Shearing ice cutting force measuring device

Abstract

The invention relates to the technical field of low-temperature environment test and ice adhesion test, and discloses a shear ice cutting force measuring device which comprises a low-temperature box, a loading mechanism, a test piece and a control system. The low-temperature box is used for providing a test space and a controllable low-temperature environment; the loading mechanism is used for applying shear load to the test piece and collecting shear force; the test piece is composed of a base and accumulated ice and is installed on the fixing clamp. The control system executes hierarchical temperature control based on a preset parameter table and a PID algorithm, when the temperature difference is large, the refrigeration unit is driven to operate at full power, and when the temperature is close to the set temperature, constant-temperature keeping is achieved through cold and heat power cooperative adjustment; and when a disturbance event is detected, the event-driven parameter table is automatically switched to, and the default parameter table is returned after a recovery condition is met, so that rapid cooling, stable temperature control and disturbance compensation are realized. According to the invention, the shearing debonding force of the ice and the substrate interface can be accurately measured, and the stability and repeatability of an experimental result are enhanced.

Description

TECHNICAL FIELD

[0001] The application relates to an ice adhesion force measuring device, in particular to a low-temperature test device for measuring shear debonding force of an ice and substrate interface, and belongs to the technical field of low-temperature environment testing and ice adhesion testing. BACKGROUND

[0002] Ice accumulation is a common natural phenomenon in low-temperature environments, and is related to key fields such as aviation, energy, transportation and infrastructure, causing serious safety, economic and reliability risks, and even triggering a series of disastrous consequences. In order to study and evaluate the ice adhesion and debonding behavior of the material surface, accurate testing of the ice adhesion force becomes a key link for the development of ice prevention technology. The existing ice adhesion force testing device usually creates an icing environment in a low-temperature chamber, and uses a loading mechanism to apply tensile, push-pull or shear load to the test piece, and finally collects and records the ice adhesion force or adhesion strength data through a force sensor.

[0003] However, the temperature control mode of such devices depends on the start-stop or power adjustment of the refrigeration unit, and a single temperature control mode cannot take into account both rapid cooling and high-precision stability, especially when disturbances such as opening the box or phase change heat release occur, the temperature in the box fluctuates significantly, thereby affecting the constancy of the test environment and the repeatability of the experimental results. In addition, the force sensor readings of the existing device often have temperature drift effects, further weakening the stability and accuracy of the measurement at different set temperatures. Therefore, providing an ice adhesion force measuring device capable of rapidly approaching the set temperature, maintaining the accuracy of the continuous temperature, and actively compensating for disturbances, has become an important technical problem to be solved in the field. SUMMARY

[0004] The purpose of the present application is to provide a shear ice adhesion force measuring device to overcome the shortcomings of the existing test in temperature control and measurement accuracy, which can rapidly approach the set temperature, maintain the accuracy of the continuous temperature, and actively compensate for disturbances, thereby improving the accuracy, stability and repeatability of the measurement of the shear debonding force of the ice and substrate interface.

[0005] To achieve the above purpose, the present application realizes the following technical solutions: A shear ice adhesion force measuring device, characterized in that it comprises a low-temperature chamber, a loading mechanism, a test piece and a control system. The low-temperature chamber comprises a chamber body, a chamber cover and a device cabin, an evaporator is fixed on one side in the chamber body, a compressor and a condenser are fixed in the device cabin, the evaporator, the compressor and the condenser are in communication to form a refrigeration unit, and a heating glass window is arranged on the chamber cover to form a heating unit. The loading mechanism comprises an electric cylinder, a force sensor, a push head and a fixed clamp, the electric cylinder is arranged in the equipment cabin and fixed to the fixed clamp, the force sensor is mechanically connected with the electric cylinder and arranged along the loading direction, the push head is mechanically connected to the end of the force sensor away from the electric cylinder, the force sensor and the push head extend into the box through the side wall of the box, and the fixed clamp is composed of a mounting plate with an array of threaded holes and directly connected with the supporting leg; The test piece is composed of a base and ice accretion adhered to the base, and the base is fixedly installed on the fixed clamp through the mounting hole thereon; The control system comprises a controller and monitoring and control software, the controller is electrically connected with the compressor, the heated glass window, a temperature sensor arranged in the box and the force sensor respectively, used for collecting the temperature signal and the shear force signal in the box and outputting the control signal to the refrigeration unit and the heating unit, and the monitoring and control software is electrically connected with the controller, used for testing parameter input and displaying collected data; The controller performs temperature control based on a preset parameter table and a PID algorithm, wherein, T box T is the real-time temperature in the box, T set T is the set temperature, Δ T fast is a temperature difference threshold value for distinguishing between rapid adjustment and fine adjustment; In the case where no disturbance event is detected E , the controller calls a default parameter table P0 to perform hierarchical temperature control, when T box - T set | ≥ Δ T fast , the refrigeration unit is controlled to operate at full power to realize rapid approximation of the temperature in the box to the set temperature, when T box - T set | ≤ Δ T fast , the controller enters a fine adjustment stage, and the output powers of the refrigeration unit and the heating unit are cooperatively adjusted through cold-heat power matching r , wherein the cold-heat power matching r is located in a preset range [ r min , r max ] and is updated with a sampling period T s to realize stable maintenance of the temperature in the box; In the hierarchical temperature control process, when a disturbance event E is detected, the controller switches to call an event-driven parameter table PE corresponding to the disturbance event, and performs disturbance compensation control on the refrigeration unit and the heating unit, and the recovery condition R is the deviation of the real-time temperature in the cabinet from the set temperature T box - T set | ≤ Δ T recover And the state is continuously maintained for not less than t hold Time, after meeting the preset recovery condition R, the controller recovers to call the default parameter table P0, and continues to execute the hierarchical temperature control to realize rapid cooling, constant temperature keeping and disturbance compensation.

[0006] Further, the heating glass window has a defogging function for ensuring the observation clarity in a low-temperature environment; the temperature sensors are arranged in an array along the height and length directions on the inner wall of the cabinet to realize multi-point temperature real-time acquisition and partition monitoring.

[0007] Further, the force sensor has a temperature compensation function, the temperature compensation function corrects the output signal of the force sensor based on a real-time temperature compensation parameter table to eliminate the zero point deviation and sensitivity change caused by temperature drift.

[0008] Further, the test piece is installed in the threaded hole on the fixed clamp through a single fixing bolt in the mounting hole on the base, and can be automatically aligned with the loading axis by micro-rotation around the fixing bolt in the initial loading stage, so that the test efficiency and the measurement accuracy are improved.

[0009] The beneficial effects of the present application are: (1) Through the hierarchical temperature control strategy of "rapid approximation + coordinated fine adjustment + disturbance compensation", rapid cooling and high-precision constant temperature are realized, and the temperature can be kept stable under disturbances such as opening the cabinet or ice heat release.

[0010] (2) The gain scheduling mechanism based on the preset parameter table and the PID algorithm is adopted to realize the dynamic switching of the main control and the sub-control loop, avoid the lag and oscillation of single PID control, and improve the temperature control efficiency, adaptability and robustness.

[0011] (3) The parameter table compensation based on the set temperature and the real-time temperature signal is introduced to correct the measurement deviation of the force sensor caused by temperature drift in real time, and the accuracy and consistency of the shear force measurement under low-temperature conditions are improved.

[0012] (4) The test piece is installed by a single fixing bolt, which can be automatically aligned with the loading axis by micro-rotation in the initial loading stage, reduces the clamping error, and improves the test efficiency and measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic diagram of the main structure of an embodiment; Figure 2 is a schematic diagram of the control flow of an embodiment; In the figure, 1 - low temperature box; 101 - box body; 102 - box cover; 103 - equipment cabin; 104 - compressor; 105 - condenser; 106 - evaporator; 107 - heated glass window; 108 - temperature sensor; 2 - loading mechanism; 201 - electric cylinder; 202 - force sensor; 203 - push head; 204 - fixed clamp; 205 - threaded hole array; 206 - leg; 3 - test piece; 301 - ice accumulation; 302 - base; 303 - fixing bolt; 4 - control system; 401 - controller; 402 - monitoring and control software. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0015] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the protection scope of the present application.

[0016] Reference Figure 1 and Figure 2 The present embodiment provides a shearing ice removal force measuring device, which comprises a low temperature box 1, a loading mechanism 2, a test piece 3 and a control system 4. The low temperature box 1 comprises a box body 101, a box cover 102 and an equipment cabin 103. An evaporator 106 is arranged in the box body 101, a compressor 104 and a condenser 105 are arranged in the equipment cabin 103, and the three constitute a refrigeration unit. The refrigeration unit can provide a low temperature environment in the range of -30℃ to 0℃, and the cooling rate can reach 1-3℃ / min. The box cover 102 is provided with a heated glass window 107 for fine adjustment and anti-fogging, to ensure the observation clarity under low temperature conditions. The inner wall of the box body 101 is distributed with an array of temperature sensors 108, which are arranged in zones along the height and length directions, with a sampling accuracy better than ±0.01℃, and can realize real-time sampling and zonal control of multiple points.

[0017] Reference Figure 1 , the loading mechanism 2 includes an electric cylinder 201, a force sensor 202 and a push head 203. The electric cylinder 201 is fixed to a fixed clamp 204 in the equipment cabin 103, and the push head 203 is connected with the force sensor 202, which is used to apply a shear load to the test piece 3. The electric cylinder loading rate can be adjusted in the range of 0.5-50 mm / min, and the rated stroke is 100 mm. The force sensor 202 has a range of 0-1kN, an accuracy of 0.1%, and has a temperature compensation function in the data acquisition link. Based on the set temperature, the corresponding parameter table is called, and the output data is revised combined with the real-time temperature signal, so as to eliminate the zero point offset and sensitivity change caused by temperature drift, and ensure the measurement accuracy in low temperature environment below -20℃.

[0018] Reference Figure 1 , the test piece 3 is composed of a base 302 and ice accumulation 301, and the base 302 is installed on the fixed clamp 204 through a single fixed bolt 303. In the initial stage of loading, the base 302 can rotate slightly around the fixed bolt to automatically align the loading axis, so as to ensure the uniformity of the shear force. The size of the test piece is generally 20mm × 20mm, and the ice thickness is about 10mm. The icing process is completed in situ in the low temperature box.

[0019] Reference Figure 1 , the control system 4 includes a controller 401 and a monitoring and control software 402. The controller 401 is electrically connected with the compressor 104, the heated glass window 107, the temperature sensor 108 and the force sensor 202.

[0020] Reference Figure 2 , the control logic is as follows: The controller collects the temperature signal in the box in real time and judges whether a disturbance event is detected.

[0021] In the case where no disturbance event is detected, the controller calls the default parameter table P0 to execute the staged temperature control, and when the difference between the real-time temperature in the box and the set temperature is T box - T set | ≥ Δ T fast , the control refrigeration unit runs at full power to realize the rapid approach of the temperature in the box to the set temperature, wherein Δ T fast is the temperature difference threshold for distinguishing between rapid adjustment and fine adjustment, which can be set according to system requirements, and the preferred range is 1-5℃; when T box - T set | ≤ ΔT fast At this point, the controller enters the fine-tuning stage, adjusting the ratio of cold and hot power. r The output power of the cooling unit and the heating unit is smoothly and coordinated, and the cooling and heating power ratio is... r The preferred range is [0.1, 0.9].

[0022] During the graded temperature control process, when the controller detects a disturbance event, it switches and calls the event-driven parameter table PE corresponding to the disturbance event to perform disturbance compensation control on the refrigeration unit and the heating unit; the recovery condition R is set as the deviation between the real-time temperature inside the chamber and the set temperature. T box - T set | ≤ 0.5 ℃, and this state is maintained continuously. t hold =60 s; When the preset recovery conditions are met, the controller resumes calling the default parameter table P0 and continues to execute the graded temperature control.

[0023] Through the above structure and control logic, this device can reduce the temperature from room temperature to the set -30℃ within 5-10 minutes, with temperature fluctuations controlled within ±0.01℃, thus ensuring the stability of the icing environment.

[0024] Referring to the accompanying drawings, the method of using this invention is as follows: 1) Test preparation and calibration Select a force sensor 202 with an appropriate range according to the test requirements, and replace it with a pusher 203 of corresponding length to ensure that its contact position matches that of the ice accumulation 301. After the loading mechanism 2 is assembled, it is electrically connected to the control system 4, and calibration can be completed in standby mode.

[0025] 2) Temperature control and logic settings Temperature is set via monitoring and control software 402. T set (For example, -20℃). Controller 401 executes graded temperature control logic based on the temperature difference conditions, when | T box - T set | ≥ Δ T fast (e.g., Δ) T fast When set to 3 ℃, the cooling unit operates at full power to achieve rapid cooling; when | T box - T set | ≤ Δ T fastWhen the system enters the cold / hot power collaborative regulation stage, high-precision and high-efficiency constant temperature control is realized.

[0026] 3) Sample preparation and specimen installation The base 302 is fixed to the fixed clamp 204 by a single fixing bolt 303, deionized water is sprayed on the surface of the base 302, or an ice mold is arranged and water is injected, the cover 102 of the low-temperature box 1 is closed, and the ice accumulation 301 is frozen in a low-temperature environment.

[0027] 4) Disturbance compensation and parameter switching When a disturbance event E (such as a temperature slope dT / dt T / d t ≥ 0.1 - 0.3 ℃ / s, or the opening angle of the cover > 5°) is detected, the controller 401 automatically switches to the event parameter table PE for compensation. After the recovery condition R is met, the system returns to the default parameter table P0 to ensure temperature control stability.

[0028] 5) Loading and shear test The loading mode (displacement control or force control) is set on the software side, and the electric cylinder 201 drives the push head 203 to gradually contact the ice accumulation 301 at a rate of 10 mm / min. In the initial loading stage, the specimen 3 can automatically rotate slightly around the fixing bolt 303 to ensure that the push head 203 fully contacts the ice accumulation 301 and aligns with the loading axis. As the loading continues, the push head 203 pushes the ice accumulation 301, the force sensor 202 collects the shear force signal in real time, and the parameter table is corrected and compensated in combination with the set temperature and real-time temperature signal. The corrected data is transmitted to the computer side in real time.

[0029] 6) Data acquisition and result analysis When the ice accumulation 301 and the base 302 interface debond, the shear force and displacement curve will have a significant drop, and this point is the interface shear deicing force. The monitoring and control software 402 automatically records the curve and outputs the deicing force value. After the test is completed, the temperature in the box remains stable, and multiple repeated tests can be performed under the same conditions to verify the consistency and reliability of the results.

[0030] It should be noted that the above examples are only used to illustrate the technical concept and characteristics of the present application, and are intended to enable those skilled in the art to understand and implement the present application, and are not intended to limit the scope of protection. Any equivalent changes or modifications made in accordance with the spirit and essence of the present application shall be covered within the scope of protection of the present application.

Claims

1. A shear de-icing force measuring device characterized by, The device comprises a low-temperature box (1), a loading mechanism (2), a test piece (3) and a control system (4). The low-temperature box (1) comprises a box body (101), a box cover (102) and a device cabin (103), a vaporizer (106) is fixed on one side in the box body (101), a compressor (104) and a condenser (105) are fixed in the device cabin (103), the vaporizer (106), the compressor (104) and the condenser (105) are communicated with each other to form a refrigeration unit, a heating glass window (107) is arranged on the box cover (102) to form a heating unit. The loading mechanism (2) comprises an electric cylinder (201), a force sensor (202), a push head (203) and a fixed clamp (204), the electric cylinder (201) is arranged in the device cabin (103) and fixed to the fixed clamp (204), the force sensor (202) is mechanically connected with the electric cylinder (201) and arranged along the loading direction, the push head (203) is mechanically connected to one end of the force sensor (202) away from the electric cylinder (201), the force sensor (202) and the push head (203) penetrate through the side wall of the box body (101) to extend into the box body (101), and the fixed clamp (204) is composed of a mounting plate with a threaded hole array (205) and directly connected with a supporting leg (206). The test piece (3) is composed of a base (302) and ice accumulation (301) adhered to the base (302), and the base (302) is fixedly installed on the fixed clamp (204) through mounting holes thereon. The control system (4) comprises a controller (401) and monitoring and control software (402), the controller (401) is electrically connected with the compressor (104), the heating glass window (107), a temperature sensor (108) arranged in the box body (101) and the force sensor (202) respectively, used for collecting temperature signals and shear force signals in the box and outputting control signals to the refrigeration unit and the heating unit, and the monitoring and control software (402) is electrically connected with the controller (401), used for testing parameter input and displaying collected data. The controller (401) performs temperature control based on a preset parameter table and a PID algorithm, wherein, T box is a real-time temperature in the cabinet (101), T set is a set temperature, Δ T fast is a temperature difference threshold value for distinguishing between fast adjustment and fine adjustment; In the case where no disturbance event is detected E , the controller (401) invokes a default parameter table P0 to perform hierarchical temperature control, when T box - T set | ≥ Δ T fast , the controller controls the refrigeration unit to operate at full power to achieve rapid approach of the temperature inside the box to the set temperature, when T box - T set | ≤ Δ T fast , the controller (401) enters a fine adjustment stage, and cooperatively adjusts the output power of the refrigeration unit and the heating unit by a cold-heat power ratio r , wherein the cold-heat power ratio r is located within a preset range [ r min , r max ] and is updated with a sampling period T s to achieve stable maintenance of the temperature inside the box. In the hierarchical temperature control process, when a disturbance event is detected E , the controller (401) switches to call an event-driven parameter table PE corresponding to the disturbance event, and performs disturbance compensation control on the refrigeration unit and the heating unit. After the preset recovery condition R is met, the controller (401) resumes calling the default parameter table P0 and continues to perform the hierarchical temperature control to achieve rapid cooling, constant temperature maintenance, and disturbance compensation.

2. The device according to claim 1, wherein: The heating glass window (107) has an anti-fog function for ensuring the observation clarity in the low-temperature environment, and the temperature sensor (108) is arranged in the inner wall of the box body (101) in the height and length directions to realize the real-time collection and partition monitoring of multiple points.

3. The device according to claim 1, wherein: The force sensor (202) has a temperature compensation function, the temperature compensation function is based on the real-time temperature to call a compensation parameter table to correct the output signal of the force sensor (202) to eliminate the zero-point deviation and sensitivity change caused by the temperature drift.

4. The device according to claim 1, wherein: The test piece (3) is installed in the threaded hole on the fixing clamp (204) through the mounting hole on the base (302) by a single fixing bolt (303), and can be micro-rotated around the fixing bolt (303) in the initial loading stage to automatically align the loading axis, so as to improve the test efficiency and result accuracy.

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