Defect measuring and calculating method in stripping detection of bonding area ratio of external wall insulation board

Abstract

The invention discloses a defect measuring and calculating method in stripping detection of the bonding area ratio of an external wall insulation board, which comprises the following steps: designing a mask template corresponding to profiling according to the size and area of the external wall insulation board, and arranging a heating system and an ultrasonic probe on the surface of the mask template; the mask template is attached to the external wall insulation board, an ultrasonic probe is started, high-frequency pulses are transmitted, reflected wave signals are recorded, and acoustic impedance change at the bonding interface causes reflected wave amplitude difference; the reflected wave amplitude in the reflected wave amplitude distribution diagram is extracted; and meanwhile, uniformly heating the back surface of the external wall insulation board, recording the change of a surface temperature field of the external wall insulation board along with time by using an infrared thermal imager, calculating a bonding area proportion by using an image segmentation algorithm, and solving an average value of an amplitude area ratio and a temperature area ratio. The method adopts non-contact detection, avoids damage to materials by a traditional stripping method, and is suitable for on-site rapid screening; and meanwhile, infrared and ultrasonic complementary detection is selected, so that the accuracy of complex working conditions (such as curved surfaces and multilayer structures) is improved, and the measurement and calculation efficiency is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of measuring the bonding area ratio of thermal insulation materials. Specifically, it relates to a method for calculating defects in the peeling detection of the bonding area ratio of exterior wall thermal insulation boards. Background Art

[0002] In most of the current exterior wall thermal insulation structures of buildings, thermal insulation materials are pasted. When using the peeling inspection method to detect the pasting area ratio of thermal insulation materials, it is necessary to peel the pasted thermal insulation materials from the wall, then measure and calculate their bonding area, and then calculate their bonding area ratio according to the formula. Comparing the obtained bonding area ratio with the standard bonding area ratio can complete the detection of the bonding area ratio of thermal insulation materials. Although this detection method obtains the actual data, it demolishes the exterior wall thermal insulation board, which is not convenient for actual use, and is also suitable for single-point extraction detection, unable to detect the entire exterior wall decoration surface. In addition, for some curved and irregular exterior wall thermal insulation boards, the demolition and bonding process is very inconvenient, and the calculation and measurement are not accurate.

[0003] Therefore, a method for detecting the bonding area ratio without peeling the exterior wall thermal insulation board needs to be studied urgently. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for calculating defects in the peeling detection of the bonding area ratio of exterior wall thermal insulation boards, which is used to avoid the troubles of low detection efficiency, troublesome restoration, and inaccurate calculation caused by the need to peel the exterior wall thermal insulation board to detect the bonding area ratio in the past.

[0005] To solve the above technical problem, the present invention discloses a method for calculating defects in the peeling detection of the bonding area ratio of exterior wall thermal insulation boards, which includes: Step a. Design a masking template corresponding to the profile according to the size and area of the exterior wall thermal insulation board. The surface of the masking template has a heating system and ultrasonic probes; Step b. Attach the masking template to the exterior wall thermal insulation board, turn on the ultrasonic probes, emit high-frequency pulses, and record the reflected wave signals. The change in acoustic impedance at the bonding interface causes a difference in the amplitude of the reflected waves; Step c. Analyze the characteristics of the reflected waves. Among them, for the well-bonded area: part of the acoustic wave energy penetrates into the thermal insulation material, and the amplitude of the reflected wave is low; for the non-bonded area: the air layer causes total reflection, and the amplitude of the reflected wave is high; distinguish the bonding state through the reflected wave amplitude distribution map; set the amplitude threshold; Step d. Calculate the amplitude-area ratio, extract the amplitude of the reflected waves in the reflected wave amplitude distribution map, and judge the reflected wave amplitude ≤ 30% as the bonding area; use the image segmentation algorithm to calculate the proportion of the bonding area: A amplitude = number of pixels in the total detection area / number of pixels in the bonding area × 100%; Step e. Attach the mask template to the exterior wall thermal insulation board, uniformly heat the back of the exterior wall thermal insulation board, and simultaneously record the change of the surface temperature field of the exterior wall thermal insulation board over time using an infrared thermal imager, with a sampling frequency ≥ 10 Hz; Step f. Conduct feature analysis on the temperature field. Among them, for the well-bonded area: heat is quickly conducted through the bonding interface, and the surface temperature rises rapidly; for the unbonded area: there is an air gap, the thermal resistance increases, and the surface temperature rises slowly; identify the bonded / unbonded areas through the temperature distribution difference; Step g. Calculate the temperature-area ratio, extract the temperature gradient threshold in the thermal image. Among them, a temperature gradient threshold ≥ 2 °C is judged as the bonded area; use the image segmentation algorithm to calculate the proportion of the bonded area: A temperature = number of pixels in the total detection area / number of pixels in the bonded area × 100%; Step h. Obtain the average value of A amplitude and A temperature.

[0006] According to an embodiment of the present invention, the mask template is fully attached to the exterior wall thermal insulation board and a constant pressure of 0.1 MPa is applied.

[0007] According to an embodiment of the present invention, the high-frequency pulse in step b is 5 - 10 MHz.

[0008] According to an embodiment of the present invention, in step b, an ultrasonic flaw detector with a high-frequency probe ≥ 5 MHz is used to lift the reflection wave amplitude; the resolution of the infrared thermal imager in step e is ≤ 0.05 °C.

[0009] According to an embodiment of the present invention, in step e, the heating power is 100 W / m² and it lasts for 10 seconds.

[0010] According to an embodiment of the present invention, the mask template is set as a flexible board, and a thermal conductive silicone layer is provided on the surface.

[0011] Compared with the prior art, the present invention can achieve the following technical effects: By combining infrared thermal imaging technology and ultrasonic pulse reflection method, and combining signal analysis and image processing, detect the physical property differences (such as changes in thermal conductivity and acoustic impedance) at the bonding interface, indirectly calculate the actual bonding area ratio, without peeling the exterior wall thermal insulation board, without causing damage to the exterior wall, with high measurement efficiency and strong accuracy.

[0012] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned technical effects simultaneously. Detailed implementation mode

[0013] The following will cooperate with embodiments to elaborate in detail on the implementation mode of the present invention, so as to fully understand how the present invention applies technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly.

[0014] The present invention discloses a defect calculation method in the peel detection of the bonding area ratio of an external wall insulation board, which includes: Step a. Design a mask template corresponding to the shape of the external wall insulation board according to its size and area. The surface of the mask template is provided with a heating system and an ultrasonic probe; the mask template is set as a flexible board, and a thermally conductive silicone layer is arranged on the surface, which can adapt to the plane or non-planar irregular external wall insulation board, and can be fully attached to ensure the accuracy during the calculation process. The mask template is fully attached to the external wall insulation board, and a constant pressure of 0.1 MPa is applied.

[0015] Step b. Attach the mask template to the external wall insulation board, turn on the ultrasonic probe, and emit high-frequency pulses, where the high-frequency pulses are 5 - 10 MHz. Record the reflected wave signal, where the change in acoustic impedance at the bonding interface causes a difference in the amplitude of the reflected wave; it can screen and detect the bonding area and the non-bonding area; Step c. Conduct a feature analysis on the reflected wave. Among them, for the well-bonded area: part of the acoustic wave energy is transmitted to the thermal insulation material, and the amplitude of the reflected wave is low; for the non-bonded area: the air layer causes total reflection, and the amplitude of the reflected wave is high; distinguish the bonding state through the amplitude distribution map of the reflected wave; set the amplitude threshold; Step d. Calculate the amplitude - area ratio. Extract the amplitude of the reflected wave from the amplitude distribution map of the reflected wave, where the reflected wave amplitude ≤ 30% is judged as the bonding area; use the image segmentation algorithm to calculate the proportion of the bonding area: A amplitude = number of pixels in the total detection area / number of pixels in the bonding area × 100%; Step e. Attach the mask template to the external wall insulation board, uniformly heat the back of the external wall insulation board, and at the same time use an infrared thermal imager to record the change of the surface temperature field of the external wall insulation board over time, with a sampling frequency ≥ 10 Hz; Step f. Conduct a feature analysis on the temperature field. Among them, for the well-bonded area: heat is quickly conducted through the bonding interface, and the surface temperature rises quickly; for the non-bonded area: there is an air gap, the thermal resistance increases, and the surface temperature rises slowly; identify the bonding / non-bonding area through the temperature distribution difference; Step g. Calculate the temperature - area ratio. Extract the temperature gradient threshold from the thermal image, where the temperature gradient threshold ≥ 2 °C is judged as the bonding area; use the image segmentation algorithm to calculate the proportion of the bonding area: A temperature = number of pixels in the total detection area / number of pixels in the bonding area × 100%; Step h. Obtain the average value of A amplitude and A temperature. First, observe the coincidence degree of the two images. If the coincidence degree is the same or relatively high, it indicates accurate detection. However, for some curved surfaces or multi-layer structures, the deviation of acoustic wave and temperature measurement will be relatively high. Therefore, it is more accurate to take the average value of the two to complete complementary detection.

[0016] The signal processing software can select MATLAB, Python OpenCV, etc.

[0017] Preferably, in step b, an ultrasonic flaw detector with a high-frequency probe ≥5MHz is used to lift the amplitude of the reflected wave; in step e, the resolution of the infrared thermal imager ≤0.05°C, and the detection is more accurate.

[0018] In step e, the heating power is 100W / m² and lasts for 10 seconds. The upper temperature limit can be adjusted according to the specific specification parameters of the thermal insulation material.

[0019] In summary, the present invention uses non-contact detection, avoiding the damage to the material by the traditional peeling method, and is suitable for on-site rapid screening; at the same time, complementary detection of infrared and ultrasound is selected to improve the accuracy in complex working conditions (such as curved surfaces and multi-layer structures), and the measurement efficiency is high.

[0020] The above description shows and describes several preferred embodiments of the present invention. However, as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the inventive concept described herein through the above teachings or the technology or knowledge in related fields. And any changes and variations made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for calculating defects in the peel test of the bonding area ratio of an exterior wall insulation board, characterized in that, Including: Step a. Design a mask template corresponding to the shape of the exterior wall thermal insulation board according to its size and area. The surface of the mask template has a heating system and ultrasonic probes. Step b. Attach the mask template to the exterior wall thermal insulation board, turn on the ultrasonic probes, emit high-frequency pulses, and record the reflected wave signals. The change in acoustic impedance at the bonding interface causes a difference in the amplitude of the reflected waves. Step c. Analyze the characteristics of the reflected waves. For the well-bonded area: part of the acoustic wave energy penetrates into the thermal insulation material, and the amplitude of the reflected wave is low; for the unbonded area: the air layer causes total reflection, and the amplitude of the reflected wave is high. Distinguish the bonding state through the amplitude distribution map of the reflected waves; set the amplitude threshold. Step d. Calculate the amplitude-area ratio. Extract the amplitude of the reflected waves in the amplitude distribution map of the reflected waves. When the amplitude of the reflected wave ≤ 30%, it is judged as the bonding area; use the image segmentation algorithm to calculate the proportion of the bonding area: A amplitude = number of pixels in the total detection area / number of pixels in the bonding area × 100%. Step e. Attach the mask template to the exterior wall thermal insulation board, uniformly heat the back of the exterior wall thermal insulation board, and at the same time use an infrared thermal imager to record the change of the surface temperature field of the exterior wall thermal insulation board over time, with a sampling frequency ≥ 10 Hz. Step f. Analyze the characteristics of the temperature field. For the well-bonded area: heat is quickly conducted through the bonding interface, and the surface temperature rises quickly; for the unbonded area: there is an air gap, the thermal resistance increases, and the surface temperature rises slowly. Identify the bonded / unbonded areas through the temperature distribution difference. Step g. Calculate the temperature-area ratio. Extract the temperature gradient threshold in the thermal image. When the temperature gradient threshold ≥ 2 °C, it is judged as the bonding area; use the image segmentation algorithm to calculate the proportion of the bonding area: A temperature = number of pixels in the total detection area / number of pixels in the bonding area × 100%. Step h. Obtain the average value of A amplitude and A temperature.

2. The defect calculation method in the peel detection of the bonding area ratio of the external wall insulation board according to claim 1, characterized in that, Wherein the mask template is fully attached to the exterior wall thermal insulation board and a constant pressure of 0.1 MPa is applied.

3. The defect measurement method in the peel test of the bonding area ratio of the exterior wall insulation board according to claim 1, characterized in that, Wherein the high-frequency pulse in step b is 5 - 10 MHz.

4. The defect calculation method in the peel test of the bonding area ratio of the external wall insulation board according to claim 1, characterized in that, Wherein in step b, an ultrasonic flaw detector with a high-frequency probe ≥ 5 MHz is used to lift the amplitude of the reflected wave; the resolution of the infrared thermal imager in step e ≤ 0.05 °C.

5. The defect measurement method in the peel detection of the bonding area ratio of the external wall insulation board according to claim 1, characterized in that Wherein the heating power in step e is 100 W / m² and lasts for 10 seconds.

6. The defect measurement method in the peel detection of the bonding area ratio of the external wall insulation board according to claim 1, characterized in that, Wherein the mask template is set as a flexible board, and a thermal conductive silicone layer is provided on the surface.