0005] 3. Limited automation: Steps such as pressure loading, image acquisition, and data processing often require manual operation, resulting in limited consistency in the operation process. Test results are easily affected by human factors, and the operation requires high professional skills from the operators.

[0006] 4. Insufficient system coordination: The gas path control, visual measurement and data processing units are relatively independent, lacking hardware-level synchronous triggering and high-precision timing coordination, which may affect the synchronous measurement accuracy of pressure and strain data during the bulging deformation process.

[0007] 5. Lack of flexibility in structural configuration: The number of test channels and sample fixture size of existing equipment are usually fixed, making it difficult to flexibly expand the test channels according to needs, and also difficult to adapt to samples of different diameters or materials.

[0008] Therefore, there is an urgent need for an improved bulging method for thin film testing that can overcome at least a number or all of the aforementioned problems, such as limited test throughput, single loading control, limited automation, insufficient system coordination, and lack of flexibility in structural configuration. Summary of the Invention

[0009] The purpose of this invention is to address the problems existing in the prior art, such as low test throughput, simple loading control, limited automation, insufficient system coordination, and lack of structural configuration flexibility, by providing a thin film bulging mechanical property testing system and method that supports multi-rate loading and parallel testing of multiple samples, so as to significantly improve the overall performance and applicability of the test.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A thin film bulging mechanical property testing system that supports multi-rate loading and multi-sample parallel testing includes: an integrated gas source control module, a vision measurement module, a multi-channel selection valve, a relay, a central control module, and a testing module;

[0012] The gas source integrated gas circuit control module is used to generate filling gas;

[0013] The visual measurement module includes an image acquisition unit and an illumination unit, which are used to perform overall visual acquisition of multiple sample chambers and obtain visual measurement information.

[0014] The test module includes multiple test components, each of which is equipped with a four-way valve. The first port of the four-way valve serves as the air inlet port of the test component and is connected to a high-speed proportional valve. It is connected to the integrated gas source control module via a multi-channel selector valve. The second port is connected to a pressure sensor. The third port is connected to a pressure relief valve. The fourth port is connected to a sample chamber.

[0015] The input end of the multi-channel selection valve is connected to the gas source integrated gas path control module, and the output end is connected to the sample chamber of each test component, forming multiple parallel and independent gas filling paths.

[0016] The input terminal of the relay is connected to the central control module, and the output terminal is electrically connected to the control terminal of the multi-channel selection valve. The relay is used to control the opening of the corresponding channel in the multi-channel selection valve according to the received channel control signal, so that the gas source integrated gas path control module fills the corresponding sample chamber with gas through the opened channel.

[0017] The central control module is also connected to the gas source integrated gas path control module, the testing module, and the vision measurement module, and is configured as follows:

[0018] It receives the first gas pressure parameters provided by the pressure sensors in each test component, the second gas pressure parameters in the gas source integrated gas path control module, and the visual measurement information acquired by the visual acquisition module;

[0019] A first control signal is generated based on the first gas pressure parameter to control the total gas output of the gas source integrated gas circuit control module;

[0020] The amount of gas introduced into the sample chamber of each test component is controlled according to the second gas pressure parameter.

[0021] A channel control signal is generated based on the first gas pressure parameter and the second gas pressure parameter, and then sent to the relay.

[0022] Furthermore, the integrated air source control module includes: an air compressor, an air tank, a precision filter, a pressure reducing valve, an electro-proportional valve, and a thermal flow meter;

[0023] The air compressor, air tank, precision filter, and pressure reducing valve are connected in sequence; the air inlet of the electro-proportional valve is connected to the pressure reducing valve, the control signal input terminal is connected to the central control module, and the air outlet is connected to the air inlet of the thermal flow meter; the air outlet of the thermal flow meter is connected to the multi-channel selector valve, and the control signal output terminal is connected to the central control module.

[0024] Furthermore, the vision measurement module also includes a synchronization triggering unit; the image acquisition unit includes at least two global shutter industrial cameras; the two global shutter industrial cameras are respectively installed at different installation positions in the sample chamber, and the optical axes of each camera intersect in the same observation area in the sample chamber, for synchronously acquiring images of the sample from different perspectives;

[0025] The illumination unit includes at least two backlights, which are respectively set on the backlight side of the sample in correspondence with two global shutter industrial cameras, and are used to provide illumination to the sample in the direction opposite to the optical axis of the corresponding camera to improve imaging contrast.

[0026] The input terminal of the synchronous trigger unit is connected to the central control module to receive trigger control signals from the central control module; the output terminal of the synchronous trigger unit is simultaneously connected to two global shutter industrial cameras and two backlights, and is used to output synchronous trigger pulses to the two global shutter industrial cameras and two backlights simultaneously according to the received trigger control signals, so that the two global shutter industrial cameras perform image exposure when the backlights are lit.

[0027] Furthermore, the central control module includes a hardware platform and a control software system;

[0028] The hardware platform uses an industrial computer as the main controller, and its internal bus is expanded with analog output cards, digital output cards, high-speed digital I / O cards, multi-channel data acquisition cards, and image acquisition cards; wherein:

[0029] The analog output card connects the electric proportional valve to the high-speed proportional valve of each test component, and is used to output analog commands to achieve precise and continuous control of the air intake.

[0030] The digital output card connects to the main pressure relief valve and the pressure relief valves of each test component, and drives the multi-channel selection valve via relays to realize the main pressure relief, the pressure relief of each channel, and the independent switching control of each channel.

[0031] The high-speed digital I / O card outputs high-precision synchronous trigger pulses to the camera and light source of the vision measurement module;

[0032] The multi-channel data acquisition card connects each analog input channel to the pressure sensor of the corresponding test component to acquire pressure feedback data in real time.

[0033] The image acquisition card receives image data captured by the camera;

[0034] All collected data is fed back to the control software system of the central control module to realize the closed-loop operation and logic control of the system.

[0035] The control software system runs in the real-time operating system environment of an industrial computer, and includes a real-time control module, a synchronization triggering module, an image acquisition and processing module, a multi-mode parameter management module, a data fusion and mechanical inversion module, a visualization and human-computer interaction module, and a data management and communication module, wherein:

[0036] The real-time control module is used to connect to the multi-channel selection valve via a digital I / O card and adjust the on / off state of the multi-channel selection valve through pulse triggering; it is also connected to the electric proportional valve and the high-speed proportional valve of each test component via an analog output card to execute a multi-channel PID control algorithm at a frequency of not less than 1kHz to adjust the air intake rate in the sample chamber.

[0037] The synchronization trigger module uses a hardware timer integrated in the multi-channel data acquisition card to generate a timing signal, and outputs a trigger control signal to the synchronization trigger unit of the vision measurement module through a high-speed digital I / O card. The synchronization trigger unit then generates a synchronization trigger pulse to drive the camera and light source, so that the timing synchronization accuracy reaches the microsecond level.

[0038] Image acquisition and processing module: communicates with at least two global shutter industrial cameras of the vision measurement module via the GigE Vision protocol to achieve synchronous image acquisition, transmission and real-time processing;

[0039] Multi-mode parameter management module: Provides unified parameter mode and independent parameter mode; in unified parameter mode, a set of global parameters is applied to all selected pressure control channels; in independent parameter mode, each pressure control channel can be configured with parameters individually; the pressure control channel refers to the gas filling path corresponding to each test component.

[0040] Data fusion and mechanical inversion module: The pressure sensor data from the multi-channel data acquisition card and the visual measurement data from the visual measurement module are fused based on timestamps to construct a pressure-deformation curve, and a nonlinear fitting algorithm is used to calculate the mechanical parameters of the material;

[0041] Visualization and Human-Computer Interaction Module: Provides a graphical user interface that displays the pressure curves, deformation images, and control status of each pressure control channel in real time;

[0042] Data Management and Communication Module: Enables structured storage, querying, and export of test data, and supports integration with MES systems or laboratory information management systems via industry-standard communication protocols.

[0043] Furthermore, in the multi-mode parameter management module, in independent parameter mode, the parameters that can be configured individually for each pressure control channel include the loading curve and / or sampling strategy.

[0044] Furthermore, in the data fusion and mechanical inversion module, the mechanical parameters include biaxial elastic modulus and / or residual stress.

[0045] Furthermore, in the data management and communication module, the industry standard communication protocol includes at least one of OPC UA or Modbus TCP / IP protocol.

[0046] A method for testing the mechanical properties of thin film bulging that supports multi-rate loading and parallel testing of multiple samples, the method comprising the following steps:

[0047] S1: Seal and install the thin film samples to be tested into the sample chambers respectively;

[0048] S2: Parameter setting: For each sample or sample group, set the test parameter mode according to the requirements, and set its pressure loading control program according to the set test parameter mode, including the sample information of the film to be tested, loading rate, target pressure and sampling frequency, etc.

[0049] S3. Synchronous test execution: The central control module controls the integrated gas circuit control unit to apply pressure to the sample chambers of each test component according to the pressure loading control program set in step S2, and synchronously controls the visual measurement module to acquire deformation images of the thin film sample under test during the pressure loading process.

[0050] S4. Data Acquisition and Processing: Real-time acquisition of pressure data from the sample chambers of each component and deformation images of each thin film sample under test, and extraction of characteristic parameters characterizing the bulging deformation of the thin film sample under test from the acquired deformation images;

[0051] S5. Mechanical property calculation: Correlate the pressure data of each film sample under test with its corresponding deformation characteristic parameters to form a pressure-deformation relationship curve, and calculate the mechanical property parameters of each film sample under test based on the preset mechanical model.

[0052] By adopting the above technical solution, the present invention has the following beneficial effects:

[0053] 1. Simple system structure: This invention uses only a four-way valve to integrate a pressure sensor, the sample to be tested, a pressure relief valve, and a high-speed proportional valve, which improves the complex circulating gas path control that traditionally requires multiple valves.

[0054] 2. This invention proposes a hardware-triggered synchronization mechanism based on valve position signals or pressure stability criteria, which fundamentally solves the data mismatch problem.

[0055] 3. This invention introduces multi-channel selection valves and relays into each test component to build an arrayed gas path and vision integration scheme for isobaric parallel testing. This not only doubles the testing efficiency but also enables accurate comparison of the performance between thin film samples under test.

[0056] 4. Integrating variable rate program control into the bulging method enables the device to characterize a wider range of material dynamic mechanical behaviors.

[0057] In summary, this invention solves the problems of limited test throughput, single loading control, limited automation, insufficient system coordination, and lack of flexibility in structural configuration in traditional thin film bulging tests. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 The following is a logic diagram of the main circuit of each gas filling path in the system, provided for the implementation example.

[0060] Figure 2 This is a schematic diagram of the test system structure provided for an embodiment.

[0061] Figure 3 This is a schematic diagram of the camera and light source distribution of the vision measurement module provided in the embodiment.

[0062] Figure 4 This is a hardware and software logic diagram of the central controller provided for an embodiment. Detailed Implementation

[0063] 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.

[0064] like Figure 2As shown in the figure, this embodiment provides a thin film bulging mechanical property testing system that supports multi-rate loading and parallel testing of multiple samples. The system includes: a gas source integrated gas path control module, a vision measurement module, a multi-channel selection valve, a relay, a central control module, and a testing module. The specific structures of each module are as follows:

[0065] The integrated gas source control module is used to generate filling gas. The integrated gas source control module includes: an air compressor, an air tank, a precision filter, a pressure reducing valve, an electro-proportional valve, and a thermal flow meter. The air compressor, air tank, precision filter, and pressure reducing valve are connected in sequence. The inlet of the electro-proportional valve is connected to the pressure reducing valve, the control signal input terminal is connected to the central control module, and the outlet is connected to the inlet of the thermal flow meter; the outlet of the thermal flow meter is connected to a multi-channel selector valve, and the control signal output terminal is connected to the central control module; it is used to monitor the total system flow. As a common gas source, this module stabilizes the pressure at 1.0 MPa through the pressure reducing valve.

[0066] The testing module includes multiple testing components, each equipped with a four-way valve. The first port of the four-way valve serves as the air inlet for that testing component, connected to the integrated gas source control module via a high-speed proportional valve. The second port is connected to a pressure sensor; the third port is connected to a pressure relief valve; and the fourth port is connected to the sample chamber. In this embodiment, the high-speed proportional valve is a piezoelectrically driven proportional valve (model: PI P-616, Germany), whose opening is continuously controlled by the input voltage (0-10V), with a response time of <3 ms; enabling precise variable-rate gas loading. The pressure relief valve is a two-position, normally closed solenoid valve used to release the pressure of the corresponding chamber to the atmosphere after the test. The sample chamber is made of transparent acrylic and connected to the integrated gas source via a multi-channel selection valve. The chamber design reduces the impact of human disturbance on the test. The input end of the multi-channel selection valve is connected to the integrated gas source control module, and the output end is connected to the sample chamber of each testing component, forming multiple parallel and independent gas filling paths.

[0067] To achieve a more compact structure, this embodiment places the testing module within the sample chamber, allowing all testing components to share a single vision measurement module. The vision measurement module, used for overall visual acquisition of multiple sample chambers and obtaining visual measurement information, includes an image acquisition unit, an illumination unit, and a synchronization triggering unit. The specific structure of the vision testing module in this embodiment is as follows: Figure 3 As shown:

[0068] The image acquisition unit includes at least two global shutter industrial cameras; the two global shutter industrial cameras are Hikvision MV-CA050-10GM models, each with 5 megapixels; they are respectively positioned on the front and top surfaces of the observation window of the sample chamber, and the optical axes of each camera intersect within the same observation area inside the sample chamber, for synchronously acquiring images of the sample from different perspectives. To eliminate parallax errors, each global shutter industrial camera is equipped with dual telecentric lenses with a magnification of 0.5X.

[0069] The illumination unit includes a backlight source of at least two uniform white LEDs, which are respectively positioned on the backlight side of the sample in correspondence with two global shutter industrial cameras, i.e., installed below and behind the sample chamber, to provide high-contrast illumination of the contour of the thin film sample to be tested.

[0070] The synchronization triggering unit consists of an FPGA-based hardware synchronization trigger. The input of the trigger is connected to the central control module to receive trigger control signals from the central control module. The output of the synchronization triggering unit is simultaneously connected to two global shutter industrial cameras and two backlights. Based on the received trigger control signals, it outputs synchronization trigger pulses to the two global shutter industrial cameras and the two backlights simultaneously, so that the two global shutter industrial cameras perform image exposure when the backlights are lit, and the error between them is configured to be less than 1 microsecond.

[0071] The input terminal of the relay is connected to the central control module, and the output terminal is electrically connected to the control terminal of the multi-channel selection valve. The relay is used to control the opening of the corresponding channel in the multi-channel selection valve according to the received channel control signal, so that the gas source integrated gas path control module can fill the corresponding sample chamber with gas through the opened channel.

[0072] The central control module is also connected to the gas source integrated gas path control module, the testing module, and the vision measurement module, and is configured as follows:

[0073] It receives the first gas pressure parameters provided by the pressure sensors in each test component, the second gas pressure parameters in the gas source integrated gas path control module, and the visual measurement information acquired by the visual acquisition module;

[0074] A first control signal is generated based on the first gas pressure parameter to control the total gas output of the gas source integrated gas circuit control module;

[0075] The amount of gas introduced into the sample chamber of each test component is controlled according to the second gas pressure parameter.

[0076] A channel control signal is generated based on the first gas pressure parameter and the second gas pressure parameter, and then sent to the relay.

[0077] like Figure 4As shown, the central control module in this embodiment includes a hardware platform and a control software system. The hardware platform uses an industrial computer as the main controller, equipped with an Intel i7 processor, 32GB of memory, and a gigabit network card. Its internal bus expansion includes analog output cards, digital output cards, high-speed digital I / O cards, multi-channel data acquisition cards, and image acquisition cards; wherein:

[0078] The analog output card connects the electro-proportional valve to the high-speed proportional valves of each test component, and is used to output analog commands to achieve precise and continuous control of the air intake.

[0079] The digital output card connects to the main pressure relief valve and the pressure relief valves of each test component, and drives the multi-channel selection valve via relays to achieve main pressure relief, pressure relief of each channel, and independent switching control of each channel.

[0080] The high-speed digital I / O card outputs high-precision synchronous trigger pulses to the camera and light source of the vision measurement module.

[0081] The multi-channel data acquisition card connects its analog input channels to the pressure sensors of the corresponding test components to acquire pressure feedback data in real time.

[0082] The image acquisition card receives image data captured by the camera.

[0083] All collected data is fed back to the control software system of the central control module to realize the closed-loop operation and logic control of the system.

[0084] The control software system runs in the real-time operating system environment of an industrial computer and is developed based on LabVIEW and the Vision Development Module. It includes a real-time control module, a synchronization triggering module, an image acquisition and processing module, a multi-mode parameter management module, a data fusion and mechanical inversion module, a visualization and human-computer interaction module, and a data management and communication module, wherein:

[0085] The real-time control module connects to the high-speed proportional valves of the electric proportional valve and each test component via an analog output card. It executes a multi-channel PID control algorithm at a frequency of not less than 1kHz and calculates and outputs the proportional valve control voltage in real time based on the set pressure curve and sensor feedback values, thereby adjusting the opening degree of the proportional valve.

[0086] The synchronization trigger module uses a hardware timer integrated in the multi-channel data acquisition card to generate a timing signal, and outputs a trigger control signal to the synchronization trigger unit of the vision measurement module through a high-speed digital I / O card. The synchronization trigger unit then generates a synchronization trigger pulse to drive the camera and light source, achieving a timing synchronization accuracy at the microsecond level.

[0087] Image acquisition and processing module: Communicates with at least two global shutter industrial cameras in the vision measurement module via the GigE Vision protocol to achieve synchronous image acquisition, transmission, and real-time processing. Specifically, it calls the NI-IMAQdx driver to synchronously capture images and utilizes the Vision module for image processing.

[0088] Multi-mode parameter management module: Provides unified parameter mode and independent parameter mode; in unified parameter mode, a set of global parameters is applied to all selected pressure control channels. In independent parameter mode, each pressure control channel can be configured with parameters individually; the pressure control channel refers to the gas charging path corresponding to each test component; the parameters that can be configured individually for each pressure control channel include the loading curve and / or sampling strategy.

[0089] Data fusion and mechanical inversion module: The pressure sensor data from the multi-channel data acquisition card and the visual measurement data from the visual measurement module are fused based on timestamps to construct a pressure-deformation curve, and a nonlinear fitting algorithm is used to calculate the mechanical parameters of the material; the mechanical parameters include biaxial elastic modulus and / or residual stress.

[0090] Visualization and Human-Computer Interaction Module: Provides a graphical user interface that displays the pressure curves, deformation images, and control status of each pressure control channel in real time.

[0091] Data Management and Communication Module: Enables structured storage, querying, and export of test data, and supports integration with MES systems or laboratory information management systems via industry-standard communication protocols. Industry-standard communication protocols include at least one of OPC UA or Modbus TCP / IP protocols.

[0092] In implementation, the system selects, based on usage requirements, a control signal sent by the central controller to the relay to control the multi-channel selection valve to select multiple or a single gas filling path. The logic for gas filling in each gas path is detailed below. Figure 1 .

[0093] Based on the aforementioned thin film bulging mechanical property testing system, this embodiment also provides a method for testing the thin film bulging mechanical properties, the method comprising the following steps:

[0094] S1: System Initialization and Sample Installation. Start the system and perform an airtightness check. Seal and install the film samples to be tested into the sample chambers and secure them with pressure rings to form a sealed test area.

[0095] S2: Parameter setting: Users can select one of the following two parameter setting modes in the central control software interface according to their testing needs.

[0096] Mode A: Uniform parameter mode, suitable for large-scale sample screening or repeatability testing:

[0097] Scenario: Select this mode when you need to perform parallel testing on multiple (usually ≥4) thin film samples with the same expected performance or from the same batch to obtain statistical data or for rapid screening.

[0098] Setup Method: Users select the "Unified Parameters" option. A set of global test parameters is set in the main parameter area; these parameters will be automatically applied to all active test channels. Core parameters include: loading control mode, such as "linear boost," "stepped loading," or "constant pressure hold"; target pressure value, the final pressure all samples need to reach; loading / boosting rate, the rate at which pressure changes over time (e.g., kPa / s), which is crucial for achieving variable rates; sampling triggering method—for example, "equal time interval trigger" or "equal pressure interval trigger" and its interval value; optical acquisition parameters, camera exposure time and gain; and light source brightness. Users only need to select the sample chambers (channels 1 to N) that will participate in this parallel test.

[0099] System behavior: After startup, the system will use the same set of parameters to execute the exact same test program on all selected channels in strict synchronization or high concurrency.

[0100] Mode B: Independent Parameter Mode (Suitable for multi-condition comparative experiments or research tests)

[0101] Scenario: Select this mode when you need to study the effects of different loading conditions (such as different rates and different final pressures) on material properties, or when you need to test samples of different materials and thicknesses at the same time.

[0102] Setup method: Users select the "Independent Parameters" option. The software interface displays a multi-channel parameter matrix table or pagination tabs, with each active channel having its own independent parameter setting area. Users can define unique test programs for each channel. For example:

[0103] Channel 1: Set to linear boost, rate 0.1 kPa / s, target pressure 10 kPa.

[0104] Channel 2: Set to linear boost, rate 1.0 kPa / s, target pressure 10 kPa (for studying rate effects).

[0105] Channel 3: Set to stepped loading, first step 5 kPa held for 30 seconds, second step 10 kPa held for 60 seconds.

[0106] Channel 4: Set to constant pressure holding mode, pressure 8 kPa, used to test creep or relaxation behavior.

[0107] System Behavior: Upon startup, the central controller will drive the pneumatic circuit units of each channel to execute their respective tasks in parallel and asynchronously, according to the independent control program for each channel. The central processing unit is responsible for multi-threaded scheduling to ensure that each task runs independently and resources do not conflict.

[0108] Step S103: Start the test. The user clicks the "Start Test" button.

[0109] Step S104: Synchronous Control and Data Acquisition. The central control module starts multiple independent control threads.

[0110] For each channel i (i=A, B, C, D):

[0111] (1) The control thread calculates the target pressure value P_target_i(t) at the current moment according to the preset mode.

[0112] (2) Read the current value P_feedback_i(t) of the corresponding pressure sensor i.

[0113] (3) Under the parameters of proportional coefficient Kp = 2.0, integral time Ti = 0.5 seconds and derivative time Td = 0.05 seconds, the digital PID controller calculates the error e_i(t) as equal to P_target_i(t) minus P_feedback_i(t) and sends the output control voltage U_i(t) to the high-speed proportional valve i.

[0114] (4) The proportional valve adjusts the opening according to U_i(t) to change the gas flow rate entering the sample chamber i, so that the pressure P_feedback_i(t) approaches P_target_i(t).

[0115] (5) At a predetermined time point or pressure point, for every 0.5 kPa pressure increment, the central control module sends an instruction to the hardware synchronous trigger; the synchronous trigger simultaneously triggers two global shutter industrial cameras and two backlights to synchronously acquire images of the film bulging.

[0116] (6) Image processing algorithm for real-time image analysis: First, Gaussian filtering is performed to remove noise. Then, the Canny operator is used to extract the outline of the bubbling of the thin film of the sample to be tested. Finally, the diameter D_i is calculated by fitting the circular outline and the maximum displacement h_i of the center is estimated according to the geometric formula of the spherical cap.

[0117] (7) Store the current timestamp t, pressure value P_feedback_i(t), and displacement value h_i(t) as a data point in an array.

[0118] Step S105: Judgment and Termination. Each channel judges whether the target pressure, membrane rupture, etc., have reached the test termination condition; if all channels have reached the test termination condition, the test is completed and proceeds to step S106; otherwise, it returns to step S104 to continue the loop.

[0119] Step S106: Safety pressure relief. Control the opening of the pressure relief valve of the component involved in the test to bring the chamber pressure back to zero.

[0120] Step S107: Mechanical property inversion. For each sample, the software automatically plots the pressure-center displacement (Ph) curve. Using a film bulging model based on the von Kármán large deflection theory (such as the Bulge Test model), the biaxial elastic modulus E and biaxial residual stress σ0 of the film are inverted by fitting the experimental Ph curve with the theoretical model using nonlinear least squares method.

[0121] Step S108: Result Output. The software generates a test report, which includes the Ph curves, fitted curves, and calculated E and σ0 values ​​for the four tested thin film samples. The data can also be exported.

[0122] In summary, the film bulging mechanical property testing system and method of this embodiment ensures microsecond-level data accuracy through a hardware synchronization mechanism, and the variable-rate control of the high-speed proportional valve provides a more realistic simulation of working conditions. By setting up multi-channel selection valves between the common air source and each test component, in conjunction with the central control module, parallel testing of multiple samples can be achieved, and the amount of data in a single experiment is increased N times, making it particularly suitable for production line quality control and material consistency screening. Furthermore, by adding a four-way valve to each component to connect the various parts within the component, the traditional multi-valve group and multiple independent systems are replaced, reducing hardware costs, simplifying the system structure, and achieving a higher degree of automation and smaller errors.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thin film bulging mechanical property testing system supporting multi-rate loading and parallel testing of multiple samples, comprising: The system includes an integrated gas source control module, a vision measurement module, a multi-channel selector valve, relays, a central control module, and a testing module. The gas source integrated gas circuit control module is used to generate filling gas; The visual measurement module includes an image acquisition unit and an illumination unit, which are used to perform overall visual acquisition of multiple sample chambers and obtain visual measurement information. The test module includes multiple test components, each of which is equipped with a four-way valve. The first port of the four-way valve serves as the air inlet port of the test component and is connected to a high-speed proportional valve. It is connected to the integrated gas source control module through a multi-channel selector valve. The second port is connected to a pressure sensor. The third port is connected to a pressure relief valve. The fourth port is connected to a sample chamber. The input end of the multi-channel selection valve is connected to the gas source integrated gas path control module, and the output end is connected to the sample chamber through the high-speed proportional valve of each test component, forming multiple parallel and independent gas filling paths. The input terminal of the relay is connected to the central control module, and the output terminal is electrically connected to the control terminal of the multi-channel selection valve. The relay is used to control the opening of one or more channels in the multi-channel selection valve according to the received channel control signal, so that the gas source integrated gas circuit control module can fill the corresponding sample chamber with gas through the opened channel. The central control module is also connected to the gas source integrated gas path control module, the testing module, and the vision measurement module, and is configured as follows: It receives the first gas pressure parameters provided by the pressure sensors in each test component, the second gas pressure parameters in the gas source integrated gas path control module, and the visual measurement information acquired by the visual acquisition module; A first control signal is generated based on the first gas pressure parameter to control the total gas output of the gas source integrated gas circuit control module; The amount of gas introduced into the sample chamber of each test component is controlled according to the second gas pressure parameter. A channel control signal is generated based on the first gas pressure parameter and the second gas pressure parameter, and then sent to the relay.

2. The system according to claim 1, characterized in that, The integrated air supply control module includes an air compressor, an air tank, a precision filter, a pressure reducing valve, an electro-proportional valve, and a thermal flow meter. The air compressor, air tank, precision filter, and pressure reducing valve are connected in sequence. The inlet of the electro-proportional valve is connected to the pressure reducing valve, the control signal input terminal is connected to the central control module, and the outlet is connected to the inlet of the thermal flow meter. The outlet of the thermal flow meter is connected to a multi-channel selector valve, and the control signal output terminal is connected to the central control module.

3. The system according to claim 1, characterized in that, The vision measurement module also includes a synchronization triggering unit; the image acquisition unit includes at least two global shutter industrial cameras; the two global shutter industrial cameras are respectively installed at different installation positions in the sample chamber, and the optical axes of each camera intersect in the same observation area in the sample chamber, for synchronously acquiring images of the sample from different perspectives; The illumination unit includes at least two backlights, which are respectively set on the backlight side of the sample in correspondence with two global shutter industrial cameras, and are used to provide illumination to the sample in the direction opposite to the optical axis of the corresponding camera to improve imaging contrast. The input terminal of the synchronous trigger unit is connected to the central control module to receive trigger control signals from the central control module; the output terminal of the synchronous trigger unit is simultaneously connected to two global shutter industrial cameras and two backlights, and is used to output synchronous trigger pulses to the two global shutter industrial cameras and two backlights simultaneously according to the received trigger control signals, so that the two global shutter industrial cameras perform image exposure when the backlights are lit.

4. The system according to claim 1, characterized in that, The central control module includes a hardware platform and a control software system; The hardware platform uses an industrial computer as the main controller, and its internal bus is expanded with analog output cards, digital output cards, high-speed digital I / O cards, multi-channel data acquisition cards, and image acquisition cards; wherein: The analog output card connects the electric proportional valve to the high-speed proportional valve of each test component, and is used to output analog commands to achieve precise and continuous control of the air intake. The digital output card connects to the main pressure relief valve and the pressure relief valves of each test component, and drives the multi-channel selection valve via relays to realize the main pressure relief, the pressure relief of each channel, and the independent switching control of each channel. The high-speed digital I / O card outputs high-precision synchronous trigger pulses to the camera and light source of the vision measurement module; The multi-channel data acquisition card connects each analog input channel to the pressure sensor of the corresponding test component to acquire pressure feedback data in real time. The image acquisition card receives image data captured by the camera; All collected data is fed back to the control software system of the central control module to realize the closed-loop operation and logic control of the system. The control software system runs in the real-time operating system environment of an industrial computer, and includes a real-time control module, a synchronization triggering module, an image acquisition and processing module, a multi-mode parameter management module, a data fusion and mechanical inversion module, a visualization and human-computer interaction module, and a data management and communication module, wherein: The real-time control module is used to connect to the multi-channel selection valve via a digital I / O card and adjust the on / off state of the multi-channel selection valve by pulse triggering; it is also connected to the electric proportional valve and the high-speed proportional valve of each test component via an analog output card to execute a multi-channel PID control algorithm at a frequency of not less than 1kHz to adjust the air intake rate in the sample chamber. The synchronization trigger module uses a hardware timer integrated in the multi-channel data acquisition card to generate a timing signal, and outputs a trigger control signal to the synchronization trigger unit of the vision measurement module through a high-speed digital I / O card. The synchronization trigger unit then generates a synchronization trigger pulse to drive the camera and light source, so that the timing synchronization accuracy reaches the microsecond level. Image acquisition and processing module: communicates with at least two global shutter industrial cameras of the vision measurement module via the GigE Vision protocol to achieve synchronous image acquisition, transmission and real-time processing; Multi-mode parameter management module: Provides unified parameter mode and independent parameter mode; in unified parameter mode, a set of global parameters is applied to all selected pressure control channels; in independent parameter mode, each pressure control channel can be configured with parameters individually; the pressure control channel refers to the gas filling path corresponding to each test component. Data fusion and mechanical inversion module: The pressure sensor data from the multi-channel data acquisition card and the visual measurement data from the visual measurement module are fused based on timestamps to construct a pressure-deformation curve, and a nonlinear fitting algorithm is used to calculate the mechanical parameters of the material; Visualization and Human-Computer Interaction Module: Provides a graphical user interface that displays the pressure curves, deformation images, and control status of each pressure control channel in real time; Data Management and Communication Module: Enables structured storage, querying, and export of test data, and supports integration with MES systems or laboratory information management systems via industry-standard communication protocols.

5. The system according to claim 1, characterized in that, In the multi-mode parameter management module, under independent parameter mode, the parameters that can be configured individually for each pressure control channel include the loading curve and / or sampling strategy.

6. The system according to claim 4, characterized in that, In the data fusion and mechanical inversion module, the mechanical parameters include biaxial elastic modulus and / or residual stress.

7. The system according to claim 4, characterized in that, In the data management and communication module, the industry standard communication protocol includes at least one of OPC UA or Modbus TCP / IP protocol.

8. A method for testing the mechanical properties of thin film bulging that supports multi-rate loading and parallel testing of multiple samples, characterized in that, The method includes the following steps: S1: Seal and install the thin film samples to be tested into each sample chamber respectively; S2: Parameter setting: For each sample or sample group, set the test parameter mode according to the requirements, and set its pressure loading control program according to the set test parameter mode, including the sample information of the film to be tested, loading rate, target pressure and sampling frequency, etc. S3. Synchronous test execution: The central control module controls the integrated gas circuit control unit to apply pressure to the sample chambers of each test component according to the pressure loading control program set in step S2, and synchronously controls the visual measurement module to acquire deformation images of the thin film sample under test during the pressure loading process. S4. Data Acquisition and Processing: Real-time acquisition of pressure data from the sample chambers of each component and deformation images of each thin film sample under test, and extraction of characteristic parameters representing the bulging deformation of the thin film sample under test from the acquired deformation images. S5. Mechanical property calculation: Correlate the pressure data of each film sample under test with its corresponding deformation characteristic parameters to form a pressure-deformation relationship curve, and calculate the mechanical property parameters of each film sample under test based on the preset mechanical model.

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